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31.
Anabela Santos Ângelo Luís Susana Ferreira Ana P. Duarte 《International Journal of Food Science & Technology》2019,54(3):862-870
In this work, heather and its flowers were studied regarding their antioxidant and antimicrobial activities. Plants were subjected to ultrasound-assisted methanolic extraction followed by fractionation. A phytochemical characterisation of extracts content in total phenols and flavonoids, and their antioxidant activity was performed. The antimicrobial activity was evaluated through the determination of minimum inhibitory concentration and by bioautography. Following, studies on the antilisterial potential were carried out by: time-kill curves, inhibition of biofilm formation and tolerance of Listeria monocytogenes to adverse conditions. The results evidenced the antioxidant activity in both extracts, as well as, the antimicrobial activity against Gram-positive bacteria. Concerning the evaluation of the antilisterial potential, a bacteriostatic behaviour and inhibition of biofilms formation ability were observed. Listeria monocytogenes showed an increased susceptibility to adverse conditions when preincubated with extracts. Thus, heather and its flowers may be a source of new compounds with antilisterial activity potential. 相似文献
32.
Romero Yesa Susana Aláez-Martínez Marian Ferran Zubillaga Ane García-Olalla Ana 《Universal Access in the Information Society》2021,20(3):573-593
Universal Access in the Information Society - This study focuses on a case study developed at a higher education institution, which comprises developing a new virtual teaching unit (VTU) aimed at... 相似文献
33.
Tamara G. Oberti Diego Larsen M. Susana Cortizo 《Polymer-Plastics Technology and Engineering》2019,58(4):443-453
New copolymers of dioctyl fumarate (DOF) and styrene (S) were synthetized by radical polymerization and used to modify bitumen. The poly(dioctyl fumarate-co-styrene) copolymers, PFS, were characterized by 1H-NMR and FTIR spectroscopies and size exclusion chromatography (SEC) in order to determine their monomer composition and weight average molecular weights, respectively. The polymer-bitumen blending conditions were optimized and the samples analyzed by different methodologies. Fluorescence microscopy, rotational viscosity and differential scanning calorimetry (DSC) were used to study the morphological changes of blends during their manufacturing and the rheological and thermal behavior, respectively. All modified bitumen (MB) exhibited higher viscosity than the based bitumen (BB) under studied conditions and this effect was more evident for the MB containing the higher molecular weight polymer. The addition of polymers to BB enhances the bitumen viscosity and thus increased the energy required for the flowing (activation energy calculated by Arrhenius equation). Thermal and morphological analysis showed that all MB exhibited good polymer- bitumen compatibility, which could be consider as a good starting point for a potential applications of this new material in road engineering. 相似文献
34.
Susana Ferreiro Basilio Sierra 《The International Journal of Advanced Manufacturing Technology》2012,60(1-4):237-249
This paper presents a particular problem dealing with the apparition of burr during the drilling process in the aeronautic industry. This burr cannot exceed a height limit of 127?μm as set out by the aeronautical guidelines and must be eliminated before riveting. If this is not performed, it can cause structural damage which would constitute a danger due to the lack of safety. Moreover, the industry needs to find an automated and optimised process in which the drilling and deburring can be carried out in real time, eliminating those other unnecessary tasks, in order to obtain high-quality pieces. The work presents the applicability of data mining and machine learning techniques so as to obtain a real time burr detection model. This model could be implanted in the computer numerical control of the machine allowing the whole process to be automated and optimised. These techniques can be applied to other types of processes. 相似文献
35.
Insight into the gas‐phase glycerol dehydration on transition metal modified aluminium phosphates and zeolites
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36.
Guardalben Lucas Gomes Tomé Salvador Paulo Sargento Susana 《Wireless Personal Communications》2017,97(2):2295-2328
Wireless Personal Communications - Mobile multimedia entertainment is pervasive on mobile devices, leading people to access, store and disseminate a diversity of multimedia contents anytime and... 相似文献
37.
Summary
Two novel polymers containing p-nitroaniline group in the side chain and diacetylene groups in the main chain, were synthesized, and characterized. The polymers
gave films of excellent optical quality by spin coating from DMF or chloroform. The one containing benzoate had a Tg of 103°C and its thermal cross-linking through the diacetylene group started at around 160°C. The one containing pentynoate
had a Tg of 35°C and its cross-linking started at around 120°C. It was shown that thermosetting resins with functional groups could
be obtained by using diacetylene-containing polymers. Although these two polymers have a same polar dye molecule, the second
order nonlinear optical property was so different, showing that the main chains are very important for nonlinear optical property.
Irradiation of UV light converted the polymer films to completely insoluble thermoset resins.
Received: 13 February 2001/Revised version: 25 July 2001/Accepted: 30 July 2001 相似文献
38.
Neill Taylor Dennis Baker Sergio Ciattaglia Pierre Cortes Joëlle Elbez-Uzan Markus Iseli Susana Reyes Lina Rodriguez-Rodrigo Sandrine Rosanvallon Leonid Topilski 《Fusion Engineering and Design》2011,86(6-8):619-622
An updated version of the ITER Preliminary Safety Report has been produced and submitted to the licensing authorities. It is revised and expanded in response to requests from the authorities after their review of an earlier version in 2008, to reflect enhancements in ITER safety provisions through design changes, to incorporate new and improved safety analyses and to take into account other ITER design evolution. The updated analyses show that changes to the Tokamak cooling water system design have enhanced confinement and reduced potential radiological releases as well as removing decay heat with very high reliability. New and updated accident scenario analyses, together with fire and explosion risk analyses, have shown that design provisions are sufficient to minimize the likelihood of accidents and reduce potential consequences to a very low level. Taken together, the improvements provided a stronger demonstration of the very good safety performance of the ITER design. 相似文献
39.
40.
Inhibition of Hydroperoxy-, Keto- and Hydroxy-FAME by Alpha- and Delta-Tocopherol at Rancimat Conditions
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Susana Marmesat Arturo Morales M. Victoria Ruiz-Méndez Gloria Márquez-Ruiz Joaquín Velasco 《Journal of the American Oil Chemists' Society》2016,93(1):93-103
The effects of α‐ and δ‐tocopherol on inhibition of hydroperoxides, keto and hydroxy compounds under Rancimat conditions, i.e. 100 °C and air bubbling, were studied in samples of fatty acid methyl esters (FAME) obtained from high linoleic (HL) and high oleic (HO) sunflower oils. Primary hydroperoxides from methyl linoleate and methyl oleate and secondary keto and hydroxy compounds derived from methyl linoleate hydroperoxides were analyzed by HPLC–UV‐ELS. Different tocopherol concentrations, namely, 10, 50, 100, 500 and 1000 mg/kg, were tested. Irrespective of the lipid substrate and the initial concentration of tocopherol, results showed that the content of hydroperoxides accumulated during the induction period was remarkably higher in the samples containing δ‐tocopherol. The relative concentrations of oleate hydroperoxides in the HO samples were also higher in the presence of δ‐tocopherol. α‐Tocopherol was more effective in inhibiting hydroperoxides at low levels, with 100 mg/kg as optimal concentration, while δ‐tocopherol displayed optimal protection at 1000 mg/kg. Under the oxidation conditions applied, neither α‐ nor δ‐tocopherol showed a protective effect on hydroperoxide decomposition at any level assayed. Formation of keto‐ and hydroxy‐dienes was more related to the concentration of their hydroperoxide precursors. Furthermore, both tocopherols gave rise to increased concentrations of ketodienes at 500 and 1000 mg/kg compared to the controls. Such an effect was more pronounced for α‐tocopherol and in the HL samples. 相似文献