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81.
Hayane Ferreira Leite Ladislau Thaísa Gabriela Silva de Farias Bruna Lúcia Mendonça Soares José Alberto da Costa Medeiros Natália Ferrão Castelo Branco Melo Thatiana Montenegro Stamford–Arnaud Thayza Christina Montenegro Stamford Tânia Lucia Montenegro Stamford 《International Journal of Food Science & Technology》2021,56(10):5395-5401
This research verified the ability of Lactobacillus rhamnosus encapsulated with inulin to tolerate the simulated digestive system and their viability in a soy blend. Probiotic encapsulated in alginate-chitosan matrix without inulin presented a better encapsulation efficiency (80.92%) than encapsulation with inulin (57.39%). On the 28th day, the count of probiotics decreased by 3.42 and 1.99 logarithmic cycles of free and encapsulated cells without inulin, respectively. In contrast, the microorganisms encapsulated with inulin showed an increase of 1.26 logs CFU g−1. During gastrointestinal simulation, cell counts decreased by 0.78, 1.55 and 1.95 CFU g−1 logs for encapsulated cells without inulin, free and encapsulated with inulin, respectively. Sensory panellists liked the fermented soy blend with encapsulated lactobacilli, and this result shows the possibility to create new probiotic foods of plant origin. Therefore, the alginate/chitosan matrix can be considered adequate for the encapsulation of L. rhamnosus. The inulin reduces the encapsulation efficiency and increases the cell loss in gastrointestinal simulation. Considering cellular losses, the best option for preparing a fermented soy blend is to use L. rhamnosus encapsulated without inulin. 相似文献
82.
Leonardo Sales Araujo Alessandra Vieira Guimarães Maísa Conceição Siqueira Matheus Campolina Mendes Loic Mallet Dilson Silva dos Santos Luiz Henrique de Almeida 《International Journal of Hydrogen Energy》2021,46(29):16164-16178
The nickel-base superalloy 718 is a precipitation hardened alloy widely used in the nuclear fuel assembly of pressurized water reactors (PWR). However, the alloy can experience failure due to hydrogen embrittlement (HE). The processing route can influence the microstructure of the material and, therefore, the HE degree. In particular, the size and distribution of the (Nb,Ti)C particles can be affected by the processing. In this regard, the objective of this work was to analyze the influence of cold and hot deformation processing routes on the development of the microstructure, and the consequences on mechanical properties and hydrogen embrittlement. Tensile samples were hydrogenated through gaseous charging and compared to non-hydrogenated samples. Characterization was performed via scanning and transmission electron microscopies, as well as electron backscattered diffraction. The processing was effective to promote significant variations in average grain size and length fraction of special Σ3n boundaries, as well as reduction of average (Nb,Ti)C particle size, being these changes more intense for the cold-rolled route. For the mechanical properties, on one side, the cold-rolled route presented the highest increase in ductility for non-hydrogenated samples, while, on the other side, had the highest degree of embrittlement under hydrogen. This dual behavior was attributed to the interaction of hydrogen with the (Nb,Ti)C particles and stringers and its ensuing influence on the fracture processes. 相似文献
83.
Total phenolic compounds,radical scavenging and metal chelation of extracts from Icelandic seaweeds 总被引:1,自引:0,他引:1
Screening of potential antioxidant activities of water and 70% acetone extracts from ten species of Icelandic seaweeds was performed using three antioxidant assays. Significant differences were observed both in total phenolic contents (TPC) and antioxidant activities of extracts from the various species evaluated using 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity, oxygen radical absorbance capacity (ORAC) and ferrous ion-chelating ability assays. Acetone extracts from three Fucoid species had the highest TPC and consequently exhibited the strongest radical scavenging activities. High correlation was found between TPC of seaweed extracts and their scavenging capacity against DPPH and peroxyl radicals, indicating an important role of algal polyphenols as chain-breaking antioxidants. However, water extracts generally had higher ferrous ion-chelating activity than 70% acetone extracts and no correlation was found with their TPC, suggesting that other components such as polysaccharides, proteins or peptides in the extracts were more effective chelators of ferrous ions than phenolic compounds. 相似文献
84.
Electrical properties of natural rubber nanocomposites: effect of 1-octadecanol functionalization of carbon nanotubes 总被引:1,自引:0,他引:1
P.?Selvin Thomas Adedigba?A.?Abdullateef Mamdouh?A.?Al-Harthi Muataz?A.?Atieh S.?K.?DeEmail author Mostafizur?Rahaman T.?K.?Chaki D.?Khastgir Sri?Bandyopadhyay 《Journal of Materials Science》2012,47(7):3344-3349
This article reports the results of studies on the effect of 1-octadecanol (abbreviated as C18) functionalization of carbon
nanotubes (CNT) on electrical properties of natural rubber (NR) composites. Dispersion of CNT in NR matrix was studied by
transmission electron microscopy (TEM) and electrical resistivity measurements. Fourier transform infra red spectrometry (FTIR)
indicates characteristic peaks for ether and hydrocarbon in the case of C18 functionalized CNT. Dielectric constant increases
with respect to the filler loading for both unmodified and functionalized CNTs, the effect being less pronounced in the case
of functionalized CNT due to its better dispersion in the matrix. Stress–strain plots suggest that the mechanical integrity
of the NR/CNT composites, measured in terms of tensile strength, increases on C18 functionalization of the nanofiller. TEM
reveals that the functionalization causes improvement in dispersion of CNT in NR matrix, which is corroborated by the increase
in electrical resistivity in the case of the functionalized CNT/NR composites. 相似文献
85.
Tânia Lopes Luísa AndradeHelena Aguilar Ribeiro Adélio Mendes 《International Journal of Hydrogen Energy》2010
The photocurrent-voltage characteristic of a photoelectrochemical cell for solar hydrogen production via water splitting, using undoped-hematite as photoanode, was obtained. Photoelectrochemical characteristics of the cell were also investigated by electrochemical impedance spectroscopy. Both techniques were carried out in the dark and under illumination. The analysis of the frequency spectra for the real and imaginary parts of the complex impedance allowed obtaining equivalent electrical analogs for the PEC cell operating in the dark and under 1 sun simulated illumination. Additionally, different electrode configurations were used (two and three-electrode arrangements). The two-electrode configuration allowed the study of the overall charge transfer phenomena occurring at the semiconductor, within the electrolyte and at the counter-electrode side of the cell, whereas the three-electrode configuration gave more detailed information concerning the double charged layer at the semiconductor/electrolyte interface. 相似文献
86.
Bruno Esteves Luísa Cruz-Lopes Artur Figueirinha Luis Teixeira de Lemos José Ferreira Helena Pereira Idalina Domingos 《Holz als Roh- und Werkstoff》2017,75(6):903-909
Heavy metals adsorption with lignocellulosic materials has been heavily researched in the last years. Since heat activation has been used with good results to increase the adsorption capacity of some materials, heat-treated wood might be a better adsorbent. This hypothesis is the basis of the present study. The adsorption tests were made with powdered pine wood, heat-treated at 190–210?°C. All the heat-treated samples showed a significantly higher adsorption compared to untreated wood. The maximum adsorption was obtained at pH 3 for heat-treated wood at 210?°C. The kinetics of the adsorption process fitted a pseudo-second-order reaction (R2 0.990–0.996). Adsorption fitted well both the Langmuir and the Freundlich model, but the Freundlich model presented higher R2 (0.988–0.998). The qmax values estimated by the Langmuir plotting were in the range 15.6–19.4 mg/g and the n values from Freundlich isotherms between 1.87 and 2.39. Heat-treated wood was a better adsorption material than untreated wood for chromium adsorption. This can be a good application for the sawdust produced by the processing of heat-treated wood at primary and secondary wood processing mills or for the recycling of heat-treated wood at the end of product life. 相似文献
87.
Ana Luísa Daniel‐da‐Silva João Carlos Moura Bordado José Miguel Martín‐Martínez 《应用聚合物科学杂志》2008,107(2):700-709
The study of the kinetics of the curing of isocyanate quasi‐prepolymers with water was performed by infrared spectroscopy and differential scanning calorimetry. The influence of the free isocyanate content, polyol functionality, and of the addition of an amine catalyst (2,2′‐dimorpholinediethylether) in the reaction kinetics and morphology of the final poly(urethane urea) was analyzed. A second‐order autocatalyzed model was successfully applied to reproduce the curing process under isothermal curing conditions, until gelation occurred. A kinetic model‐free approach was used to find the dependence of the effective activation energy (Ea) with the extent of cure, when the reaction was performed under nonisothermal conditions. The dependence of Ea with the reaction progress was different depending on the initial composition of the quasi‐prepolymer, which reveals the complexity of the curing process. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2008 相似文献
88.
Nacása & Partners Inc. 《城市环境设计》2012,(7):194-195
这个环游世界的酒亭是专为一家香槟酿制商所设计的。设计者试图尽可能地跳出建筑给人的刻板印象,摆脱固定不变的形态。选用一种名为EVA薄片,以2mm直径绳树脂超软膜材料所制成,并由形状记忆合金的框架来支撑。框架上不只是2mm直径绳树脂材料,而且含有一种吸收膜,目的是使膜与框架就算框架伸展到最大时也可以紧密地粘在一起。因为这个形状记忆合金的形状将随着温度的改变,这样的变化使得这个圆拱形KXK如同生物般的 相似文献
89.
Maria Luísa Braga FARINHA José Vieira de LEMOS Emanuel MARANHA DAS NEVES 《Frontiers of Architecture and Civil Engineering in China》2012,(1)
This paper presents the application of a methodology which can be used to assess arch dam foundation stability,using the discrete element method (DEM) and the code 3DEC.A global three-dimensional model... 相似文献
90.
Vojtech VargaMichal Horá?ek Zdeněk BastlJan Merna Ivana Císa?ováJan Sýkora Ji?í Pinkas 《Catalysis Today》2012,179(1):130-139
The efficient catalytic dehydropolymerization of phenylsilane by homogeneous zirconocene bissilanolates ([{(c-C5H9)7Si8O12O}2Zr(η5-C5H5)2] (1a); [{(c-C5H9)7Si8O12O}2Zr(η5-C5H4Bu)2] (1b) [{(c-C5H9)7Si7O9(OSiMe3)O2}Zr(η5-C5H5)2] (4); [{(Me3CO)3SiO}2Zr(η5-C5H5)2] (5)) and chlorosilanolates ([{(c-C5H9)7Si8O12O}ZrCl(η5-C5H4Bu)2] (2); ([{(c-C5H9)7Si7O9O3}Zr2Cl(η5-C5H5)4] (3a); [{(c-C5H9)7Si7O9O3}Zr2Cl(η5-C5H4Bu)4] (3b)) has been demonstrated. The presence of at least one silanol ligand in the zirconocene moiety was found essential for high catalytic performance. Solid state structure of complex 1a was determined by single crystal X-ray diffraction analysis. A series of nine zirconocene-siliceous catalysts were prepared by grafting of zirconocene moiety onto silica using three general methods: (a) reaction of [(η5-C5H5)2ZrCl2] with silica in the presence of NEt3; (b) reaction of [(η5-C5H5)2ZrMe2] with silica; (c) reaction of solely [(η5-C5H5)2ZrCl2] with silica. Supported catalysts were characterized by ICP-MS, FT-IR, TGA and selected examples by XPS analysis. Those catalysts prepared by method (a) and (b) were found efficient in the phenylsilane polymerization although a higher Zr/monomer ratio had to be used in comparison with homogeneous analogues. The low concentration of residual silanol groups in supported catalysts was found essential for their high catalytic performance. Advantageous reusability of supported catalysts was demonstrated using SiO2(500)/Cp2ZrCl2/NEt3(5.8). The catalytic performance was retained in three consecutive cycles producing polymers with almost identical properties. 相似文献