Engenharia Química
URI permanente desta comunidadehttps://repositorio.fei.edu.br/handle/FEI/25
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170 resultados
Resultados da Pesquisa
Artigo 0 Citação(ões) na Scopus Development of highly resistant fibers for use in solid phase micro extraction (SPME)(2010-01-05) RODRIGUES, J. C.; LEITE, D. W.; LANCAS, F. M.The commercially available fibers for solid-phase microextraction (SPME) made of optical fibers are fragile and can be easily broken. Thus, there is a clear need for the development of efficient, simple and highly resistant SPME fibers. This work describes the preparation of highly resistant fibers in which a polymer is coated onto an open tubular fused silica capillary tubing (0.360 mm O.D.) fitted with a stainless steel wire (0.200 mm O.D.) previously inserted and cemented into the capillary tube opening to guarantee higher mechanical resistance. The fiber was coated with 70-μm poly (dimethyl siloxane) (PDMS) and evaluated for the extraction of polycyclic aromatic hydrocarbons.Artigo 23 Citação(ões) na Scopus Composition and screening of antifungal activity against Cladosporium sphaerospermum and Cladosporium cladosporioides of essential oils of leaves and fruits of Piper species(2010-09-05) Andreia de Araújo Morandim Giannetti; PIN, A. R.; PIETRO, N. A. S.; ALECIO, A. C.; KATO, M. J.; YOUNG, C. M.; OLIVEIRA, J. E. DE; FURLAN, M.This study investigated the composition and antifungal activity against Cladosporium sphaerospermum and Cladosporium cladosporioides of essential oils of leaves of Piper cernuum, Piper diospyrifolium, Piper crassinervium, Piper solmsianum and Piper umbelata and fruits of P. cernuum and P. diospyrifolium. The essentials oils were analyzed by GC-MS and submitted of the antifungal activity tests. The essential oils of fruits from P. cernuum and leaves of P. crassinervium and P. solmsianum showed potential antifungal activity against C. sphaerospermum and C. cladosporioides. In addition, this is the first report of the composition of essential oils of fruits of P. cernuum and P. diospyrifolium. © 2010 Academic Journals.Artigo 34 Citação(ões) na Scopus Composition and antifungal activity against candida albicans, candida parapsilosis, candida krusei and cryptococcus neoformans of essential oils from leaves of piper and peperomia species(2010-09-04) Andreia de Araújo Morandim Giannetti; PIN, A. R.; PIETRO, N. A. S.; OLIVEIRA, H. C. DE; MENDES-GIANNINI, M. J. S.; ALECIO, A. C.; KATO, M. J.; OLIVEIRA, J. E. DE; FURLAN, M.This study was addressed to investigate the composition and antifungal activity of essential oils from leaves of Piperaceae species (Piper aduncum, Piper amalago, Piper cernuum, Piper diospyrifolium, Piper crassinervium, Piper gaudichaudianum, Piper solmsianum, Piper regnellii, Piper tuberculatum, Piper umbelata and Peperomia obtusifolia) against Candida albicans, C. parapsilosis, C. krusei and Cryptococcus neoformans. The essential oils from P. aduncum, P. gaudichaudianum and P. solmsianum showed the highest antifungal activity against Cryptococcus neoformans with the MIC of 62.5, 62.5 and 3.9 mg.mL-1, respectively. The oil from P. gaudichaudianum showed activity against C. krusei with MIC of 31.25 mg.mL-1. © 2010 Academic Journals.Artigo 6 Citação(ões) na Scopus Study of salmonella typhimurium mutagenicity assay of (z)-piplartine by the ames test(2011-06-15) Andreia de Araújo Morandim Giannetti; Cotinguiba F.; REGASINI, L. O.; FRIGIERI, M. C.; VARANDA, E. A.; COQUEIRO, A.; KATO, M. J.; BOLZANI, V. S.; FURLAN, M.Phytochemical studies carried out with Piperaceae species have shown great diversity of secondary metabolites among which are several displayed considerable biological activities. The species Piper tuberculatum has been intensively investigated and a series of amides have been described. For instance, (E)-piplartine showed significant cytotoxic activity against tumor cell lines, especially human leukemia cell lines; antifungal activity against Cladosporium species; trypanocidal activity and others. Considering the popular use of P. tuberculatum and the lack of pharmacological studies regarding this plant species, the mutagenic and antimutagenic effect of (Z)-piplartine was evaluated by the Ames test, using the strains TA97a, TA98, TA100 and TA102 of Salmonella typhimurium. No mutagenic activity was observed for this compound. © 2011 Academic Journals.Artigo de evento 1 Citação(ões) na Scopus DMLM III device development for enzymes biochemical reactions in microgravity(2011-05-22) LA NEVE, A.; BELLODI, M.; MELO, M. A. A.; FERREIRA, M.; PEREIRA, A. N.; LUCARINI, A. C.The goal of this experiment was to investigate the invertase enzyme kinetics in microgravity to better understand the mechanism action inside and outside biological cells. To do this DMLM 111 device was developed, which is responsible for mixing liquids in microgravity. It consists of a mechanical part, with ten sets of reaction systems, and embedded electronics. Each reaction system consists of three chambers, for the enzyme, the substrate and the reaction inhibitor, and two valves to keep the liquids separated. When microgravity signal is triggered, enzyme and substrate are mixed to start the biochemical reaction. After five minutes the reaction is interrupted with the inhibitor. This experiment was embedded on a VSB-30 Brazilian sounding rocket, and payload remained in microgravity for approximately six minutes. Biochemical analyses of the samples are under way, and the results will be compared with the data obtained on earth, under similar conditions.Artigo de evento 3 Citação(ões) na Scopus CIM device for enzyme kinetics experiment aboard the International Space Station(2011-10-03) LA NEVE, A.; BELLODI, M.; FERREIRA, M.; LUCARINI, A. C.The main objective of this experiment is to verify the differences in kinetic parameters of enzymes reaction aboard the ISS. For this experiment the invertase enzyme was selected, as a case study in microgravity. It is expected that significant differences occur in the sucrose hydrolysis by invertase, due to diffusion phenomenon in microgravity. The experiment consists of two series of tests, each one with five different sucrose concentrations, to evaluate the invertase kinetics. The reaction is allowed during a period of time, after which the reactions are interrupted by addition of an enzyme inhibitor. The samples of the enzymes, after reaction, must return to earth for biochemical analysis in laboratory. It is expected that significant differences should occur in the hydrolysis of sucrose by invertase, due the diffusion phenomenon, that suffers alterations in microgravity. To perform this experiment in microgravity on ISS, CIM device was developed, with two sets of 5 chambers each, in a total of 10, to realize the mixture of two liquids and the enzyme. This compact device requires no electric power, and it can easily be operated by an astronaut manually. This device is an important evolution over the previous version, MEK device, which flew on ISS Brazilian "Centenary Mission", in March, 2006. The results were partly satisfactory and indicated an increase in reaction rate values, but a metal contamination of the samples due to the resistor oxidation, interfered in the biochemical reaction: this required confirmation and of the experiment and confrontation of data. This experiment aims at the study of the enzymatic kinetics of invertase, which catalyzes carbohydrates hydrolysis, such as sucrose, producing glucose and fructose. The study of enzymatic kinetics is fundamental for the comprehension of the enzymes action mechanism, in and out of the cells, and this may lead to the design of more efficient enzymatic bioreactors. Therefore, the study of the effects of microgravity on the enzymes action can be helpful to better understand their action mechanism on earth, and then to think of enzymatic processes and microorganisms applications, both on earth and in space. Copyright ©2010 by the International Astonautical Federation. All rights reserved.Artigo de evento 0 Citação(ões) na Scopus Biodiesel production from vegetal oil and ethanolvia transesterification in supercritical conditions(2014-11-16) SIDI NETO, V.; João Guilherme Rocha PoçoArtigo de evento 0 Citação(ões) na Scopus Density and speed of sound of binary mixtures of (diethyl malonate + methanol) at different temperatures and atmospheric pressure(2014-11-16) LIBORIO, M. N.; Ricardo TorresArtigo de evento 0 Citação(ões) na Scopus Influence of feedstock on biodiesel corrosiveness and degradation(2014-11-16) Isabella Aquino; ALVES, T. P.; SILVA, F. F. R; AOKI, I. V.; Ricardo TorresArtigo de evento 0 Citação(ões) na Scopus Transesterification of sunflower oil produced by solvent extraction(2014-11-16) Maristhela Passoni de Araújo Marin; Luis Novazzi; DENARI, M. L.In this work, the leaching of oil from sunflower seeds using hexane was studied. The solution of oil / hexane was thereafter transesterified, with methanol and potassium hydroxide (KOH) as the catalyst, in a batch reactor, for 1 hour and with a constant temperature of 45 °C. It is important to point out that the extracted oil was not refined and was directly used on transesterification reactions. The hexane in the oil / hexane solution acted as a cosolvent and made the oil / methanol mixture forms a single-phase. Experimental results obtained in the transesterification reactions showed that the increase of methanol / oil mole ratio on reaction yield is negative, whereas the increase of catalyst concentration on reaction yield is positive. Reaction yields decreased 18.00% on average when the mole ratio methanol / oil was increased. When catalyst concentration was augmented, reaction yields increased 15.19%, on average. These results are statistically meaningful, since the standard deviation was equal to 0.48%. Moreover, an interaction between methanol / oil mole ratio and catalyst concentration on reaction yield was observed.