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71.
Rogério A. Saraiva Edinardo F. F. Matias Henrique D. M. Coutinho José G. M. Costa Heloísa Helena F. Souza Cícera Norma Fernandes João B. T. Rocha Irwin R. A. Menezes 《European Journal of Lipid Science and Technology》2011,113(8):967-972
The oil obtained from the Caryocar coriaceum Wittm. (pequi) fruit pulp (C. coriaceum fixed oil – CCFO), rich in fatty acids, has been secularly employed by traditional medicine in the treatment of respiratory affections, skin inflammation, and wounds. These observations encouraged us to investigate the antimicrobial activity of CCFO and to investigate its effect in combination with aminoglycosides. The minimum inhibitory concentration (MIC) of CCFO alone and associated with aminoglycosides against Escherichia coli and Staphylococcus aureus strains were determined using microdilution assay. CCFO alone had a MIC of 512 µg/mL against E. coli and S. aureus resistant strains. Combining the CCFO with aminoglycosides reduced the MIC of aminoglycosides against the resistant strains of E. coli and S. aureus. The results obtained indicate that CCFO displays a significant synergistic antibiotic effect when combined with aminoglycosides, demonstrating that the oil constituents (fatty acids) may act as potentiators of the antibiotic activity of aminoglycosides. These properties make CCFO oil an interesting alternative as a remedy or nutraceutical against multiresistant bacteria, preventing the development of resistance by these microorganisms. Practical applications: This article demonstrates the capacity of the C. coriaceum oil to enhance the antibiotic activity of aminoglycosides. This activity could represent a new way to combat the growing bacterial resistance to antibiotics, an important problem of public health. 相似文献
72.
Real‐time monitoring by proton relaxometry of radical polymerization reactions of acrylamide in aqueous solution 下载免费PDF全文
Elton Jorge da Rocha Rodrigues Roberto Pinto Cucinelli Neto Pedro José Oliveira Sebastião Maria Inês Bruno Tavares 《Polymer International》2018,67(6):675-683
The potential of time‐domain nuclear magnetic resonance (TD‐NMR) for the real‐time monitoring of solution radical polymerizations is demonstrated. A model system composed of a redox‐pair initiator system, acrylamide as monomer and water as solvent was investigated. A second‐generation continuous wave free precession technique was employed to measure the longitudinal relaxation time constant (T1) of the samples throughout the polymerization reactions. This parameter was shown to be sensitive to the reactant feed free‐radical enhancement of the water molecule relaxation time, making it a good probe to monitor monomer conversion in real time in an automated, non‐destructive fashion. It was found that the T1 value was better than the transverse relaxation time constant (T2) for describing the evolution of the polymerization reactions, due to its greater sensitivity to paramagnetic effects. The TD‐NMR signal variation observed was linked to the formation, propagation and termination steps of the radical polymerization kinetics scheme. These first results may contribute to the application of real‐time monitoring of radical polymerization reactions employing low‐cost and robust TD‐NMR spectrometers. © 2018 Society of Chemical Industry 相似文献
73.
Denise Maria Loureiro Contente Rayanne Rocha Pereira Antonio Manoel Cruz Rodrigues Edilene Oliveira da Silva Roseane Maria Ribeiro-Costa José Otavio Carrera Silva-Júnior 《化学工程与技术》2020,43(7):1424-1432
Nanoemulsion-based acai oil was obtained by the phase inversion method using two nonionic surfactants, Ceteareth-20 (Brij™ CS20) and polyoxyethylene-hydrogenated castor oil (Croduret™ 50), with the concentration of each surfactant varying from 7 to 10 %. The formulation with 10 % Brij CS20 presented the best values for droplet size, zeta potential, and polydispersity index (PDI). Ketoconazole was incorporated into this formulation, with an encapsulation efficiency of 98.31 % and equally good zeta potential, droplet size, and PDI, and spherical shape when observed by transmission electron microscopy. Overall, nanoemulsions of acai oil proved to be a good vehicle for imidazole antifungals such as ketoconazole. 相似文献
74.
Daniela F. S. Fonseca ?ngelo C. Salvador Sónia A. O. Santos Carla Vilela Carmen S. R. Freire Armando J. D. Silvestre Sílvia M. Rocha 《International journal of molecular sciences》2015,16(6):14194-14209
The lipophilic composition of wild Arbutus unedo L. berries, collected from six locations in Penacova (center of Portugal), as well as some general chemical parameters, namely total soluble solids, pH, titratable acidity, total phenolic content and antioxidant activity was studied in detail to better understand its potential as a source of bioactive compounds. The chemical composition of the lipophilic extracts, focused on the fatty acids, triterpenoids, sterols, long chain aliphatic alcohols and tocopherols, was investigated by gas chromatography–mass spectrometry (GC–MS) analysis of the dichloromethane extracts. The lipophilic extractives of the ripe A. unedo berries ranged from 0.72% to 1.66% (w/w of dry weight), and consisted mainly of triterpenoids, fatty acids and sterols. Minor amounts of long chain aliphatic alcohols and tocopherols were also identified. Forty-one compounds were identified and among these, ursolic acid, lupeol, α-amyrin, linoleic and α-linolenic acids, and β-sitosterol were highlighted as the major components. To the best of our knowledge the current research study provides the most detailed phytochemical repository for the lipophilic composition of A. unedo, and offers valuable information for future valuation and exploitation of these berries. 相似文献
75.
Daniele da Silva Bastos Maria do Pilar Gonçalves Cristina Tristão de Andrade Kátia Gomes de Lima Araújo Maria Helena Miguez da Rocha Leão 《Food and Bioproducts Processing》2012,90(4):683-692
The aim of this work was to obtain a new stable food product from cashew apple juice encapsulated by spray-drying technique using chitosan–whey protein isolate systems. The materials were evaluated according to their physicochemical stability during storage at different conditions and characterized with respect to their particle size distribution and structure. Encapsulated commercial and natural juices showed homogenous and unimodal particle size distribution with diameters ranging from 0.2 to 5.0 μm and from 0.2 to 40.0 μm, respectively. Both juices demonstrated higher physicochemical stability for vitamin C and color measurements than their respective non-encapsulated juices. X-ray diffractograms evidenced that the powder juices after the 140th day of storage were still in amorphous state. These results indicate that the new product was effective in protecting sensitive compounds present in the food matrix and it was also able to remain stable throughout the study period. 相似文献
76.
G. N. Da Rocha Filho M. H. S. Bentes D. Brodzki G. Djéga-Mariadassou 《Journal of the American Oil Chemists' Society》1992,69(3):266-271
Catalytic hydrocracking ofHevea brasiliensis (Seringa) andVirola sebifera (Ucuuba) oils was carried out in the presence of a NiMo/Al2O3 catalyst sulfidizedin situ with elemental sulfur at 360°C. The initial pressure of hydrogen was 140 bars. Conversions of nearly 100% of the vegetable
oils were achieved. The compositions of the liquid fuels were studied in detail by gas chromatography/mass spectrometry. The
main products were found to be alkanes, cycloalkanes, aromatics and carboxylic acids. 相似文献
77.
Maria Jos O. C. Guimares Fernanda M. B. Coutinho Marisa C. G. Rocha Maria Elizabeth F. Garcia 《应用聚合物科学杂志》2001,81(8):1991-1995
Mechanical, thermal, and morphological properties of blends of high density polyethylene and poly(ethylene‐co‐1‐octene) (PEO) were evaluated. The blends were prepared in a single screw extruder at 230°C and 50 rpm with volume fraction of elastomer varying in the range from 0.05 to 0.8. Factors such as chemical similarity and melt viscosity favor the interdiffusion process of phases, resulting in better interfacial adhesion. A synergistic effect on the strength at break and elongation at break for a particular range of blend composition was observed. Blends with a volume fraction of PEO higher than 5% presented a super tough behavior at room temperature. Thermal analysis showed that there is a certain degree of interaction between high density polyethylene and PEO. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 1991–1995, 2001 相似文献
78.
Catarine Massucato Nishijima Flavia Karina Delella Clenilson Martins Rodrigues Daniel Rinaldo Monica Valdyrce dos Anjos Lopes-Ferreira Lucia Regina Machado da Rocha Wagner Vilegas Sergio Luis Felisbino Clélia Akiko Hiruma-Lima 《International journal of molecular sciences》2015,16(6):12454-12466
Inflammation and haemorrhage are the main characteristics of tissue injury in botropic envenomation. Although some studies have shown that anti-venom prevents systemic reactions, it is not efficient in preventing tissue injury at the site of the bite. Therefore, this work was undertaken to investigate the anti-inflammatory effects of the methanolic extract and fractions from D. elliptica and to evaluate the role of matrix metalloproteinases (MMPs) in this process. Effects of the extract and fractions from D. elliptica were evaluated using a carrageenan-induced paw oedema model in rats, and leukocyte rolling was visualized by intravital. The quantification of MMPs activities (MMP-2 and MMP-9) extracted from the dermis of mice treated with extract and fractions alone or incubated with venom was determined by zymographic analyses. Our results show that intraperitoneal (i.p.) injection of fractions significantly reduced paw oedema after the carrageenan challenge. Treatment with the tannins fraction also resulted in considerable inhibition of the rolling of leukocytes and this fraction was able to decrease the activation of MMP-9. These results confirmed the anti-inflammatory activity of the methanolic extract and tannins fraction of D. elliptica and showed that the dermonecrosis properties of B. jararaca venom might be mediated through the inhibition of MMP-9 activity. 相似文献
79.
Polycarbonate/1‐(2‐hydroxyethyl)‐2,3‐dimethylimidazolium chloride composite membranes and short‐range chain mobility analysis 下载免费PDF全文
In this investigation, the incorporation of imidazolium salt, 1‐(2‐hydroxehtyl)‐2,3‐dimethylimidazolium chloride [hydemmim][Cl] within bisphenol A polycarbonate (PC) matrix and the subsequent formation of membranes via casting were studied. Characterizations that aimed to establish structure‐property correlations by Fourier transform infrared spectroscopy, differential scanning calorimetry, thermogravimetric analysis, dynamic mechanical thermal analysis, and water vapor transport (WVT) were performed. The results indicated that the presence of ionic liquid (IL) within the PC matrix significantly alter the local and macromolecular structure. The thermal stability is increased for all levels of incorporation. The plasticizing and antiplasticizing effects were observed due to the influence of the proportions of IL incorporated and of the cation's substituent chain of this IL. Distinct mechanisms of WVT were also observed in the presence of IL. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 45117. 相似文献
80.
Miguel Pinto Marlene Rebola Henriqueta Louro Alexandra M. M. Antunes Silvia S. José Maria Rocha 《Polycyclic Aromatic Compounds》2013,33(4):356-371
Polycyclic aromatic hydrocarbons (PAHs) are among the most persistent and toxic organic micropollutants present in water and several of them are mutagenic and carcinogenic. Although it has been shown that chlorinated derivatives of PAHs (Cl-PAHs) may be formed during the water chlorination procedure, little is known about their potential genotoxic and carcinogenic effects. The objectives of the present work were to prepare and characterize the major chlorinated derivatives of benzo[a]pyrene (BaP) and fluoranthene (Fluo), to develop an analytical methodology for their quantification in water samples and to analyse their potential genotoxicity. Chlorinated standards were prepared by a newly developed two phase method (water/n-hexane) using sodium hypochlorite. 6-Chloro-benzo[a]pyrene was selectively obtained from BaP, while 1,3-dichloro-fluoranthene and 3-chloro-fluoranthene were obtained from Fluo. All products were isolated and characterized by nuclear magnetic resonance and mass spectrometry. The formation of BaP- and Fluo-chlorinated derivatives under aqueous chlorination conditions was observed using a SPE-HPLC-FLD methodology. In addition, the cytotoxic and genotoxic activities of the three chlorinated derivatives were analyzed in comparison to their parent compounds, in a human-derived hepatoma cell line using the neutral red uptake and comet assays, respectively. The results showed that, at the equimolar doses of 100 and 125 μM, 6-Cl-BaP was able to induce a significantly higher level of DNA damage than BaP, suggesting a more potent genotoxic effect. In contrast, neither Fluo nor its chlorinated derivatives were genotoxic in the same cell line. The identification of new and possibly hazardous water chlorination by-product from PAHs emphasizes the need to minimize total organic carbon content of raw water and the implementation of safer water disinfection methods. 相似文献