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Efeito metabolico in vitro do derivado benzimidazolico (RCB15) em cisticercos de taenia crassiceps / In vitro metabolic effect of benzimidazole derivative (RCB15) in taenia crassiceps cysticerciPicanço, Guaraciara de Andrade 25 August 2016 (has links)
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Previous issue date: 2016-08-25 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / The high prevalence of intestinal and tissue parasites combined with the breakthrough of parasites resistat to albendazole, encouraged the search for new drugs. Studies on the biochemical response of Taenia crassiceps metacestode to drugs has been shown to be important for the detection of modes of action of drugs within the parasite metabolic pathways. In order to develop new anti-parasitic drugs, the benzimidazole derivative 6-Chloro-5- (2,3-dichlorophenoxy) -2- (trifluoromethyl) -1H-benzimidazole (RCB15) was synthesized. The objective of this study was to determine the in vitro effect of a benzimidazole derivative, RCB15, in the energetic and respiratory metabolism of T. crassiceps cysticerci. For this, 30 larval stage cysticerci were plated in culture plates containing supplemented RPMI and albendazole sulfoxide (ABZSO) (6,5 μM, 13 μM, 26 μM, 52 μM or 104 μM) or RCB15 (6,5 μM, 13 μM, 26 μM, 52 μM or 104 μM) diluted in dimethyl sulfoxide (DMSO). After 24 hours of cultivation, the cysticerci were separated from the culture medium and frozen in liquid nitrogen. Analysis on high-performance liquid chromatography to assess the energetic and respiratory metabolism were performed. There was a decrease in glucose concentrations detected in vesicular fluid in all groups treated with RCB15 and the groups treated with the highest dosages of ABZSO. The non detection of lactate in the culture medium of the groups treated with RCB15 indicates that this acid was used as a precursor of gluconeogenesis. The group treated with RCB15 52 uM performed the aerobic energetic pathways due to the non detection of lactate neither in the vesicular fluid nor in the culture medium. With respect to the tricarboxylic acid (TCA) cycle, low concentrations of α-ketoglutarate or non-detection of this organic acid, indicates that the parasite has preferably used the fumarate reductase pathway. Probably the detected α-ketoglutarate was from the protein catabolism. The alternative routes of energy production, were observed in the groups treated with RCB15 26 uM and 104 uM and ABZSO 13 uM. In those groups acetate was used to produce β-hydroxybutyrate which was completely excreted in other treatments and in the control group acetate was excreted due to excess of acetyl-CoA which was not used in the TCA cycle. It is possible to conclude that the TCB15 treatment influenced glycolysis, diminished the energetic sources as it induced the parasite to use other sources to produce energy such as gluconecogenesis and fatty acid oxidation. Cysticerci that were treated with RCB15 and ABZSO preferred the fumarate reductase pathway. The drugs used
in this study did not influence the proteins catabolism. The RCB15 treatment presented greater influence in the glucose uptake and consequently in glycolytic pathway when compared to the ABZSO treatment. / A alta prevalência de parasitoses intestinais e teciduais aliada ao surgimento de casos de resistência parasitária ao albendazol, incentivou a busca por novos fármacos. Os estudos da resposta bioquímica de Taenia crassiceps exposto a fármacos tem se mostrado importante para a detecção dos mecanismos de ação dos fármacos sobre as vias metabólicas do parasito. A fim de desenvolver-se novos fármacos anti-parasitários, sintetizou-se o derivado benzimidazólico 6-Cloro-5-(2,3-diclorofenoxi)-2-(trifluorometil)-1H-benzimidazol (RCB15). O objetivo deste trabalho foi determinar o efeito in vitro do derivado benzimidazólico, RCB15, no metabolismo energético e respiratório de cisticercos de T. crassiceps. Para tanto, 30 cisticercos em estádio larval foram semeados em placas de cultura contendo meio RPMI suplementado e acrescido de sulfóxido de albendazol (ABZSO) (6,5 μM, 13 μM, 26 μM, 52 μM ou 104 μM) ou RCB15 (6,5 μM, 13 μM, 26 μM, 52 μM ou 104 μM) diluídos em Dimetilsulfóxido (DMSO). Após 24 horas de cultivo, os cisticercos foram separados do meio de cultura e ambos congelados em nitrogênio líquido. Foram realizadas análises em Cromatografia Líquida de Alta Eficiência para avaliação do metabolismo energético e respiratório dos cisticercos, e por espectrofotometria para dosar glicose, ureia, creatinina e proteínas totais. Observou-se uma diminuição nas concentrações de glicose detectada no fluído vesicular em todos os grupos tratados com RCB15 e nos grupos tratados com as dosagens mais altas de ABZSO. A não detecção de lactato no meio de cultura dos grupos tratados com RCB15 indica que este ácido foi utilizado como precursor da glicose na via da gliconeogênese, o grupo tratado com RCB15 52 μM fez aerobiose, isto é comprovado pelo fato de não haver lactato nem no fluido vesicular nem no meio de cultura. Com relação ao ciclo do ácido cítrico, as baixas concentrações de α-cetoglutarato ou a não detecção deste ácido, indicam que o parasito deu preferência pela via da fumarato-redutase, assim o α-cetoglutarato detectado foi oriundo do catabolismo de proteínas. Quanto as vias alternativas de produção de energia, observou-se que nos grupos tratados com RCB15 26 μM e 104 μM e com ABZSO 13 μM o acetato foi utilizado para produzir β-hidroxibutirato que foi totalmente excretado, nos demais tratamentos e no grupo controle o acetato foi excretado devido ao excesso de acetil-CoA que não foi utilizado no ciclo do ácido cítrico. Conclui-se que o tratamento com RCB15 influenciou a glicólise, diminuiu as fontes energéticas induzindo o parasito a utilizar outras vias para a produção de energia, tais como, a gliconeogênese e a oxidação de ácidos graxos. Os cisticercos que receberam o tratamento com RCB15 e ABZSO preferiram utilizar a via da fumarato redutase. Os compostos utilizados neste estudo não influenciaram no catabolismo de proteínas. O tratamento com RCB15 teve maior impacto na captação de glicose e consequente maior influência na via glicolítica em comparação ao ABZSO.
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Avaliação da toxicidade aguda e subaguda de um novo protótipo candidato a fármaco cardiovascular / Assessment of acute and subacute toxicity of a new cardiovascular drug candidate prototypeMoura, Soraia Santana de 28 November 2012 (has links)
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Previous issue date: 2012-11-28 / Fundação de Apoio à Pesquisa - FUNAPE / Conselho Nacional de Pesquisa e Desenvolvimento Científico e Tecnológico - CNPq / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / Financiadora de Estudos e Projetos- Finep / Cardiovascular diseases are among the diseases of higher mortality rates in Brazil and worldwide . In contrast, it is reducing deaths of cardiovascular diseases due, in large part, to the production of drugs that can control their risk factors, but the wide reporting of side effects and contraindications persist and interfere negatively in the context of mortality these diseases. In this point, it is necessary to develop new drugs more effective and safer. The process of development of new drug requires numerous preclinical studies that generate information regarding safety profile in vivo determinants for making the decision to start clinical trials. Although it is a conventional practice, the use of animals in scientific research should happen consciously, always considering the ethical issues of animal experimentation. In this study, we investigated the basal cytotoxicity against 3T3 cells of seven pyrazole compounds (LQFM011, LQFM012, LQFM020, LQFM021, LQFM022, and LQFM023 LQFM024) and classified then in GHS system. Whereas the compound LQFM021 proved to be the most effective in the tests performed in parallel pharmacodynamic study, we investigated whether acute oral toxicity, subacute and mutagenicity of this compound. The results showed that the compounds have low cytotoxicity profile in basal cell line (3T3). The estimated LD50 values for compounds LQFM011, LQFM012, LQFM020, LQFM021, LQFM022, and LQFM023 LQFM024 were 548, 551, 568, 533, 457, 482, 565 mg / kg, respectively. The compounds LQFM020, LQFM023 LQFM024 were classified in category 5 GHS system and LQFM021 was classified in category 4. The subacute toxicological research for 28 days LQFM021 the compound showed that this compound did not affect the metabolic, hematological and biochemical animal parameters in any of the doses of exposure However, the histopathology indicated hepatotoxic and nephrotoxic potential of this compound and interference in the process of hematopoiesis, but did not indicate mutagenic potential. . Given the above, we conside / As doenças cardiovasculares estão entre as doenças de maior letalidade no Brasil e no mundo. Em contrapartida, vê-se um quadro redução das mortes atribuídas às enfermidades cardiovasculares devido, em grande parte, à produção de medicamentos capazes de controlar seus fatores de risco, porém, o vasto relato de efeitos colaterais e contraindicações persistem e interferem negativamente no quadro de morbimortalidade dessas doenças. Neste sentindo, é imprescindível buscar novos fármacos mais efetivos e seguros. O processo de desenvolvimento de um novo fármaco exige numerosos estudos pré-clínicos que geram informações quanto ao seu perfil de segurança in vivo, determinantes para a tomada de decisão de se iniciar os estudos clínicos. Embora seja uma prática convencional, o uso de animais em pesquisas científicas deve ocorrer de forma consciente, considerando sempre as questões éticas de experimentação animal. Neste trabalho, investigou-se a citotoxicidade basal frente as células 3T3 de sete compostos pirazolínicos (LQFM011, LQFM012, LQFM020, LQFM021, LQFM022, LQFM023 e LQFM024) e suas classificações no sistema GHS. Considerando que o composto LQFM021 demonstrou ser o mais eficaz nos ensaios realizados em paralelo de farmacodinâmica, investigou-se toxicidade oral aguda, subaguda e mutagenicidade do composto. Os resultados mostraram que os compostos possuem perfil de baixa citotoxicidade em linhagem basal (3T3). Os valores de DL50 estimados para os compostos LQFM011, LQFM012, LQFM020, LQFM021, LQFM022, LQFM023 e LQFM024 foram 548, 551, 568, 533, 457, 482, 565 mg/kg, respectivamente. Os compostos LQFM020, LQFM023 e LQFM024 foram classificadas na categoria 5 do sistema GHS e o composto LQFM021 foi classificado na categoria 4. A investigação toxicológica subaguda por 28 dias do composto LQFM021 mostrou que este composto não interferiu nos parâmetros metabólico, hematológico e bioquímico dos animais em nenhuma das doses de exposição. No entanto, o estudo histopatológico indicou potencial nefrotóxico e hepatotóxico deste composto e interferência sobre o processo de hematopoiese, entretanto, não apresentou potencial mutagênico. Diante do exposto, consideramos que o composto LQFM021 apresenta um baixo perfil de toxicidade e os estudos de continuidade devem ser encorajados.
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Estudo diacrônico da função e dos valores semânticos dos sufixos -ança/ -ença, -ância/ -ência no português / Diachronic study of the functions and the semantic values of suffixes -ança/-ença, -ância/-ência in the PortugueseAndréa Lacotiz 20 September 2007 (has links)
O percurso histórico de derivações sufixais é muito pouco estudado, pois é lugar-comum concentrarem a análise de formação de palavras sob a ótica sincrônica. O presente trabalho constitui-se de um estudo calcado em diacronia sobre as ocorrências dos sufixos -ança/-ença, -ância/-ência, em suas funções transcategorial e semântica. Em manuais de gramática normativa, afirma-se, comumente, que esses sufixos se prestam apenas a transpor a classe gramatical de uma palavra, de verbo a substantivo abstrato, e acrescentam à base um significado superficial. Os modelos gerativos de estudo morfológico, por sua vez, embora reconheçam a polissemia dos sufixos, instituem regras de derivação sufixal que não abrangem a total possibilidade formativa, encontrada no processo histórico dos sufixos abordados. O objetivo de nossa pesquisa tratava-se de precisar dados etimológicos encontrados no Dicionário Houaiss, para com isso investigar os valores semânticos variáveis no percurso diacrônico dos sufixos, avaliar a tendência formativa transcategorial, desde o latim clássico, e verificar a relação que os substantivos derivados estabelecem com seus verbos e adjetivos cognatos. Com base em um corpus de 250 palavras usuais formadas por esses sufixos, investigamos a etimologia dos vocábulos, utlizando-se de dicionários de latim, clássico e medieval, inglês, francês, espanhol e italiano, confrontando os dados encontrados com aqueles fornecidos pelo Dicionário Houaiss. Descrevemos os valores semânticos dos sufixos em forma de paráfrases, discernindo os prototípicos daqueles advindos de empréstimos ou por extensão de sentido. Averiguamos a cognação desses substantivos derivados entre adjetivos em -nte e verbos, no português atual. Dessa forma, pudemos concluir que esses sufixos se revestem de variáveis valores semânticos, prototípicos e adquiridos em seu percurso diacrônico; prestam-se à criação de substantivos majoritariamente abstratos, pois há ocorrências de substantivos concretos, e possuem a tendência de formar derivados a partir de bases adjetivais e verbais, ainda que, ao longo da história, desde o latim, tenham existido formações com outras categorias. / The historical trajectory of suffixal derivations is too little studied, since it is a commonplace to concentrate the analysis of words formation under a synchronical point of view. The present work deals with a study set in the diachronical perspective of the suffixal occurrences of Portuguese suffixes -ança/-ença, -ância/-ência, in their transcategorical and semantical functions. In normative grammar manuals, it is used to affirm that these suffixes are useful in order to cross over the grammatical class of a word, from a verb to an abstract noun, and to add it on the basis of a superficial meaning. The generative models of Morphology, in their turn, recognize even though the polysemy of the suffixes and establish suffixal derivation rules that do not embrace all formative possibilities, found in the historical process of the broached suffixes. The purpose of this research was specify etymological data found in the Dicionário Houaiss, to, hereby, investigate the changeable semantic values in their suffixal diachronic trajectory, evaluate their transcategorical formative tendency, since the Classic Latin, and verify the relation that the derivative nouns establish with their verbs and cognate adjectives. Based on a corpus of 250 usual words formed by these suffixes, we investigate the etymology of the terms, consulting dictionaries of Classic and Medieval Latin, English, French, Spanish and Italian, confronting the found data with those supplied by the Dicionário Houaiss. We describe the semantical values of the suffixes in the form of paraphrases, discriminating the prototypical one from those ocurred by loans or by meaning extensions. We inquire the cognation of these derivative nouns among adjectives in -nte and verbs, in the current Portuguese. This way, we could conclude that these suffixes resemble themselves with changeable semantical values, prototypical and acquired in their diachronical trajectory; they are useful to the creation of nouns mainly the abstract ones, because there are occurrences of concrete nouns, and have the tendency to form derivatives from adjectival and verbal bases, although, alongside the history, since the Latin, formations with other categories have also existed.
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Hedge accounting no Brasil / Hedge accounting in BrazilFernando Chiqueto da Silva 24 April 2014 (has links)
Esta tese é motivada pelas recentes alterações das normas contábeis brasileiras, as quais passaram a requerer o reconhecimento, no resultado, da volatilidade causada pela mensuração ao valor justo de instrumentos derivativos. A prática contábil hedge accounting (HA) possibilita eliminar tal volatilidade. Investidores cobram prêmio de risco por resultados mais difíceis de serem previstos (Allayannis & Simko, 2010; Rountree, Weston, & Allayannis, 2008; Graham, Harvey, & Rajgopal, 2005; Thomas & Zhang, 2002; Allayannis & Weston, 2001; Michelson, Jordan, & Wootton, 1995), o que leva à hipótese H1: O custo de capital próprio (CCP) das companhias brasileiras é negativamente associado com instrumentos financeiros designados para fins de HA. O impacto da adoção do HA na volatilidade foi analisado com base em testes de comparação de médias. A associação entre CCP e HA foi analisada com base na abordagem de dados em painel. A amostra foi definida pelas empresas que compõem o índice Ibovespa e o período pelo intervalo de 31/12/2008 a 31/12/2012 (17 trimestres). Os resultados revelam fortes evidências de que a adoção do HA resultou em diminuição da volatilidade. Verificou-se redução da média da volatilidade de todas as proxies de retorno analisadas: ROE trimestral, ROE anual, ROA trimestral e ROA anual (respectivamente, redução de 63,8%, 40,4%, 20,9% e 11,9%). Também, os achados revelam forte associação negativa entre o CCP e instrumentos financeiros designados para fins de HA. Análises adicionais corroboram a robustez dos achados. Programas de remuneração baseada em opções de ações (PRBOA) aumentariam os incentivos para a administração tomar risco, pois maior risco aumentaria o valor das opções (Smith & Stulz, 1985; Tufano, 1996; Supanvanij & Strauss, 2006). Tal conjectura conduz à hipótese H2: A probabilidade de adoção (PA) de HA é negativamente associada com PRBOA. A PA de HA foi estimada com base em modelo de regressão logística, compreendendo as 100 maiores companhias brasileiras abertas por patrimônio líquido. Verificou-se que a PA do HA é positivamente associada com PRBOA, o que contraria a hipótese de pesquisa, suportada pela teoria das finanças (Supanvanij & Strauss, 2006). Reportar resultados voláteis reduz o valor de mercado das ações devido à aversão a incertezas por parte de investidores e analistas (Allayannis & Weston, 2001; Thomas & Zhang, 2002; Graham et al., 2005; Hodder, 2006 et al.; Rountree et al., 2008; Allayannis & Simko, 2010). Portanto, ao adotar HA, a administração maximizaria sua remuneração, pois o preço da ação subjacente aumentaria com a diminuição da volatilidade dos resultados contábeis, o que justificaria tais achados. Os resultados também revelam que a PA do HA é positivamente associada com captações no exterior, retorno sobre ativos, faturamento em moeda estrangeira, tamanho, investimentos no exterior, nível de endividamento e quando a companhia é emissora de American Depository Receipts (ADR) ou instituição financeira. Meta de resultado projetada por analistas é um importante indicador de performance da administração (Graham et al., 2005; Choi, Walker, & Young, 2006). HA é uma prática contábil voluntária. Logo, a discricionariedade em relação à decisão sobre adotar ou revogar o HA leva à hipótese de pesquisa H3: Os efeitos contábeis decorrentes da designação e revogação do HA contribuem para maior aderência entre metas de resultado e o resultado contábil do trimestre em que ocorreu a designação inicial ou revogação da relação de HA. As técnicas estatísticas utilizadas foram análise descritiva e testes de comparação de médias. A amostra é definida pelas empresas que compõem o índice Ibovespa (período de 31/12/2008 a 31/12/2012). Para coleta manual dos dados foram revisadas 1.017 demonstrações financeiras. Não foram encontradas evidências de que a adoção inicial ou revogação do HA tenha contribuído para atingir oportunisticamente a meta de resultado projetada por analistas ou o resultado do mesmo período do ano anterior. Também não foram encontrados indícios de que empresas tenham mudado oportunisticamente o resultado contábil de prejuízo para lucro em virtude da adoção ou revogação do HA. / This thesis is inspired by recent changes in the Brazilian accounting standards, which now require the volatility caused by the fair value measurement of derivatives to be recorded in profit or loss. Hedge accounting (HA) can be used to eliminate such volatility. Investors charge a risk premium for earnings that are more difficult to forecast (Allayannis & Simko, 2010; Rountree, Weston, & Allayannis, 2008; Hodder, 2006; Graham, Harvey, & Rajgopal, 2005; Thomas & Zhang, 2002; Allayannis & Weston, 2001; Michelson, Jordan, & Wootton, 1995), which leads to hypothesis H1: Cost of equity (CE) of Brazilian companies is negatively associated with financial instruments designated for HA purposes. The impact of HA adoption on earnings volatility was investigated on the basis of means comparison tests. The association between CE and HA was analysed on the basis of panel data approach. The sample is defined by the entities which compose the Ibovespa index and the period analysed by the interval from 31/12/2008 to 31/12/2012 (17 quarters). The findings reveal strong evidences that the HA adoption resulted in reduction of earnings volatility. A reduction was observed in the average earnings volatility for all proxies of return analysed: quarterly ROE, annual ROE, quarterly ROA and annual ROA (decreases of 63.8%, 40.4%, 20.9% and 11.9%, respectively). The findings also reveal a strong negative association between CE and financial instruments designated for HA purposes. Additional analysis corroborate the robustness of such findings. Programs of option-based compensation (POBC) would increase management\'s appetite for risk, given that more risk would increase options\' market price (Smith & Stulz, 1985; Tufano, 1996; Supanvanij & Strauss, 2006). Such conjecture leads to hypothesis H2: The probability of adoption (PA) of HA is negatively associated with POBC. The PA of HA was estimated based on logistic regression model, comprising the 100 biggest Brazilian companies in terms of equity. It was found that PA of HA is positively associated with POBC, contradicting the research hypothesis supported by the finance theory (Supanvanij & Strauss, 2006). Reporting volatile earnings reduces the options\' market value due to the aversion of investors and analysts to uncertainties (Allayannis & Weston, 2001; Thomas & Zhang, 2002; Graham et al., 2005; Hodder et al, 2006; Rountree et al., 2008; Allayannis & Simko, 2010). Therefore, when adopting HA management would maximize its compensation, because the market value of the underlying stock would increase as a result of the decrease in earnings volatility, thereby justifying such findings. The results also reveal that PA of HA is positively associated with outstanding foreign debt, return on assets, revenue denominated in foreign currency, size, investments in foreign currency, indebtedness ratio and when the entity is American Depository Receipts (ADR) issuer or financial institution. Analysts\' earnings forecasts are one of management\'s most important performance indicators (Graham et al., 2005; Choi, Walker, & Young, 2006). Therefore, management\'s discretion on the decision of adopting or discontinuing HA leads to the research hypothesis H3: The accounting effects caused by the initial designation and de-designation of HA increase the consistency between analysts\' earnings forecasts and quarterly profit or loss in which the designation or de-designation of HA occurred. The analysis is based on descriptive statistics and means comparison tests. The sample is defined by the entities which composed the Ibovespa index (in the period from 31/12/2008 to 31/12/2012). Data was manually collected from 1.017 financial statements. The findings reveal no evidence that the initial designation and de-designation of HA have contributed to opportunistically meeting or beating analysts\' earnings forecasts or the profit or loss of the same period in the previous year. The findings also show no evidence that entities had opportunistically changed loss to profit due to designation or de-designation of HA.
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Using derivatives to manage price risk in a deregulated electricity industryVenter, Francois Jacobus. 16 August 2012 (has links)
M.Comm. / This study is to investigate the derivatives instruments used in other international deregulated electricity markets and how some of these may be used to manage risks incurred in a local Electricity Supply Industry after deregulation. To determine which of the derivatives may be used in the South African market as the most effective hedging instrument. To determine which is most effective will be determined by the contribution to the income of the market participant.
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An analysis of the Libor and Swap market models for pricing interest-rate derivativesMutengwa, Tafadzwa Isaac January 2012 (has links)
This thesis focuses on the non-arbitrage (fair) pricing of interest rate derivatives, in particular caplets and swaptions using the LIBOR market model (LMM) developed by Brace, Gatarek, and Musiela (1997) and Swap market model (SMM) developed Jamshidan (1997), respectively. Today, in most financial markets, interest rate derivatives are priced using the renowned Black-Scholes formula developed by Black and Scholes (1973). We present new pricing models for caplets and swaptions, which can be implemented in the financial market other than the Black-Scholes model. We theoretically construct these "new market models" and then test their practical aspects. We show that the dynamics of the LMM imply a pricing formula for caplets that has the same structure as the Black-Scholes pricing formula for a caplet that is used by market practitioners. For the SMM we also theoretically construct an arbitrage-free interest rate model that implies a pricing formula for swaptions that has the same structure as the Black-Scholes pricing formula for swaptions. We empirically compare the pricing performance of the LMM against the Black-Scholes for pricing caplets using Monte Carlo methods.
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Úlohy rozvrhování s pevnými časy prací - stochastická rozšíření, formulace a algoritmy / Fixed interval scheduling problems - stochastic extensions, formulations and algortihmsLeder, Ondřej January 2017 (has links)
Fixed interval scheduling problems have wide range of practical use in production planning, transportation, in hospitals or in schools when planning timetables. When solving these problems we often encounter requirement of integrality of solutions. Ignoring this condition is often not possible. In this thesis we propose some formulations of scheduling problems and their stochastic extensions. We also propone a new formulation of stochastic FIS problem, for which integrality of solution is byproduct of its definition. We present Gâteaux derivative and its relationship to stability of optimal value function of stochastic optimization problems under the influence of contamination. We propose a new theorem on the stability of such functions for fixed interval scheduling problems.
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Synthese und Charakterisierung neuartiger Cellulosederivate und deren Einsatz als VerkapselungsmaterialienRohowsky, Juta 24 July 2017 (has links) (PDF)
Neuartige Cellulosederivate werden ausgehend von kommerziellen Celluloseethern synthetisiert. Aufgrund der guten Löslichkeit der Celluloseether in polaren Lösungsmitteln erfolgt eine homogene Reaktionsführung, wodurch eine regelmäßige Verteilung der Sulfatgruppen entlang der Polymerkette gewährleistet wird. Durch Variation der Reaktionsparameter wie Sulfatierungsmittel, Lösungsmittel, Reaktionszeit und -temperatur erfolgte die Synthese zahlreicher Celluloseethersulfate mit unterschiedlichen Eigenschaften bezüglich Sulfatierungsgrad und kinematischer Viskosität.
Durch Bestimmung des Schwefelgehaltes und entsprechender Berechnungen konnten die Anzahl der Sulfatgruppen im Molekül (DSSul) ermittelt werden, wobei die Werte für die synthetisierten Proben im Bereich zwischen DSSul = 0.1 bis DSSul = 2.7 lagen. Der Abbau der Polymerkette wurde ebenfalls durch die Reaktionsbedingungen gesteuert, sodass sowohl Produkte mit hohen (1698 mm2/s) als auch sehr niedrigen (2 mm2/s) kinemtischen Viskositäten resultierten. Wasserlöslichkeit der Produkte wurde durch Trübungsmessungen von 1%igen wässrige Lösungen und der daraus erhaltenen geringen Trübungswerte (NTU < 10) ermittelt.
Die Funktionalisierung der Celluloseether mit Sulfatgruppen konnte mittels spektroskopischer Methoden nachgewiesen werden. In 13C-NMR-Spektren von Hydroxypropylcellulosesulfaten wurden zusammen-hängende strukturelle Veränderungen mit dem Anstieg des DSSul der Produkte korreliert. Durch charakteristische Signale im Bereich der Ether-Kohlenstoffatome und deren Verschiebung wurde belegt, dass die Sulfatierung des Celluloseethers an den freien Hydroxylgruppen der Etherseitenkette erfolgte.
Mittels FT-RAMAN-Spektroskopie konnten für Sulfatgruppen charakteristische Banden der in den Spektren der sulfatierten Celluloseether nachgewiesen und zugeordnet werden.
Aufgrund der ionischen Sulfatgruppen dissoziieren die Celluloseethersulfate in Wasser in geladene Polymerketten. Dadurch ist in Gegenwart von kationischen Polyelektrolyten (polyDADMAC) die Bildung von Polyelektrolytkomplexen in Form von Kapseln und Folien/Membranen möglich.
Die Fähigkeit solcher Polyelektrolytkapseln aus Celluloseethersulat und polyDADMAC zu Verkapselung von Substanzen und deren anschließende Freisetzung wurde am Beispiel der Verkapselung des Fluoreszenzfarbstoffes Rhodamin B gezeigt. Mittels fluoreszenzspektroskopischer Messungen konnte der aus den Kapseln freiwerdende Farbstoff detektiert werden. Anhand der Messungen wurde gezeigt, dass die Farbstofffreigabe im Fall von Rhodamin B abhängig von den Probeneigenschaften ist. Durch die Wahl des Ausgangsstoffes und deren Funktionalisierung mit Sulfatgruppen kann die Farbstofffreisetzung gesteuert werden. Mit zunehmendem DSSul des Celluloseethersulfates verlängert sich die Verweilzeit des Fluoreszenz-farbstoffes in der Kapsel. Zusätzliche Funktionelle Gruppen in der Seitenkette des Ausgangsstoffes führen zu sterischen Hinderung bei der Wechselwirkung mit polyDADMAC, wodurch eine gegenseitige Durchdringung der Polymerketten bei der Ausbildung des Polyelektrolytkomplexes gehindert wird, sodass weniger kompakte Membranstrukturen der Kapseln resultieren.
In Zellexperimente mit adhärenten Zelllinien an entsprechenden mit Celluloseethersulfat präpartierten Oberflächen wurde gezeigt, dass die Zelladhäsion durch den Sulfatierungsgrad der Proben beeinflusst wird. Auf Proben mit höherem Sulfatierungsgrad findet eine verbesserte Adhäsion im Vergleich zu Proben statt, die einen geringen Sulfatierungsgrad aufweisen. Demnach wird die Kompatibilität der Zellen auf solche Oberflächen durch die Erhöhung des Substitutionsgrades der Proben begünstigt.
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The tax treatment of receipts and accruals arising from equity option contractsDoidge, Stephen January 2013 (has links)
In this thesis the tax treatment of equity option contracts is examined. The writer gives an overview of the derivatives market in general and discusses the nature and effect of equity options in detail. Limited amendments have been made to the South African Income Tax Act No 58 of 1962 ('the Act') since the emergence of derivative instruments and at present only three types of derivative instruments are recognised: forward exchange and option contracts relating to forward exchange, interest rate swaps based on notional capital amounts and option contracts. Other than section 241 of the Act which deems all receipts and accruals from foreign exchange contracts to be income, the other sections dealing with derivatives do not concern themselves with capital or revenue classification. Accordingly, the classification of receipts and accruals arising from an equity option transaction is generally governed by the ordinary principles of South African tax law with the added problem of there being limited South African case law applying these general prinCiples to such transactions. The research undertaken in this thesis results in the establishment of a framework designed to determine the classification as revenue or capital the receipts and accruals arising from equity option contracts. Speculating, trading and investing in equity options is examined with regard to the general principles of South African tax and available case law. Hedging transactions are analysed with specific reference to their exact nature as well as general tax principles and available case law. The analogy of Krugerrands is used to draw parallels with the tax treatment of receipts and accruals arising from equity options used for hedging purposes. Once the theoretical framework has been established for revenue or capital classification, the actual tax treatment of both revenue and capital receipts is examined with reference to the Act and issues such as the gross income definition, the general deduction formula, trading stock and timing provisions are analysed and applied to receipts and accruals arising from equity option transactions. The thesis concludes with a summary of the findings and recommendations are made based on the research conducted.
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Synthesis And Aggregation Behavior Of Novel Bile Acid DerivativesMukhopadhyay, Samrat 04 1900 (has links) (PDF)
No description available.
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