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171.
Manuel Brenes Francisco J. Hidalgo Aranzazu García José J. Rios Pedro García Rosario Zamora Antonio Garrido 《Journal of the American Oil Chemists' Society》2000,77(7):715-720
Polyphenols of olive oil show autoprotective, sensory, and nutritional-therapeutic effects. Two new phenolic compounds have
been isolated from virgin olive oils by preparative high-performance liquid chromatography and their structures established
on the basis of their mass spectra and nuclear magnetic resonance spectral data. The compounds identified are the lignans
pinoresinol and 1-acetoxypinoresinol. Both have been found in all the commercial virgin olive oils analyzed. Pinoresinol concentration
was rather similar in all the oils. In contrast, 1-acetoxypinoresinol concentration was higher in oils of the Arbequina and
Empeltre cultivars than in Picual or Picudo cultivars. Pinoresinol and 1-acetoxypinoresinol may represent the major phenolic
compounds in some Arbequina and Empeltre oils. Lignans possess biological and pharmacological properties and, therefore, the
two new compounds identified in olive oils may contribute to the reported beneficial effects which are attributed to polyphenols
on human health of a diet rich in olive oil. 相似文献
172.
Marina Villegas Amador C. Caballero Carlos Moure Pedro Durán José F. Fernández Robert E. Newnham 《Journal of the American Ceramic Society》2000,83(1):141-46
Pb(Zn1/3 Nb2/3 )O3 -based ceramics have been prepared by two different processing methods: conventional (PZN-C) and reaction-sintering (PZN-RS). The conventionally prepared PZN-based ceramics densified at lower temperatures (950°C) than the reaction-sintered samples (1100°C), but the perovskite/pyrochlore ratio was always higher in PZN-RS. The presence of a substantial amount of pyrochlore phase in PZN-C ceramics caused a decrease in the electrical properties. The maximum dielectric constant values in PZN-C ceramics were 10%–15% lower than those of PZN-RS, despite a similar average grain size, 7 ± 0.2 μm. The temperature of the maximum of the dielectric constant ( T max ) was lower than that expected from the mixing rule because of the possible formation of Ba–Nb clusters. The higher chemical homogeneity in PZN-RS ceramics is the main reason for the higher dielectric constant, T max and electromechanical response, as well as for the lower difference between T max and the depolarization temperature ( T d ) and the lower diffusiveness parameter (δ). 相似文献
173.
174.
Synthesis and characterization of the polyols by air oxidation of soybean oil and its effect on the morphology and dynamic mechanical properties of poly(vinyl chloride) blends
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Pedro A. Ourique Jérôme M. L. Gril Gaëlle W. Guillaume Cesar H. Wanke Sergio G. Echeverrigaray Otávio Bianchi 《应用聚合物科学杂志》2015,132(24)
The use of natural additives, with low toxicity and good compatibility, for PVC is becoming increasingly attractive. In this study, soybean oil additives were prepared by air oxidation reactions and blending with PVC. The oxidation reaction produced a significant increase in the number of hydroxyl groups in soybean oil; however, this kind of reaction results in the formation of a heterogeneous structure due to free radical reactions in the medium. The oxidized soybean oil improved the compatibility with PVC due to an increase in the number of polar groups, such as hydroxyls, and thus a reduction in the amount of atactic polymer was observed. Furthermore, an increase in the molecular weight of the oxidized oil, as well as large amounts of polar groups contributes to reducing the migration of oil in the PVC. Regarding the crystallinity of PVC, the use of pure and oxidized soybean oil causes small changes in the crystalline phase of the polymer. Oxidized soybean oil has great potential for usage as a secondary plasticizer for PVC. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42102. 相似文献
175.
176.
Effect of the drying process on the compressive strength and cell proliferation of hydroxyapatite‐derived scaffolds
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Francisco Martínez‐Vázquez Antonia Pajares Pedro Miranda 《International Journal of Applied Ceramic Technology》2017,14(6):1101-1106
The compressive strength and MC3T3 cell proliferation response of robocast hydroxyapatite‐derived scaffolds was evaluated for samples fabricated by conventional and freeze‐drying methods followed by sintering at 1100 or 1300°C. Both the sintering temperature and, especially, the drying method affected significantly the size and morphology of the residual microporosity within the robocast scaffold's struts. The freeze‐drying method generated a persistent large (1‐10 μm) microporosity of dendritic morphology that was found to improve the biological response of hydroxyapatite‐derived scaffolds. Conversely, conventional drying enhances the compressive strength of the structures. Strength was also increased at the higher sintering temperature, although at the expense of a poorer cell proliferation behavior. The results of this study suggest that the use of a freeze drying process after printing by robocasting provides a very appropriate method for enhancing the biological performance and reliability of bioceramic robocast scaffolds without severely reducing their compressive strength. And, thus, shows promise as an effective method to optimize the performance of robocast scaffolds for bone tissue regeneration. 相似文献
177.
Laccase‐mediated grafting of polyphenols onto cationized cotton fibers to impart UV protection and antioxidant activities
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Suyeon Kim Hyunkyung Lee Juhea Kim Fernando Oliveira Pedro Souto Hyerim Kim Javier Nakamatsu 《应用聚合物科学杂志》2018,135(6)
Enzyme‐mediated in situ functionalization of cotton fibers was studied using laccase. Caffeic acid and morin were used as reactive phenolic substrates for laccase and further employed to the modification of fiber surfaces. Laccase‐mediated oxidation and polymerization reactions of caffeic acid were monitored by ultraviolet–visible spectroscopy. During the wetting process, initial cationization of fiber surfaces using poly(diallyldimethylammonium chloride) followed by enzymatic treatment with phenolic substrates resulted ineffective polymer grafting evidenced by high color stability. Changes of fiber surface properties by polymer grafting, such as morphology and hydrophilicity/hydrophobicity, were tested using scanning electron microscopy and gravimetric absorption tests. An acceptable level of color resistance to washing stress was obtained on caffeic acid treated samples, and a high level of rubbing resistance was obtained on samples treated with both caffeic acid and morin. Regarding the ultraviolet protection test, the cationized and enzymatically functionalized samples showed a very good protection grade (ultraviolet protection factor = 25). Finally, the antioxidant activity test of the modified fibers presented an improvement for radical scavenging potential due to the phenolic compounds incorporated to cotton fibers by laccase‐mediated catalysis. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 45801. 相似文献
178.
Rodrigo F. P. Martins Arman Ahnood Nuno Correia Luís M. N. P. Pereira Raquel Barros Pedro M. C. B. Barquinha Ricardo Costa Isabel M. M. Ferreira Arokia Nathan Elvira E. M. C. Fortunato 《Advanced functional materials》2013,23(17):2153-2161
The ability to process and dimensionally scale field‐effect transistors with and on paper and to integrate them as a core component for low‐power‐consumption analog and digital circuits is demonstrated. Low‐temperature‐processed p‐ and n‐channel integrated oxide thin‐film transistors in the complementary metal oxide semiconductor (CMOS) inverter architecture are seamlessly layered on mechanically flexible, low‐cost, recyclable paper substrates. The possibility of building these circuits using low‐temperature processes opens the door to new applications ranging from smart labels and sensors on clothing and packaging to electronic displays printed on paper pages for use in newspapers, magazines, books, signs, and advertising billboards. Because the CMOS circuits reported constitute fundamental building blocks for analog and digital electronics, this development creates the potential to have flexible form factor computers seamlessly layered onto paper. The holistic approach of merging low‐power circuitry with a recyclable substrate is an important step towards greener electronics. 相似文献
179.
Many natural structures can be naturally represented by complex networks. Discovering network motifs, which are overrepresented patterns of inter-connections, is a computationally hard task related to graph isomorphism. Sequential methods are hindered by an exponential execution time growth when we increase the size of motifs and networks. In this article we study the opportunities for parallelism in existing methods and propose new parallel strategies that adapt and extend one of the most efficient serial methods known from the Fanmod tool. We propose both a master–worker strategy and one with distributed control, in which we employ a randomized receiver initiated methodology capable of providing dynamic load balancing during the whole computation process. Our strategies are capable of dealing both with exact and approximate network motif discovery. We implement and apply our algorithms to a set of representative networks and examine their scalability up to 128 processing cores. We obtain almost linear speedups, showcasing the efficiency of our proposed approach and are able to reach motif sizes that were not previously achievable using conventional serial algorithms. 相似文献
180.
Zhen‐Yu Du Dr. Pedro Araujo Ingunn Stubhaug Livar Frøyland 《European Journal of Lipid Science and Technology》2010,112(3):333-342
The information on binding capacity of different fatty acids (FAs) to albumin is incomplete, however, in the majority of in vitro experiments, FAs and albumin were simply mixed and their affinity believed to be complete. In this study, seven [1‐14C] FAs were mixed with albumin and assayed for β‐oxidation in rat liver homogenates. In the process of identifying the radioactive background of control assay by LCMS/MS, the results indicated different binding capacity of FAs to albumin. The percentage of unbound FAs recovered in clarified acidic solution was lower than 2% with 16:0 and 18:1n‐9, nearly 5% with EPA, 7% with 18:2n‐6, 18:3n‐3 and 20:4n‐6, and surprisingly high to 41% with DHA. Various FA/albumin molar ratios as well as different types of albumin only marginally affected these data. Thus, the big mass of unbound free DHA led to a high blank value, which is 60 times higher than the real value in the procedure of β‐oxidation measurement in vitro. In the design of future FA research in vitro, the binding capacity of FA to albumin or other proteins must be considered, especially for DHA research. 相似文献