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91.
Food Science and Biotechnology - The main objective of this study was to examine the phenolic compounds and the antibacterial, antioxidant, anti-α-glucosidase and anti-α-amylase... 相似文献
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Purification,structural data and biological properties of polysaccharide from Prunus amygdalus gum 下载免费PDF全文
Fatma Bouaziz Mohamed Koubaa Claire Boisset Helbert Fatma Kallel Dorra Driss Imen Kacem Raoudha Ghorbel Semia Ellouz Chaabouni 《International Journal of Food Science & Technology》2015,50(3):578-584
This work demonstrates the efficiency of almond gum polysaccharides (AGPs) as bioactive compounds. AGPs were first extracted using H2O2, in the presence of NaOH, at different times and temperatures. The optimal extraction conditions were 4% H2O2 and 2 N NaOH, for 7 h at 50 °C, leading to an extraction yield of 58.2% (w/w). After a purification step, the retained AGPs were characterised using high‐performance liquid chromatography showing a molecular weight of 99.3 kDa. The monosaccharide composition of AGPs were assessed using gas chromatography–mass spectrometry. AGPs were found to be a complex heteropolysaccharide with a repeating unit mainly composed of galactose, arabinose, xylose, mannose, rhamnose, and glucuronic acid with the respective ratios: 45:26:7:10:1:11. The acidic nature of the polysaccharide is due to the presence of glucuronic acid. Total antioxidant activity, free radical‐scavenging activity and reducing power assay of AGPs were investigated. The obtained results showed high antioxidant activities of AGPs. Furthermore, beyond 60 mg mL?1, AGPs exhibited bacterial growth inhibition for five pathogenic strains: Escherichia coli, Staphylococcus aureus, Enterococcus feacalis, Pseudomonas aeruginosa and Salmonella typhimurium. 相似文献
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M. Erdem Günay Fatma AkpinarZ. Ilsen Onsan Ramazan Yildirim 《International Journal of Hydrogen Energy》2012
The water gas shift activity of promoted Pt–CeO2/Al2O3 catalysts were investigated in this work. The catalysts were prepared by incipient to wetness impregnation and tested using a microflow reaction system. It was found that K has beneficial effects under product-containing feed compositions while Co and Ni promoters worsen catalyst performance. The reaction temperature and feed H2O/CO ratio positively affect the catalytic activity, whereas CO2 and H2 addition to the feed decreases CO conversion, as expected. The experimental results were also modeled using modular neural networks, at which the catalyst preparation and operational (reaction) variables were used together in the same network because they are interacting but processed differently because they are dissimilar in their form (i.e. categorical versus continuous) and their effects on catalytic activity. It was concluded that the effects of catalyst preparation and operational variables and their relative importance could be comprehended more accurately by using this approach, which may be also employed in other similar systems. 相似文献
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This study aims to achieve effects of improved hydrophilicity and microorganism inhibition, which are rarely simultaneously present in wound dressings. Cotton gauzes were modified using the grafting of a polymer-based β-cyclodextrin. After optimizing the grafting conditions, the untreated and modified cellulosic samples were principally characterized using FT-IR spectroscopy, TGA/DTA analysis, in vitro drug release, and wettability measurements. In light of desired characteristics of wound dressings, the effectiveness of procedures was evaluated. It was found that contact angles for cotton gauzes decreased after functionalization, which means that hydrophilicity was proven to become excellent. A successful Methylene Blue complexation was confirmed through measure of the dyebath exhaustion using UV-spectrophotometry. Then, during Methylen Blue release test, we reported an initial burst release of active ingredient over 7?h, followed by zero-order release. The treatment effect on antimicrobial activity was investigated by growth inhibition, which was proven against Staphylococcus aureus and Escherichia coli. 相似文献
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Fatma Ceyhun Şahin 《国际能源研究杂志》2017,41(4):526-539
There is no general rule in the literature to help choose a correct flow control device for any given case of turbomachinery applications. This suggests individual optimization of flow control devices for each specific case. The objective of this study is to prove experimentally the benefits of passive control methods in improving the compressor performance. This allows to reduce the fuel consumption, leading to energy saving and reduction of atmospheric pollution. Two features have been controlled in this study: flow separation over the blade surfaces and the secondary flow over the cascade endwalls. Vortex generator ribs are tested on the blade suction side for flow reattachment on the blade surfaces, and low‐profile vortex generators are tested on the side walls of the compressor cascade against secondary flow losses. Different vortex generator designs are compared for total pressure recovery, flow turning, boundary layer characteristics, and pressure distributions over the endwalls. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献
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Motivated by the search for universal orbits in geometric control theory and universal topological semigroups over local semigroups in topological groups, particularly Lie groups, we introduce a very general axiomatic notion of “trajectory,” namely a topological space equipped with a family of paths satisfying certain properties that make it what we call an “admissible family.” Considering one-parameter families of these paths as a homotopy allows us to construct a homotopy path space, our main object of consideration. We identify a distinguished subfamily of admissible paths via what we call a selection or partial selection and show how this insures collapses in the homotopy path space structure. We establish sufficient conditions to identify the homotopy path space as the simply connected covering or as residing in the simply connected covering and point out certain of its universal properties in this setting. We close by applying and illustrating our results in the setting of Lie groups and semigroups. 相似文献
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This paper discusses a Sensors Fault Detection and Isolation (FDI) and Fault Tolerant Control (FTC) of three phase inverter for PV system application. All sensors used in the inverter control strategy are addressed in this work. The developed FDI algorithm focuses on residuals generation; it is defined by the different between measurement and reconstituted signal. So, estimators block are investigated, such as, two Models References Adaptive Systems (MRAS) are developed to reconstitute the information of three phase line currents and dc link voltage sensors. The reconstituted information is injected to the corresponding FDI algorithm. Grid voltage sensors FDI is presented in this contribution trough the use of scaled virtual flux estimator, based on Second Order Generalized Integrator and Frequency Looked Loop. When a fault detected, FTC is ensured by replacing the erroneous measurement by its corresponding estimator. Theoretical study and simulations results are presented to validate the effectiveness of the proposed method. 相似文献