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1.
Maurício L. Sforça Inez V. P. Yoshida Cristiano P. Borges Suzana P. Nunes 《应用聚合物科学杂志》2001,82(1):178-185
Hybrid materials were prepared incorporating silica networks by the sol–gel process into the poly(amide-b-polyether) block copolymer PEBAX®. PEBAX®/silica hybrids were characterized by transmission electron microscopy, atomic force microscopy, differential scanning calorimetry, and X-ray diffraction. The pervaporation of phenol from dilute aqueous solutions through hybrid membranes was investigated. Films prepared with lower silica contents showed better dispersed inorganic networks and were more selective in the pervaporation of phenol/water solutions. Films prepared with higher silica contents had a clear phase-separated morphology with lower performance in pervaporation. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 178–185, 2001 相似文献
2.
Mariana Gava Segatelli Inez Valéria Pagotto Yoshida Maria do Carmo Gonçalves 《Composites Part B》2010,41(1):98-105
Short silica fiber (SF) content on the mechanical and morphological properties of composites based on nylon 6 and rubber-toughened nylon 6 matrices was examined. Binary nylon 6/SF and ternary [nylon 6/EPDM-g-MA (ethylene–propylene–diene grafted with maleic anhydride)/SF] composites containing 0–20 wt% SF were formulated. The flexural modulus increased with the SF content at all fiber compositions investigated; however, the value of this property gradually diminished when 20 wt% rubber was added to the polymer. Notched Izod impact strength of 80/20 nylon 6/EPDM-g-MA blend was reduced up to 50% with the addition of 5 wt% SF. However, these composites still retained good stiffness and toughness and presented a good interfacial adhesion between the phases. The results suggest that silica fibers can be employed as an alternative reinforcement of nylon 6 matrices, resulting in materials with useful properties. 相似文献
3.
Laurent Picot Rozenn Ravallec Martine Fouchereau‐Péron Laurent Vandanjon Pascal Jaouen Maryse Chaplain‐Derouiniot Fabienne Guérard Aurélie Chabeaud Yves LeGal Oscar Martinez Alvarez Jean‐Pascal Bergé Jean‐Marie Piot Irineu Batista Carla Pires Gudjon Thorkelsson Charles Delannoy Greta Jakobsen Inez Johansson Patrick Bourseau 《Journal of the science of food and agriculture》2010,90(11):1819-1826
BACKGROUND: Numerous studies have demonstrated that in vitro controlled enzymatic hydrolysis of fish and shellfish proteins leads to bioactive peptides. Ultrafiltration (UF) and/or nanofiltration (NF) can be used to refine hydrolysates and also to fractionate them in order to obtain a peptide population enriched in selected sizes. This study was designed to highlight the impact of controlled UF and NF on the stability of biological activities of an industrial fish protein hydrolysate (FPH) and to understand whether fractionation could improve its content in bioactive peptides. RESULTS: The starting fish protein hydrolysate exhibited a balanced amino acid composition, a reproducible molecular weight (MW) profile, and a low sodium chloride content, allowing the study of its biological activity. Successive fractionation on UF and NF membranes allowed concentration of peptides of selected sizes, without, however, carrying out sharp separations, some MW classes being found in several fractions. Peptides containing Pro, Hyp, Asp and Glu were concentrated in the UF and NF retentates compared to the unfractionated hydrolysate and UF permeate, respectively. Gastrin/cholecystokinin‐like peptides were present in the starting FPH, UF and NF fractions, but fractionation did not increase their concentration. In contrast, quantification of calcitonin gene‐related peptide (CGRP)‐like peptides demonstrated an increase in CGRP‐like activities in the UF permeate, relative to the starting FPH. The starting hydrolysate also showed a potent antioxidant and radical scavenging activity, and a moderate angiotensin‐converting enzyme (ACE)‐1 inhibitory activity, which were not increased by UF and NF fractionation. CONCLUSION: Fractionation of an FPH using membrane separation, with a molecular weight cut‐off adapted to the peptide composition, may provide an effective means to concentrate CGRP‐like peptides and peptides enriched in selected amino acids. The peptide size distribution observed after UF and NF fractionation demonstrates that it is misleading to characterize the fractions obtained by membrane filtration according to the MW cut‐off of the membrane only, as is currently done in the literature. Copyright © 2010 Society of Chemical Industry 相似文献
4.
Mariana Gava Segatelli Eduardo Radovanovic Maria do Carmo Gonalves Inez Valria Pagotto Yoshida 《Journal of the European Ceramic Society》2009,29(15):3279-3287
This study focuses on the structural and morphological changes promoted by heating of silicon oxycarbide ceramics obtained from hybrid polymeric precursors based on poly(methylsiloxane) and divinylbenzene, with or without nickel acetate, by pyrolysis under Ar at different temperatures. The increase of the temperature from 950 to 1500 °C promoted the densification and crystallization of SiC and graphite nanodomains in the ceramic bulk with or without Ni, as identified by HRTEM. Moreover, the Ni-containing precursor led to the formation of ultra-long amorphous nanowires on the surface and voids in the ceramic body obtained at 1500 °C. These nanowires presented different sizes and morphologies, but similar compositions, basically composed by silicon and oxygen, with the presence of carbon at their external layers. The growth mechanism and the nature of the nanowires are also proposed. The addition of nickel acetate in the polymeric precursor induced the formation of nanowires with different morphologies in the Si–O–C system. 相似文献
5.
Hendrix JA Shimshock SJ Shutske GM Tomer JD Kapples KJ Palermo MG Corbett TJ Vargas HM Kafka S Brooks KM Laws-Ricker L Lee DK de Lannoy I Bordeleau M Rizkalla G Owolabi J Kamboj RK 《Chembiochem : a European journal of chemical biology》2002,3(10):999-1009
A new class of potent dopamine D(4) antagonists was discovered with selectivity over dopamine D(2) and the alpha-1 adrenoceptor. The lead compound was discovered by screening our compound collection. The structure-activity relationships of substituted isoindoline rings and the chirality about the hydroxymethyl side chain were explored. The isoindoline analogues showed modest differences in potency and selectivity. The S enantiomer proved to be the more potent enantiomer at the D(4) receptor. Several analogues with greater than 100-fold selectivity for D(4) over D(2) and the alpha-1 adrenoreceptor were discovered. Several selective analogues were active in vivo upon oral or intraperitoneal administration. A chiral synthesis starting from either D- or L-O-benzylserine is also described. 相似文献
6.
Cristiane Aparecida da Silva Márcia Maria Favaro Inez Valéria Pagotto Yoshida Maria do Carmo Gonçalves 《应用聚合物科学杂志》2011,121(5):2559-2566
Highly branched alkoxysilane (HB) units were prepared in situ via a Michael‐type reaction between pentaerythrithol triacrylate and aminopropyltriethoxysilane. These units were used as an inorganic component for the modification of cellulose acetate (CA) films using the sol–gel process. The thermal and dynamic‐mechanical behaviors, the morphology, and the dimensional stability of the modified CA films were analyzed. The siloxane‐modified CA films showed thermal stability similar to pure CA, but the residue content at 900°C increased with the addition of HB units. The morphology of these films was characterized by siloxane nanodomains dispersed in the CA matrix, with good interfacial adhesion between the phases. Moreover, the CA/siloxane nanocomposite films showed improved dimensional stability in comparison with CA, i.e., in the presence of HB, the dimensional change was reduced to around 50% of the value observed for pure CA. Finally, a complex dynamic‐mechanical behavior was obtained for the nanocomposite films, as a consequence of the heterogeneous morphology. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011 相似文献
7.
Nesma A. Saleh Inez M. Zwetsloot Mahmoud A. Mahmoud William H. Woodall 《Quality Engineering》2016,28(4):402-415
We study the effect of the Phase I estimation error on the cumulative sum (CUSUM) chart. Impractically large amounts of Phase I data are needed to sufficiently reduce the variation in the in-control average run lengths (ARL) between practitioners. To reduce the effect of estimation error on the chart's performance we design the CUSUM chart such that the in-control ARL exceeds a desired value with a specified probability. This is achieved by adjusting the control limits using a bootstrap-based design technique. Such approach does affect the out-of-control performance of the chart; however, we find that this effect is relatively small. 相似文献
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Kaptein Ad A.; van Korlaar Inez M.; Cameron Linda D.; Vossen Carla Y.; van der Meer Felix J.M.; Rosendaal Frits R. 《Canadian Metallurgical Quarterly》2007,26(6):807
Objective: This study applied the Common-Sense Model (CSM) to predict risk perception and disease-related worry in 174 individuals with a genetic predisposition to venous thrombosis (thrombophilia). Design: Participants completed an adapted version of the Illness Perception Questionnaire-Revised (IPQ-R) and measures assessing risk perception and worry. Results: Regression analyses revealed that illness perceptions were predictors of risk perception and thrombosis worry. The hypothesis that illness perceptions mediate the relationship between a person's experience of venous thrombosis and perceived risk and thrombosis worry could not be confirmed. Conclusions: Further research should refine the IPQ-R for populations at risk of a disease and examine the value of the CSM in explaining the relationship between risk perception, worry, and health behavior. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
10.
Examined the predictors of general union attitudes in a sample of 84 high school and 42 first year university students (aged 15–21 yrs) who were employed part-time. In addition to two aspects of family socialization towards unions (parents' perceived union attitudes and perceived union activities), Ss' job quality and satisfaction with both co-workers and supervisors were also assessed as predictors of their own general union attitudes. Results show that only Ss' perception of their parents' general union attitudes was significantly associated with their own general union attitudes. Thus, family socialization contributed the greatest amount of variance to general union attitudes. Neither job quality, nor supervisory or co-worker satisfaction were associated with Ss' union attitudes. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献