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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.
351

Walking into the Future : Exploring WiFi fingerprinting in pedestrian-oriented planning

Boström, Carl Vilhelm January 2022 (has links)
In order to investigate what place WiFi fingerprinting has in pedestrian-oriented planning, an interview study was carried out by conducting 12 semi-structured interviews with different actors working in pedestrian-related fields. The actors represent both the private and the public sector, and work in various geographical scales. The interviews investigate what pedestrian-related questions actors work with, what data their work requires and what methods they use to gather the data. For each of these three categories, topics that appeared in over half of the interviews were analyzed qualitatively. With this analysis, relevant applications of WiFi fingerprinting in pedestrian-oriented planning today are identified, namely determining capacity and dimensions, determining the spatial layout of small-scale environments, measuring congestion and providing validation data. The data needs not filled by WiFi fingerprinting are found to be spot-specific information suitable for qualitative analysis, visitor composition and network level flows and movements. Lastly, WiFi fingerprinting can be combined with other data sources to complement its drawbacks as a piece in a puzzle, such as using spot visits to better understand the reasons behind the flow data.
352

Identification of H. Pylori in Saliva by a Nested PCR Assay Derived From a Newly Cloned DNA Probe

Jiang, C, Li, C, Ha, T, Ferguson, D. A., Chi, D. S., Laffan, J. J., Thomas, E. 01 June 1998 (has links)
A novel probe was developed from genomic DNA of Helicobacter pylori ATCC type strain 43629. It hybridized with all 73 H. pylori clinical isolates tested but not with any of 183 non-H. pylori DNAs in dot blot hybridization. Typing tests revealed 41 different HaeIII-digestion patterns from 57 H. pylori strains tested. Based on the sequence of the probe, a nested PCR was developed that detected as little as 2 fg of H. pylori DNA or approximately equivalent to one cell. No PCR products were amplified from any of 21 non-H. pylori strains tested. Using this nested PCR, H. pylori DNA was detected in 33 of 45 (73%) saliva samples collected from patients with gastric H. pylori infection. These data suggest that the probe is useful for typing H. pylori and that the nested PCR is a valuable tool for detecting H. pylori DNA in saliva.
353

Generic Encrypted Traffic Identification using Network Grammar : A Case Study in Passive OS Fingerprinting / Generisk Krypterad Trafikidentifiering med Nätverksgrammatik : En fallstudie i passiv osfingeravtryck

Rajala, Lukas, Scott, Kevin January 2022 (has links)
The increase in cybercrime and cyber-warfare has spurred the cat-and-mouse game of finding and attacking vulnerable devices on government or private company networks. The devices attacked are often forgotten computers that run operating systems with known exploits. Finding these devices are crucial for both an attacker and defender since they may be the only weak link on the network. Device discovery on a network using probing or active fingerprinting methods results in extra traffic on the network, which may strain fragile networks and generates suspect traffic that may get flagged as intrusive. Using passive OS fingerprinting allows an actor to listen in and classify active devices on a network. This thesis shows the features that can be exploited for OS fingerprinting and discusses the importance of TLS payload and time-based features. We also present a data collection strategy that could be utilized for simulating multiple OSs and collecting new datasets. We found that the TLS attributes such as cipher suites play an important role in distinguishing between OS versions.
354

Partial Volume Quantification Using Magnetic Resonance Fingerprinting

Deshmane, Anagha Vishwas 02 June 2017 (has links)
No description available.
355

Signals and metabolic consequences during the interaction of Brassicaceae and <i>Verticillium longisporum</i> / Signale und metabolische Konsequenzen während der Interaktion von Brassicaceen und <i>Verticillium longisporum</i>

Possienke, Mareike 29 February 2012 (has links)
No description available.
356

Molecular approaches to direct diagnosis and characterization of Leishmania donovani in clinical isolates

Tai, Nahla Omer Ahmed El 06 March 2003 (has links)
Die vorliegende Studie wurde in einer Gruppe von Dörfern im Ostsudan, Gedaref State, durchgeführt. Bei 100 Patienten mit der Verdachtsdiagnose Kala Azar- oder Post-Kala Azar- Leishmaniose war der Erregernachweis mit der PCR direkt in klinischen Proben, die auf Filterpapier aufgebracht worden waren, ohne vorherige Kultivierung erfolgreich. In dieser PCR wurden die ribosomalen, internal transcribed spacer (ITS1 & ITS2) amplifiziert, weil sie sehr variabel sind, eine klare Speziesidentifizierung gestatten und bei weiterführenden Analysen der PCR-Produkte auch der Nachweis stammspezifischer Unterschiede erwartet werden konnte. Für die Analyse der Diversität von Leishmania donovani-Isolaten aus dem Sudan wurden 4 verschiedene PCR-basierte Methoden eingesetzt: das PCR-Fingerprinting mit unspezifischen Einzelprimern, die RFLP- Analyse des amplifizierten ITS-Locus, ,,single strand conformation polymorphism (SSCP)- Analysen der amplifizierten ITS-Region, des Gens, welches für die Hauptoberflächenprotease (gp63) kodiert, und anonymer DNA- Fragmente sowie Sequenzanalysen der entsprechenden Zielregionen. Das PCR-Fingerprinting und die Restriktionsanalyse der ITS-Region lieferten weitgehend übereinstimmende Fragmentmuster für alle untersuchten L.donovani-Stämme. 12 unterschiedliche Profile wurden bei der SSCP-Analyse des ITS1-Locus für 86 Isolate aus dem Sudan erhalten, während der ITS2-Locus bei diesen Stämmen hochkonserviert war und nur ein Stamm ein unterschiedliches SSCP-Muster aufwies. L. Donovani -Stämme anderer geographischer Herkunft hatten unterschiedliche ITS2-Profile in der SSCP. Für den gp63 - Locus waren 3 polymorphe SSCP-Muster bei 31 untersuchten sudanesischen Isolaten nachweisbar. Für die meisten der anonymen DNA-Fragmente, L510, L413, LK413, L0308 UND L0114, konnten leider nur von 8 kultivierten Stämmen gute PCR-Produkte erhalten werden. Lediglich das Fragment L0110 konnte erfolgreich von 31 auf Filterpapier aufgebrachten Proben direkt amplifiziert werden. Die Suche nach Polymorphismen mit der SSCP ergab keine Unterschiede in diesen anonymen DNA-Regionen, mit Ausnahme des Fragments L0114, das zwei verschiedene Muster aufwies. Die Ergebnisse der SSCP-Analysen und der DNA- Sequenzierung stimmten gut überein, wodurch bestätigt wurde, dass die SSCP genetische Unterschiede auf dem Niveau einzelner Basenaustausche nachweisen kann. Die SSCP- Technik hat Vorteile gegenüber den anderen Methoden, die für die Untersuchung von Sequenzvariationen innerhalb der Spezies L. donovani angewandt wurden. Es konnten keine Korrelationen zwischen der Form der klinischen Manifestation und den Ergebnissen des PCR- Fingerprinting, der ITS-RFLP- und ITS-SSCP- Analysen festgestellt warden. Diese Studie ist von besonderem Nutzen in epidemiologischen Feldstudien, bei denen die Kultivierung der Erreger besonders in Entwicklungsländern extrem schwierig sein kann. / This study was carried out in clusters of villages that represent an endemic focus of visceral leishmaniasis (VL). These villages were located in Gedaref state, eastern Sudan. For diagnostic purposes polymerase chain reaction (PCR) was performed successfully, directly from clinical samples spotted on filter papers with no prior cultivation from 100 patients suspected of having kala-azar or post kala-azar dermal leishmaniasis. Mainly the ribosomal internal transcribed spacer (ITS1 & ITS2) were targeted in PCR because this region is more variable and allows clear species identification and also strain differences could be expected by further analysis of these PCR products. PCR was found to be more sensitive compared to the gold standard microscopic method. Four PCR based approaches were used to analyse diversity within Sudanese isolates of Leishmania donovani. Methods compared were fingerprinting with single non-specific primers, restriction analysis of the amplified ITS locus (RFLP), single-stranded conformation polymorphism (SSCP) of the ITS region, major surface protease (gp63) gene, anonymous DNA fragments and sequencing of these targeted regions. When PCR fingerprinting and restriction analysis of ITS region were applied, highly similar fragment patterns were observed for all strains of L. donovani studied. The ITS1 locus gave 12 different SSCP profiles among the 86 Sudanese isolates, where as the ITS2 locus was highly conserved among the 86 samples with the exception of 1 isolate. Strains of L. donovani derived from other geographical areas were found to have different ITS2 patterns. The gp63 locus gave 3 polymorphic patterns among 31 Sudanese isolates. Concerning most of the anonymous DNA fragments namely, L510, L413, LK413, L0308 and L0114 unfortunately, we succeeded to get good PCR products only from DNA extracted 8 successful cultures. Only for the fragment L0110 we were able to get good PCR products from 31 samples spotted on filter papers. When these PCR products were investigated for polymorphisms using SSCP no differences were observed with exception of L0114 region, which showed 2 patterns. SSCP analysis correlates well with results of DNA sequencing and confirmed that SSCP was able to detect genetic diversity at the level of a single nucleotide. SSCP had advantages over the other methods employed for investigating of sequence variation within the species L. donovani. There was no correlation between the form of clinical manifestation of the disease and the PCR fingerprinting, ITS-RFLP, or ITS-SSCP characteristics. This study is beneficial particularly in epidemiological studies based on field-work where obtaining cultures can be extremely difficult especially in developing countries.
357

Preimplantation genetic diagnosis : new methods for the detection of genetic abnormalities in human preimplantation embryos

Konstantinidis, Michalis January 2013 (has links)
Preimplantation genetic diagnosis (PGD) refers to the testing of embryos produced through in vitro fertilization (IVF) in order to identify those unaffected by a specific genetic disorder or chromosomal abnormality. In this study, different methodologies were examined and developed for performance of PGD. Investigation of various whole genome amplification (WGA) methods identified multiple displacement amplification as a reliable method for genotyping single cells. Furthermore, this technology was shown to be compatible with subsequent analysis using single nucleotide polymorphism (SNP) microarrays. Compared to conventional methods used in this study to perform single cell diagnosis (e.g. multiplex PCR), WGA techniques were found to be advantageous since they streamline the development of PGD protocols for couples at high risk of transmitting an inherited disorder and simultaneously offer the possibility of comprehensive chromosome screening (CCS). This study also aimed to develop a widely applicable protocol for accurate typing of the human leukocyte antigen (HLA) region with the purpose of identifying embryos that will be HLA-identical to an existing sibling affected by a disorder that requires haematopoietic stem cell transplantation. Additionally, a novel microarray platform was developed that, apart from accurate CCS, was capable of reliably determining the relative quantity of mitochondrial DNA in polar bodies removed from oocytes and single cells biopsied from embryos. Mitochondria are known to play an important role in oogenesis and preimplantation embryogenesis and their measurement may therefore be of clinical relevance. Moreover, real-time PCR was used for development of protocols for CCS, DNA fingerprinting of sperm samples and embryos and the relative quantitation of telomere length in embryos (since shortened telomeres might be associated with reduced viability). As well as considering the role of genetics in terms of oocyte and embryo viability assessment and the diagnosis of inherited genetic disorders, attention was given to a specific gene (Phospholipase C zeta) of relevance to male infertility. A novel mutation affecting the function of the resulting protein was discovered highlighting the growing importance of DNA sequence variants in the diagnosis and treatment of infertility.
358

The application of sediment source fingerprinting techniques to river floodplain cores, to examine recent changes in sediment sources in selected UK river basins

Haley, Stephen Mark January 2010 (has links)
In recent years there has been an increasing awareness of the detrimental influence of diffuse sources of pollution on aquatic systems and of the integral role played by sediment in the mobilisation and transport of pollutants. The recognition of the environmental, societal and economic importance of the ecological health of aquatic environments has led to a change in emphasis regarding agricultural and environmental policy. To implement successful delivery of emerging policy requirements, there is a current need to have an enhanced understanding of the relationship between different forms of land use and sources of diffuse pollution, particularly sources of fine sediment. To understand the potential impacts of future land use changes, including environmental conservation measures on sources of sediment, it is useful to consider them within a longer-term context. This study has successfully applied the sediment source fingerprinting technique to floodplain overbank sediment cores in a retrospective study of six diverse UK river catchments with identified sediment problems. The varying estimates of relative sediment contributions from differing sources have been compared to known land use change in the study catchments over concurrent time periods, to explore any associations which might be apparent. Over the last 40 years, the increased cultivation of high erosion risk crops, such as those which are harvested late in the season (e.g. maize) and those which are sown in the autumn (e.g. winter wheat), has contributed disproportionately to the total sediment load relative to the area of land occupied by such cultivation. Increased stocking densities have resulted in increased relative sediment contributions from grassland sources, particularly intensively managed temporary grassland, but can have an even greater impact on sediment contributions derived from channel bank sources. The installation and maintenance of drainage for agriculture or for flood risk management has resulted in increased relative sediment loads from channel bank and associated sub-surface sources. Through the further development of such research, the efficacy of mitigation measures can be tested against evidence-based historic trends and those management approaches which provide identifiable improvements can be developed as best practice options for future land management targeted at reducing the negative impacts of excessive sediment ingress to river systems. The design of the source fingerprinting methodology used in this work was based on an established successful approach and this was developed further through the incorporation of a number of refinements designed to improve the robustness of the technique and expedite its implementation.
359

Campylobacter dans différents environnements aquatiques : quantification et génotypage afin de mieux évaluer les risques potentiels d’infection pour l’être humain

Gosselin-Théberge, Maxime 05 1900 (has links)
Campylobacter est l’agent pathogène zoonotique responsable de la majorité des gastro-entérites d’origine bactérienne chez l’homme. Les produits de volaille représentent la principale source d’infection; toutefois, l’exposition peut également découler de contacts directs avec les animaux ou avec l’eau. Une forte variation saisonnière est présente dans les cas rapportés, qui n’est toujours pas élucidée : les eaux environnementales, sources d’infection connues, sont soupçonnées. Cette étude transversale a été réalisée dans la région Sud-Est du Québec (Canada) où Campylobacter fut quantifié et génotypé à partir de différentes sources d’eau (eaux de captage, récréatives et usées) et de cas cliniques afin d’évaluer les risques potentiels posé par l’eau environnementale. Différents essais PCR en temps réel furent appliqués à l’eau environnementale et comparés: 2 ont été sélectionnés pour leur spécificité et sensibilité de quantification. Les courbes standards ont été calibrées en utilisant la PCR digitale pour déterminer précisément les concentrations. Les isolats environnementaux et cliniques furent comparés génétiquement en utilisant le CGF (« comparative genomic fingerprinting »). Les eaux usées étaient plus contaminées que les eaux de captage et récréatives (3.9Log, 1.7Log et 1.0Log cellules/L en moyenne, respectivement). Six pour cent des isolats d’eaux environnementales étaient génétiquement similaires (100 % homologie) aux isolats cliniques. Les cas cliniques de campylobactériose d’été montraient des isolats avec davantage de similarités génétiques avec les isolats retrouvés dans l’eau environnementale comparativement aux autres saisons (p<0.01). Les faibles concentrations et similarités génétiques entre les isolats d’eau et cliniques suggèrent un risque de transmission possible, mais faible. / Campylobacter is a zoonotic pathogen that is responsible for the majority of cases of bacterial gastroenteritis. Among the numerous Campylobacter transmission routes including direct contact, food and water, poultry consumption has been recognized as the major route. A strong seasonal variation in campylobacteriosis cases exists for reasons that are not well understood; environmental water is suspected to be involved. This cross-sectional study was conducted in the Southeastern region of Quebec (Canada), wherein Campylobacter from different waters (drinking water source, recreational and sewage) and clinical sources was quantified and genotyped in order to evaluate the potential risks posed by environmental water. Several real-time PCR assays were compared for specific application to environmental water: two were selected for their specificity and sensitivity of quantification. Standard curves were calibrated using digital PCR to accurately determine concentrations. Campylobacter isolates from clinical and water sources were genetically compared using CGF (comparative genomic fingerprinting). Sewage waters showed the highest Campylobacter concentrations, while drinking water source and recreational waters showed the lowest (average of 3.9Log, 1.7Log and 1.0Log cells/L, respectively). CGF revealed that 6% of water isolates were genetically similar (100% homology) to clinical isolates. Summer cases of campylobacteriosis revealed isolates showing more genetic similarities with environmental water isolates compared to other seasons (p<0.01). The low Campylobacter concentrations and genetic similarities between water and clinical isolates from the same region, suggests that these environmental waters pose a real, but low risk of transmission.
360

Metabolisme secondaire des éponges Homoscleromorpha : diversité et fluctuation de son expression en fonction des facteurs biotiques et abiotiques / Secondary metabolism of Homoscleromorpha sponges : diversity and fluctuation of its expression as a fonction of biotic and abiotic factors

Ivanisevic, Julijana 27 May 2011 (has links)
Le métabolisme secondaire joue un rôle écologique majeur dans les interactions des organismes avec leur environnement. Une étude intégrée de la biologie, de l’écologie des organismes et des variations de leur métabolisme est essentielle pour comprendre le rôle des métabolites secondaires au sein des écosystèmes. Or ce type d’approche est rare en milieu marin.Le petit clade d’éponges Homoscleromorpha constitue un vrai potentiel de découverte de nouvelles espèces et de molécules bioactives valorisables. Par ailleurs, leur position de dominance dans certaines communautés benthiques de Méditerranée en faisait un modèle de choix pour démarrer des recherches en écologie chimique marine.Ce travail a débuté avec la description d’une espèce du genre Oscarella, O. balibaloi ainsi que de nouvelles molécules produites par cet organisme. Cette nouvelle espèce avec deux autres espèces communes du même genre, O. tuberculata et O. lobularis constituent parfois de vrais faciès au sein des communautés du coralligène et des grottes semi-obscures. L’étude comparée du cycle de vie de ces Oscarella a montré dans tous les cas une reproduction saisonnière, avec des différences dans les périodes de gamétogénèse et d’émission des larves, et des sensibilités variables face aux changements des conditions de régime thermique. Deux composés majoritaires de type lysophospholipides ont été isolés et caractérisés pour la première fois dans O. tuberculata, et retrouvés dans O. lobularis. Leur rôle potentiel de médiateurs moléculaires impliqués dans le processus de reproduction (embryogenèse et développement) a été proposé, et devra être confirmé par des études expérimentales. Une nouvelle famille de sesterterpènes glycosylés (dénommés balibalosides) a été découverte dans O. balibaloi.Une étude pluriannuelle des variations du métabolisme de ces espèces a été réalisée à travers trois approches complémentaires permettant de tester les modalités d’allocation des ressources à la production de métabolites secondaires. Les patrons de variation des niveaux d’expression de métabolites ciblés, des signatures métaboliques et des bioactivités des extraits d’éponges ont montré une influence significative du cycle de reproduction sur le métabolisme secondaire. Les méthodes globales (métabolomique et bioactivité) ont permis de montrer que le cycle de variation du métabolisme secondaire était marqué par une modification importante de sa production accompagnée par une baisse de bioactivité pendant les périodes les plus coûteuses de la reproduction (reproduction asexuée, embryogenèse et développement larvaire). Ces résultats montrent un compromis d’allocation des ressources entre un métabolisme primaire (la reproduction) et la production des métabolites secondaires, et soutient ainsi la théorie de défense optimale.L’approche de métabolomique s’est avérée un bon indicateur de la chimio-diversité. Appliquée à l’étude des relations inter-spécifiques, cette méthode de chimio-systématique a permis de proposer une classification des espèces méditerranéennes d’Homoscleromorpha. Cette classification soutient les résultats les plus récents de phylogénie moléculaire et propose la restauration de deux anciens clades au sein des Homoscleromorpha: les Plakinidae, un groupe qui ne contient aujourd’hui que des espèces à squelette, et les Oscarellidae qui ne contient que des espèces sans squelette. Les approches développées au cours de cette thèse permettent de nombreuses perspectives en chimio-systématique et écologie chimique marine. L’utilisation des signatures métaboliques peut être transposée à d’autres questions de systématique, particulièrement pour démontrer l’existence d’espèces cryptiques, et pour soutenir des hypothèses phylogénétiques au sein d’autres clades problématiques [...] / Secondary metabolism plays a major ecological role in the interactions between the organisms and their environment. An integral study of the organisms’ biology and ecology and the variations of their metabolism is essential for understanding the role of secondary metabolites in the ecosystems. This kind of approach is rare in the marine environment. Small sponge clade Homoscleromorpha constitutes a real potential for the discovery of new species and potentially bioactive molecules. In addition, its dominance in some Mediterranean benthic communities makes it a good model in marine chemical ecology research. This work has started with a description of new species of Oscarella genus, O. balibaloi. This new species forms sometimes, with two other commun Oscarella species, O. tuberculata and O. lobularis, special facies within the coralligenous and semi-dark cave communities. All three Oscarella species are caraterized by a seasonal reproductive cycle with differences in the period of gametogenesis and larval emission as well as the variation in sensitivity facing the changes in thermal regime. Two major lysophospholipid compounds were isolated and caracterized for the first time in O. tuberculata and confirmed in O. lobularis. Their potential role as signal molecules in the reproduction process (embryogenesis and development) was proposed and should be confirmed by experimental studies. One new familly of glycosilated seterterpens (named balibalosides) was found in O. balibaloi. A pluriannual study of species metabolism was performed using three complementary approaches and enabled to test the models of resource allocation to secondary metabolite production. Variation patterns in the expression level of target metabolites, in the metabolic fingerprints and the bioactivities of sponge extracts reflected the significant influence of the reproductive cycle to the secondary metabolite production. Holisitic approaches (métabolomics and bioactivity) pointed out the important modification in the secondary metabolism variation pattern followed by the decrease in bioactivity during the costly period of reproduction (asexual reproduction, embryogenesis and larval development). These results highlight the trade-off in resource allocation between the primary (reproduction) and secondary metabolism and therefore support the Optimal Defense Theory. Metabolomic approach applied to the study of interspecific relations turned out as a good indicator of chemical diversity which allowed the classification of Mediterranean Homoscleromorpha sepcies. The obtained classification was congruent with recent molecular phylogeny results proposing the restauration of two ancient clades within Homoscleromorpha, the Plakinidae, a group of species possesing skeleton and the Oscarellidae, a group of species lacking skeleton. Approaches developed during my thesis opened a numerous perspectives in chemosystematics and marine chemical ecology. The use of metabolic fingerprints can be transposed to other questions in systematics, particularly to demonstrate the existance of cryptic species and to support phylogenetic hypothesis within other problematic clades. [...]

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