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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

Syndromic Surveillance using Poison Center Data: An Examination of Novel Approaches

Law, Kai Yee 09 August 2016 (has links)
Early detection of a new outbreak or new information about a public health issue could prevent morbidity and mortality and reduce healthcare expenditures for the economy. Syndromic surveillance is a subset of public health surveillance practice that uses pre-diagnostic data to monitor public health threats. The syndromic surveillance approach posits that patients first interface with the healthcare system in non-traditional ways (e.g., buying over-the-counter medications, calling healthcare hotlines) before seeking traditional healthcare avenues such as emergency rooms and outpatient clinics. Thus detection of public health issues may be more timely using syndromic surveillance data sources compared to diagnosis-based surveillance systems. One source of information not yet fully integrated in syndromic surveillance is calls to poison centers. United States poison centers offer free, confidential medical advice through a national help line to assist in poison exposures. Call data are transmitted and stored in an electronic database within minutes to the National Poison Data System (NPDS), which can be used for near-real-time surveillance for disease conditions or exposures. The studies presented in the dissertation explore new ways for poison center records to be used for early identification of public health threats and for evaluating policy and program impact by identifying changing trends in poison center records. The approach and findings from these three studies expand upon current knowledge of how poison center records can be used for syndromic surveillance and provide evidence that justifies expansion of poison center surveillance into avenues not yet explored by local, state, and federal public health.
12

Hostile Takeovers and Corporate Purpose: The Role of Poison Pills in Ontario Securities Law

Snyder, Matthew 28 November 2013 (has links)
This paper examines the Ontario Securities Commission's regulation of poison pills as well as several proposals to reform the current regulatory regime. In particular, the paper argues that regulation and reforms should be viewed within the context of two fundamental, normative questions that underlie much of corporate law: what is the purpose of the corporation, and who should determine whether these goals are being met. After outlining several competing theories, the paper explains why a corporate model based on the shareholder-centric, wealth maximization theory is best suited for hostile takeover situations. Additionally, the paper argues that a structural bid reform that would require hostile bidders to include minimum tender conditions and additional opportunities for target company shareholders to tender following a successful bid would provide the best way to incorporate this corporate model into Ontario securities regulation.
13

Hostile Takeovers and Corporate Purpose: The Role of Poison Pills in Ontario Securities Law

Snyder, Matthew 28 November 2013 (has links)
This paper examines the Ontario Securities Commission's regulation of poison pills as well as several proposals to reform the current regulatory regime. In particular, the paper argues that regulation and reforms should be viewed within the context of two fundamental, normative questions that underlie much of corporate law: what is the purpose of the corporation, and who should determine whether these goals are being met. After outlining several competing theories, the paper explains why a corporate model based on the shareholder-centric, wealth maximization theory is best suited for hostile takeover situations. Additionally, the paper argues that a structural bid reform that would require hostile bidders to include minimum tender conditions and additional opportunities for target company shareholders to tender following a successful bid would provide the best way to incorporate this corporate model into Ontario securities regulation.
14

Ecology and movements of brown rats (Rattus norvegicus) in rural populations containing individuals resistant to the anticoagulant poison warfarin

Hartley, D. J. January 1977 (has links)
No description available.
15

Poison hemlock (conium Maculatum L.) biology, implications for pastures and response to herbicides /

Woodard, Carl Andrew. January 2008 (has links)
Thesis (M.S.)--University of Missouri-Columbia, 2008. / The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file. Title from title screen of research.pdf file (viewed on September 19, 2008) Includes bibliographical references.
16

The effect of the portfolio of takeover provisions on operating performance, takeovers, and takeover premiums /

Blease, John Robert. January 2002 (has links)
Thesis (Ph. D.)--University of Oregon, 2002. / Typescript. Includes vita and abstract. Includes bibliographical references (leaves 112-118). Also available for download via the World Wide Web; free to University of Oregon users.
17

AÃÃo tripanocida de um mastoparano de Polybia paulista e seu possÃvel mecanismo de aÃÃo / Trypanocidal action: A mastoparan isolated from Polybia paulista and its possible mechanism action

Juliana Freire Chagas Vinhote 18 June 2015 (has links)
FundaÃÃo Cearense de Apoio ao Desenvolvimento Cientifico e TecnolÃgico / FundaÃÃo de Amparo à Pesquisa do Estado do Cearà / A doenÃa de Chagas, considerada uma doenÃa negligenciada, à uma infecÃÃo parasitÃria causada pelo Trypanosoma cruzi e endÃmica em diversos paÃses. No Brasil, apenas o Benzonidazol à usado para o tratamento da doenÃa. Nesse contexto, o potencial terapÃutico das toxinas vem cada vez mais conquistando espaÃo e despertando grandes interesses da comunidade cientÃfica. Os venenos de invertebrados tÃm apresentado grande interesse como fonte de substÃncias bioativas. Os mastoparanos, a classe mais amplamente descrita de peptÃdeos isolados a partir da peÃonha de vespas, ja evidenciaram diferentes atividades biolÃgicas. Assim, os peptÃdeos isolados tÃm despertado interesse cientÃfico como fonte de modelos moleculares para o possÃvel desenvolvimento de novas terapias farmacolÃgicas. Este estudo investigou o efeito do peptideo mastoparano (MP) isolado do veneno da vespa Polybia paulista sobre cepa Y de Trypanosoma cruzi e seu possÃvel mecanismo de aÃÃo. Formas epimastigotas de T. cruzi foram cultivadas, tratadas com diferentes concentraÃÃes de MP e incubadas durante 24, 48 e 72 horas. Formas tripomastigotas de T. cruzi obtidas atravÃs de infecÃÃo de cÃlulas LLCMK2 foram subcultivadas, tratadas com diferentes concentraÃÃes de MP e incubadas durante 24 horas. Para investigar a participaÃÃo das espÃcies reativas de oxigÃnio (ERO) no efeito citotÃxico do mastoparano sobre formas epimastigotas de T.cruzi, placas foram incubadas com a CI50 de 24h de MP e a anÃlise da emissÃo de fluorescÃncia foi realizada em citometria de fluxo apÃs adiÃÃo de DCF. O efeito de mastoparano sobre o potencial de membrana mitocontrial das formas epimastigotas foi realizado pelo ensaio com rodamina 123. A citotoxicidade foi avaliada sobre celulas Raw 264.7 e a viabilidade dos macrÃfagos foi determinada utilizando o ensaio com MTT. No estudo de Docking molecular, obteve-se inicialmente a estrutura tridimensional do mastoparano a partir da sequÃncia primÃria em programa especÃfico. ApÃs anÃlise dos sÃtios de ligaÃÃo entre peptÃdeo e enzima TcGAPDH, a estrutura cristalogrÃfica do complexo TcGAPDH-chalepina foi utilizada para comparaÃÃo. O mastoparano inibiu o crescimento das formas epimastigotas de T. cruzi, apresentando uma CI50 de 102 Âg/mL, 53,95 Âg/mL e 58,51 Âg/mL para 24, 48 e 72 horas de incubaÃÃo respectivamente. Na anÃlise da produÃÃo de espÃcies reativas houve um aumento significativo na intensidade relativa de fluorescÃncia, quando comparado ao grupo controle. O peptideo alterou o potencial da membrana mitocondrial do parasita. Para as formas tripomastigotas a CI50 foi 8,83 Âg/mL apÃs 24h de incubaÃÃo. A citotoxidade do mastoparano avaliada em macrÃfagos nÃo induziu morte celular significativa nas diferentes concentraÃÃes estudadas. No estudo de docking, foi evidenciado o acoplamento do mastoparano na TcGAPDH, demonstrando os diferentes sÃtios de ligaÃÃo dos resÃduos de aminoÃcidos do centro ativo da enzima e comparando a semelhanÃa na posiÃÃo ocupada pela molÃcula chalepina na TcGAPDH. Conclui-se que o mastoparano apresentou atividade tripanocida envolvendo a participaÃÃo do estresse oxidativo e alteraÃÃo do potencial de membrana sem apresentar citotÃxica em cÃlulas de macrÃfagos e parece inibir a TcGAPDH de T. cruzi. Portanto, o mastoparano se destaca como importante molÃcula bioativa contra os parasitas.
18

Conception, synthèse et évaluations pharmacologiques de nouveaux perturbateurs du fuseau mitotique / Design, synthesis and pharmacological evaluation of new antitumor drugs

Verones, Valérie 26 November 2011 (has links)
Le cancer est l’une des principales causes de mortalité en France, après les maladies cardiovasculaires. Il est responsable de plus de 11 millions de décès dans le monde chaque année. Le cancer résulte d’une prolifération anarchique de cellules qui mène à la formation d’une tumeur. Les cellules tumorales peuvent ensuite migrer vers d’autres tissus pour former des métastases. La chimiothérapie est l’un des traitements les plus utilisés pour traiter le cancer. Elle consiste en l’utilisation d’agents antitumoraux qui provoquent la mort cellulaire en bloquant la mitose. Dans le but d’induire cette apoptose, nous nous sommes intéressés aux poisons du fuseau mitotique, agents cytotoxiques qui ont pour cible les microtubules et qui ont la particularité de se fixer sur leur constituant majeur, la tubuline. La dynamique des microtubules joue un rôle crucial dans la multiplication cellulaire. Bloquer cette dynamique est suffisant pour bloquer la mitose. Par ailleurs, suite à cet arrêt de la polymérisation, un second mécanisme se mettrait en place, notamment au niveau des cellules endothéliales, pour empêcher la néovascularisation, ce qui inhiberait ainsi l’angiogénèse. Notre travail consiste en la conception et la synthèse de nouveaux inhibiteurs de la polymérisation de la tubuline, potentiellement anti-angiogéniques et anti-vasculaires. Il s’agit de tricycles, qui ont la particularité d’interagir spécifiquement avec le site de fixation de la colchicine, au niveau de la tubuline, ce qui inhibe la polymérisation des microtubules et par conséquent la division cellulaire. Des tests d’inhibition enzymatique et de cytotoxicité sur plusieurs lignées cellulaires cancéreuses ont été réalisés et les résultats sont présentés dans ce rapport. / Cancer is one of the leading cause of death in France after cardiovascular diseases. Cancer results from an abnormally excessive cell proliferation which leads to the formation of a tumor. The following processes in invasion of tumoral cells and metastasis in the other tissues. Stopping mitosis by chemotherapy can cause death of cancer cells. In order to induce this apoptosis, we are interested by a class of antitumoral drugs which disrupt mitotic spindle function by focusing on its major component: the microtubules. These agents set exactly on their main structural element: the tubulin. The microtubule was recognised as a subcellular target of major strategic importance with regard to anticancer therapeutics. Our work consisted of the design and the synthesis of new antitumor drugs which influence microtubules dynamics. Theses molecules should inhibit tubulin polymerization by binding to the colchicine site. Moreover, we expect theses compounds selectively target tumor vasculature and thus can also be considered vascular disrupting agents. Enzymatic inhibition and cytotoxic assays were performed on different cell lines and are presented in this report.
19

A Suffocating Nature: Environment, Culture, and German Chemical Warfare on the Western Front

Johnson, Ryan Mark January 2013 (has links)
The story of chemical warfare is that of a relationship between nature, the military, industry, and culture. By the turn of the twentieth century, German industry, especially its chemical companies, came to dominate Europe. Their success brought both considerable economic development and considerable environmental damage from chemical pollution, especially to rivers such as the Rhine and the Emscher. These economic changes made in exchange for landscape degradation conflicted with long-held cultural beliefs in Germany that promoted the beauty of nature and the importance of conserving its aesthetics. The First World War's effect of the environment, including the effects of chemical weaponry, highlighted this paradox on a nationwide scale. In an effort to win the Great War, German military leaders turned to their chemical industry for answers. Using the flat terrain of Western Europe, winds strong enough to push massive toxic clouds, and their extensive knowledge of chemistry, the Germans chose chemical warfare agents based on meteorological conditions and their ability to overcome the obstacles of trench warfare. Millions of acres were doused in chemical clouds and shells, killing every form of life at the front and all but permanently altering the landscape and soils. This created an atmosphere of total environmental war, where chemicals were intentionally used to contaminate land and kill all life for the sake of military gains. The home front also suffered, as in Germany where the levels of chemical contaminants in their rivers were directly linked to the course of the chemical war. Germans wrote numerous diaries, journals, and memoirs that documented the ecological damage caused by these poisonous agents. These visceral descriptions of gas warfare and chemical disasters relating to clean up operations helped to solidify a national picture of what the gas war experience was like, and how many Germans came to see warfare and humanity as a destroyer of nature. Simultaneously, Europeans faced the daunting task of cleaning and repairing their landscapes. Millions of acres of land were contaminated, and tons of chemical ordnance was to be disposed. Yet an antagonistic political climate, steep financial costs, and the German leadership's desire to continue chemical weapons research limited Europeans' ability to restore their land. Their actions resulted in horrific environmental and human consequences, including everything from the contamination of land with buried ordnance to the phosgene cloud catastrophe at Hamburg in 1928. Not only did the damage caused by chemical weaponry force German military officials to rethink military operations and tactics, chemical weapons also compelled the German people to solidify new cultural relationships between war and nature, specifically those which took environmental damage into account when thinking about the war experience. German artistic and written culture at that time reflected the environmental damage through pacifistic and anti-technological lenses, creating a framework where modern environmentalism could take shape. Ultimately, the use of chemical weapons for military gain shaped German cultural attitudes and changed European landscapes. It ushered in a new form of total war, and demonstrated how the environment directly influenced both the outcome of the chemical war in the field but also German cultural beliefs regarding the relationship between nature and warfare. / History
20

The Curious Poisoned Weed: Poison Ivy Ecology and Physiology

Dickinson, Christopher Cody 11 July 2019 (has links)
Poison ivy (Toxicodendron radicans (L.) Kuntze) is a native perennial liana widely recognized for the production of urushiol, and the associated contact dermatitis it causes in humans. Poison ivy is predicted to become both more prevalent and more noxious in response to projected patterns of global change. Moreover, poison ivy is an important food source for avian species, and urushiol has numerous applications as a high-value engineering material. Thus, this curious weed has many avenues for future concern, and promise. Here, I address gaps in knowledge about poison ivy ecology and physiology so that we may better understand its weediness and utilize its benefits. I address three core areas: poison ivy establishment patterns; biotic interactions with multiple taxa; and the development of molecular tools for use in poison ivy. I found that the early life stage of seedling emergence is a critical linchpin in poison ivy establishment due largely to herbivore pressure from large grazers. I also describe the multifaceted relationship between poison ivy and avian frugivores that not only disperse the drupes of poison ivy but also aid in reduction of fungal endophytic phytopathogens. A survey of poison ivy urushiols yielded that while variation in urushiol congeners was high across individuals, relative congener levels were stable within individuals over a two month period. Lastly I demonstrate best practices for introducing and transiently expressing recombinant DNA in poison ivy as a step towards future reverse genetic procedures. / Doctor of Philosophy / Poison ivy is a native plant best known for its capacity to cause allergenic skin reactions in humans due to the chemical urushiol, which is found in all parts of the plant. While most people prefer to avoid this plant, poison ivy is an important food source for birds. In addition, urushiol has numerous applications as an engineered material. Despite these positive aspects, poison ivy is among those plants that are responding well to global change, such as increasing CO₂ levels and habitat fragmentation. Poison ivy has been shown to increase in size and produce more allergenic forms of urushiol under elevated CO₂ levels and there are concerns that poison ivy prefers the disturbed areas created by habitat fragmentation. These attributes suggest that poison ivy will become more prevalent and more noxious in the coming years. Thus, this curious weed has many avenues for both future concern and promise. To aid in our ability to manage poison ivy in the future, I used a combination of field, greenhouse, and laboratory studies to study the ecology of poison ivy. I investigated the early stages of the poison ivy life cycle, and the relationship between poison ivy and the animals that interact with it. I found that the earliest life stages of poison ivy are a critical linchpin for poison ivy survival due largely to large animals like deer eating the seedlings. I also describe the multifaceted relationship between poison ivy and birds, which not only disperse the seeds of poison ivy but also aid in reducing pathogens associated with the seeds. I surveyed the amounts and types of urushiols that poison ivy produces and found them to be highly variable from plant to plant, but relatively stable over time within a plant. Lastly, I demonstrate best practices for transient transgene expression in poison ivy leaves as a step towards future genetic studies. These studies help expand our understanding of a problematic weed, and pave the way for future studies in weed ecology and in the utilization of urushiol in positive applications, showing that even poison ivy can be of benefit to the environment and humans.

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