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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.
1

Efficacy of F10 against amphibian chytrid fungus / Maria Susanna de Jong

De Jong, Maria Susanna January 2014 (has links)
Outbreaks of pathogens that threaten both human and nature have increased in recent years. Infectious and transmittable diseases, such as chytridiomycosis, which is caused by the emerging pathogen Batrachochytrium dendrobatidis, has been identified as one of the most important drivers of the current declines in amphibian numbers. This pathogen has spread globally and is not only responsible for the declines in amphibian population numbers, but also for the extinction of species in several countries. As part of the Amphibian Conservation Action Plan, the IUCN recommended ex situ breeding of amphibian species to try and stem the global loss of amphibian species. Due to chytridiomycosis being one of the most eminent threats for amphibians, it poses an additional threat for the ex situ breeding plan. There is thus a need for safe and effective measures to treat chytridiomycosis, especially in breeding programs for endangered species. F10 (Health and Hygiene) is a veterinary antiseptic that has shown to be 100% effective in killing B. Dendrobatidis in vitro. Before any chemical treatment can be applied the efficacy and toxicity of F10 has to be determined to establish if F10 can be effectively applied across different amphibian species and across different life stages. We propose to develop a treatment protocol for F10 for the effective treatment of amphibian chytridiomycosis by challenging juveniles of Amietophrynus gutturalis with B. dendrobatidis and subsequently treating the infection with a proposed concentration of F10. The survival of B. dendrobatidis zoospores was also determined in the presence of F10. The results obtained showed survival of tadpoles at a 1:10,000 concentration of F10 for 30min, and juveniles at a concentration of 1:2000 for 15 min. Furthermore the in vitro tests showed that the B. dendrobatidis zoospores died after 10 min at a 1:10,000 concentration and 30 min at a 1:15,000 concentration. The successful treatment of tadpoles as well as juveniles will increase any species chance for survival, especially when treating tadpoles as the pathogen will then be eradicated before the tadpole metamorphoses and reaches the disease-susceptible life stage. By establishing a partnership between the industry, academic and zoo/wildlife communities we hope to maximise the likelihood of implementing this program in the future and thus ensuring long term sustainability. / MSc (Environmental Sciences), North-West University, Potchefstroom Campus, 2015
2

Efficacy of F10 against amphibian chytrid fungus / Maria Susanna de Jong

De Jong, Maria Susanna January 2014 (has links)
Outbreaks of pathogens that threaten both human and nature have increased in recent years. Infectious and transmittable diseases, such as chytridiomycosis, which is caused by the emerging pathogen Batrachochytrium dendrobatidis, has been identified as one of the most important drivers of the current declines in amphibian numbers. This pathogen has spread globally and is not only responsible for the declines in amphibian population numbers, but also for the extinction of species in several countries. As part of the Amphibian Conservation Action Plan, the IUCN recommended ex situ breeding of amphibian species to try and stem the global loss of amphibian species. Due to chytridiomycosis being one of the most eminent threats for amphibians, it poses an additional threat for the ex situ breeding plan. There is thus a need for safe and effective measures to treat chytridiomycosis, especially in breeding programs for endangered species. F10 (Health and Hygiene) is a veterinary antiseptic that has shown to be 100% effective in killing B. Dendrobatidis in vitro. Before any chemical treatment can be applied the efficacy and toxicity of F10 has to be determined to establish if F10 can be effectively applied across different amphibian species and across different life stages. We propose to develop a treatment protocol for F10 for the effective treatment of amphibian chytridiomycosis by challenging juveniles of Amietophrynus gutturalis with B. dendrobatidis and subsequently treating the infection with a proposed concentration of F10. The survival of B. dendrobatidis zoospores was also determined in the presence of F10. The results obtained showed survival of tadpoles at a 1:10,000 concentration of F10 for 30min, and juveniles at a concentration of 1:2000 for 15 min. Furthermore the in vitro tests showed that the B. dendrobatidis zoospores died after 10 min at a 1:10,000 concentration and 30 min at a 1:15,000 concentration. The successful treatment of tadpoles as well as juveniles will increase any species chance for survival, especially when treating tadpoles as the pathogen will then be eradicated before the tadpole metamorphoses and reaches the disease-susceptible life stage. By establishing a partnership between the industry, academic and zoo/wildlife communities we hope to maximise the likelihood of implementing this program in the future and thus ensuring long term sustainability. / MSc (Environmental Sciences), North-West University, Potchefstroom Campus, 2015
3

Studium mechanismů působících při nádorové imunoterapii založené na instalaci ligandů fagocytárních receptorů na povrch nádorových buněk

SVÁČKOVÁ, Denisa January 2016 (has links)
The aim of thesis was to study murine melanoma B16- F10 therapy based on the use of TLR agonists combinedwith activation of phagocytosis. Mechanisms of this therapy were studied on the bases of analysis of tumor infiltrating immune cells and evaluationof thein effect on tumor cells.
4

Why is Income Inequality Increasing in the Developed World?

Roser, Max, Crespo Cuaresma, Jesus 03 1900 (has links) (PDF)
We address empirically the factors affecting the dynamics of income inequality among industrialized economies. Using a panel for 32 developed countries spanning the last four decades, our results indicate that the predictions of the Stolper-Samuelson theorem concerning the effects of international trade on income inequality find support in the data if we concentrate on imports from developing countries as a trade measure, as theory would imply. We find that democratization, the interaction of technology and education and changes in the relative power of labour unions affect inequality dynamics robustly.
5

Learning to trade and mediate

Dawid, Herbert January 1997 (has links) (PDF)
In this paper we study the behavior of boundedly rational agents in a two good economy where trading is costly with respect to time. All individuals have a fixed time budget and may spend time for the production of good one, the production of good two and trading. They update their strategies, which determine their time allocation, according to a simple imitation type learning rule with noise. In a setup with two different type of agents with different production technologies we show by the means of simulations that both direct trade and trade via mediators who specialize in trading can emerge. We can also observe the transition from a pure production economy via direct trade to an economy with mediated trade. (author's abstract) / Series: Report Series SFB "Adaptive Information Systems and Modelling in Economics and Management Science"
6

Gaining and losing competitive advantage

Bellak, Christian January 2003 (has links) (PDF)
Efficient policies to stimulate the competitiveness of firms require knowledge of future firm-strategies and a proper assessment of the location advantages of a country or region. Therefore, industry comparative advantage analysis needs to be complemented by firm competitive advantage analysis. This yields four hypotheses of firm strategies on the basis of the existing advantage combination. Detailed empirical analysis of a representative sample of Austrian manufacturing firms during 1990- 2000 shows that changes in employment, value-added and exports are in line with the suggested development. Three of the 3-digit industries lost their advantages while seven industries gained advantages, yet overall industry distribution has been remarkable stable over the four advantage combinations. In terms of number of firms, however, a large share (30%) of the total population shifts between advantage combinations even during short periods of time. The firm strategies outlined suggest a differentiated policy approach, yet the short-term dynamics revealed empirically imply a high potential for policy failure. / Series: Working Papers Series "Growth and Employment in Europe: Sustainability and Competitiveness"
7

Mechanismy imunitní odpovědi při léčbě rakoviny kotvením ligandů fagocytárních receptorů na povrch nádorových buněk / Mechanisms of the immune response during the cancer treatment with ligands of phagocytic receptors anchored to the surface of malignant cells

AUEROVÁ, Marie January 2014 (has links)
The aim of this thesis was to obtain some insights into mechanisms by which the immune system affects melanoma cells after anchoring agonists of phagocytic receptors (laminarin and f-MLF) to their surface. To verify the hypothesis that innate immune system plays a critical role, in vivo experiments were performed on SCID mice. To elucidate the importance of CR3, CD11b-deficient mice were used. In in vitro experiments production of inflammatory cytokines in tumor tissue was examined as well as the release of myeloperoxidase from neutrophil granules after incubation with malignant cells.
8

Analýza imunitních procesů při nádorové imunoterapii založené na synergii agonistů TLR a ligandů stimulujících fagocytózu

UHER, Ondřej January 2018 (has links)
This thesis is focused on analysis of immune processes during cancer immunotherapy which is based on synergistic combination of TLR agonists and phagocytosis stimulating ligands anchored into the tumour cell membrane. This immunotherapy was tested in murine melanoma B16-F10 and murine pancreatic adenocarcinoma Panc02 models. The aims of this thesis were to analyse the tumor infiltration, elucidate the role of innate immunity in this immunotherapy, and study the possibility of strengthening immunotherapeutic effect using anti-CD40 and anti-CTLA-4.
9

Efeito da Luz e Temperatura Sobre a Expressão de Genes do Relógio em Mamífero: Tecidos Periféricos como Modelo de Estudo / Effect of light and temperature on the mammalian clock genes expression: peripheral tissues as study model

Mezzalira, Nathana Fernandes 10 December 2015 (has links)
O surgimento e a evolução da vida na terra foram possíveis graças ao desenvolvimento de mecanismos temporais precisos capazes de ajustar os processos fisiológicos que ocorriam no interior do organismo com os ciclos ambientais, promovendo assim, ganhos na capacidade adaptativa e reprodutiva dos indivíduos. Neste contexto, luz e temperatura são as duas pistas temporais mais relevantes para resetar o relógio endógeno e, aparentemente, esses dois zeitgebers trabalham juntos para manter os ritmos circadianos. Uma ampla gama de fotorreceptores e fotopigmentos evoluiu no sentido de perceber com alta sensibilidade a informação fótica fornecida pelo ambiente e, recentemente, foi demonstrado que a detecção de temperatura também pode ser exercida pelos fotopigmentos rodopsina e melanopsina, sendo mediada por canais TRP (Shen et al., 2011). Consideramos as células B16-F10 Per1::Luc como um modelo promissor para o estudo de luz e temperatura em relógios periféricos, uma vez que essa linhagem expressa os dois fotopigmentos apontados com função de termorreceptores em Drosophila. Nossos estudos nos permitiram verificar que a luz não atua como um agente sincronizador nessas células, que se mantiveram em livre curso mesmo após um pulso de 10 min de luz azul (650 lux). Por outro lado, um pulso de temperatura de 2,5º C acima da temperatura de manutenção por 1h atuou ajustando a expressão do gene Per1, imprimindo um ritmo circadiano, diferentemente do observado no controle. Com base nessas informações, hipotetizamos que a informação de luz, percebida via melanopsina na retina de mamíferos, levaria a regulação da temperatura circadiana pelo NSQ, e a temperatura corporal, por sua vez, poderia atuar como uma pista interna para a sincronização dos tecidos periféricos, tendo os canais TRP como mediadores. Para responder esta questão, utilizamos camundongos WT e TrpV1 KO submetidos a diferentes protocolos de luz e avaliamos a expressão de genes do relógio Per1, Per2, Clock e Bmal1 e dos canais TrpV1 e TrpA1 em tecidos periféricos. Identificamos que a glândula suprarrenal, fígado e tecido adiposo marrom possuem uma maquinaria do relógio tipicamente ativa e acreditamos que a oscilação dos genes de relógio observada nesses tecidos é expressiva. Interessantemente, vimos também que o TrpV1, além de ser expresso nos tecidos analisados em animais WT, apresenta uma transcrição rítmica no fígado e tecido adiposo marrom de animais em LD, corroborando nossa hipótese de que canais TRP atuam como mediadores da informação de luz aos tecidos periféricos. Dadas as diferenças encontradas entre os animais WT e TrpV1 KO, sugerimos que a presença do canal TRPV1 pode ser essencial, embora seu grau de envolvimento varie de acordo com o tecido. No que diz respeito ao canal TRPA1, encontramos dois resultados que merecem ser destacados. Primeiramente, identificamos no fígado de camundongos TrpV1 KO mantidos em LD uma provável compensação da expressão de TrpA1 na ausência de TrpV1 e, curiosamente, que o tecido adiposo marrom não expressa o canal TrpA1. Considerando os resultados deste trabalho sobre o envolvimento dos canais TRP em resposta à luz e temperatura, acreditamos ter fortalecido nossa hipótese inicial, principalmente após demonstrarmos o papel do canal TRPV1 e que tecidos periféricos são sincronizados por alterações de temperatura. / The life emergence and evolution on Earth were made possible by the development of precise temporal mechanisms able to adjust the physiological processes within an organism with environmental cycles, thus promoting gains in the adaptive and reproductive capacity of the individuals. In this context, light and temperature are the two most relevant time cues to reset the endogenous clock; apparently these two zeitgebers work together to keep the circadian rhythms. A wide variety of photoreceptors and photopigments evolved in order to precisely perceive the photic information provided by the environment, and recently it has been shown that the temperature detection can also be exerted by the photopigments rhodopsin and melanopsin, being mediated by TRP channels (Shen et al., 2011). We have identified B16-F10 Per1::Luc cells as a promising model for the study of light and temperature effects on peripheral clocks, since this cell line expresses both photopigments pointed as thermoreceptors in Drosophila. Our studies allowed us to demonstrate that light does not act as a synchronizing agent on those cells, which remained in free running after a 10 min pulse of blue light (650 lux). On the other hand, a temperature pulse of 2.5º C above the maintenance temperature, for 1h, adjusted Per1 gene expression, imprinting a circadian rhythm, which was not observed in the control. Based on this information, we hypothesized that the light perceived via melanopsin by the mammalian retina would lead to the regulation of the circadian temperature by the SCN, and the body temperature, in turn, could act as an inner cue for the synchronization of the peripheral tissues, having the TRP channels as mediators. To answer this question, we have used WT and TrpV1 KO mice under different light protocols and evaluated the expression of clock genes Per1, Per2, Clock and Bmal1 and TrpV1 and TrpA1 channels in peripheral tissues. We found that the adrenal gland, liver and brown adipose tissue have a typically active clock machinery, and the oscillation of clock genes observed in these tissues is significant. Interestingly, we observed that TrpV1 is expressed in those tissues, and presents a rhythmic transcription in the liver and brown adipose tissue of LD maintained animals, confirming our hypothesis that TRP channels act as mediators of light information to peripheral tissues. In face of the differences between WT and trpV1 KO animals, we suggest that the presence of the TRPV1 channel may be essential, although its degree of involvement may vary according to the tissue. In terms of TRPA1 channel, we found two results that deserve to be highlighted. Firstly, we identified in the liver of TrpV1 KO mice maintained in LD a presumable compensation of TrpA1 expression in the absence of TrpV1 and, interestingly, the brown adipose tissue does not express TrpA1 channel. Considering the findings of this study on the participation of TRP channels in responses to light and temperature, we believe we have strengthened our initial hypothesis, especially after we have demonstrated the role of TRPV1 channel, and that peripheral tissues may be synchronized by temperature changes.
10

Studium klinicky aplikovatelné nádorové imunoterapie a jejich mechanismů / Study of clinically applicable cancer immunotherapy and their mechanisms

GLASEROVÁ, Simona January 2015 (has links)
The aim of this thesis was study of replacement of LPS in innate immunity based cancer immunotherapy. Application of poly (I:C) with mixture of mannan-SMCC + R-848.HCl leads to synergy, higher reduction of tumor growth and significant prolongation of survival. The significance and mechanism of action of neutrophils have also been studied within this therapy.

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