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  • 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.
41

Evaluation of Wind-Induced Internal Pressure In Low-Rise Buildings: A Multi Scale Experimental and Numerical Approach

Tecle, Amanuel Sebhatu 10 November 2011 (has links)
Hurricane is one of the most destructive and costly natural hazard to the built environment and its impact on low-rise buildings, particularity, is beyond acceptable. The major objective of this research was to perform a parametric evaluation of internal pressure (IP) for wind-resistant design of low-rise buildings and wind-driven natural ventilation applications. For this purpose, a multi-scale experimental, i.e. full-scale at Wall of Wind (WoW) and small-scale at Boundary Layer Wind Tunnel (BLWT), and a Computational Fluid Dynamics (CFD) approach was adopted. This provided new capability to assess wind pressures realistically on internal volumes ranging from small spaces formed between roof tiles and its deck to attic to room partitions. Effects of sudden breaching, existing dominant openings on building envelopes as well as compartmentalization of building interior on the IP were systematically investigated. Results of this research indicated: (i) for sudden breaching of dominant openings, the transient overshooting response was lower than the subsequent steady state peak IP and internal volume correction for low-wind-speed testing facilities was necessary. For example a building without volume correction experienced a response four times faster and exhibited 30-40% lower mean and peak IP; (ii) for existing openings, vent openings uniformly distributed along the roof alleviated, whereas one sided openings aggravated the IP; (iii) larger dominant openings exhibited a higher IP on the building envelope, and an off-center opening on the wall exhibited (30-40%) higher IP than center located openings; (iv) compartmentalization amplified the intensity of IP and; (v) significant underneath pressure was measured for field tiles, warranting its consideration during net pressure evaluations. The study aimed at wind driven natural ventilation indicated: (i) the IP due to cross ventilation was 1.5 to 2.5 times higher for Ainlet/Aoutlet>1 compared to cases where Ainlet/AoutletCFD based IP responses. Comparisons with ASCE 7-10 consistently demonstrated that the code underestimated peak positive and suction IP.
42

In vivo FLIM-FRET as a novel technique to assess cAMP and cGMP in the intact zebrafish heart

Janßen, Julia Annika 05 December 2017 (has links)
Introduction: 23 million patients worldwide suffer from heart failure. These patients depend on cardiac research, because cardiac research enables the development of new therapeutic strategies and –targets. In cardiomyocytes, the compartmentalization of cAMP and cGMP depends on many factors. T-tubuli and PDEs are responsible for the division of cells in microdomains in which localized and specific cAMP and cGMP-signaling occurs. The aim of this thesis was to develop a method to answer the open questions that remain about the physiological and pathophysiological significance of cAMP/cGMP compartmentalization. Methods: I used the zebrafish as a model, because the transparency of zebrafish larvae enabled non-invasive fluorescent imaging in cardiomyocytes in the living animal. I cloned the Fluorescence Resonance Energy Transfer (FRET) sensors EPAC1-camps for cAMP and cGi500 for cGMP and injected them into zebrafish fertilized embryos. Then I used the F0 generation for Fluorescence Lifetime Imaging (FLIM) -FRET-measurements of cAMP and cGMP. Ca2+ is an important downstream mediator of cAMP and cGMP, because Ca2+ regulates cardiac contraction. Therefore, I also cloned the Ca2+ sensor GCaMP6 and used the dye Fluo-4 AM to include intracellular Ca2+ in the imaging. Results: The cloned sensors for cAMP, cGMP and Ca2+ were successfully injected into the zebrafish and showed expression in individual cardiomyocytes. I developed a protocol to mount the living zebrafish embryos and to measure intracellular cAMP and cGMP with FLIM-FRET in vivo with high spatial resolution. I characterized the sensors in their functionality by showing that the sensors react to changes in intracellular concentrations of cAMP and cGMP. The results of this study include evidence that zebrafish have mechanisms that lead to cAMP/cGMP compartmentalization in the absence of T-tubuli, and these mechanisms keep compartmentalization constant even under extreme cAMP or cGMP increasing drug treatment. Furthermore, I imaged intracellular Ca2+ by confocal microscopy and developed a protocol to use Fluo-4 AM for Ca2+ imaging. Conclusion: The method used in this thesis should allow the investigation of subcellular cAMP/cGMP compartmentalization and Ca2+ and to subsequently answer open questions in the field, for example whether a change of cAMP compartmentalization leads to the pathological phenotypes of cardiac disease or if a changed compartmentalization of cAMP in cardiac disease influences Ca2+ concentrations and therefore contraction. Additionally, this method can be used to learn more about cAMP, cGMP und Ca2+ during regeneration in the heart, because the zebrafish cardiomyocytes can regenerate. / Einleitung: Weltweit sind mehr als 23 Millionen unter Herzinsuffizienz leidende Patienten auf die kardiologische Grundlagenforschung angewiesen, da diese die Voraussetzung für eine bessere Versorgung durch adaptierte und neue Behandlungswege schafft. In Kardiomyozyten hängt die Kompartimentierung von cAMP und cGMP von vielen Faktoren ab. T-Tubuli und PDEs werden unter anderem für die Aufteilung der Zellen in Mikrodomänen, in denen lokalisierte und spezifische cAMP- und cGMP-Signalgebung stattfinden kann, verantwortlich gemacht. Das Ziel dieser Arbeit war die Etablierung einer Methode, mithilfe derer offene Fragen bezüglich der physiologischen und insbesondere der pathophysiologischen Relevanz der cAMP- und cGMP Kompartimentierung beantwortet werden können. Methode: Als Modell diente der Zebrafisch, da die Transparenz von Zebrafisch Embryonen eine nicht-invasive Bildgebung von Fluoreszenz in Kardiomyozyten im lebenden Tier ermöglicht. Dafür klonierte ich die Förster Resonance Energy Transfer (FRET) -Sensoren EPAC1-camps als cAMP-Sensor und cGi500 als cGMP-Sensor und injizierte diese in befruchtete Zebrafisch Embryonen. Anschließend benutzte ich die F0-Generation für Fluorescence Lifetime Imaging (FLIM) -FRET-Messungen von cAMP und cGMP. Da Ca2+ als wichtiger downstream Mediator von cAMP und cGMP die kardiale Kontraktion reguliert, klonierte ich außerdem den Ca2+-Sensor GCaMP6 und benutzte den Farbstoff Fluo-4 AM, um intrazelluläres Ca2+ darzustellen. Ergebnisse: Die klonierten Sensoren für cAMP, cGMP und Ca2+ konnten erfolgreich in den Zebrafisch injiziert werden und zeigten alle Expression in einzelnen Kardiomyozyten. Ich entwickelte ein Protokoll, dass die Fixierung von lebenden Zebrafisch Embryonen und nachfolgender Bildgebung von cAMP und cGMP mit hoher zellulärer Auflösung mit FLIM-FRET in vivo erlaubte. Ich konnte eine funktionelle Charakterisierung der Sensoren durchführen, indem ich zeigte, dass sie auf Konzentrationsänderungen von intrazellulärem cAMP und cGMP reagieren sowie zeigen, dass Zebrafische trotz fehlender T-Tubuli eine signifikante cAMP- und cGMP Kompartimentierung aufweisen, auch unter extremen Bedingungen nach Gabe von cAMP/cGMP stimulierenden Substanzen in hoher Dosierung. Ich konnte zudem subzelluläres Ca2+ durch konfokale Mikroskopie bildgebend darstellen und entwickelte ein Protokoll, um mit Fluo-4 AM eine schnelle Möglichkeit zu haben, Ca2+ mit in die Messungen einzubeziehen. Ausblick: Die in dieser Arbeit benutzte Methode bietet eine gute Möglichkeit, subzelluläre cAMP- und cGMP-Kompartimentierung und Ca2+ zu untersuchen und damit zum Beispiel die Fragen zu beantworten, ob eine veränderte cAMP/cGMP Kompartimentierung zu Herzkrankheiten wie Hypertrophie führt oder ob eine veränderte cAMP Kompartimentierung den zellulären Ca2+ Haushalt und damit die kardiale Kontraktion beeinflusst. Darüber hinaus kann das von mir etablierte Protokoll dazu genutzt werden, mehr über cAMP, cGMP und Ca2+ während der Regeneration im Herzen zu lernen, da der Zebrafisch über ausgeprägte Regenerationsfähigkeiten verfügt.
43

Compartimentation du cycle viral du bactériophage SPP1 dans le cytoplasme de la bactérie Gram-positive Bacillus subtilis. / Compartmentalization of bacteriophage SPP1 replication and assembly in the Gram-positive bacterium Bacillus subtilis.

Labarde, Audrey 20 June 2019 (has links)
Les virus bactériens (bactériophages), durant leur co-évolution avec les bactéries, ont su trouver de nombreuses voies pour détourner les machineries cellulaires dans le but de se multiplier efficacement. L’infection par le phage dès son entrée dans le cytoplasme est un bouleversement pour la bactérie en termes de ressources monopolisées à ses dépens et probablement de restructuration de l’espace cytoplasmique. Dans ce travail de thèse, l’impact de l’infection de la bactérie Gram-positive Bacillus subtilis par le bactériophage SPP1 a été étudié.La réplication de l’ADN est initiée par des protéines précoces virales. Elle mène au chargement de l’hélicase virale gp40 sur l’origine de réplication de SPP1 dont les brins d’ADN ont été ouverts par la protéine de liaison à l’origine, gp38. Le réplisome bactérien est ensuite recruté de manière massive au sein de l’usine de réplication formant un foyer défini dans le cytoplasme bactérien. L’interaction de gp40 avec les protéines cellulaires DnaX et DnaG assure fort probablement le recrutement du complexe cellulaire au foyer de réplication. La quantité d’ADN viral synthétisée représente presque 500 copies d’ADN viral par bactérie après 30 minutes d’infection, ce qui est équivalent à la taille de 5 génomes de B. subtilis. Des études de FRAP (Fluorescence Recovery After Photobleaching) montrent que l’usine de réplication est très dynamique. Ce comportement est inhibé par la présence de HPUra montrant qu’il dépend de la présence d’un réplisome actif.Les concatémères résultant de la réplication de l’ADN viral sont le substrat pour l’encapsidation du génome de SPP1 dans des procapsides préformées. La maturation de ces procapsides en particules virales infectieuses suit une voie d’assemblage spécifique. Deux protéines rapportrices de différentes étapes de cette voie ont été suivies : la protéine d’échafaudage gp11, présente à l’intérieur de la procapside avant encapsidation de l’ADN, et la protéine auxiliaire gp12, qui se fixe à la surface de la capside pendant l’encapsidation. Les procapsides colocalisent partiellement avec l’usine de réplication du génome viral. Après encapsidation de l’ADN, les capsides vont s’accumuler dans des foyers de stockage qui ont une localisation indépendante du foyer de réplication. Cette organisation est également observée dans des bactéries très allongées où deux régions de stockage sont retrouvées situées de part et d’autre de l’usine de réplication mais éloignées des pôles cellulaires. La microscopie électronique combinée à des immuno-marquages révèlent que cette compartimentation corrèle avec une réorganisation majeure de l’ultrastructure du cytoplasme bactérien.L’assemblage et la dynamique des foyers viraux dans la bactérie ont été suivis pendant toute la durée du cycle viral dans un système de microfluidique. Elle montre que les étapes de réplication de l’ADN viral et la formation de la particule du phage sont des processus compartimentés dans le cytoplasme de la bactérie tant spatialement que temporellement. Bien que la croissance cellulaire soit retardée, les bactéries continuent de s’allonger et de se diviser pendant l’infection par SPP1. Le virus exploite donc de manière efficace les machineries cellulaires et l’architecture de la bactérie pour une multiplication optimale. Ces stratégies sont probablement utilisées par de nombreux phages pour remodeler la cellule bactérienne à leur avantage. / During the co-evolution of viruses and cells, viruses exploited numerous ways to hijack cell machineries for their optimal multiplication and dissemination. Phage infection is a major challenge to bacteria, exploiting extensively cellular biosynthetic ressources and possibly re-organizing the cytoplasm space. The work in this thesis investigated the cellular impact of infection by SPP1, a well-characterized model tailed bacteriophage that infects the Gram-positive bacterium Bacillus subtilis.Viral DNA replication is initiated by early phage proteins whose activity culminates in loading of the SPP1 helicase gp40 at the melted phage origin of replication. The bacterial replisome is then massively recruited to the phage replication factory that is localized at a defined position of the cytoplasm. The interaction of gp40 with its two cellular partners DnaX and DnaG mediates most likely the hijacking of the B. subtilis replication machinery. More than 500 copies of the viral genome are synthesized within 30 minutes after initiation of infection, which is roughly the equivalent to five B. subtilis genomes. FRAP (Fluorescence Recovery After Photobleaching) experiments showed that the viral DNA factory is highly dynamic, a behavior that depends on active DNA replication.The concatemers resulting from DNA replication are the substrate for encapsidation of the SPP1 genome into preformed procapsids. Maturation of procapsids to infectious viral particles follows a defined pathway. The SPP1 scaffolding protein gp11, that occupies the interior of the procapsid before DNA packaging, and gp12, that binds to capsids during DNA packaging, were followed to dissect the steps of this process. Procapsids partially co-localize with DNA replication factories. After packaging the DNA-filled capsids fully segregate to spatially distinct warehouses where viral particles accumulate. Recruitment of SPP1 proteins to these compartments recapitulates the sequential order of their assembly to build the viral particle. The replication factory is most frequently flanked by two warehouses. Such pattern is also observed in very elongated cells where the viral compartments remain localized nearby each others and far from the bacterial poles. Immuno-electron microscopy of cryo-sections from infected cells highlights a complete remodelling of the bacterial cytoplasm dedicated to virus multiplication.The assembly and dynamics of the SPP1 replication factory and virions warehouses were visualized during the complete phage infection cycle in microfluidics experiments. The viral compartments are well individualized in the cytoplasm both in terms of space and time. Although bacterial growth is retarded, cells continue to elongate and to divide during SPP1 infection. Structuration of viral factories appears as a very efficient way for SPP1 to exploit bacterial resources and cytoplasmic space to optimize its multiplication. This strategy might be widely used by phages for remodelling the bacterial cell.
44

Testing the differential adhesion hypothesis across the epithelial− mesenchymal transition

Pawlizak, Steve, Fritsch, Anatol W., Grosser, Steffen, Ahrens, Dave, Thalheim, Tobias, Riedel, Stefanie, Kießling, Tobias R., Oswald, Linda, Zink, Mareike, Manning, M. Lisa, Käs, Josef A. 12 August 2022 (has links)
Weanalyze the mechanical properties of three epithelial/mesenchymal cell lines (MCF-10A, MDAMB- 231, MDA-MB-436) that exhibit a shift in E-, N- and P-cadherin levels characteristic of an epithelial−mesenchymal transition associated with processes such as metastasis, to quantify the role of cell cohesion in cell sorting and compartmentalization. Wedevelop a unique set of methods to measure cell–cell adhesiveness, cell stiffness and cell shapes, and compare the results to predictions from cell sorting in mixtures of cell populations.Wefind that the final sorted state is extremely robust among all three cell lines independent of epithelial or mesenchymal state, suggesting that cell sorting may play an important role in organization and boundary formation in tumours.Wefind that surface densities of adhesive molecules do not correlate with measured cell–cell adhesion, but do correlate with cell shapes, cell stiffness and the rate at which cells sort, in accordance with an extended version of the differential adhesion hypothesis (DAH). Surprisingly, theDAHdoes not correctly predict the final sorted state. This suggests that these tissues are not behaving as immiscible fluids, and that dynamical effects such as directional motility, friction and jamming may play an important role in tissue compartmentalization across the epithelial−mesenchymal transition.
45

Securing resource constrained platforms with low-cost solutions.

Arslan Khan (17592498) 11 December 2023 (has links)
<p dir="ltr">This thesis focuses on securing different attack surfaces of embedded systems while meeting the stringent requirements imposed by these systems. Due to the specialized architecture of embedded systems, the security measures should be customized to match the unique requirements of each specific domain. To this end, this thesis identified novel security architectures using techniques such as anomaly detection, program analysis, compartmentalization, etc. This thesis synergizes work at the intersection of programming languages, compilers, computer architecture, operating systems, and embedded systems. </p>
46

Hardware-Aided Privacy Protection and Cyber Defense for IoT

Zhang, Ruide 08 June 2020 (has links)
With recent advances in electronics and communication technologies, our daily lives are immersed in an environment of Internet-connected smart things. Despite the great convenience brought by the development of these technologies, privacy concerns and security issues are two topics that deserve more attention. On one hand, as smart things continue to grow in their abilities to sense the physical world and capabilities to send information out through the Internet, they have the potential to be used for surveillance of any individuals secretly. Nevertheless, people tend to adopt wearable devices without fully understanding what private information can be inferred and leaked through sensor data. On the other hand, security issues become even more serious and lethal with the world embracing the Internet of Things (IoT). Failures in computing systems are common, however, a failure now in IoT may harm people's lives. As demonstrated in both academic research and industrial practice, a software vulnerability hidden in a smart vehicle may lead to a remote attack that subverts a driver's control of the vehicle. Our approach to the aforementioned challenges starts by understanding privacy leakage in the IoT era and follows with adding defense layers to the IoT system with attackers gaining increasing capabilities. The first question we ask ourselves is "what new privacy concerns do IoT bring". We focus on discovering information leakage beyond people's common sense from even seemingly benign signals. We explore how much private information we can extract by designing information extraction systems. Through our research, we argue for stricter access control on newly coming sensors. After noticing the importance of data collected by IoT, we trace where sensitive data goes. In the IoT era, edge nodes are used to process sensitive data. However, a capable attacker may compromise edge nodes. Our second research focuses on applying trusted hardware to build trust in large-scale networks under this circumstance. The application of trusted hardware protects sensitive data from compromised edge nodes. Nonetheless, if an attacker becomes more powerful and embeds malicious logic into code for trusted hardware during the development phase, he still can secretly steal private data. In our third research, we design a static analyzer for detecting malicious logic hidden inside code for trusted hardware. Other than the privacy concern of data collected, another important aspect of IoT is that it affects the physical world. Our last piece of research work enables a user to verify the continuous execution state of an unmanned vehicle. This way, people can trust the integrity of the past and present state of the unmanned vehicle. / Doctor of Philosophy / The past few years have witnessed a rising in computing and networking technologies. Such advances enable the new paradigm, IoT, which brings great convenience to people's life. Large technology companies like Google, Apple, Amazon are creating smart devices such as smartwatch, smart home, drones, etc. Compared to the traditional internet, IoT can provide services beyond digital information by interacting with the physical world by its sensors and actuators. While the deployment of IoT brings value in various aspects of our society, the lucrative reward from cyber-crimes also increases in the upcoming IoT era. Two unique privacy and security concerns are emerging for IoT. On one hand, IoT brings a large volume of new sensors that are deployed ubiquitously and collect data 24/7. User's privacy is a big concern in this circumstance because collected sensor data may be used to infer a user's private activities. On the other hand, cyber-attacks now harm not only cyberspace but also the physical world. A failure in IoT devices could result in loss of human life. For example, a remotely hacked vehicle could shut down its engine on the highway regardless of the driver's operation. Our approach to emerging privacy and security concerns consists of two directions. The first direction targets at privacy protection. We first look at the privacy impact of upcoming ubiquitous sensing and argue for stricter access control on smart devices. Then, we follow the data flow of private data and propose solutions to protect private data from the networking and cloud computing infrastructure. The other direction aims at protecting the physical world. We propose an innovative method to verify the cyber state of IoT devices.
47

Untersuchung der submitochondrialen Verteilung von Oxa1 und Mba1 in Saccharomyces cerevisiae / Analysis of the submitochondrial distribution of Oxa1 and Mba1 in Saccharomyces cerevisiae

Stäglich, Marlen Marina 15 October 2015 (has links)
Die Mitochondrien eukaryotischer Zellen sind an einer Reihe zellulärer Prozesse beteiligt und übernehmen essentielle Funktionen, wie die der Energiegewinnung aus der oxidativen Phosphorylierung. Sie weisen ein hohes Maß an struktureller Komplexität auf. Das gesamte Organell wird von der äußeren mitochondrialen Membran umgeben und ist durch diese gegenüber dem Zytoplasma abgegrenzt. Die innere mitochondriale Membran kann morphologisch in zwei Bereiche unterteilt werden: Der der äußeren Membran direkt gegenüberliegende Teil wird als „innere Grenzflächenmembran“ bezeichnet, während zahlreiche Einstülpungen die sogenannte „Cristaemembran“ bilden. Vorhergehende Studien lieferten Hinweise darauf, dass es sich bei der Subkompartimentierung der Innenmembran auch um eine funktionale Gliederung handeln könnte, da für zahlreiche mitochondriale Proteine eine heterogene Verteilung nachgewiesen werden konnte. Darunter befindet sich auch das Protein Oxa1 der Bäckerhefe Saccharomyces cerevisiae, das sowohl bei der Insertion von kernkodierten als auch von mitochondrial kodierten Proteinen eine zentrale Rolle spielt. In vorausgegangenen Arbeiten wurde belegt, dass Oxa1 bevorzugt in der inneren Grenzflächenmembran vorliegt, wenn die Hefen mit einer fermentierbaren Kohlenstoffquelle wachsen. Diese Verteilung ist jedoch dynamisch und verändert sich in Abhängigkeit von den physiologischen Bedürfnissen der Zellen. Wachsen die Hefen mit einer nicht-fermentierbaren Kohlenstoffquelle, weist Oxa1 eine präferentielle Lokalisation in der Cristaemembran auf. Eine Anreicherung in der Cristaemembran ist auch zu beobachten, wenn die hoch konservierte Aminosäure Tryptophan an Position 128 mit Phenylalanin substituiert wird. Die Substitutionsmutation oxa1-W128F führt darüber hinaus zu einer Verringerung der durchschnittlichen Größen der Oxa1-enthaltenden Komplexe. Hieraus ergab sich die Frage, ob die Komplexgröße und die submitochondriale Lokalisation von Oxa1 in direktem Zusammenhang stehen könnten. Im Rahmen dieser Arbeit wurden daher die Größen der Oxa1-enthaltenden Komplexe in Abhängigkeit zu der zur Verfügung stehenden Kohlenstoffquelle untersucht. Es zeigte sich jedoch, dass die durchschnittlichen Größen der Oxa1-enthaltenden Komplexe, die in der inneren Grenzflächenmembran angereichert sind, ungefähr den Größen der Komplexe entsprechen, die bevorzugt in der Cristaemembran vorliegen. Demzufolge gibt es keinen Zusammenhang zwischen der Komplexgröße und der Lokalisation von Oxa1, weshalb der Veränderung der Lokalisation ein anderer Mechanismus zu Grunde liegen muss. Die Untersuchung der Variante Oxa1-W128F zeigte, dass diese im Vergleich zu Oxa1, wie bereits beschrieben, in kleineren Komplexen vorliegt, bei denen es sich sogar um Dimere sowie Tetramere von Oxa1 handeln könnte, und, dass die Verringerung der Komplexgrößen auf eine beeinträchtigte Homooligomerisierung zurückgeführt werden kann. Zusammen mit der Tatsache, dass neben Oxa1 selbst keine weiteren Interaktionspartner identifiziert werden konnten, legen diese Ergebnisse nahe, dass Oxa1 sowohl unter fermentativen als auch respiratorischen Bedingungen in größeren homooligomeren Komplexen agieren könnte und, dass seine Dynamik möglicherweise auf transiente Interaktionen mit Substraten zurückzuführen ist. Es ist bekannt, dass in S. cerevisiae neben Oxa1 noch weitere Proteine existieren, die ebenfalls Teil der Proteininsertionsmaschinerie der inneren mitochondrialen Membran sind. Dazu gehören Pnt1 und Mba1, über deren Verteilung in der inneren Membran bisher keine gesicherten Erkenntnisse vorlagen. Im Rahmen dieser Arbeit stellte sich heraus, dass auch Pnt1 und Mba1 heterogen verteilt sind. So ist sowohl für Pnt1 als auch für Mba1 bei Wachstum mit einer fermentierbaren Kohlenstoffquelle eine Anreicherung in der inneren Grenzflächenmembran zu verzeichnen. Bei Wachstum mit einer nicht-fermentierbaren Kohlenstoffquelle verschiebt sich die präferentielle Lokalisation von Pnt1 zu einer Anreicherung in der Cristaemembran, wie es bereits für Oxa1 beobachtet wurde. Mba1 hingegen liegt unverändert bevorzugt in der inneren Grenzflächenmembran vor. Somit konnte für die heterogene Verteilung von Pnt1 eine von den physiologischen Bedingungen abhängige Dynamik und für die heterogene Verteilung von Mba1 eine Statik nachgewiesen werden. Auf Grund des differenzierten Lokalisationsverhaltens von Mba1 im Vergleich zu Oxa1 und Pnt1, wurde eine nähere Charakterisierung der submitochondrialen Verteilung von Mba1 vorgenommen. Bei der Untersuchung der Ursachen der statischen Lokalisation von Mba1 auf molekularer Ebene, wurde festgestellt, dass bereits die Deletion von nur fünf Aminosäuren (mba1 1-273) sowie die Substitution einer einzelnen Aminosäure (mba1-I272A) im C-Terminus von Mba1 zu einer drastischen Veränderung der heterogenen Mba1-Verteilung führt. Die Untersuchung der Auswirkungen der Genmutationen auf die Funktion von Mba1 zeigte, dass es infolge der Deletionsmutation zu einer verminderten Respirationskompetenz der Zellen kommt, die auf eine Beeinträchtigung der Assemblierung eines Superkomplexes der Atmungskette (2 x KomplexIII / 2 x KomplexIV) zurückgeführt werden kann. Somit liefert die vorliegende Arbeit erstmals Hinweise darauf, dass die dokumentierte heterogene und statische Verteilung von Mba1 in der inneren Membran ausschlaggebend für die korrekte Funktionsweise von Mba1 ist. Möglicherweise wird der Funktionsort von Mba1 durch die Bindung eines bisher nicht eindeutig identifizierten Interaktionspartners bestimmt.
48

Zoneamento ecológico-econômico no Tocantins: contribuição metodológica e processual para sua execução

Dias, Ricardo Ribeiro [UNESP] 25 September 2008 (has links) (PDF)
Made available in DSpace on 2014-06-11T19:32:18Z (GMT). No. of bitstreams: 0 Previous issue date: 2008-09-25Bitstream added on 2014-06-13T18:43:32Z : No. of bitstreams: 1 dias_rr_dr_rcla.pdf: 9964110 bytes, checksum: f65d067cdcd2e35253f28bf3bd83424b (MD5) / Apresenta-se a problemática do assunto Zoneamento Ecológico-Econômico (ZEE), a polêmica em torno dele e suas atribuições como instrumentos político e técnico para ordenamento territorial. A hipótese do trabalho foi definida com base na situaçãoproblema ZEE Tocantins, discutindo-se os procedimentos metodológicos e métodos usados. Assumiu-se que o mapeamento e o zoneamento geotécnico tenham uma importante aplicação no ZEE, sobretudo pela forma com que as unidades são caracterizadas, quer seja diretamente ou indiretamente. Demonstrou-se que o mapeamento geotécnico, embasado em unidades de compartimentação do meio físico classificadas por atributos inerentes ao ZEE, permite melhorar a percepção acerca dos usos potenciais da terra, pretendidos em um projeto de ZEE, principalmente pela possibilidade de elaboração de cartas específicas ou de síntese. Trabalhou-se criteriosamente na descrição dos processos de: (i) montagem e organização de uma base de dados geográficos para facilitar e permitir o desenvolvimento das atividades que se apóiam tecnologicamente em SIG e sistema de processamento digital de imagens de sensores remotos; (ii) aplicação do método Seplan-TO usado no ZEE Norte do Estado do Tocantins para a geração do plano de zoneamento ambiental, com ênfase na compartimentação ambiental (unidade territorial básica - UTB); (iii) aplicação do mapeamento geotécnico com base no Método Vedovello para a geração de um plano de zoneamento geoambiental, com ênfase na compartimentação ambiental (unidade básica de compartimentação - UBC) e inclusão de fatores bióticos; e (iv) comparação e avaliação dos resultados obtidos pela aplicação dos diferentes métodos com o intuito de indicar aquele que deve ser usado para estudos de ZEE no Tocantins. Os focos da avaliação foram a compartimentação do meio físico e a execução do ZEE em termos... / The problematics of the subject Ecological-Economic Zoning (EEZ) is presented, as well as the controversy about it and its role as a political and technical instrument for a territorial ordenation. The hypothesis was defined based on the EEZ Tocantins problem-situation, discussing the methodological procedures and methods used. It was assumed that geotechnical mapping and zoning have an important application in the EEZ, particularly by the way the units are characterized, whether directly or indirectly. It was demonstrated that a geotechnical mapping based on compartmentalization units of the physical medium and classified by attributes inherent to the EEZ permits to improve the perception about the potential uses of land as intended in a EEZ project, particularly due to the possibility of preparing specific or synthetic charts. A judicious work was performed in the description of the processes of: (i) assembly and organization of a geographic data bank in order to facilitate and permit the development of the activities technologically supported by SIG and a digital image-processing system with remote sensors; (ii) application of the Seplan-TO method used at EEZ Northern of the State of Tocantins for generating the environmental zoning plan, emphasizing the environmental compartmentalization (basic territorial unit - BTU); (iii) application of the geotechnical mapping based on Vedovello Method for generating a geoenvironmental zoning plan emphasizing the environmental compartmentalization (basic compartmentalization unit - BCU) and inclusion of biotic factors; and (iv) comparison and assessment of the results obtained by the application of the different methods, with the intent of indicating that one that should be used for EEZ studies at Tocantins. The assessment was focused on the compartmentalization of the physical medium and the execution of the EEZ in terms of repeatability ...(Complete abstract click electronic access below)
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La transmission intergénérationnelle des connaissances dans les banques tunisiennes : Ebauche d’une comparaison avec les banques allemandes / The intergeneration transfer of technical and professional knowledge within the Tunisian banking system : a rough comparison with german banks

Zarrouk, Khaled 17 November 2011 (has links)
La transmission intergénérationnelle des connaissances au sein de la banque tunisienne au moyen de la formation sur le tas fait traditionnellement partie de la culture de branche inhérente au secteur bancaire. Ce mode de formation archaïque n’a pas disparu, et la banque tunisienne a même intégré de nouveaux modes plus modernes. La comparaison avec la situation des banques allemandes, pionnières dans le domaine de la formation professionnelle et surtout de la formation duale permet d’une part de mettre en relief l’avènement d’une entrouverture au recrutement externe de jeunes diplômés issus de l’université. Mais, également et d’autre part de montrer que l’adoption par les banques tunisiennes de ce mode de formation censé créer davantage de synergies entre les salariés contribue au contraire à dégrader davantage le climat social aussi bien entre qu’avec la hiérarchie. En effet, dans un contexte de renouvellement des générations, couplé avec une ouverture à la concurrence internationale, le management introduit de nouvelles pratiques gestionnaires, et veut modifier rapidement la culture interne tout en gardant cette transmission à des fins de codification / The intergeneration transfer of technical and professional knowledge within the Tunisian banking system thanks to the training on the job belongs to the traditional culture of the financial sector. This kind of archaic training, it hasn’t disappeared. The Tunisian banks have as well already integrated new and modern ways of training. The international comparison with German banks allows to underline the external recruiting of young graduated people from universities. Moreover, and despite the fact that the Tunisian banking system is following the German training example which is due to lead to more synergies between employees and hierarchy, we notice that the internal culture is deteriorating more and more because of the introduction of managing practises which only take into account the maximisation of the banks profit abilities. In a context of renew generation and opening to the international competition, the management introduce new management practices and want to change the internal culture with keeping this technical and professional knowledge to permitting a codification.
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Nanoscale imaging of synapse morphology in the mouse neocortex in vivo by two-photon STED microscopy / Imagerie nanométrique de la morphologie synaptique dans le néocortex de souris in vivo par microscopie deux-photon STED

Ter Veer, Mirelle Jamilla Tamara 25 November 2016 (has links)
Le cerveau est un organe complexe composé de neurones et des cellules non-neuronales. La communication entre les neurones a lieu via les synapses, dont le remodelage morphologique est considéré essentiel pour le traitement et le stockage des informations dans le cerveau des mammifères. Récemment, ce point de vue neuro-centré de la fonction synaptique a évolué, en prenant également en compte les processus gliaux à proximité immédiate de la synapse. Cependant, comme leur structure est bien en deçà de la résolution spatiale de la microscopie optique conventionnelle, les progrès dans les enquêtes dans leur environnement physiologique, le cerveau intact, ont été entravés. En effet, on sait peu sur les variations nanométriques de la morphologie des épines dendritiques et l'interaction avec les processus gliaux, et, finalement, comment elles affectent la transmission synaptique in vivo. Dans cette thèse, nous cherchons à visualiser la dynamique de la nano-morphologie des épines dendritiques et les processus gliaux dans le cortex à tonneaux de souris in vivo. Nous avons donc mis en place l’imagerie super-résolution 2P-STED en temps réel, ce qui permet une haute résolution spatiale et la pénétration profonde des tissus, chez la souris anesthésiée in vivo. Nous montrons que la nano-morphologie des épines est diversifiée, variable, mais globalement stable, et que les différences dans la morphologie des épines peut avoir un effet sur leur compartimentation in vivo. En outre, la mise en œuvre de l’imagerie super-résolution en double couleur in vivo et le développement d'une approche de marquage astrocytaire, nous ont permis de fournir la caractérisation à l'échelle nanométrique des interactions neurone-glie. Ces résultats apportent un aperçu sans précédent dans la dynamique de la synapse à l'échelle nanométrique in vivo, et ouvrent la voie à une meilleure compréhension de la façon dont les réarrangements morphologiques des synapses contribuent à la physiologie du cerveau. / The brain is a complex organ consisting of neurons and non-neuronal cells. Communication between neurons takes place via synapses, whose morphological remodeling is thought to be crucial for information processing and storage in the mammalian brain. Recently, this neuro-centric view of synaptic function has evolved, also taking into account the glial processes in close vicinity of the synapse. However, as their structure is well below the spatial resolution of conventional light microscopy, progress in investigating them in a physiological environment, the intact brain, has been impeded. Indeed, little is known on the nanoscale morphological variations of dendritic spines, the interaction with glial processes, and how these affect synaptic transmission in vivo. Here, we aim to visualize the dynamic nano-morphology of dendritic spines in mouse somatosensory cortex in vivo. We implemented super-resolution 2P-STED time-lapse imaging, which allows for high spatial resolution and deep tissue penetration, in anesthetized mice, and show that the nano-morphology of spines is diverse, variable, but on average stable, and that differences in spine morphology can have an effect on spine biochemical compartmentalization in vivo. Moreover, implementation of dual color in vivo super-resolution imaging and a novel astrocytic labeling approach provided the first steps towards nanoscale characterization of neuron-glia interactions in vivo. These findings bring new insights in synapse dynamics at the nanoscale in vivo, and our methodological endeavors help pave the way for a better understanding of how nanoscale aspects of spine morphology and their dynamics might contribute to brain physiology and animal behavior.

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