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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

Factors related to the selection of apparel worn by horse show exhibitors

Pearcy, Sandra Jessee January 1977 (has links)
The purpose of this exploratory study was to investigate the factors associated with the selection of riding attire worn by horse show exhibitors. The second purpose was to compare this data to similar data obtained from professional judges. Two instruments were developed to provide data to meet objectives and hypotheses. Data was collected from 127 horse show exhibitors from the mailing list of the Appalachian Horse Show Association, and also from 24 judges of the American Horse Show Association. Statistical analysis included condescriptive information, one way analysis of variance, frequency distribution, Chi-square, t-tests, and z-tests to investigate relationships between variables for significance. The most important appearance factor in selection of riding apparel on the part of both exhibitors and professionals was that apparel be appropriate for the class entered. Exhibitors felt that apparel plays more than average importance in a judge's evaluation. Professionals placed average importance on apparel in their evaluation. Professionals were most frequently consulted by exhibitors about colors and styles to select. Professionals indicated they most frequently gave advice on rules governing dress, then on styles and colors to select. The most difficult problem for exhibitors in locating desired apparel items was the distance to an appropriate store. There was a significant difference between horse's breed and the desire for the color of the habit to be compatible with the exhibitors' horse. There was no significant difference for the following variables: amount of competition by breed, appearance factors with source of income or education, amount of competition with source of income or education. Professionals' and exhibitors' opinions governing riding apparel did show some significant relationships.: / Master of Science
2

Studies of deer-related dog activity in Virginia

Perry, Matthew Calbraith January 1970 (has links)
Three study areas and five techniques were used in this study of movements and activities of dogs and influence of dogs on deer. Radiotracking with telemetry equipment was ineffective due to infrequent and unpredictable movement of dogs. The percentage of licensed dogs estimated from surveys of rural inhabitants was suggested to be inversely related to the number of residents under a dog warden's responsibility. Activity indices determined from sand plot track counts for dogs were insignificantly different for three study areas and for the three seasons. Dogs appeared to be most active in the morning between 7:00 AM and 10:00 AM. Activity and movement data from this study were compared with questionnaire responses from game wardens and biologist and other data. Six dogs were trapped at Big Levels during the fall. Two were instrumented but tracking was ineffective. Approximately 70 percent of the dogs trapped and seen during this study were hounds. Data concerning the age and condition of deer killed by dogs in Virginia were scarce. Freerunning dogs may present less of a problem in eastern Virginia than in western Virginia due to physiography of the region. Dogs are probably a serious mortality factor in deer stocking programs or in areas of low deer numbers. Enforcing dog laws seems to be the most effective way to control free-running logs. Trapping, poisoning, and shooting are desirable techniques only when enforcement methods fail. Deer mortality of dogs is probably neither large nor significant in influencing deer population dynamics statewide. / Master of Science
3

Analyse d'un peptide P42 protecteur de la maladie de Huntington / Analyze of the protective effect of a peptide : P42, in Huntington disease

Couly, Simon 18 October 2018 (has links)
La maladie de Huntington (MH) est une maladie neurodégénérative progressive héréditaire. Aucun traitement curatif n’a encore été trouvé. La MH est provoquée par une mutation dans le gène HTT induisant l’augmentation anormale du domaine PolyQ (>36) contenue dans la Huntingtine (Htt), la protéine codée par le gène HTT. Les conséquences et les mécanismes de cette mutation sont maintenant bien décrits et ont permis d’identifier une interaction importante entre la Htt et la voie de signalisation du BDNF. Le BDNF est un facteur neurotrophique qui joue des rôles importants, à travers l’activation de son récepteur TrkB, dans le développement et le maintien des neurones et également dans la plasticité des réseaux synaptiques. La Htt mutante (mHtt) diminue l’expression et le transport du BDNF et de TrkB dans les neurones.P42, une partie de 23 acides aminés de la Htt, est capable de sauver de nombreux phénotypes pathologiques induits dans la MH.L’objectif de ma thèse était de mieux comprendre les mécanismes d’action de P42, dans le but d’optimiser son potentiel thérapeutique. Pour cela, j’ai développé plusieurs expériences sur plusieurs modèles. Dans un article, publié dans HMG, je montre les effets d’un traitement avec P42 sur la voie de signalisation BDNF/TrkB dans un modèle de MH : les souris R6/2. Pour cela, j’ai analysé plusieurs phénotypes pathologiques, comportements et mécanismes cellulaires développés par les souris R6/2 et connus pour être dépendants de la voie BDNF/TrkB. J’ai également mesuré les taux d’ARNm et de protéine, du BDNF et de TrkB, dans le cortex et le striatum. Ce que j’ai trouvé est que P42 agit sur la voie BNDF/TrkB principalement en augmentant l’expression de TrkB dans le striatum.Afin d’observer l’effet de P42 sur le transport vésiculaire, j’ai également utilisé la drosophile comme modèle. Grâce à ce modèle, j’ai pu observer in vivo le transport vésiculaire dans différentes conditions avec ou sans mHtt ou P42.Egalement, dans le but de mieux suivre l’évolution des différents phénotypes pathologiques induits par la MH et l’effet du traitement par P42, j’ai expérimenté le Hamlet test®, un test innovant multi-comportemental.Enfin, j’ai observé sur les souris R6/2, l’effet d’une bithérapie P42 avec P3, un peptide ciblant les effets toxiques induits par les ARN codants pour un PolyQ.Tous ces résultats permettent ou vont permettre de mieux comprendre les mécanismes d’action de P42. / Huntington’s disease (HD) is a rare genetic neurodegenerative disorder. Curative treatments are still actively sought. HD is induced by a mutation in the HTT gene inducing an abnormal expansion of the polyQ domain contained in the Huntingtin protein (Htt). Mechanisms and consequences of this mutation are now well described and allowed to identify an interaction of the Htt with the brain derived neurotrophic factor (BDNF) signaling pathway. BDNF is a neurotrophic factor, which plays important roles, through TrkB, one of its receptor, in neuronal development and plasticity. Mutant Htt (mHtt) down-regulates BDNF and TrkB transcription and transport along the axons.P42, a part of the Htt protein, is a 23aa peptide able to rescue HD pathological phenotypes, such as aggregation, axonal transport and neuronal viability.The aim of my PhD was to better understand the mechanisms of action of P42, in a purpose to optimize its therapeutic potential. To this end I developed different studies using different models.In a paper now accepted for publication in HMG, I first used a P42-based treatment on R6/2 HD mice, to analyze the effect of P42 on the BDNF/TrkB signaling pathway. To this end I analyzed pathologic phenotypes: behaviors or cell mechanisms developing in R6/2 mice and are related to the BDNF/TrkB pathway. I also measured BDNF and TrkB, mRNA or protein levels in both striatum and cortex. What I found is that P42 is acting on BDNF/TrkB pathway mainly by increasing the protein level of TrkB in the striatum.To observe the effect of P42 on vesicular transport, I rather used a Drosophila model, to perform live imaging based studies, in different transgenic conditions: with or without mHTT or P42.Also, in a way to better follow the progression of different pathological phenotypes and the effect of treatments on R6/2 mice, I benefited from a very recent and innovative tool, the HAMLET, which allows a multi-behavioral test.Finally, a bitherapy was used on R6/2 mice combining P42 and P3, a peptide raised against PolyQ mRNA that are also toxic.All those results contribute or will contribute to a better understanding of P42 mechanisms of action.
4

Acute and chronic ethanol effects on liver p42/44 mitogen activated protein kinase /

Weng, Yu-I, January 2001 (has links)
Thesis (Ph. D.)--University of Missouri--Columbia, 2001. / "December 2001." Typescript. Vita. Includes bibliographical references (leaves 181-193). Also available on the Internet.
5

Small oscillations of a beam-column with finite electrical conductivity in a constant transverse magnetic field

Peddieson, John January 1966 (has links)
Small oscillations of a beam-column with finite electrical conductivity in a transverse magnetic field are examined under the assumption that the vibration of the bar causes only a weak perturbation in the electromagnetic-field. The frequency equation is derived for a column and reduced to that for free vibration of a beam by equating the end load to zero. The roots of this equation are obtained approximately and the effect of the magnetic field on the frequencies is noted. In addition, the elastic stability of a conducting column and beam-column are investigated. The effect of the magnetic field on the buckling load is determined. Numerical results are presented which indicate that the effect of the dynamic electromagnetic forces is negligible except at extremely high frequencies of vibration. / M.S.
6

Acute and chronic ethanol effects on liver p42/44 mitogen activated protein kinase

Weng, Yu-I, January 2001 (has links)
Thesis (Ph. D.)--University of Missouri--Columbia, 2001. / Typescript. Vita. Includes bibliographical references (leaves 181-193). Also available on the Internet.
7

Rôle et mécanismes d'action du récepteur AT[indice inférieur 2] de l'angiotensine II dans la différentiation neurale

Gendron, Louis January 2003 (has links)
L'activation du récepteur AT[indice inférieur 2] de l'angiotensine II (Ang II) est associée à différentes réponses cellulaires dont l'inhibition de prolifération, le contrôle de l'apoptose et l'induction de la différenciation. Au cours du développement, le récepteur AT[indice inférieur 2] est fortement présent dans les tissus foetaux mais son expression chute drastiquement, quelques heures après la naissance. Chez l'adulte, seulement quelques tissus expriment ce récepteur (cellules glomérulées de la surrénale, utérus, cellules granulosa de l'ovaire et certaines zones du cerveau) mais sa ré-expression peut être observée au cours de certaines conditions pathologiques (défaillance cardiaque ou rénale, dommages tissulaires, lésions du système nerveux central). Ces observations suggèrent que le récepteur AT[indice inférieur 2] joue un rôle important au cours du développement, dans les processus de réponses aux blessures et dans les mécanismes d'adaptation. Dans les cellules NG108-15, l'activation du récepteur AT[indice inférieur 2] par l'Ang II induit la différenciation neuronale (Laflamme et al . 1996). Puisque les cibles intracellulaires du récepteur AT[indice inférieur 2] sont peu connues, le but de nos études était de déterminer les mécanismes d'action associés à son activation dans l'induction de l'élongation des neurites. Le récepteur AT[indice inférieur 2] n'est couplé à aucun des seconds messagers classiques (AMPc, production d'InsPs, Ca[indice supérieur 2+] ). Les effets connus du récepteur AT[indice inférieur 2] sont une augmentation ou une diminution des niveaux de monoxyde d'azote (NO) et de GMPc et, selon les modèles cellulaires et les conditions de culture utilisés, il peut activer ou inhiber les phosphatases et les p42/p44[indice supérieur mapk] en plus de modifier l'excitabilité membranaire (inhibition des courants calciques et activation des canaux potassiques). Dans les cellules NG108-15, nous avons trouvé que l'activation du récepteur AT[indice inférieur 2] par l'Ang II induit l'activation des p42/p44[indice supérieur mapk] par un mécanisme indépendant de la petite protéine G p21[indice supérieur ras] , un processus essentiel à l'induction de l'élongation des neurites (Gendron et al . 1999). Les travaux présentés dans le cadre de cette thèse montrent que la production de NO, suite à l'activation du récepteur AT[indice inférieur 2] par l'Ang II, est impliquée dans l'induction de la différenciation neuronale. Nous avons en effet observé que l'Ang II, par un mécanisme dépendant des protéines G[alpha indice inférieur i] , mène à une augmentation rapide des niveaux intracellulaires de GMPc, un second messager impliqué dans l'élongation et dans le branchement neuritique des cellules NG108-15. Bien que cette voie est essentielle à la différenciation neuronale, nous avons trouvé qu'elle n'est pas impliquée dans l'activation des p42/p44[indice supérieur mapk] .L'activation des p42/p44[indice supérieur mapk] par l'Ang II, qui est Ras- et NO-indépendante, est plutôt induite par une voie alternative impliquant les protéines Rap1 et B-Raf.L'application d'Ang II dans les cellules NG108-15 mène en effet à l'activation rapide de Rap1 (1-5 min) et de B-Raf (5-15 min), événement essentiel à la fois pour l'activation des p42/p44[indice supérieur mapk] et pour l'induction de la différenciation des cellules NG108-15. Finalement, nous avons montré que l'activation de cette voie se fait par un mécanisme indépendant de l'AMPc et de la PKA. Ensemble, nos résultats montrent que le récepteur AT[indice inférieur 2] active les voies nNOS/NO/GCs/GMPc et Rap1/B-Raf/MEK/MAPK, et que ces cascades participent de façon parallèle, à l'induction de la différenciation neuronale des cellules NG108-15, par un mécanisme indépendant de l'AMPc et de la PKA.
8

Mechanism and regulation of ERK2 subcellular localization

Whitehurst, Angelique Wright. January 2004 (has links) (PDF)
Thesis (Ph. D.) -- University of Texas Southwestern Medical Center at Dallas, 2004. / Vita. Bibliography: 118-130.
9

Modulação da sinalização celular e do complexo de início de tradução como estratégias para o tratamento do carcinoma de células renais / Cell signaling and translation initiation complex modulation as strategies to the treatment of renal cell carcinoma

Costa, Luciano José Megale 21 November 2005 (has links)
Introdução: O carcinoma de células renais (CCR) representa uma causa crescente de mortalidade por câncer. Apesar da sua curabilidade em estádios iniciais, agentes citotóxicos e imunomodulatórios têm homogeneamente alcançado nenhum ou pouco benefício no tratamento do CCR avançado. Um melhor entendimento da biologia tumoral pode levar ao desenvolvimento de terapias mais eficientes e dirigidas aos mecanismos moleculares de manutenção do tumor. Sinalização aumentada através do receptor do fator de crescimento epitelial (EGFR), sistema de quinases proteicas ativadas por mitógenos (MAPK) e via da fosfatidilinositol 3-quinase (PI3K) assim como estimulação do complexo de início de tradução (CIT) foram caracterizados em linhagens celulares e amostras tumorais de CCR. Nós investigamos o efeito de um inibidor de EGFR (gefitinibe), de um inibidor de MAPK (UO126) e de um inibidor do CIT (rapamicina) nos intermediários de sinalização celular e nos elementos do CIT assim como no crescimento in vitro de linhagens celulares de CCR. Métodos: Linhagens celulares de CCR (PRC3, WT8, SKRC-02, SKRC-17, SKRC-39, SKRC-45, ACHN e KRCY) foram mantidas em condições ideais para a cultura de células de mamíferos e expostas a drogas e/ou inibidores nas concentrações e por períodos de tempo variáveis. A fosforilação de intermediários da sinalização celular foi determinada utilizando-se western blots. Nível de mRNA para genes de interesse foram determinados por qRT-PCR. Crescimento celular foi avaliado por método colorimétrico em diferentes concentrações de gefitinibe, UO126 e rapamicina, isoladamente ou em combinação. Resultados: UO126 levou a defosforilação não apenas de intermediários de MAPK como também de substratos do alvo da rapamicina em mamíferos (mTOR) revelando sinalização cruzada entre essas vias. Nós identificamos ainda que ERK5 é a quinase potencialmente responsável por esta sinalização cruzada. No entanto, tratamento com UO126 não afetou o nível de mRNA para o substrato de mTOR 4EBP1. Gefitinibe foi capaz de bloquear a sinalização iniciada por EGF na via de PI3K em todas as linhagens wt-PTEN e de bloquear a sinalização através de ERK1/2 e ERK5 ao menos parcialmente em todas as linhagens celulares. Rapamicina mostrou-se um potente inibidor do crescimento na maioria das linhagens celulares de CCR e tal efeito foi freqüentemente amplificado com a combinação com UO126 ou gefitinibe.Conclusão: EGFR, MAPK e CIT são alvos promissores no tratamento do CCR / Background: Renal cell carcinoma (RCC) is an increasing cause of cancer mortality. Despite its curability in early stages, conventional cytotoxic and immunomodulatory agents have been homogeneous in providing minimal or no benefit in the treatment of advanced RCC. Better understanding of tumor cell biology may lead to development of more efficient targeted therapies. Signaling intensification through epithelial growth factor receptor (EGFR), mitogenactivated protein kinase (MAPK) pathway, Phosphatidylinositol 3-kinase (PI3K) pathway and overactivation of the translation initiation complex (TIC) has been previously characterized in RCC cell lines and tumor samples. We investigated the effect of an EGFR inhibitor (gefitinib) as well as a MAPK inhibitor (UO126) and a TIC inhibitor (rapamycin) in the intermediates of cell signaling, in the elements of TIC and in the in vitro growth of RCC cell lines. Methods: RCC cell lines (PRC3, WT8, SKRC-02, SKRC-17, SKRC-39, SKRC-45, ACHN and KRCY) were maintained on standard mammalian cells culture conditions and exposed to drugs and/or inhibitors in variable concentrations and for variable periods of time as required in each experiment. Phosphorylation status of signaling intermediates were determined using western blots. Levels of mRNA for genes of interest were determined by qRT-PCR. Cell growth was assessed by colorimetric method in control conditions or in different concentrations of gefitinib, UO126 or rapamycin, alone or in combination. Results: UO126 caused dephosphorylation not only of MAPK intermediates but also of mammalian target of rapamycin (mTOR) substrates revealing crosstalk between these pathways. We also identified ERK5 as a kinase potentially responsible for such cross talk. However, treatment with UO126 did not affect mRNA levels of the downstream target of mTOR 4EBP1. Gefitinib was able to block EGF signaling through PI3K in all wt- PTEN cell lines and the signaling through ERK1/2 and ERK5 at least partially in all cell lines. Rapamycin was found to be a potent growth inhibitor in most RCC cell lines and such effect was often increased by its combination with UO126 or gefitinib. Conclusion: EGFR, MAPK and CIT are promising targets for the treatment of RCC
10

Methodological development in peptide chemistry for synthesis of antimicrobial and antifungal derivatives of marine natural peptides / Développement méthodologique en synthèse peptidique pour l'obtention de composés antifongiques et antibactériens dérivés de peptides marins.

Das, Sanjit 16 November 2018 (has links)
La chimie de clic est devenue indispensable dans les nombreux domaines de chimie associée à la conception de médicament. Dans ce contexte, comme nous savons(connaissons) l'étude concernant l'impact d'insertion triazole sur la conformation de peptaibol est limitée, nous avons conduit l'étude pour examiner l'impact et l'adaptabilité de 1, 1 4-disubstituted, 2, l'insertion 3-triazole dans peptaibols différent. Selon le résultat de cette expérience touchant à l'activité réduite et la conformation perturbée de l'analogue peptaibol, le substitut dipeptide décoré du fragment triazole portant substituents hydrophobe divers a été inséré à très N-ter la partie du peptaibol. L'amélioration du bioactivity et de la restauration de la conformation pour les analogues peptaibol a été observée et le fait a été aussi soutenu par les résultats obtenus de l'étude biophysique des analogues choisis d'ALM F50/5. Nous avons plus loin prolongé notre étude pour employer notre stratégie à être appliqué sur le peptide P42 thérapeutique qui souffre de la limitation de manque de perméabilité et de stabilité. Le peptide P42 est impliqué dans le pathophysiology de la maladie d'Huntington neurodégénératif. Un total de 12 analogues de peptide de P42-camelote a été synthétisé par SPPS par notre protocole optimize. Dans la deuxième partie, nous avons développé une stratégie pour synthétiser lipopeptide cyclique produit de l'espèce cynaobacterial marine. Notre objectif principal était de synthétiser Hormothamnin A, undecapeptide cyclique consistant de plusieurs acides aminés artificiels incluant dehydroamino acide (Dhaa) qui fait la synthèse de ce peptide compliqué. En raison de cette raison, premièrement, nous avons voulu appliquer notre stratégie de synthétiser Trichormamide A, une sorte relativement plus simple de cylic lipopeptide. Après l'accomplissement de cette tâche, une première tentative a été faite pour synthétiser Hormothamnin A. Le résultat préliminaire de ceci est présenté dans cette section. Enfin, nous avons essayé de développer une méthodologie robuste pour synthétiser Fmoc-Dhaa dans la phase de solution et son insertion dans l'ordre peptaibol par une norme(un standard) SPPS le protocole. Les résultats préliminaires que nous avons concernant la synthèse Dhaa et son insertion dans peptaibol sont aussi discutés ici de plus avec la synthèse de phase solide de Bergofungin naturel D. / The click chemistry has become indispensible in the many areas of chemistry associated with drug design. In this context, as we know the study concerning the impact of triazole insertion on the conformation of peptaibol is limited, we have conducted the study to investigate the impact and adaptability of the 1, 4-disubstituted 1, 2, 3-triazole insertion into different peptaibols. Depending on the outcome of this experiment relating to reduced activity and perturbed conformation of the peptaibol analogue, the dipeptide surrogate decorated with the triazole moiety bearing various hydrophobic substituents was inserted at the very N-ter part of the peptaibol. The improvement of the bioactivity and restoration of the conformation for the peptaibol analogues was observed and the fact was also supported by the results obtained from the biophysical study of the selected analogues of ALM F50/5. We have further extended our study to employ our strategy to be applied on the therapeutic P42 peptide which suffers from the limitation of lack of permeability and stability. P42 peptide is involved in the pathophysiology of neurodegenerative Huntington’s disease. A total of 12 analogues of P42-TAT peptide were synthesized through SPPS by our optimized protocol. In the second part, we have developed a strategy for synthesizing the cyclic lipopeptide originated from marine cynaobacterial species. Our main objective was to synthesize Hormothamnin A, a cyclic undecapeptide consisting of several unnatural amino acids including dehydroamino acid (Dhaa) which makes the synthesis of this peptide complicated. Due to this reason, firstly, we have chosen to apply our strategy to synthesize Trichormamide A, a relatively simpler kind of cylic lipopeptide. After accomplishing this task, a first attempt was made to synthesize Hormothamnin A. The preliminary result of this is presented in this section. At last, we have tried to develop a robust methodology to synthesize Fmoc-Dhaa in solution phase and its insertion into the peptaibol sequence through a standard SPPS protocol. The preliminary results we have got concerning the Dhaa synthesis and its insertion into peptaibol are also discussed here in addition with the solid phase synthesis of natural Bergofungin D

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