Orientadores: Theo Guenter Kieckbusch, Mariana Altenhofen da Silva, Mara Elga Medeiros Braga / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Química / Made available in DSpace on 2018-08-25T14:59:57Z (GMT). No. of bitstreams: 1 Bierhalz_AndreaCristianeKrause_D.pdf: 3476268 bytes, checksum: abb7f538beee2f7625671122ea9f53a4 (MD5) Previous issue date: 2014 / Resumo: Filmes ativos à base de alginato de sódio reticulados com íons cálcio e/ou bário e contendo natamicina como antimicrobiano foram confeccionados por um processo envolvendo duas etapas. Inicialmente, filmes com baixo grau de reticulação foram formados por casting (1º estágio). Após a secagem, estes pré-filmes foram submetidos a um segundo tratamento por imersão em soluções mais concentradas de agentes reticulantes, gerando quatro diferentes formulações (Ca-Ca, Ba-Ca, Ba-Ba e Ca-Ba, dependendo do íon utilizado no 1º e no 2º estágio de reticulação). Foram avaliadas as propriedades físico-químicas, a cinética de liberação da natamicina e o efeito antimicótico in vitro e em fatias de queijo Prato das diferentes formulações. O Ba2+ apresentou potencialidade para uso em filmes de alginato somente quando a reticulação era combinada com íons Ca2+. Os filmes Ca-Ca e Ba-Ca apresentaram características adequadas para aplicações como embalagem. Os filmes Ba-Ba tiveram um aspecto insatisfatório, alta solubilidade em água e alto intumescimento. O tempo de imersão na solução reticuladora influenciou as propriedades dos filmes Ca-Ba, que apresentaram maior permeabilidade ao vapor de água e ao oxigênio, maior opacidade e rugosidade, consequência de uma reticulação ineficiente da estrutura interna do filme. Três métodos de incorporação de natamicina foram avaliados: o método convencional, em que o antimicrobiano é adicionado diretamente à solução polimérica, a impregnação por imersão dos filmes em soluções contendo natamicina e a impregnação por solvente supercrítico. Filmes ativos confeccionados pelo método convencional apresentaram maior quantidade de natamicina, mas a formação de cristais na superfície afetou a sua transparência, rugosidade e resistência mecânica. O processamento com CO2 supercrítico (200 bar, 40°C) e etanol como cossolvente (10% molar) resultou em filmes Ca-Ca com alta transparência devido à micronização da natamicina, e com carga adequada de antimicrobiano, mas o processo é extremamente lento. Todos os filmes contendo natamicina apresentaram efeito antimicótico frente às espécies testadas, porém uma inibição menos intensa do crescimento fúngico foi observada para os filmes Ba-Ca. Em amostras de queijos Prato, os filmes Ca-Ca sem natamicina foram capazes de inibir o crescimento microbiano por 5 dias a 25°C. Filmes ativos impediram o crescimento por até 30 dias a 25°C. Ensaios de liberação da natamicina em água apresentaram bom ajuste ao modelo difusional da segunda Lei de Fick, com valores de difusividades na ordem de 10-11 cm2/s para os filmes impregnados pelo método convencional e de 10-10 cm2/s para os filmes processados com CO2 supercrítico. Um novo modelo baseado na solução matemática de difusão em dois meios compostos semi-infinitos foi desenvolvido e aplicado aos dados de liberação de natamicina em materiais semi-sólidos (géis de ágar e gelatina e fatias de queijo). Utilizando difusividades de natamicina nos filmes com a mesma atividade de água dos meios sólidos de liberação, o modelo foi adequado para estimar a difusividade nos géis e no queijo / Abstract: Alginate antimycotic films crosslinked with calcium and/or barium ions and containing natamycin as antimicrobial agent were prepared in a two step process. Initially, films with a low degree of reticulation were obtained by casting. After solvent evaporation, these pre-films were further crosslinked by immersion in a more concentrated Ca2+ or Ba2+ solution resulting in four different formulations (Ca-Ca, Ba-Ca, Ba-Ba e Ca-Ba, depending on the ion used in the 1st and 2nd stage). Physico-chemical properties, release behavior of natamycin and antimicrobial activity in vitro and on cheese slices of the different film formulations were monitored. Ba2+ ions were relevant as crosslinking agents only if combined with Ca2+ ions. Ca-Ca and Ba-Ca films presented appropriated features as packaging material. Ba-Ba films showed unsuitable attributes such as heterogeneities and high soluble matter in water and high swelling degree. The immersion time in the crosslinking solution affected the properties of Ca-Ba films. These films showed high opacity, surface roughness and water vapor and oxygen permeabilities due to inefficient bulk crosslinking. Three loading methods were tested: the conventional method, with natamycin added directly to the polymeric film forming solution, the absorption technique when prepared films are immersed in solutions containing natamycin and by supercritical CO2 impregnation. Active films manufactured by the conventional method showed higher loading capacities, but crystal deposits across the film affected their transparency, roughness and mechanical properties. The supercritical method (200 bar, 40°C) using ethanol as cosolvent (10% molar) resulted in Ca-Ca transparent films due to natamycin micronization, with suitable loading yields but the process is extremely time-consuming. All films containing natamycin exhibited antimycotic activity against the tested species and the smallest halo inhibition diameter was observed for Ba-Ca films. On cheese slices, Ca-Ca films without natamycin were able to inhibit the microbial growth for 5 days at 25°C, due to low O2 permeability. Active films inhibit the growth up to 30 days at 25°C. Data of natamycin release in water fitted well to Fick¿s diffusional model, with effective diffusivity values of the order of 10-12 cm2/s in conventional loaded films but 10-10 cm2/s for CO2 loaded films. Release tests in aqueous ethanolic solutions indicated a strong influence of the water activity on the diffusivities. A new release model based on the mathematical solution of the diffusion in two semi-infinite composite media was developed and applied to data of natamycin transferred to semi-solid material (agar and gelatine gels, and cheese slices). Using natamycin diffusivities in films with the same water activity of the solid release media, the model was able to estimate natamycin diffusivities in the gels and in cheese / Doutorado / Engenharia de Processos / Doutora em Engenharia Quimica

Orientadores: Theo Guenter Kieckbusch, Mariana Altenhofen da Silva / Dissertação (mestrado) - Universidade Estadual de Campínas, Faculdade de Engenharia Química / Made available in DSpace on 2018-08-21T16:22:52Z (GMT). No. of bitstreams: 1 Vaz_JulianaMiguel_M.pdf: 25278318 bytes, checksum: 2af6f4b99f503d19043c081e804f17b7 (MD5) Previous issue date: 2012 / Resumo: Alginatos são polissacarídeos compostos pela co-polimerização de unidades de beta-D-manuronato (M) e alfa-L-guluronato (G), arranjados em bloco homopoliméricos (poli-M ou poli-G) ou blocos em sequencia alternada, capazes de formar filmes resistentes quando reticulados com cálcio. ...Observação: O resumo, na íntegra, poderá ser visualizado no texto completo da tese digital / Abstract: Alginates are linear copolymers of (1,4)-linked beta-D-mannuronate (M) and alfa-L-guluronate (G) units, arranged as homopolymeric blocks (poly-M and poly-G) and blocks with alternating sequence....Note: The complete abstract is available with the full electronic document / Mestrado / Engenharia de Processos / Mestra em Engenharia Química

No description available.

Mast cells are critical effectors of allergic disease that can be activated by numerous stimuli. We have examined mast cell control by the inflammatory cytokine, IL-33, as well as IgG. In the first study reported here, we found that the synthetic glucocorticoid, dexamethasone, potently and rapidly suppressed IL-33-induced cytokine production from murine bone marrow–derived and peritoneal mast cells, as well as human mast cells. Dexamethasone also antagonized IL-33-mediated enhancement of IgE-induced cytokine production and migration. Although dexamethasone had no effect on IL-33-induced phosphorylation of MAP kinases or NFκB p65 subunit, it antagonized AP-1 and NFκB-mediated transcriptional activity. Finally, intraperitoneal administration of dexamethasone completely abrogated IL-33-mediated peritoneal neutrophil recruitment and prevented plasma IL-6 elevation. These data demonstrate that steroid therapy may be an effective means of antagonizing the effects of IL-33 on mast cells in vitro and in vivo, acting partly by suppressing IL-33-induced NFκB and AP-1 activity. In the second study reported here, we found that Fcγ receptor crosslinkage activated the transcription factor Stat5B through a Fyn kinase-dependent pathway. We then showed that STAT5B is critical for IgG-induced cytokine production by mast cells but not macrophages. To expand these studies, we employed the K/BxN model of inflammatory arthritis, which has roles for mast cells and macrophages. In this model, Fyn or STAT5B deficiency only affected the arthritic flare that primarily depends on mast cell degranulation, without affecting the severity of the joint swelling. By contrast, Lyn kinase deficiency significantly exacerbated arthritis. These studies indicate a clinically relevant, lineage-restricted role for the Lyn/Fyn-STAT5 cascade. Collectively, our work demonstrates that mast cell activation by diverse stimuli can be suppressed by steroid intervention and selectively targeted by disrupting kinase-transcription factor pathways.

Améliorer le recyclage des caoutchoucs est un enjeu majeur de la société actuelle. Ces matériaux sont classiquement réticulés de manière permanente par chimie covalente, ce qui empêche toute modification ultérieure de la structure du réseau. Au cours de cette thèse, nous avons cherché à concevoir le recyclage en amont, en utilisant des méthodes de réticulation non-permanentes. Le caoutchouc naturel époxydé (ENR), choisi comme élastomère de base de l'étude, est efficacement réticulé par l'action de diacides carboxyliques qui réagissent sur les fonctions oxiranes pour former des ponts esters. D'une part, l'ajout d'un catalyseur de transestérification au sein du matériau a permis d'envisager l'obtention de propriétés vitrimères. Les avantages de cette chimie covalente échangeable sont mis en évidence par comparaison avec les réseaux permanents faiblement réticulés qui montrent eux aussi des propriétés de relaxation et d'adhésion. D'autre part, l'utilisation d'un diacide comportant dans sa chaîne une fonction disulfure dynamique apporte un certain degré de recyclabilité, comparable à ce qui peut être obtenu par vulcanisation conventionnelle au soufre. La chimie décrite ici présente cependant l'avantage majeur de ne pas être toxique pour l'environnement, contrairement à la vulcanisation. Enfin, le greffage d'acides gras à chaîne cristallisable sur l'ENR conduit à l'obtention d'élastomères thermoplastiques. L'étude par diffraction des rayons-X sous traction cyclique montre que ces réseaux physiques cristallisent sous contrainte aussi bien que l'ENR réticulé chimiquement aux diacides. / Improving rubber recyclability is a major challenge of today’s society. These materials are usually crosslinked through permanent covalent chemistry, which prevents any further modification of the network structure. The aim of this thesis was to design the recyclability up-stream by using non-permanent chemistry for rubber crosslinking. Epoxidized natural rubber (ENR), chosen as the base rubber, is efficiently crosslinked by reaction of dicarboxylic acids on oxirane rings to form ester bonds. On the one hand, the addition of a transesterification catalyst let foresee the obtaining of vitrimer properties. The advantages of this exchangeable chemistry are shown by comparison to lightly permanently crosslinked rubbers that also show stress relaxation and adhesion properties. On the other hand, using a functionalized diacid with a central disulphide function, a certain degree of reprocessability could be obtained, comparable to what was obtained by conventional sulphur vulcanization. A major advantage of the presented diacid chemistry over vulcanization is the non-toxicity towards the environment. Lastly, by grafting long crystallizable fatty acids onto ENR, we synthesized thermoplastic elastomers. Like diacid-crosslinked ENR (chemical network), these physical networks show strain-induced crystallization measured by X-ray diffraction during cyclic tensile tests.

Orientador: Fábio Cesar Gozzo / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Química / Made available in DSpace on 2018-08-27T10:34:23Z (GMT). No. of bitstreams: 1 Ferrari_AllanJhonathanRamos_M.pdf: 2074796 bytes, checksum: a9fd65df7da4d527a33e2ef562c91f73 (MD5) Previous issue date: 2015 / Resumo: A Stanniocalcina-1 (STC1) é um hormônio glicoproteico que apresenta padrão de expressão diferencial destacado em diversas patologias, notadamente em neoplasias, mas seus aspectos funcionais e estruturais são pouco explorados até o momento. Nesse sentido, a STC1 foi escolhida como alvo para a utilização de uma abordagem integrativa das técnicas que utilizam os reagentes de ligação cruzada, espectrometria de massas e modelagem molecular para a modelagem estrutural. A partir dos experimentos de ligação cruzada, foram obtidas 37 restrições de distância envolvendo espécies ligadas com DSS, sendo 11 destas espécies com N-terminal e uma restrição envolvendo a espécie dimérica, além das cinco ligações de dissulfeto já publicadas. Essas restrições foram utilizadas para a geração de modelos estruturais nas plataformas online I-Tasser e Quark e, localmente, mais de 100.000 modelos pelo protocolo Ab Initio Relax do software Rosetta em quatro diferentes condições iniciais de modelagem. O Rosetta apresentou maior eficiência na geração de modelos quando ausente arquivo de predição de estrutura secundária. As restrições de distância foram ferramenta discriminatória fundamental para a seleção de estruturas candidatas para a STC1. O agrupamento utilizando o parâmetro global distante test (gdt) das 1500 modelos de menor score que respeitavam todas as restrições identificou 22 estruturas representativas estruturalmente distintas. Essas estruturas representativas podem agora ser utilizadas em testes envolvendo substituição molecular nos dados de difração de raios-X / Abstract: The Stanniocalcin-1 (STC1) is a glycoproteic hormone, which shows a differential expression pattern in a variety of pathologies, especially in neoplasia, but its functional and structural aspects have not been explored. Accordingly, the STC1 was chosen as a target to the use of an integrative approach including chemical cross-linking, mass spectrometry and molecular modeling. From cross-linking experiments,37 distance constrains were identified involving the DSS cross-linker, 11 of them in the N-terminus part of the protein and one involving the dimeric specie, in addition to five disulfide bonds already published. These constrains were used to generate structural models by I-Tasser and Quark online platforms and, locally, more than 100,000 models in the Ab Initio Relax protocol package present in the Rosetta software in four different modeling conditions. Rosetta was the most efficient in generating models when secondary structure prediction was absent. The distance constrains were found to be a key discriminatory tool for the selection of candidate structures for the STC1. For the 1,500 lowest score structures that satisfied the distance constrains, the clustering method employing the global distance test parameter (gdt) identified 22 structurally distinct representative structures. These representative structures can be used to in molecular replacement test to solve the X-Ray diffraction data / Mestrado / Quimica Organica / Mestre em Química

Orientador: Maria Regina Wolf Maciel / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Química / Made available in DSpace on 2018-08-27T14:16:37Z (GMT). No. of bitstreams: 1 ParadaHernandez_NataliaLorena_D.pdf: 3619653 bytes, checksum: 89e5fe01b39a1e7b4df6202248e4f9c5 (MD5) Previous issue date: 2015 / Resumo: O objetivo desta pesquisa é sintetizar um biopolímero a partir do óleo de mamona usando um processo não tóxico, tanto na síntese da resina epoxídica quanto no processo da sua cura, visando obter assim um biomaterial com características adequadas para uso na área médica. Para isso, foi necessária a funcionalização do óleo de mamona, por meio do processo de epoxidação, para posterior utilização como monômero na síntese do biopolímero. O processo de epoxidação foi realizado utilizando um sistema catalítico verde (H2O2/Al2O3/acetato de etila). Inicialmente, foi realizada a epoxidação do ricinoleato de metila (componente modelo), para a avaliação da eficiência do processo de epoxidação. Neste estudo foi utilizada a metodologia de planejamento de experimentos, a qual possibilitou definir as variáveis significativas do processo de epoxidação. A epoxidação do componente modelo foi monitorada por meio de Cromatografia Gasosa acoplada a um Detector de Ionização de Chama (GC-FID). Os resultados mostraram alta conversão (99%), em poucas horas de reação (2h), e ausência de subprodutos (99% de seletividade). Com esses resultados, procedeu-se com a epoxidação do óleo de mamona, cuja eficiência do processo foi avaliada por meio de Espectroscopia no Infravermelho por Transformada de Fourier (FTIR) e Espectroscopia Raman (FT-Raman) e Ressonância Magnética Nuclear de Prótons (1HNMR). Após epoxidação do óleo de mamona, foi avaliada a reação de polimerização do óleo de mamona epoxidado (ECO) usando ácidos carboxílicos (ácido cítrico) como comonômero, utilizando a técnica de Calorimetria Exploratória Diferencial (DSC), FTIR, Análise Termogravimétrica (TGA) e testes de capacidade de inchamento. Os resultados obtidos indicam que o processo de polimerização estudado é viável, obtendo-se um poliéster reticulado. Visando a possível aplicação do poliéster obtido na engenharia de tecidos e área médica, foi realizada a análise de citotoxicidade do polímero obtido, usando células Vero (fibroblastos). O resultado da análise de citotoxicidade mostrou a não toxicidade do polímero sintetizado em células Vero (fibroblastos) / Abstract: The target of this research is to synthesize a biopolymer from castor oil using a nontoxic process, not only in the epoxy resin synthesis but also in its curing process, aiming to obtain a biomaterial with suitable characteristics for medical applications. With this purpose, castor oil was functionalized using an epoxidation process in order to be used as monomer in the biopolymer synthesis. Epoxidation process was performed using a green catalytic system (H2O2/Al2O3/ethyl acetate). Initially, it was carried out the epoxidation of methyl ricinoleate (model compound) for evaluating the epoxidation process efficacy by using experimental design methodology, allowing in this way to define the significant epoxidation process variables. Model compound epoxidation was monitored by gas chromatography equipped with a flame ionization detector (GC-FID). The evaluation of the results showed high conversion (99%) in a few hours (around 2hs) without byproduct formation (99% selectivity). Taking into account these results, it was performed the castor oil epoxidation and the process efficacy was evaluated by Fourier transform infrared (FT-IR), Raman Spectroscopy and 1H NMR. After castor oil epoxidation, epoxidized castor oil (ECO) polymerization using carboxylic acids (citric acid) as comonomer was evaluated by Differential Scanning Calorimetry (DSC), FTIR, Thermogravimetric Analyses (TGA) and swelling tests. The obtained results showed that polymerization process is viable and it was obtained a cross-linked polyester. In order to evaluate the potential application of the obtained polymer in the medical field, it was performed a cytotoxicity assay using Vero cells (fibroblast type). Cytotoxicity results showed nontoxic effect of synthesized polyester on Vero cells / Doutorado / Engenharia Química / Doutora em Engenharia Quimica

Content: The utilization of mink waste generated through the industrial process attracted both industry and academia interests. In this study, the use of hydrogen peroxide as an oxidizing agent onto collagen producing self-crosslinking which extracting from mink solid waste was studied by infrared spectrum, fluorescence spectrum and thermal properties. The effect of hydrogen peroxide dosage and reaction temperature on the degree of oxidative self-crosslinking of collagen was analyzed by the changes of molecular structure and thermal stability. It was found that, hydroxide groups on the collagen side-chains can be oxidized to aldehyde groups and carboxyl groups by hydrogen peroxide in alkaline environment. These oxidized groups can crosslink with functional groups on collagen by covalent bond and ionic bond, changing collagen molecular structure and improving thermal stability. When the dosage of hydrogen peroxide was 14.74% and reaction temperature was 40℃ ±, the oxidative self-crosslinking of collagen was the strongest. This study provided theoretical basis for the high-value utilization of mink wastes. Take-Away: 1. The oxidative self-crosslink of collagen extracted mink solid waste was studied. 2. Hydrogen peroxide was applied as environment friendly oxidant. 3. The change of functional groups and degree of crosslinks during the oxidation was studied via infrared, fluorescence spectrum and differential scanning calorimetry.

This thesis focuses on the characterization of PEDOT:DBSA, a new semiconducting polymer for use in bioelectronic devices. It also deals with possibilities of surface treatment in order to enhance its biocompatibility and stability in aqueous environments. For this purpose, the organic polymer films were crosslinked with two crosslinking agents – GOPS and DVS. The ability of these agents to prevent leaching of some fractions of the polymer films in an aqueous environment and the ability to bind polymer molecules to each other as well as to the glass substrate was studied using the delamination test. Subsequently, the effects of these crosslinking agents on the film properties essential for the proper functions of bioelectronics made of these materials, was studied by contact angle measurements and four-point probes respectively. Moreover, several OECTs were prepared using original and crosslinked material as an active layer and were characterized by measuring transconductance and volumetric capacitance. PEDOT:DBSA has been shown to be a suitable material for use in bioelectronics, but its thin layers need to be stabilized in an aqueous environment. The agent DVS appears to be unsuitable for this purpose, mainly due to its insufficient film stabilization and its increased hydrophilicity of the film surface, thus increased tendency to interact with water, resulting in degradation of these thin layers. In contrast, GOPS, despite some reduction in film conductivity, has been able to stabilize the polymer layer over the long term, and thus appears to be a suitable way to stabilize PEDOT:DBSA.

This Master’s thesis deals with the problematics of radically initiated compounding of polyethylene by 1-vinyladamantane. Theoretical part focuses on the theory of grafting processes and how they are influenced by chosen process parameters, as well as the properties of used monomer. In experimental part, two sets of experiments were designed, in both cases the chemicals used were polyethylene LITEN MB 87, (2,5-dimethyl-2,5-bis(tert-butylperoxy) hexane), also called Trigonox 101, as the initiator, and chemicals called Ionol and Irgafos 168 as stabilizers. The experiments were carried out in a Brabender batch mixer, the temperature was 180 – 185 °C, the reaction time was 5 minutes. The analytic methods used to evaluate the prepared samples’ properties were the tensile testing, the Charpy notch test, measuring of the melt flow index, analyzing the torque during kneading and the analysis of infrared spectra of the samples. By carrying out of these experiments it was found that excessive crosslinking was present with mass fraction of initiator being as low as 2 %. It was also concluded that under these conditions the modification does not improve tensile properties of the material, but it does improve the impact strength, albeit slightly. The influence of the modification on flow properties needs to be investigated further. A presence of vinyl groups was observed in infrared spectra, suggesting the presence of ungrafted vinyladamantane.