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- ItemMetadata onlyCharacterization and biological evaluation of the introduction of PLGA into biosilicate(Wiley, 2017) Fernandes, Kelly Rossetti [UNIFESP]; Magri, Angela Maria Paiva [UNIFESP]; Kido, Hueliton Wilian [UNIFESP]; Ueno, Fabio Roberto [UNIFESP]; Assis, Livia [UNIFESP]; Fernandes, Kristianne Porta Santos; Mesquita Ferrari, Raquel Agnelli; Martins, V. C.; Plepis, Ana M.; Zanotto, Edgar Dutra; Peitl Filho, Oscar; Ribeiro, Daniel Araki [UNIFESP]; Van den Beucken, Jeroen J.; Renno, Ana Claudia Muniz [UNIFESP]The aims of this study were to characterize different BS/PLGA composites for their physicochemical and morphological characteristics and evaluate the in vitro and in vivo biological performance. The physicochemical and morphological modifications were analyzed by pH, mass loss, XRD, setting time, and SEM. For in vitro analysis, the osteoblast and fibroblast viability was evaluated. For in vivo evaluations, histopathology and immunohistochemistry were performed in a tibial defect in rats. After incubation, all composites presented lower values in pH and mass loss over time. Moreover, XRD and SEM analysis confirmed that the composites degraded over time. Additionally, pore formation was observed by SEM analysis after incubation mainly in BS/PLGA groups. BS/PLGA showed significantly increased in osteoblast viability 24 h. Moreover, BS/PLGA composites demonstrated an increase in fibroblast viability in all periods analyzed when compared to BS. In the in vivo study, after 2 and 6 weeks of implantation of biomaterials, histopathological findings revealed that the BS/PLGA composites degrades over time, mainly at periphery. Moreover, can be observed the presence of granulation tissue, bone formation, Runx-2, and RANKL immunoexpression in all groups. In conclusion, BS/PLGA composites present appropriate physicochemical characteristics, stimulate the cellular viability, and enhance the bone repair in vivo. (C) 2016 Wiley Periodicals, Inc.
- ItemMetadata onlyCorrosion protection of AA2024-T3 by poly (phenylenesulfide-phenyleneamine) (PPSA), a soluble copolymer of polyaniline(Pergamon-Elsevier Science Ltd, 2016) Xavier, Thiago Henrique Andrade [UNIFESP]; Liu, Andrea Santos; Camilo, Fernanda Ferraz [UNIFESP]This work focused on the elucidation of the corrosion behavior of a soluble copolymer of polyaniline, called poly(phenylenesulfide-phenyleneamine) (PPSA), deposited on aluminum alloy (AA2024-T3). The insulating (reduced) and conducting (oxidized) forms of this polymer were analyzed and it was observed that the reduced form of a PPSA film with a thickness of about 40 pm showed the best performance as physical barrier. Thicker films did not show satisfactory results due to their poor adherence to the alloy surface. In the conducting form, PPSA was not efficient. (C) 2016 Elsevier Ltd. All rights reserved.
- ItemOpen AccessDerivados poliméricos de produtos naturais bioativos – preparação e avaliação da influência da polimerização nas propriedades químicas e microbiológicas do timol isolado de Thymus vulgaris (LAMIACEAE)(Universidade Federal de São Paulo, 2019-02-20) Parolin, Giovana Artuzo [UNIFESP]; Philadelphi, Laura Oliveira Péres [UNIFESP]; Lago, João Henrique Ghilardi [UNIFESP]; http://lattes.cnpq.br/2325513222088331; http://lattes.cnpq.br/7511492642565571; http://lattes.cnpq.br/5165382247780718Neste trabalho, foram realizadas reações a fim de se obter um polímero usando timol, obtido do óleo essencial de Thymus vulgaris (Lamiaceae) como unidade monomérica. O trabalho foi desenvolvido de maneira análoga à literatura que utilizava o fenol como unidade monomérica. Os resultados mostraram que o material formado apresentava substituições nas posições 2 e 4 em relação à hidroxíla do monômero de timol. O produto foi caracterizado através de diversas técnicas como ressonância magnética nuclear, espectroscopia na região do infravermelho e UV-Vis, fluorescência, cromatografia de permeação em gel e termogravimetria. Para avaliação da propriedade antimicrobiana, foi realizado um teste de concentração mínima inibitória afim de avaliar a influência da polimerização do timol em suas propriedades. A partir do espectro de UV-Vis, foi observada a banda referente ao grupo aromático presente na molécula de timol e da macromolécula. No cromatograma de permeação em gel, o material se mostrou polidisperso com massa molar por volta de 3000 g/mol, bem como foi observado um aumento na resistência térmica do polímero em relação ao monômero (com temperatura inicial de degradação por volta de 210 °C). Foi analisada também a atividade antifúngica do politimol a partir de um bioensaio de concentração mínima inibitória (MIC), onde foi obtido um valor próximo e, em um dos casos, equivalente à MIC para o timol (0,08 μg/μL com inibição às cepas de até 99 %).
- ItemEmbargoEfeito dos compostos naturais na atividade enzimática da urease em biossensores(Universidade Federal de São Paulo, 2024-06-05) Souza, Thaísa da Silva de [UNIFESP]; Philadelphi, Laura Oliveira Péres [UNIFESP]; http://lattes.cnpq.br/7511492642565571; http://lattes.cnpq.br/7900547637593708Os biossensores são dispositivos projetados para detectar e quantificar a presença de substâncias específicas em um meio. Atualmente, seu uso tem crescido devido a diversos benefícios, como alta sensibilidade e especificidade, fácil utilização e, principalmente, baixo custo em comparação com outras técnicas analíticas. Neste trabalho, foram estudadas maneiras de aprimorar a detecção de ureia através da adição de compostos naturais aromáticos a biossensores enzimáticos de urease. Os compostos naturais avaliados foram o eugenol e o bis eugenol, que possuem propriedades antioxidantes, antimicrobianas e anti-inflamatórias, além de suas propriedades sensoriais. Ambos os compostos têm potencial para aumentar a eficiência na detecção de ureia devido à sua estrutura conjugada e possível capacidade de interagir com a enzima urease, resultando em maior imobilização da enzima no filme e melhorando sua estabilidade, permitindo que ela mantenha sua atividade enzimática por mais tempo. Para a construção do biossensor, foram produzidos filmes finos de várias camadas (1 a 5) pelo método de spin coating, utilizando o polímero conjugado poli(9,9-dioctilfluoreno-co-fenileno) (PFPh) como matriz, a urease como enzima catalisadora da reação com a ureia, e o composto natural (eugenol ou bis-eugenol) para intensificar a imobilização e atividade da urease. Diferentes concentrações dos compostos naturais (0,1, 0,3 e 0,5 mg/mL) foram avaliadas para determinar sua eficácia nos filmes. Para comprovar os resultados, foram realizadas caracterizações dos compostos e dos filmes obtidos, utilizando espectroscopia na região do infravermelho, UV-vis e fluorescência, além de avaliações da atividade enzimática, variando a concentração de ureia de 5 a 40 mM. Os resultados obtidos foram comparados com filmes de mesma estrutura, porém sem a presença de compostos naturais, confirmando o aumento da atividade enzimática devido à inclusão desses compostos no sistema.
- ItemMetadata onlyEndoscopic ultrasound-guided celiac plexus neurolysis using a reverse phase polymer(W J G Press, 2010-02-14) Obstein, Keith L.; Martins, Fernanda P. [UNIFESP]; Fernandez-Esparrach, Gloria; Thompson, Christopher C.; Brigham & Womens Hosp; Universidade Federal de São Paulo (UNIFESP); Hosp Clin BarcelonaAIM: To assess the feasibility of endoscopic ultrasound (EUS)-guided celiac plexus neurolysis (CPN) using a poloxamer.METHODS: in this prospective evaluation, six Yorkshire pigs underwent EUS-guided CPN. Three received an injection of 10 mL of 0.25% Lidocaine plus methylene blue (group 1) and three received an injection of 10 mL of 0.25% Lidocaine plus blue colored poloxamer (PS137-25) (group 2). Necropsy was performed immediately after the animals were sacrificed. the abdominal and pelvic cavities were examined for the presence of methylene blue and the blue colored poloxamer.RESULTS: EUS-guided CPN was successfully performed in all 6 pigs without immediate complication. Methylene blue was identified throughout the peritoneal and retroperitoneal cavity in group 1. the blue colored poloxamer was found in the retroperitoneal cavity immediately adjacent to the aorta, in the exact location of the celiac plexus in group 2.CONCLUSION: EUS-guided CPN using a reverse phase polymer in a non-survival porcine model was technically feasible. the presence of a poloxamer gel at the site of the celiac plexus at necropsy indicates a precise delivery of the neurolytic agent. (C) 2010 Baishideng. All rights reserved.
- ItemMetadata onlyEstudo do efeito barocalórico em borracha natural, vulcanizada e blendas com pó de pneu(Universidade Federal de São Paulo (UNIFESP), 2019-09-06) Usuda, Erik Oda [UNIFESP]; Carvalho, Alexandre Magnus Gomes [UNIFESP]; Universidade Federal de São Paulo (UNIFESP)The current refrigeration systems based on vapor compression cycles, also known as conventional refrigeration, have some problems inherent to their technology. One of the problems is the substance used as refrigerant, in most of the cases it is based on hydrocarbons that can contribute to global warming when released to the atmosphere. Furthermore, some refrigerants use chloride in their composition, which contributes to the depletion of the ozone layer. Another problem is related to energy efficiency, which is not high and is reaching their technological limits. Therefore, it is important to search for other alternatives which are more efficient and eco-friendly. A promising technology is the solid-state refrigeration, which is based on materials that present i-caloric effects. In this dissertation, it was studied the barocaloric effect, a class of i-caloric effects, in vulcanized natural rubber (BNV), natural rubber (BN), ground tire rubber (GTR) and blends composed by BNV and GTR (BNV/GTR). In the latter case, it was studied samples with different contents of GTR. In all materials, the results obtained for the barocaloric effect (isothermal entropy change, ΔST, and adiabatic temperature change, ΔTS) reached values above 15 K of ΔTS and surpassed 60 J kg-1 K-1 of ΔST for pressure change up to 390 MPa around room temperature. Such values are comparable or superior to the best i-caloric materials in the literature. Besides, other properties were obtained from these materials, such as the pressure dependence of the glass transition temperature (Tg) and estimated entropy curves under pressure as function of temperature. Also, it was verified that the glass transition reduces the values of ΔST and ΔTS. Among the materials studied here, natural rubber presented the higher values of ΔST and ΔTS, surpassing vulcanized natural rubber. This can be attributed to the greater chain deformation and mobility under pressure. Increasing the GTR content in the blends resulted in a lower effect, still, the results were high. The materials studied in this dissertation presented promising barocaloric effect, envisaging the viability for application in solid-state refrigeration with low environmental impact.
- ItemMetadata onlyInteração da enzima Beta-galactosidase em filmes lipídicos e poliméricos de Langmuir e Langmuir-Blodgett(Universidade Federal de São Paulo (UNIFESP), 2019-11-29) Araujo, Felipe Tejada [UNIFESP]; Caseli, Luciano [UNIFESP]; Universidade Federal de São Paulo (UNIFESP)In this work we studied the interaction of β-galactosidase in Langmuir and Langmuir-Blodgett (LB) films of stearic acid (HSt) and poly (9,9-dioctylfluorene) -co-thiophene polymer (PDF-TF). The lipid was spread at the air-water interface forming Langmuir monolayers and the enzyme was inserted into the supporting aqueous phase of the lipid monolayer. The adsorption of the enzyme to the monolayer was studied by surface-area pressure isotherms, surface-area potential isotherms, Brewster angle microscopy and vibrational spectroscopy. The mixed monolayer (lipid / enzyme / polymer) was transferred to solid supports by the LB methodology and characterized by luminescence spectroscopy, vibrational spectroscopy, and atomic force microscopy, indicating the presence of the polymer and the enzyme. The enzymatic activity of immobilized lactase as LB film was evaluated against lactose hydrolysis was evaluated with UV-visible spectroscopy. In conclusion, the enzyme can be inserted into lipid films, partially maintaining its secondary structures and altering the morphology of LB films. Catalytic activity could be maintained at up to 60% of activity after one month after transfer to LB film, which makes the system viable for future applications in lactose biosensors.
- ItemOpen AccessMicroplastic contamination in seawater across global marine protected areas boundaries(Elsevier, 2023-01) Nunes, Beatriz Zachello; Huang, Yuyue; Ribeiro, Victor Vasques [UNIFESP]; Wu, Siqi; Holbech, Henrik; Moreira, Lucas Buruaem [UNIFESP]; Xu, Elvis Genbo; Castro, Ítalo Braga de [UNIFESP]; http://lattes.cnpq.br/8251258719894689; Universidade Federal de São Paulo (UNIFESP)Despite the relatively rich literature on the omnipresence of microplastics in marine environments, the current status and ecological impacts of microplastics on global Marine Protected Areas (MPAs) are still unknown. Their ubiquitous occurrence, increasing volume, and ecotoxicological effects have made microplastic an emerging marine pollutant. Given the critical conservation roles of MPAs that aim to protect vulnerable marine species, biodiversity, and resources, it is essential to have a comprehensive overview of the occurrence, abundance, distribution, and characteristics of microplastics in MPAs including their buffer zones. Here, extensive data were collected and screened based on 1565 peer-reviewed literature from 2017 to 2020, and a GIS-based approach was applied to improve the outcomes by considering boundary limits. Microplastics in seawater samples were verified within the boundaries of 52 MPAs; after including the buffer zones, 1/3 more (68 MPAs) were identified as contaminated by microplastics. A large range of microplastic levels in MPAs was summarized based on water volume (0–809,000 items/m3) or surface water area (21.3–1,650,000,000 items/km2), which was likely due to discrepancy in sampling and analytical methods. Fragment was the most frequently observed shape and fiber was the most abundant shape. PE and PP were the most common and also most abundant polymer types. Overall, 2/3 of available data reported that seawater microplastic levels in MPAs were higher than 12,429 items/km2, indicating that global MPAs alone cannot protect against microplastic pollution. The current limitations and future directions were also discussed toward the post-2020 Global Biodiversity Framework goals.
- ItemRestrictedPerna perna e crassostrea brasiliana como sentinelas da contaminação por microplásticos em zonas costeiras(Universidade Federal de São Paulo, 2022-10-31) Ribeiro, Victor Vasques [UNIFESP]; Castro, Ítalo Braga [UNIFESP]; http://lattes.cnpq.br/0426330018731301; http://lattes.cnpq.br/1530887375287181; Universidade Federal de São Paulo (UNIFESP)A poluição marinha é um importante problema ambiental na atualidade, tendo as atividades antropogênicas como fontes histórias de substâncias e materiais potencialmente danosos para o ambiente. Resíduos sólidos, principalmente os plásticos, geram impactos aos ecossistemas, e estudos sobre o tema têm aumentado nos últimos anos. Estima-se que em 2050 haverá mais plástico que peixes nos oceanos, devido a lenta degradabilidade que lhes garante vasta distribuição, até em locais remotos. Microplásticos (MPs) são partículas plásticas com tamanho entre 1 µm e 5 mm, resultantes do processo de degradação de partículas maiores, ou já produzidas nesta faixa de tamanho. De fato, MPs têm sido encontrados associados à tecidos de várias espécies de organismos aquáticos. Nesse sentido, bivalves filtradores são particularmente suscetíveis a acumulá-los em seus tecidos. Dessa forma, ostras e mexilhões parecem ser boas sentinelas da contaminação por MPs, por serem sésseis, apresentarem ampla distribuição geográfica, e responderem fisiologicamente à exposição a contaminantes ambientais. Apesar disso, poucos estudos realizados até o momento avaliaram comparativamente a performance de diferentes espécies de bivalves no que tange a seu emprego em monitoramentos ambientais. O Sistema Estuarino de Santos (SES) está sob a influência de aportes de resíduos oriundos de diversas indústrias, além de abrigar um relevante complexo portuário para a América Latina. Costões rochosos do SES abrigam bancos naturais de Perna perna e Crassostrea brasiliana, cronicamente expostos a um gradiente de contaminação. Com base neste cenário, hipotetizamos que diferenças qualitativas e quantitativas no acúmulo de MPs podem ser detectadas entre estas espécies. Assim, o presente estudo avaliou comparativamente o acúmulo de MPs considerando as concentrações totais, forma, tamanho e composição polimérica em ostras e mexilhões expostos à diferentes níveis de contaminação no SES. Foram encontrados 2.534 MPs associadas ao tecido dos bivalves C. brasiliana e P. perna no SES. Os organismos obtidos no ponto mais contaminado (S1) foram os que apresentaram os piores estados de nutrição e saúde. Além disso, a concentração de MPs em bivalves de S1 estão entre os mais altos já reportados para moluscos até o presente momento (até 44,1 itens.g -1). Os MPs amostrados eram compostos principalmente de Celulose e polimetilmetacrilato (PMMA). Além disso, MPs foram principalmente < 1.000 µm (67,6%), fibras (97,3%) e sem coloração (87%). A avaliação espacial da distribuição de MPs em ostras e mexilhões do SES confirmou a presença de um gradiente de contaminação que já fora identificado por outros estudos de monitoramento da contaminação ambiental. As ostras apresentaram estado de nutrição e saúde mais consistente ao longo do gradiente de contaminação, além de acumularem uma maior diversidade de polímeros e mais MPs em pontos de amostragem sob menor pressão antropogênica. Entretanto, as duas espécies foram igualmente capazes de diagnosticar diferenças espaciais na concentração de MPs assim como os tipos mais frequentes de polímeros, classes de tamanho, forma e cor. Portanto, as duas espécies apresentam alto nível de equivalência quando usadas como sentinelas da contaminação por MP, apesar de algumas diferenças interespecíficas. Nossa abordagem pode servir como um guia valioso para selecionar espécies com bom desempenho para serem utilizadas em programas de monitoramento ambiental nas perspectivas local e global.
- ItemMetadata onlyPhysicochemical and chromatographic evaluation of benzhydrylamine-resin as an anion exchanger solid support(Elsevier B.V., 2003-07-31) Carvalho, Regina Siqueira Haddad [UNIFESP]; Nakaie, Clovis Ryuichi [UNIFESP]; Silva, Elias Horacio da [UNIFESP]; Santos, Isabel Anunciacao Neves dos [UNIFESP]; Dietrich, Carl Peter von [UNIFESP]; Nader, Helena Bonciani [UNIFESP]; Tersariol, Ivarne Luis dos Santos [UNIFESP]; Universidade Federal de São Paulo (UNIFESP)Benzhydrylamine-resin (BHAR), a copolymer of styrene-divinylbenzene containing phenylmethylamine groups, used as solid support for peptide synthesis, was examined regarding physicochemical and anion exchanger chromatographic properties. the greater the ionic strength of the medium the poorer the solvation of beads. This effect is less pronounced the higher the amino group content of BHAR. the BHAR chromatographic behavior was compared with commercial cationic resins in columns of constant cation binding capacity. Three negatively charged heparan sulfate disaccharides were successfully purified in a 2.4 mmol/g BHAR that showed as good or better anion exchange performance than classical tertiary or quaternary amino group-containing resins. the BHAR chromatographic resin exclusion limit was estimated to be 30 kDa based on purification experiments of heparins of different molecular weight. (C) 2003 Elsevier Science B.V. All rights reserved.
- ItemOpen AccessSimulações computacionais de eletrólitos em interfaces(Universidade Federal de São Paulo, 2018-06-19) Cardoso, Pierluigi Fortunato [UNIFESP]; Siqueira, Leonardo José Amaral de [UNIFESP]; Universidade Federal de São Paulo (UNIFESP)In this work the molecular dynamics, which is a computational simulation method, is used for the study of electrical, structural and dynamics properties of electrolytes for lithium and / or supercapacitor batteries. The electrolytes formed by ionic liquid and polymer were simulated at the interface with a flat electrode model, ionic liquid (IL), P(EO)7,8-IL, P(EO)15,6-IL e P(EO)15,6-Li+-IL at different densities of charges, 0q/nm2, 0,25 q/nm2, 0,5q/nm2, 0,75 q/nm2 and 1,0 q/nm2. The potential drop were calculated and assisted the analysis of the differential capacitances, being possible to observe the effect of the polymer poly (ethylene oxide) that acted like solvent, causing the decrease of the overscreening in relation to the system composed only by ionic liquid [EMIm]-[TFSI]. In this way, it was possible to calculate the differential capacitances that were also calculated for the different systems, noting that the increase in the number of molecules of PEO influences the decrease of the differential capacitances for each of the systems, such as the P(EO)15,6-IL, which has the highest amount of polymer PEO, had the lowest differential capacitance (3.4 on the positive electrode and 2.9 on the negative electrode) in relation to the other systems studied. In the case of batteries, the values obtained for the lithium ion to adsorb on the surface of the negative electrode is between 3,66V ~ 5,74V.
- ItemMetadata onlySolid-phase peptide synthesis in highly loaded conditions(Elsevier B.V., 2011-02-01) Nakaie, Clovis R. [UNIFESP]; Oliveira, Eliandre; Vicente, Eduardo F.; Jubilut, Guita N. [UNIFESP]; Souza, Sinval E. G. [UNIFESP]; Marchetto, Reinaldo; Cilli, Eduardo M.; Universidade Federal de São Paulo (UNIFESP); Barcelona Sci Pk; UNESP Univ Estadual PaulistaThe use of very highly substituted resins has been avoided for peptide synthesis due to the aggravation of chain-chain interactions within beads. To better evaluate this problem, a combined solvation-peptide synthesis approach was herein developed taking as models, several peptide-resins and with peptide contents values increasing up to near 85%. Influence of peptide sequence and loading to solvation characteristics of these compounds was observed. Moreover, chain-chain distance and chain concentration within the bead were also calculated in different loaded conditions. of note, a severe shrinking of beads occurred during the alpha-amine deprotonation step only when in heavily loaded resins, thus suggesting the need for the modification of the solvent system at this step. Finally, the yields of different syntheses in low and heavily loaded conditions were comparable, thus indicating the feasibility of applying this latter prohibitive chemical synthesis protocol. We thought these results might be basically credited to the possibility, without the need of increasing molar excess of reactants, of carrying out the coupling reaction in higher concentration of reactants - near three to seven folds - favored by the use of smaller amount of resin. Additionally, the alteration in the solvent system at the alpha-amine deprotonation step might be also improving the peptide synthesis when in heavily loaded experimental protocol. (C) 2011 Elsevier Inc. All rights reserved.