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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.
11

MECHANICAL ABRASION AND ELECTROPORATION IN THE TRANSFORMATION OF INTACT PLEUROTUS OSTREATUS HYPHÆ and NUTRIENT-DEPENDANT RESISTANCE TO HYGROMYCIN B

Cordesman, Alexander 01 January 2008 (has links)
ABSTRACT 1: Abrasive treatment and subsequent electroporation of the basidiomycete Pleurotus ostreatus in a hypertonic buffer was investigated as a potential method of transforming of intact hyphæ. Mycelia, which are not capable of being transformed via electroporation due to interference by the cell wall, were abraded in an attempt to mechanically degrade the cell wall prior to electroporation. An electroporation field strength of 12,500 V/cm for 500 μs to 1.25 ms was found to be optimal based upon mortality effects. A 32 μm carborundum abrasive was initially evaluated but was quickly found to be inappropriately large so a corundum abrasive with an average size of 300 nm was focused on. Vortexing as well as low and medium power ultrasonic agitation with the corundum abrasive were investigated for their potential to cause mechanical degradation of the cell walls. Vortexing and low power sonication were found to be ineffective at causing adequate degradation while medium power sonication was found to be both ineffective and super lethal. While the possibility of mechanical abrasion facilitating transformation via electroporation remains, it is unlikely that conventional methods of agitation will be effective. ABSTRACT 2: The dose response of the basidiomycetes Pleurotus ostreatus, Agrocybe aegerita and Cordyceps millitaris to the antibiotic hygromycin B was tested on two common and one in-house solid growth media. The three species were grown on Potato dextrose agar, malt extract agar and an agar containing maltose, yeast-extract, peptone and glucose with concentrations of hygromycin B from zero to 100 μg/ml for 11 to 14 days. Micrometer measurements were used to determine the growth rate of each species on each media. Significant differences in hygromycin B tolerance for each species between the three media types were evident (p-value < .0001 by ANOVA for all). Neither the media type nor the growth rate on hygromycin B free plates were useful predictors of effective hygromycin B doses so optimization should be performed on every strain and media type used for selection.
12

Modélisation des flux de carbone, d'énergie et d'eau entre l'atmosphère et des écosystèmes de steppe sahélienne avec un modèle de végétation global / Modelisation of carbon, water and energy fluxes between the atmosphere and sahelian ecosystems with a dynamic global vegetation model.

Brender, Pierre 29 May 2012 (has links)
Compte tenu de la vulnérabilité de la population rurale de la région sahélienne aux aléas pluviométriques, et devant les ambitions de certains acteurs d’utiliser le levier de l’usage des terres pour contribuer à l’atténuation du changement climatique, il est important de comprendre les facteurs contribuant à la variabilité de la couverture végétale au Sahel.Une synthèse de la littérature expliquant l’évolution récente de la végétation au Sahel est donc d’abord présentée. Les études s’intéressant au paradigme qui souligne l’impact de l’usage des terres sur les précipitations en Afrique de l’Ouest évaluent principalement ces effets par le couplage de modèles dynamiques globaux de végétation – DGVM – avec des modèles de circulation générale. C’est à l’amélioration d’un tel DGVM, ORCHIDEE, développé à l’Institut Pierre Simon Laplace, que le reste du travail cherche à contribuer.Comme d’autres études ont montré qu’il était possible d’utiliser en première approximation les steppes pâturées et les jachères pour décrire le comportement global de la surface sahélienne, les écarts entre modèle et mesures sont caractérisés pour une jachère située à proximité de Wankama (Niger). Plus précisément, les forces et faiblesses de la paramétrisation et de la structure par défaut du modèle sont diagnostiqués, et l’importance de la réduction d’erreur permise par l’optimisation de certains des paramètres est donnée. En particulier, l’emploi d’une résolution aux différences finies de la diffusion de l’eau dans la colonne de sol est évalué, dans la mesure où cela permet de mieux simuler la réponse rapide du flux évaporatoire aux événements pluvieux que le schéma conceptuel utilisé par défaut dans ORCHIDEE.Le réalisme du modèle est également mesuré à l’échelle régionale, par la comparaison d’observations de NDVI GIMMS_3G à la couverture végétale simulée par le modèle en réponse à différents forçages climatiques . Si les modifications introduites au cours du travail ne permettent pas de mieux décrire les tendances de la végétation au cours des dernières décennies, tirer partie des leçons du présent travail pourra se révéler utile. Il en est de même des conclusions de l’étude de la transitivité des biais conditionnels du modèle réalisée avec Tao Wang et présentée en annexe B. / The evolution of the land-surface conditions is often assessed through the use of “dynamic global vegetation models”, as is shown in a review of the current understanding of the factors of variability and of the recent evolution of the vegetation cover in the Sahel. Such models are also coupled to atmospheric general circulation models to evaluate the land feedback on precipitation in monsoonal climates.Thus, the improvement of the skills of such surface models to simulate the radiative and turbulent fluxes between the land of surface and the atmosphere in the Sahel over a range of scales from hourly to multi-annual has a potential to have significant implications. This is especially true considering the vulnerability of the rural population of the region, which largely relies on rainfed agriculture and the interest on the evolution of the carbon stocks of ecosystems in the context of climate change. Such a work on the ORCHIDEE model is presented here. In complement to croplands, rangelands and fallows represent a large share of the sahelian landscapes and have intermediate characteristics between erosion glacis and acacia bushes. As such, their evolution (in terms of albedo, roughness length,…) may be used to study the Sahel ecosystem behaviour as a first approximation. Differences between model outputs and field observations are quantified for a fallow close to Wankama (Niger). More precisely, some of the drawbacks of the standard parametrisation and structure of the model are diagnosed, and the range of reduction of the model-observation mismatch that results from optimizing some of the parameters are given (plant phenology,…). In particular, the use of a finite difference resolution of the soil water diffusion is considered as it enables to better simulate the fast response of evaporative fluxes to rainfall than the conceptual scheme routinely used in ORCHIDEE. The benefits of the use of such a “physical” hydrological scheme on the different outputs of the surface scheme is evaluated.The realism of the model is also measured at the regional scale, through a comparison with GIMMS_3G NDVI time series over West Africa. If the modifications that have been introduced in the model don’t improve its ability to describe the vegetation cover trends over the last decades in the region, several lessons can be kept from the analysis that has been realised, especially from the work on the transitivity of state-dependant model biases that has been conducted with Tao Wang and which is presented in annex B.
13

Un environnement de modélisation et d'aide à la décision pour un problème de livraison - collecte sous incertitudes : application à la PFL de l'AP-HM

Laval, Quentin 19 July 2017 (has links)
Ce travail de thèse s’inscrit dans le projet logistique de l’Assistance Publique Hôpitaux de Marseille. En effet l’AP-HM a ouvert une plateforme logistique en avril 2013 afin de centraliser les activités de production de repas, de stérilisation, de stockage de produits hôteliers et de blanchiment de linge. Ces produits finis sont ensuite transportés dans des contenants, grâce à une équipe de transport, vers les quatre centres hospitaliers de Marseille. Le but de cette étude de recherche est de proposer une méthode et un outil permettant d’aider l’équipe de régulation des transports pour la gestion des ressources de transport. Cette étude prend en compte la variabilité des temps de trans- port ainsi que les aléas pouvant intervenir dans le cycle de vie d’une tournée de transport.Pour cela nous commençons par réaliser un modèle de connaissance du système logistique existant grâce à la méthodologie ASCI. Nous proposons ensuite une méthode et un outil permettant la génération de planning de tournées quotidien. Cette méthode est une solution ad-hoc qui intègre la résolution d’un problème de charge- ment, la planification de véhicules et d’équipages, ainsi qu’une représentation et une mo- délisation statistique de la variabilité des temps de transports en milieu urbain. En effet, le taux de congestion quotidien peut faire varier un temps de transport du simple au double. Enfin pour la gestion des aléas, nous proposons une méthode de réparation de planning que nous modélisons grâce aux systèmes multi agents. Ce dernier point de ce travail de thèse permet, en fonction des scénarios de défaillance, de proposer la solution la plus adaptée aux équipes de transport. / This thesis work is part of the logistics project of the Assistance Publique-Hôpitaux de Marseille. Indeed the AP-HM opened a logistics platform in April 2013 in order to central- ize production activities of meals, sterilization, storage product and bleaching of linen. These products are then transported in containers, thanks to a team of transport, to the four hospitals in Marseille. After consumption of the products, by healthcare units, used containers must be re- ported to the logistics platform that they are disinfected and reinstated in the production loop. The purpose of this research study is to propose a method and a tool to help the team of regulation of transport for the management of transport resources. This study takes into account the variability of the transport time and the hazards that could inter- vene in the life cycle of a tour of transport.For this we make a knowledge model of logistics system using the ASCI methodology. This model of knowledge is then validated with a simulation model. We offer then a method and a tool allowing the generation of daily tour schedule. This method is an ad - hoc solu- tion that integrates solving a problem loading, planning for vehicle and crew, as well as representation and statistical modelling of variability in the time of transport in urban areas. Indeed, the daily congestion rate can vary a transport time of one to two. Finally, for the management of the ups and downs, we propose a method of repair of planning that we model with multi agent systems. This last point of this thesis according to failure sce- narios, makes it possible to propose the best solution to the transport staff.
14

A Friction and Adhesion Characterization Setup for Extreme Temperatures

January 2016 (has links)
abstract: It is well known that the geckos can cling to almost any surface using highly dense micro/nano fibrils found on the feet that rely on Van Der Waals forces to adhere. A few experimental and theoretical approaches have been taken to understand the adhesion mechanism of gecko feet. This work explains the building procedure of custom experimental setup to test the adhesion force over a temperature range and extends its application in space environment, potentially unsafe working condition. This study demonstrates that these adhesive capable of switching adhesive properties not only at room environment but also over a temperature range of -160 degC to 120 degC in vacuum conditions. These conditions are similar to the condition experienced by a satellite in a space orbiting around the earth. Also, this study demonstrated various detachment and specimen patch preparation methods. The custom-made experimental setup for adhesion test can measure adhesion force in temperature and pressure controlled environment over specimen size of 1 sq. inch. A cryogenic cooling system with liquid nitrogen is used to achieve -160 degC and an electric resistive heating system are used to achieve 120 degC in controlled volume. Thermal electrodes, infrared thermopile detectors are used to record temperature at sample and pressure indicator to record vacuum condition in controlled volume. Reversibility of the switching behaviour of the specimen in controlled environment confirms its application in space and very high or very low-temperature conditions. The experimental setup was developed using SolidWorks as a design tool, Ansys as simulation tool and the data acquisition utilizes LabVIEW available in the market today. / Dissertation/Thesis / Masters Thesis Mechanical Engineering 2016
15

Ce que la dépendance fait au métier d'infirmière libérale : ethnographie d'une épreuve de professionnalité / How dependence is shaping the profession of self-employed nurses : ethnography of the challenge of professionalism

Feyfant, Véronique 09 December 2016 (has links)
Depuis le début des années 2000, la législation française autorise les infirmières libérales à décider quels professionnels prodigueront les soins de continuité de la vie à des personnes dépendantes vivant à domicile. Elles doivent juger si la situation d’une personne relève d’un soin infirmier ou d’une intervention sociale. À partir d’une enquête ethnographique mobilisant des entretiens semi-directifs, des observations de professionnelles en situation de travail, et des écrits professionnels, la thèse analyse en quoi le fait de travailler auprès des personnes dépendantes recompose le métier d’infirmière libérale.Nous contribuons à une sociologie des groupes professionnels à double titre. D’une part, l’étude d’un métier modeste exercé avec un statut libéral nous apprend que le statut apparaît comme un élément essentiel de la professionnalité de ce métier en autorisant (partiellement) les infirmières à autodéterminer le contenu, la finalité et les moyens de leur activité professionnelle. D’autre part, nous montrons que le contexte d’exercice auprès des personnes dépendantes (travailler avec des professionnels du social, dans des domiciles, auprès de personnes avec qui la relation s’envisage sur le long terme) constitue une épreuve de professionnalité pour les infirmières libérales. L’autodétermination du travail infirmier libéral est éprouvée par le jeu interactionnel qui se déroule entre les travailleurs du sanitaire et ceux du social. Entre eux se crée un nouvel espace dans lequel nous observons, entre autres, des échanges de sale boulot, un abandon de modèles de pensée infirmiers au profit de lignes de conduite observées dans le travail social, ou encore une façon toute infirmière de considérer la dépendance, et donc de la définir. Cette thèse montre une dynamique de profession « en situation » qui conduit à une ouverture du métier d’infirmière libérale vers les métiers du social. / Since the early 2000s, French law has allowed self-employed nurses to decide which professionals will dispense continuity of care to dependent persons living at home. They have to decide whether an individual's situation requires nursing care or social intervention. The purpose of this thesis is to analyse how self-employed nurses working with dependent individuals have reconstructed the profession, based on an ethnographic survey involving semi-structured interviews, observations of professionals in the workplace, and professional writings.We have contributed to a sociology of professional groups on two counts. First, studying a modest profession exercised on a self-employed basis tells us that this is an essential element in terms of the professionalism of this profession by (partially) allowing nurses to determine the content, purpose and means of their own professional activity. Second, we will show that the context in which this profession is exercised with dependant individuals (whose working relationship, alongside social professionals, with individuals in the home is deemed "long-term") constitutes a challenge of professionalism for self-employed nurses. Self-employed nurses' self-determination is proven by the interactional relationship between both health care and social workers. A new space is therefore created between them, in which we observe, among other things, discussions on the dirty work, the abandon of nurses' models of thought in favour of the guidelines observed in social work, or even the way nurses consider dependence, and thus define it. This thesis demonstrates the dynamic of a real-life profession which opens up self-employed nurses to social professions.
16

Pracovněprávní problematika v oblasti profesionálního sportu / Labour law issues in the area of professional sports

Dušek, Šimon January 2021 (has links)
Title of the thesis: Labour law issues in the area of professional sports Abstract This thesis concerns the relationship between labour law and the specifics of sports and sports activities as a mass society-wide phenomenon with a significant overlap into law. Legislation in the Czech Republic still does not follow the global trend in the area of status of professional sportsmen, which is oriented towards the explicit recognition of sportsmen as employees so the sportsmen are provided with the highest amount of rights possible as the weaker parties in relation to sports clubs. On the contrary, the position of the Czech sportsmen within the legal system is still unclear and the desired clarification is not provided even by the relatively extensive case law of the Supreme Administrative Court. In the vast majority of cases, the Czech sportsmen use the status of self-employment. In general, this thesis will focus on professional team sports, especially the football environment, whose legal framework provides the most suitable sample to demonstrate theoretical conclusions contained herein. For the purposes of comparison, the practice of Great Britain and its legal structure of sports environment will be analysed. The first part of this work will focus generally on sports and its specifics, mainly its separation...
17

Family Enablers of the Resilience of Youth Living in Industrialised Communities

Van Aswegen, Rozhé January 2019 (has links)
My study is a sub-study of the Resilient Youth in Stressed Environments (RYSE) Project. RYSE endeavours to better understand the resilience shown by youth who reside in communities that are affected by the petrochemical industry, and the risks associated with this industry. My study is of limited scope, and aims to explore the role of families in facilitating resilience amongst youth between the ages of 15 and 24 years who reside in the petrochemical-affected community of eMbalenhle in the Mpumalanga region of South Africa. My study made use of the social ecology of resilience theory (SERT) as proposed by Ungar (2011). Furthermore, my study followed a phenomenological research design, seeking to better understand the experiences of the 30 adolescent participants recruited for this research. Participants were selected from the community of eMbalenhle, and engaged in arts-based activities, namely, body mapping and draw-write-talk. Data generated from these activities was analysed using thematic content analysis, in which coding was used to identify key themes. The themes identified include family members work at Sasol, families provide affective support to youth, and families motivate youth to create positive futures. My study serves to provide information that is absent from current resilience literature relating to the resilience of youth affected by the petrochemical industry in South Africa, and how family (both immediate and extended) can champion resilience in this context. / Dissertation (MEd)--University of Pretoria, 2019. / Educational Psychology / MEd / Unrestricted
18

Evaluation multi-échelle de toxines de venins comme agents antinociceptifs potentiels / Multiscale evaluation of venom toxins as potential antinociceptive agents

Gonçalves, Tânia Cristina 19 December 2018 (has links)
L’objectif de ma thèse était d’identifier, comme agents antinociceptifs potentiels, des toxines de venins originales par leur séquence et/ou leur provenance. Dans cette optique, un criblage à haut débit de deux banques de venins a été réalisé par des méthodes électrophysiologiques de "patch-clamp" automatique, sur des lignées cellulaires exprimant le sous-type neuronal hNaV1.7 de canaux sodium (versus celles exprimant le sous-type cardiaque hNaV1.5), une cible antidouleur validée génétiquement et fortement exprimée au niveau des neurones sensoriels primaires des ganglions de la racine dorsale, premier support de la transmission du message nociceptif.Le criblage de la première banque de venins (appartenant à Smartox Biotechnology) a permis l’identification et la caractérisation, par des approches structurales et fonctionnelles multi-échelles (de la cellule in vitro à l’organisme in vivo), de 2 peptides de venins d’araignées ayant des propriétés potentiellement antinociceptives : (1) la cyriotoxine-1a du venin de Cyriopagopus schioedtei, dont les propriétés fonctionnelles sont proches de celles des peptides appartenant à la famille 1 des toxines d’araignées inhibant les canaux sodium, et (2) la poecitoxine-1a du venin de Poecilotheria subfusca, qui présente une meilleure affinité pour le sous-type hCaV1.2 de canaux calcium que pour le sous-type hNaV1.7. Nous avons également mené une étude de "structure-activité" afin d’améliorer le profil de sélectivité de la phlotoxine-1 d’une araignée Phlogiellus, connue pour son activité antinocieptive. Finalement, nous avons mis en évidence une interaction directe entre l’huwentoxine-IV, déjà connue comme agent antinociceptif potentiel, et le sous-type neuronal NaV1.6, responsable d’effets neuromusculaires indésirables. Le criblage de la deuxième banque de venins (appartenant à SANOFI) a permis d’identifier des hits intéressants provenant de venins d’araignées et de scorpions non étudiés jusqu’à présent et ayant une séquence originale présentant peu d’homologie avec les séquences déjà connues. / The aim of my thesis was to identify original venom toxins, by their sequence and/or origin, as potential antinociceptive agents. In this context, a high-throughput screening of two venom libraries was performed, by automated patch-clamp electrophysiology, on cell lines expressing the hNaV1.7 neuronal subtype of sodium channels (versus those expressing the hNaV1.5 cardiac subtype), a genetically-validated and strongly expressed pain target in the primary sensory neurons of dorsal root ganglia, the first support of nociceptive message transmission.The screening of the first venom library (belonging to Smartox Biotechnology) allowed the identification and characterization, by structural and multiscale functional approaches (from the cell in vitro to the organism in vivo), of 2 peptides from spider venoms having potential antinociceptive properties : (1) cyriotoxin-1a from Cyriopagopus schioedtei venom, whose functional properties are close to those of peptides belonging to family 1 of spider toxins inhibiting sodium channels, and (2) poecitoxin-1a from Poecilotheria subfusca venom, which has a better affinity for the hCaV1.2 subtype of calcium channels than for the hNaV1.7 subtype. We also conducted a "structure-activity" study to improve the selectivity profile of phlotoxin-1 from a Phlogiellus spider, known for its antinociceptive activity. Finally, we evidenced a direct interaction between huwentoxin-IV, already known as a potential antinociceptive agent, and the NaV1.6 neuronal subtype which is the main cause of undesirable neuromuscular effects. The screening of the second venom library (belonging to SANOFI) allowed to identify interesting hits from spider and scorpion venoms, not studied until now, having an original sequence with little homology with already known sequences.
19

Radiation Induced Bystander Responses In Vertebrates Given Low Doses Of In Vivo Radiation / Bystander Resposes In Vertebrates Given In Vivo Radiation

Singh, Harleen January 2009 (has links)
<p> The bystander response phenomenon shows that radiation induced changes in cells that have not been directly targeted, but are neighbors to or receive medium from directly hit cells. Our group has performed a range of single and serial, low dose irradiations (in vivo) on two strains of mice that have been documented to show genetic differences in their response to radiation. This thesis also explores the impact of environmental radiation contamination on female and male Mink frogs (Rana septentrionalis) sampled from contaminated and background (control) radiation sites. Bladder explants established from these vertebrates are incubated in culture medium, which is then used to measure apoptotic response (cell survival and calcium flux) in the keratinocyte reporter system. </p> <p> This study reveals that culture medium from acutely irradiated C57Bl6 mice, but not Balb/c mice, induces dose-dependant clonogenic death. The administration of a priming dose(s) to C57BL6, but not Balb/c mice, leads to stimulatory growth effects in reporters regardless of the time separation between the priming and challenge dose. Similarly, ITCM corresponding to male and female contaminated frogs results in a sexdependent decrease in reporter survival, but no reduction is induced from ITCM sampled from explants from female and male frogs from uncontaminated sites. When the ITCM is measured for its calcium inducing ability, results show abnormal calcium levels in both strains of mice only after the administration of a priming dose. However, chronic exposures to male and female frogs results in the production of ITCM that induces transient calcium flux in reporters. These results indicate that genetic predisposition in mice influences the type of bystander signal that is produced after exposure to low, acute doses of radiation. However, when mice are repeatedly exposed to radiation, the bystander signal is modified in a way that may be causing unregulated growth in reporter cells. </p> / Thesis / Master of Science (MS)
20

Examination of 2-Oxoglutarate Dependant Dioxygenases Leading to the Production of Flavonols in <i>Arabidopsis thaliana</i>

Owens, Daniel Kenneth 21 October 2005 (has links)
The flavonols are a varied and abundant sub-class of flavonoids that are associated with a number of essential physiological functions in plants and pharmacological activities in animals. The 2-oxoglutarate-dependant dioxygenases(2-ODDs), flavonol synthase (FLS) and flavanone 3-hydroxylase (F3H), are essential for flavonol synthesis. The primary goal of this study has been to gain a deeper understanding of the biochemistry of these enzymes in Arabidopsis. To accomplish this goal, an activity assay employing recombinant protein expression and HPLC as a detection system was developed for F3H and adapted for use with FLS. The assay was employed to establish the biochemical parameters of F3H from Arabidopsis, and to further characterize the F3H mutant allele, <i>tt6</i>(87). Enzymatic activity was demonstrated for F3H enzymes from <i>Ipomoea alba</i> (moonflower), <i>Ipomoea purpurea</i> (common morning glory), <i>Citrus sinensis</i> (sweet orange), and <i>Malus X domestica</i> (newton apple), each of which had previously been identified solely based on sequence homology. Arabidopsis contains six genes with high similarity to <i>FLS</i> from other plant species; however, all other central flavonoid pathway enzymes in Arabidopsis are encoded by single genes. The hypothesis that differential expression of FLS isozymes with varying substrate specificities is responsible for observed tissue-specific differences in flavonol accumulation was tested. Sequence analysis revealed that <i>AtFLS2, 4</i> and <i>6</i> contain premature stop codons that eliminate residues essential for enzyme activity. AtFLS1 was found to have a strong preference for dihydrokaempferol as a substrate. However, no enzyme activity was observed for AtFLS3 or AtFLS5 with a number of different substrates under a variety of reaction conditions. To identify structural elements that may contribute to the observed differences in biochemical activity, homology models for each of the isoforms were generated utilizing Arabidopsis anthocyanin synthase (ANS) as a template. A domain at the N-terminus of AtFLS1 that is missing in the other isozymes was insufficient to convey activity to an AtFLS1/5 chimera. These findings suggest a single catalytically-active form of FLS exists in Arabidopsis. The possibility that the apparently expressed but non-catalytic proteins, AtFLS2, 3, and 5, serve noncatalytic roles in flavonol production were explored by yeast 2-hybrid analysis. / Ph. D.

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