Background: According to Webster et al. (2013, p. 4) “the idea of the circular economy is capturing the attention of businesses, academics and the next generation of entrepreneurs as a framework for re-designing the economy”. This can be traced back to growing evidence of environmental risks like ozone depletion, climate change, threats to biodiversity and changes in the nitrogen cycle (Geissdoerfer et al., 2017). Although the European economy still relies on a linear economic model, operating on a take-make-dispose basis (Rossé et al., 2016), circular business model have recently experienced a rapid growth and are perceived increasingly attractive by businesses (Ellen MacArthur Foundation, 2017a). Research Question: How do individuals in a multi-national organization make sense of circular economy and their goal of transforming to a circular business? Purpose: Exploring how individuals in an organization make sense of the circular economy concept when pursuing the goal to transform to a circular business by 2030. Method: The research is an exploratory case study with empirical data collected through semi- structured interviews at the case company IKEA Conclusion: By establishing the circularity goal, the organization changes the ambiguity of circular economy to uncertainty for employees that enact it. The individuals are making sense of the circular economy concept triggered by uncertainty due to the missing practical approach defined in the strategy. There is no collective agreement if circular economy is mainly business- driven or sustainability-driven, but they establish collective sense on engaging in many local solutions of circular economy instead of choosing one global approach, representative for the concept of a circular economy. Conclusion: By establishing the circularity goal, the organization changes the ambiguity of circular economy to uncertainty for employees that enact it. The individuals are making sense of the circular economy concept triggered by uncertainty due to the missing practical approach defined in the strategy. There is no collective agreement if circular economy is mainly business- driven or sustainability-driven, but they establish collective sense on engaging in many local solutions of circular economy instead of choosing one global approach, representative for the concept of a circular economy.

Sustainability is a keyword in society today and industries have to contribute to reduce emissions and the use of virgin resources. Every year 90 000 ton old tires are gathered in Sweden. Today mostly used for energy recovery. End-of-life tires has been used in asphalt in the US for almost 50 years and is an effective way to utilize them. There are several possible advantages for rubberized asphalt: noise reduction, higher rutting resistance, increased durability, thinner layers etc. In Sweden, the rubberized asphalt has been tested in 25 different roads, where the Swedish Transport Administration have led the development. Commercially, the product have not yet been successful. There are several different studies for the product in Sweden, but nothing on the business side. The aim in this thesis was to develop a business model for the product on the Swedish market by finding key actors in the value chain, advantages and risks for the rubberized asphalt and studying different market segments. The study has two different research questions, Is there a need for a business model innovation for rubberized asphalt? and How can a business model be created for rubberized asphalt on the Swedish market and what will be the most important factors for establishing the business model? To answer the research questions, qualitative interviews were conducted with 15 different actors in the value chain. The result of the study presents; the value chain for the rubberized asphalt in Sweden, external forces in the industry, a business model and a proposed procurement model. The first question was evaluated and the answer was that business model innovation was needed for rubberized asphalt on the Swedish market, as well as product development and technical statements. The most important factors to penetrate the Swedish market were: spread the information of rubberized asphalt, find segments for market entry, process rubber granulate, handle the product correctly, push for changes in the procurement model and for actors in the value chain to work together. The results can serve as a tool for business model innovation and may be used for other sustainable and recycled products. The report also presents several practical contributions that can be of interest for the asphalt industry.

Submitted by Monuque Luise Liette (monique_liette@yahoo.com.br) on 2015-12-22T13:16:53Z No. of bitstreams: 1 Dissertação final Completa_menor.pdf: 3116390 bytes, checksum: c329a2b70f37bd5912e6b6a9f026742f (MD5) / Approved for entry into archive by Ana Luiza Holme (ana.holme@fgv.br) on 2015-12-22T13:28:54Z (GMT) No. of bitstreams: 1 Dissertação final Completa_menor.pdf: 3116390 bytes, checksum: c329a2b70f37bd5912e6b6a9f026742f (MD5) / Made available in DSpace on 2015-12-22T13:39:51Z (GMT). No. of bitstreams: 1 Dissertação final Completa_menor.pdf: 3116390 bytes, checksum: c329a2b70f37bd5912e6b6a9f026742f (MD5) Previous issue date: 2015-11-30 / Em resposta à crise financeira de 2008, em 2010 o Comitê de Basileia em Supervisão Bancária (Basel Committee on Banking Supervision - BCBS) emitiu a metodologia do cálculo do indicador de Risco de Liquidez de curto prazo (Liquidity Coverage Ratio - LCR) que é um dos componentes do conjunto de normas conhecido como Basileia III. Esse índice mede se cada conglomerado possui um estoque de ativos financeiros líquidos de alta qualidade de forma a suportar uma crise severa por 30 dias. Esse trabalho calculou o índice de liquidez de curto prazo dos dez maiores bancos brasileiros em ativos totais nos últimos cinco anos, seguindo as diretrizes do documento acima mencionado e do Banco Central do Brasil. A finalidade desse estudo foi verificar se houve uma melhora na liquidez dos grandes bancos após a divulgação da metodologia de cálculo do LCR, uma vez que a partir de 2015 é esperado pelo Banco Central do Brasil que os bancos possuam pelo menos 60% de ativos líquidos para suportar uma crise de 30 dias. A análise foi conduzida utilizando dados contábeis oriundos tanto do banco de dados do Banco Central do Brasil quanto das publicações individuais de cada instituição. Essa análise permitiu avaliar que os principais bancos do sistema financeiro brasileiro já estão preparados para atender aos requisitos internacionais e que não serão necessárias grandes alterações na estrutura do balanço das instituições analisadas, evitando a migração seus ativos de empréstimos, aplicações em certificados de depósitos interbancários e títulos privados para títulos de alta qualidade e liquidez.

Nos últimos anos a discussão acerca da autonomia da política monetária esteve polarizada entre dois grupos de autores. Baseados numa concepção arqueológica da moeda (Cencini, 1997), alguns afirmam que os Bancos Centrais, diante da integração entre os mercados financeiros, teriam perdido a autonomia para praticar políticas monetárias em favor do crescimento econômico. Em contraste, outro grupo de autores sustenta que mesmo no atual contexto de “perfeita mobilidade do capital”, sob certas condições, a autoridade monetária conserva amplos graus de liberdade para definir o nível da taxa de juros doméstica, em qualquer contexto considerado. O objetivo principal do estudo é analisar teoricamente a questão da autonomia da política monetária nos termos em que a mesma vem sendo discutida na atualidade, e subseqüentemente, através de um modelo macroeconômico de simulação, examinar as conseqüências de uma política de juros alternativa àquela que o Banco Central do Brasil vem adotando. Constatou-se que em uma economia de mercado, em que muitos insumos produtivos são reproduzíveis, incluindo a força de trabalho e os bens de capital, emerge uma relação definida entre a dimensão do consumo produtivo da força de trabalho, visando a preservação das condições materiais da economia, e a magnitude dos meios de pagamento existentes: os meios de pagamento podem ser criados e destruídos no sistema bancário por causa do pagamento de salários aos trabalhadores, sob demanda das empresas. Sob essa ótica há certa dificuldade analítica para se conceber os meios de pagamento exogenamente determinados. Ao contrário, o caráter institucional, discricionário da taxa monetária de juros segue simples e logicamente. O mercado financeiro atua no sentido de restaurar a liquidez das empresas de negócios facilitando a liquidação de seus empréstimos passados junto aos bancos comerciais. Através da aplicação de um modelo macroeconômico de simulação dois cenários alternativos foram gerados para os próximos oito anos de política (2008-2015). No cenário de mudança uma política de redução progressiva da taxa de juros para o patamar de 3,66% ao ano resulta em uma taxa de inflação muito similar ao cenário de continuidade, caracterizado por uma taxa de juros de 15,39% ao ano. Porém, no primeiro caso ocorre um aumento substancial no crescimento da capacidade produtiva da economia com uma taxa cambial mais competitiva, que estaria situada, em média, em R$/US$ 2,51. Por outro lado, no cenário de continuidade a perda anual, em média, no acréscimo da capacidade produtiva da economia é de 7,44%, associada a uma taxa cambial não competitiva, que em média estaria situada em R$/US$ 2,35. A estabilidade de preços foi preservada em todos os cenários. / In recent years several authors have questioned the power of monetary authority to fix domestic money rate of interest at lower levels of their neighbors. The main reason would be the increasing financial integration of markets, and their “capital flows”. The “Flow Theory” (Branson, 1970) asserts that in a world where capital is perfectly mobile the power of Central Bank would be reduced at minimal levels, because of the exogenous character of money. So, active monetary policies to attain and maintain full employment would be not possible in that world, as a low and still positive interest rate. The aim of this study is to evaluate theoretical and empirically this claim for a market economy, considering the case of Brazilian economy. The main theoretical conclusion does not confirm that claim. On the contrary, in a market economy where several inputs are reproducible, including labor force and capital equipment, a definite relation comes about between the length of productive consumption, to guarantee material conditions of the economy, and means of payment: immaterial means of payment can be created and destroyed by banks because of wages, on demand of enterprises in money market. In this way there are some analytical difficulties to conceive money as a stock of wealth, as a material and exogenous object. Yet, the institutional and conventional character of money rate of interest, in any context, follows simple and direct because of the social and circular nature of production. The power of monetary authority is reinforced this way. By applying a macroeconomic simulation model designed to Brazilian economy to investigate the effect of an interest rate at an international level over the accumulation rate, inflation and exchange rate, alternative scenarios were obtained to the next eight years of policy (2008-2015). The main results suggest that if Central Bank would decide to fix the money rate of interest at 3,66% per year, the accumulation rate would be substantially greater and the exchange rate would stabilize around R$/US$ 2,51. But, if the monetary authority chooses to fix politically a higher rate, say 15,39% per year, the accumulation rate would be substantially lower and the exchange rate would be around R$/US$ 2,35 for the next eight years. The stable prices were maintained in all scenarios. There is no trade-off between growth and stability. So, the best choice of monetary authority would be a low but still positive money rate of interest to permit a greater production level and competitiveness at international arena.

TEIXEIRA, C. S. Expressão de uma quitinase de Chromobacterium Violaceum em Pichia Pastoris: purificação e caracterização parcial da proteína recombinante. 2011. 110 f. Dissertação (Mestrado em Bioquímica) - Centro de Ciências, Universidade Federal do Ceará, Fortaleza, 2011. / Submitted by Francisco Lacerda (lacerda@ufc.br) on 2014-11-10T18:58:20Z No. of bitstreams: 1 2011_dis_csteixeira.pdf: 2266830 bytes, checksum: cf710a23bf6fe474186662c855e584ee (MD5) / Approved for entry into archive by José Jairo Viana de Sousa(jairo@ufc.br) on 2015-01-20T16:54:04Z (GMT) No. of bitstreams: 1 2011_dis_csteixeira.pdf: 2266830 bytes, checksum: cf710a23bf6fe474186662c855e584ee (MD5) / Made available in DSpace on 2015-01-20T16:54:04Z (GMT). No. of bitstreams: 1 2011_dis_csteixeira.pdf: 2266830 bytes, checksum: cf710a23bf6fe474186662c855e584ee (MD5) Previous issue date: 2011 / Microorganisms are a valuable tool for the expression of proteins from a variety of sources, including plants, animals and other microorganisms. Thus, chitinases, a group of glycosil hydrolases capable to hydrolize chitin, have already been expressed and purified from different systems including bacteria and yeast. Chitin, a linear polymer of N-acetyl-β-D-glucosamine (GlcNAc), is an important structural component found in the crustacean shells, in the peritrophic membrane of insect guts as well as in the fungi cell walls. The aim of this work was to express a chitinase (encoded by the ORF CV3316) from Chromobacterium violaceum ATCC 12472, using the methylotrophic yeast Pichia pastoris strains GS115 and KM71H. Furthermore, purification and partial characterization of the recombinant protein were also achieved. The GS115 strain carrying the expression cassette pPICZαA-CV3316 was selected due to its higher expression level as compared to KM71H strain. Immobilized metal ion affinity chromatography was employed to purify the recombinant chitinase which was eluted as a single peak at 0.04 M imidazol. The homogeneity of the purified protein was confirmed as judged by polyacrylamide gel electrophoresis (SDS-PAGE). In these conditions, the recombinant chitinase migrated as a single protein band with an apparent molecular mass of about 87 kDa. Thus, a chitinase from C. violaceum ATCC 12472 was successfully expressed in P. pastoris and the soluble recombinant protein purified. The content of secondary structure was investigated by circular dichroism (CD) spectroscopy. At 24 oC the CD spectrum revealed secondary structure contents of 37% (alpha helix), 26% (beta sheet) and 38% (random coil). The CD spectra obtained in the temperature range 10-50 oC were characteristic of beta sheet. In contrast, the CD spectra generated in the range 60-90 oC were characteristic of alpha helix. The midpoint temperature of this conformational transition was 59.6 1.2 oC as calculated from the CD experimental data. Fluorescence spectroscopy was carried out with excitation at 280 and 290 nm, producing emission spectra in which the wavelengths of maximum emission were 339 and 342 nm, respectively. This behavior is characteristic of tryptophan residues in limited contact with water. Chitinolytic activity against several substrates and the pH dependency of the enzymatic activity of the pure protein were all accessed. The purified enzyme showed hydrolytic activity on the following substrates: colloidal chitin (1,189.4 U.mgP-1), 4-nitrophenyl N-N’-diacetyl--D-chitobioside (30,411.0 U.mgP-1) and 4-nitrophenyl β-D-N-N’-N”-triacetylchitotriose (13,150.0 U.mgP-1); and, respectively. In contrast, no activity was detected using 4-nitrophenyl N-acetyl-β-D-glucosaminide as substrate. The enzyme presented an optimal chitinolytic activity at pH 5.0 using colloidal chitin as a substrate. Additionally, the antifungal activity against the phytopathogenic fungi, Fusarium solani, Fusarium oxysporum, Rhizoctonia solani and Penicillium herquei was investigated. The recombinant chitinase did not inhibit the spore germination and the mycelium growth of the tested fungi, at the 0.63 mgP.ml-1 concentration. Further studies should be carried out in order to discover potential applications of this protein as a biotechnological tool in the control of other phytopathogenic fungi as well as economically important pests. / A utilização de microrganismos como sistemas heterólogos de expressão de proteínas tem se mostrado uma estratégia alternativa e/ou complementar aos passos tradicionais utilizados no processo de purificação de proteínas. Diante deste contexto, quitinases (EC 3.2.1.14), enzimas hidrolíticas capazes de degradar quitina, têm sido expressas em diferentes sistemas heterólogos, incluindo bactérias e leveduras. Quitina é um polímero linear composto de resíduos de N-acetil-β-D-glucosamina (GlcNAc), sendo um importante constituinte estrutural da carapaça de crustáceos e membrana peritrófica de insetos e, ainda, da parede celular de fungos. Este trabalho teve por objetivo expressar uma quitinase, codificada pela ORF cv3316, de Chromobacterium violaceum ATCC 12472 na levedura metilotrófica Pichia pastoris, estirpes GS115 e KM71H, além de purificar e caracterizar a proteína recombinante (rCHI3316). A estirpe GS115, portando a construção (pPICZαA-CV3316), foi selecionada para os experimentos posteriores, pois apresentou um maior nível de expressão quando comparada à cepa KM71H. Cromatografia de afinidade em coluna de níquel imobilizado foi utilizada para purificar a quitinase recombinante (rCHI3316), que foi eluída como um único pico com imidazol 0,04 M. A proteína purificada se mostrou homogênea quando submetida à eletroforese em gel de poliacrilamida 15% em presença de SDS e -mercaptoetanol (SDS-PAGE). Nessas condições, uma única banda com massa molecular aparente de aproximadamente 87 kDa foi observada. A quitinase rCHI3316 de C. violaceum foi expressa de forma solúvel utilizando o sistema de expressão P. pastoris e, além disso, sua purificação foi realizada de forma satisfatória. O conteúdo de estrutura secundária foi estimado por espectroscopia de dicroísmo circular (CD), com a proteína submetida a diferentes temperaturas (10-90 °C). Na temperatura de 24 °C, o espectro de CD revelou a predominância do conteúdo de hélice alfa (38%), folha beta (26 %) e estrutura randômica (37%). Entre as temperaturas de 10-50 °C, rCHI3316 exibiu um espectro característico de folha beta. A partir de 60 °C até 90 °C, rCHI3316 adquiriu uma conformação característica de hélice alfa. A temperatura média para essa transição conformacional foi calculada como sendo 59,6  1,21 °C. Experimentos de espectroscopia de fluorescência, com excitação a 280 e 290 nm, produziram espectros de emissão com comprimentos de onda máximos iguais a 339 e 342 nm, respectivamente. Esses valores são característicos de resíduos de triptofano parcialmente expostos ao solvente. Atividade quitinolítica contra vários substratos e dependência de pH da atividade enzimática da proteína pura foram avaliados. A rCHI3316 exibiu atividade hidrolítica sobre os substratos quitina coloidal (1.189,40 U/mgP), 4-nitrofenil N-N’-diacetil-β-D-quitobiosídeo (30.411,0 U/mgP) e 4-nitrofenil N-N’-N’’-triacetilquitotriose (13.150,0 U/mgP); entretanto, nenhuma atividade enzimática da rCHI3316 foi detectada frente a 4-nitofenil N-acetil-β-D-glucosaminídeo. A enzima exibiu atividade quitinolítica ótima (100%) em pH 5,0; quando quitina coloidal foi utilizada como substrato. Em adição, a atividade antifúngica contra fungos fitopatogênicos, Fusarium solani, Fusarium oxysporum, Rhizoctonia solani e Penicillium herquei foi investigada. rCHI3316 não inibiu a germinação e o crescimento micelial dos esporos dos fungos testados, na concentração de 0,63 mgP.ml-1. Estudos subseqüentes deverão ser realizados na intenção de descobrir potenciais aplicações desta proteína como uma ferramenta biológica no controle de outros fungos fitopatogênicos bem como insetos considerados pragas.

Made available in DSpace on 2016-06-02T20:21:19Z (GMT). No. of bitstreams: 1 DissFAHB.pdf: 1628733 bytes, checksum: fd3eaf59b3ea3ad27f519f1d97d21f33 (MD5) Previous issue date: 2007-11-01 / Financiadora de Estudos e Projetos / Lectins are (glico) proteins of non immune origin able to cause cellular agglutination or precipitation of glicoconjugates. Legume lectin refers to plant lectins that are found exclusively in species of the Leguminosae family. A notable characteristic of legume lectins is that all their proteins share tertiary structure consisting of a jelly-roll motif, which is basically composed by β sheet, but present great variability the quaternary association. This variability is considered responsible for conferring different degrees of stability to the legume lectins. This work presents the isolation and characterization of the camptosemin, a protein of legume lectins family, isolated from seeds of Camptosema ellipticum, a plant that belongs to the Brazilian open pasture. Camptosemin found to be a tetrameric protein, whose protomers exhibits approximately 26 kDa. It was able to agglutinate erythrocyte of all ABO sanguineous types and it was showed high affinity for N-acetylgalactosamin carbohydrate. Spectroscopic assays have demonstrated that camptosemin is an extremely resistant protein against the thermal and chemical unfolding. Through the analysis of the unfolding curves and the refolding assays, a model of two states for the unfolding of the protein was proposed. According to this model, at the equilibrium, only presents native tetramers and unfolded monomers. The obtained values of Tm and are in agreement with the ones described for other lectins. G O H Δ 2 / Lectinas são (glico)proteínas de origem não imune capazes de causar aglutinação celular e/ou precipitação de glicoconjugados. O termo lectina de legume refere-se às lectinas de plantas que são encontradas exclusivamente em exemplares da família Leguminosae. Uma característica notável das lectinas de legumes é que todas as proteínas compartilham estrutura terciária constituída pelo motivo jelly-roll , que é basicamente composto por folhas-β, mas apresentam grande variabilidade nas formas de associação quaternária. Acredita-se que esta variabilidade seja responsável por conferir diferentes graus de estabilidade a estas lectinas. Este trabalho descreve o isolamento e a caracterização da camptosemina, uma proteína da família das lectinas de leguminosas, isolada a partir de sementes de Camptosema ellipticum, uma planta pertencente ao cerrado brasileiro. Camptosemina mostrou-se como uma proteína tetramérica, cujos protômeros apresentam aproximadamente 26 kDa, capaz de hemoaglutinar todos os tipos sanguíneos do sistema ABO e com afinidade de ligação ao carboidrato N-acetilgalactosamina. Ensaios de estabilidade estrutural utilizando técnicas espectroscópicas demonstraram que camptosemina é uma proteína extremamente resistente a desnaturação térmica e química. Através da análise das curvas de desnaturação e dos ensaios de reenovelamento, foi proposto um modelo de dois estados para o processo de desnaturação da proteína, no qual, durante o equilíbrio, só existem tetrâmeros completamente enovelados e monômeros completamente desnaturados. Os valores de Tm e obtidos estão em conformidade com os de outras lectinas, encontrados na literatura. G O H Δ 2

Made available in DSpace on 2015-09-17T15:24:13Z (GMT). No. of bitstreams: 0 Previous issue date: 2014-01-10. Added 1 bitstream(s) on 2015-09-17T15:48:10Z : No. of bitstreams: 1 000845702_20180120.pdf: 420550 bytes, checksum: c8157ced2528f61f2d07a208c18d603f (MD5) Bitstreams deleted on 2018-01-29T11:44:58Z: 000845702_20180120.pdf,. Added 1 bitstream(s) on 2018-01-29T11:45:45Z : No. of bitstreams: 1 000845702.pdf: 26123214 bytes, checksum: f7fe9f4bcbb4d061d089a48d81ecacc7 (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / Peptídeos bioativos são de grande interesse como substitutos de antibióticos e quimioterápicos convencionais já que, alguns deles apresentam atividades antimicrobiana, antifúngica e/ou anticâncer. Eles são predominantemente catiônicos e sua atividade tem se mostrado ser modulada por interações eletrostáticas, contribuições hidrofóbicas e por características elásticas da membrana, o seu alvo. O peptídeo mastoparano Polybia MP1 (MP1) possui dois resíduos ácidos (D2 e D8) e três resíduos básicos (K4, K5 and K11), que somados ao C terminal amidado conferem a ele uma carga elétrica líquida relativamente baixa, Q= +2. Nesta tese, foi analisada a importância da sequência de aminoácidos do MP1, da sua carga elétrica líquida e da sua hidrofobicidade média na interação com distintas membranas modelo, já que a presença de resíduos ácidos é rara dentre os peptídeos bioativos e além disto, o MP1 apresenta elevadas atividades antimicrobiana e anticâncer sem ser hemolítico. Para entender a sua especificidade e o seu mecanismo de ação em células bacterianas e de câncer, a atividade e a afinidade do MP1 foi acessada através de espectroscopia de fluorescência e de dicroísmo circular, medidas de potencial eletrocinético e de espalhamento de luz dinâmico e microscopia confocal. Estas técnicas permitiram a observação da estruturação do peptídeo, da sua partição da água para a interface de membranas modelo, da sua atividade lítica e da agregação dos lipossomos devido a sua adição. Assim, foi possível estimar as contribuições energéticas envolvidas no sistema além das dimensões dos danos causados pelo MP1 na superfície da membrana. MP1 mostrou que sua baixa carga elétrica líquida e a presença de dois resíduos ácidos na sua sequência de aminoácidos apresentam um papel importante em modular a sua estruturação e a sua atividade em uma ampla gama de composições lipídicas. Isso é atribuído... / Bioactive peptides are of high interest as substitutes of conventional drugs since some of them present antimicrobial, antifungal and/or anticancer action. They are predominantly cationic and it has been shown that their activity is modulated by electrostatic interactions, hydrophobic contributions and the elastic features of the membranes their target. The mastoparan peptide Polybia MP1 (MP1) possesses two acidic residues (D2 and D8) and three basic ones (K4, K5 and K11), which together with the amidation of the C-terminal confers to it a relatively low net charge Q=+2. In this thesis, we analyzed the importance of the MP1 amino acid sequence, charge and hidrophobicity to the interaction with distinct model membranes, since the presence of acidic residues is a rare characteristic among the bioactive peptides and, beyond this, MP1 presents high antimicrobial and anticancer activities without being hemolytic. In search of understand its specificity and mechanism of action for bacteria and cancer cells, the activity and affinity of MP1 was assessed through circular dichroism and fluorescence spectroscopy, electrophoretic and dynamic light scattering measurements, and confocal microscopy. These techniques allowed the observation of the peptide structuration, the peptide partitioning from water to the model membranes interface, the peptide lytic activity, and the liposome aggregation due to peptide addition. From this, it was possible estimate the energetic contributions involved in the system, besides the dimension of the damages caused by MP1 on the membranes surface. MP1 showed that its low net charge and the presence of two acidic residues play an important role in modulating its structuration and activity in a wide range of lipid compositions, by equilibrating electrostatic and non-electrostatic contributions giving basis to understand its action as bioactive...

Made available in DSpace on 2015-09-17T15:24:47Z (GMT). No. of bitstreams: 0 Previous issue date: 2014-12-16. Added 1 bitstream(s) on 2015-09-17T15:47:13Z : No. of bitstreams: 1 000846885.pdf: 505151 bytes, checksum: ad11474b84c8cf10e34014ace8c2c242 (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / Peptdeos antimicrobianos possuem em geral cadeias curtas, carga líquida positiva devido ao excesso dos res duos b asicos e são ricos em amino acidos hidrof obicos. Possuem um grande potencial farmacológico, com atividade antimicrobiana modulada por interações eletrost aticas e hidrof obicas. Neste trabalho utilizou-se o pept deo sintético L1A (IDGLKAIWKKV ADLLKNT NH2), que devido aos res duos de acido asp artico e lisinas constituintes de sua cadeia, possui carga liquida +3, em pH neutro. Foram analisadas as insuficiências do pH e da carga de ves culas aniônicas na adsorçãao do pept deo. Este estudo utilizou medidas de potencial eletrocin etico de ves culas e experimentos de titulação monitorados por dicro smo circular (CD). A adsorção do L1A a LUVs de POPC e misturas POPC/POPG em diferentes proporções de POPG, foi medida nos pHs 4, 7 e 10. Os espectros de dicro smo circular dos peptídeos, na presença de vesícula, apresentaram caracter sticas de estruturas helicoidais, enquanto apresentaram estruturas desordenadas em tampão. As frações de hélices obtidas são maiores quando o pept deo adsorve em ves culas com maiores quantidades de POPG, indicando forte contribuição eletrost atica. As constantes aparentes de adsorção dos pept deos as membranas modelo foram calculadas atrav es da elipticidade de CD normalizada em 222 nm, obtidas por titulações de pept deo com ves culas. A a - nidade do pept deo a ves culas aniônicas e signi cativamente maior do que a ves culas zwitteriônicas, o que refor ca a import ancia das interçõeoes eletrost aticas no processo de adsorção do pept deo na bicamada. O efeito conjunto de carga das ves culas e de pH resultaram em signi cativa regulação de carga do pept deo resultando em valores de carga efetiva alta em pH 4,0 devido a protonação dos res duos de asp artico. Em pH 10,0 a pequena carga efetiva calculada deve-se as desprotona ações do N-terminal e das lisinas... / Antimicrobial peptides have in general short chains, positive net charge due to the excess of basic residues and are rich in hydrophobic amino acids. They have pharmacological potential as antimicrobial agents and their activity is modulated by electrostatic and hydrophobic interactions. In this work, we used the synthetic peptide L1A (IDGLKAIWKKV ADLLKNT NH2) that due to its acid and basic residues have an net charge +3, at neutral pH. The e ects of the pH and of the charges of anionic vesicles on the adsorption of L1A were analized. This study used measurement of electrokinetic potential of vesicles and titration experiments monitored by circular dichroism spectroscopy (CD). Adsorption of L1A to POPC and POPC/POPG LUVs in di erent POPG contents were assessed in the pH 4.0, 7.0 and 10.0. Circular dichroism spectra of the peptides in the presence of vesicles showed to features of helical structures; while random coil structures were observed at bu er for all the used pHs. The helical content was evaluated and showed to increase when the peptide adsorbs into vesicles with increasing amounts of POPG, indicating that there is a strong electrostatic contribution. Partition coe cients were calculated through the normalized CD ellipticities at 222 nm and showed that the a nity of the peptide for anionic model membranes is e ectively higher than those found for zwitterionic ones. It reinforces the importance of the electrostatic contribution to the process of peptide-lipid interaction. The coupled e ect of the vesicle charge and pH lead to signi cant charge regulation of the peptide resulting in high values of e ective charge at pH 4.0 due to the deprotonation of aspartic acid residues. At pH 10.0 the estimated e ective charge is small as a consequence of the deprotonation of both N-terminus and the lysines. The electrostatic and interfatial free energies seems to be additive only at pH 4.0, especially for the bilayers with higher content...

Made available in DSpace on 2015-03-03T11:52:25Z (GMT). No. of bitstreams: 0 Previous issue date: 2014-10-24Bitstream added on 2015-03-03T12:07:18Z : No. of bitstreams: 1 000806896_20161029.pdf: 604503 bytes, checksum: 09b8247bf974f840e6a01780c107b6bb (MD5) Bitstreams deleted on 2016-10-31T10:32:33Z: 000806896_20161029.pdf,. Added 1 bitstream(s) on 2016-10-31T10:33:09Z : No. of bitstreams: 1 000806896.pdf: 21070065 bytes, checksum: 3cf0584410dc2cae4f214389ef036569 (MD5) / Levando em consideração a diversidade química das estirilpironas isoladas de Cryptocarya mandioccana, este trabalho teve por objetivo estudar o mecanismo de fragmentação de 6 dessas substâncias por ESI-MS/MS e por GC-EI-MS e também determinar a configuração absoluta dos centros metínicos hidroxilados e do centro C6 do anel pirônico. Foram isoladas seis estirilpironas polihidroxiladas: desacetilcriptocarialactona (1), criptomoscatona D1 (2), criptomoscatona E2 (3), criptomoscatona E1 (4), criptomoscatona E3 (5) e criptomoscatona F1 (6). As análises por ESI-MS/MS e os cálculos teóricos indicaram que em fase gasosa os sítios de protonação e cationização das estirilpironas ocorrem no oxigênio carbonílico, similarmente aos anéis lactônicos descritos na literatura. O mecanismo de fragmentação proposto para as estirilpironas cationizadas com Na+ é comum a todas, apresentando perda neutra de C10H12O [M+Na?148]+ e as substâncias tri-hidroxildas sofreram uma segunda fragmentação com perda neutra de acetaldeído [M+Na?148?44]+. Nos espectros de massas de íons totais não é observado o íon referente às moléculas protonadas [M+H]+, mas sim o íon [M+H?H2O]+ referente à perda de água, portanto uma dissociação na fonte. Assim como para a espécie cationizada, este íon foi submetido à CID e no espectro MS/MS é observado novas eliminações de água referentes as perdas das demais hidroxilas, íons [M+H?nH2O]+, e posteriormente abertura do anel pirônico e eliminação de mais uma molécula de água, seguida de CO [M+H?nH2O?CO]+. A derivação das estirilpironas com MSTFA permitiu analisá-las por CG-MS, porém em quase todos os casos não foi possível detectar o íon molecular. O pico base sempre é referente ao cátion de TMS (m/z 73), comum para substâncias derivadas com este reagente, enquanto que os outros íons fragmentos são resultantes da clivagem homolítica... / Taking into account the chemical diversity of styrylpyrones isolated from Cryptocarya mandioccana, this work aimed to study the mechanism of fragmentation of six compounds belonging to this class by means of ESI-MS/MS and GC-EI-MS analysis and also to assign the absolute configuration of hydroxylated methinic centers and that at C6 in the pyrone ring. Six styrylpyrones poli-hydroxilated: desacetilcryptocaryalactone (1), cryptomoscatone D1 (2), cryptomoscatone E2 (3), cryptomoscatone E1 (4), cryptomoscatone E3 (5), e cryptomoscatone F1 (6) were isolated. Analysis by ESI-MS/MS and data from theoretical calculations in gas phase suggest the carbonyl oxygen as protonation and cationization site of the styrylpyrones, which is in accordance to data reported for the lactone rings. The fragmentation mechanism proposed for cationized styrylpyrones with Na+ is common to compounds 1-6, with loss of neutral C10H12O [M+Na?148]+. Tri-hydroxylated substances showed a second fragmentation with loss of an acetaldehyde unit [M+Na??148?44]+. Although it was not possible to observe the protonated molecule ions [M+H]+ in the MS total ion spectrum, the ion [M+H?H2O]+ referring to water loss was observed, which indicates in-source dissociation. As for the cationized species, this ion was subjected to CID process and the MS/MS spectrum showed an additional water loss related to a second hydroxyl group, ions [M+H?nH2O]+. It was then followed by pyrone ring-opening and eliminations of a water molecule and CO [M+H?nH2O?CO]+. Derivatization of the styrylpyrones with MSTFA was conducted to allow the analysis by GC-MS. On the mass spectra, in almost all cases, it was not possible to detect the molecular ion, and the base peak was always related to cation TMS (m/z 73). This ion is common for substances derived with this reagent, while the others ions are fragments resulting from the homolytic ? cleavage with...

An experimental and computational study was made of a single circular jet impinging onto a flat ground board. A 1/2' nozzle running at a fixed nozzle pressure ratio of 1.05 was used in the experimental phase (giving an nozzle exit Reynolds number of 90xlO'), the nozzle to ground plane separation being varied between 2 and 10 nozzle diameters. Measurements were performed in the free and wall jets using single and cross-wire hot-wire anemometry techniques and pitot pressure probes in order to detemine mean velocity and normal and shear stress distributions. Some analysis is also presentedo f earlier measurementso n high pressurer atio impinging jets. Nozzle height was found to effect the initial thickness of the wall jet leaving the impingement region, increasing nozzle to ground plane separation increasing the wall jet thickness, although this separation distance did not seem to affect the rate at which the wall jet grew. Nozzle height was also found to have a large effect on the peak level of turbulence found in the wall jet up to a radial distan ce from the jet axial centre line of 4.5 nozzle diameters, after which the profiles become self-similar. Lowering the nozzle tended to increase the peak level measured in all the turbulent stresses within this development region. The production of turbulent kinetic energy in the wall jet, which is an indication of the amount of work done against the mean flow by the turbulent flow was found to increase dramatically with decreasing nozzle height. This was attributed to greater shearing of the flow at lower nozzle heights due to a thinner wall jet leaving the impingement region. A moving impingement surface was found to cause separation of the wall jet inner boundary layer on the 'approach' side leading to very rapid decay of peak velocity. The point of separation was found to occur at radial positions in the region of 7.0 to 8.0 nozzle diameters, this reducing slightly for lower nozzle heights. A parametric investigation was performed using the k-e turbulence model and the PHOENICS CFD code. It was found that due to inadequacies in the model, it failed to predict accurately the growth of the wall jet, both in terms of its initial thickness and the rate of growth. It did, however, predict an increase in wall jet thickness with both increasing nozzle height and exit turbulence intensity and decreasing nozzle pressure ratio. Modifications were made to the constants in the model to try and improve the predictions,w ith a limited degreeo f successT. he low Reynoldsn umber k-F-t urbulence model was shown to give a slightly improved non-dimensional wall jet profile, although this did not improve the predicted rate of growth of the wall jet.