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991.
María A. Bertinetti Pablo A. Turner Raú E. Bolmaro Carlos N. Tomé† 《Journal of the American Ceramic Society》1996,79(6):1466-1472
The sintering of Al2 O3 /SiC ceramic composite leads to a state of high internal stresses in the composite material at room temperature because of the difference in thermal contraction between matrix and particles. It has been shown in a previous work1 that the interaction among fibers must be accounted for in order to predict correctly the residual stresses. In the present paper we develop a numerical scheme that permits taking into account such interaction for an arbitrary distribution of fiber directions (DFD) and for completely anisotropic properties of the phases. We apply the formulation to calculate the average strain in the matrix (due to the interaction among fibers) and the effective thermal coefficients of the composite. We find that the average strain in the matrix depends strongly on the DFD and that the predictions agree with measurements done by Majumdar and Kupperman.3 We prove that the effective thermal coefficients of the composite are not sensitive to the DFD when the matrix and the fibers exhibit isotropic thermal and elastic properties. Finally, we analyze the effect of the DFD and of the fiber interaction on the internal stresses inside the SiC fibers and compare with experimental values. 相似文献
992.
Pablo Basanta‐Val Marisol García‐Valls Iria Estvez‐Ayres Jorge Fernndez‐Gonzlez 《Concurrency and Computation》2011,23(11):1236-1260
The proliferation of a new generation of distributed real‐time embedded systems (DRE) characterized by special restrictions on its storage capacities, its available computation time, and the messages they can send through the network suggests a comprehensive redesign of the current distribution infrastructure in order to tune its performance. In this changing panorama, the paper concerns one of the protocols, Java's Remote Method Protocol (JRMP), used nowadays to interconnect different nodes of a distributed Java system, and explores the cost of integrating an improved protocol‐level multiplexing strategy in the context of an end‐to‐end remote invocation. The new multiplexing strategy helps middleware manage more efficiently unscheduled invocations that appear at runtime generated from a certain client node, especially in cases where preallocation of resources or dimensioning for the worst‐case are techniques not plausible. To this end, the paper examines an alternative based on the definition of a new subprotocol, called ConnectionLess, which offers built‐in multiplexing facilities for distributed Java applications. The performance of the new subprotocol is compared against the three already defined by JRMP (namely SingleOp, Stream, and Multiplex), taking into consideration parameters such as memory consumed in the Java's virtual machine and end‐to‐end response times. Copyright © 2011 John Wiley & Sons, Ltd. 相似文献
993.
994.
Entropy is calculated for a representative set of acyclic and aromatic compounds within the realm of QSAR/QSPR theory. Flexible topological molecular indices are chosen as independent variables in the fitting equations. The comparison with results derived from quantum mechanical calculations shows that the present approach gives better predictions. Some possible future extensions are pointed out. 相似文献
995.
Legua P Melgarejo P Abdelmajid H Martínez JJ Martínez R Ilham H Hafida H Hernández F 《Journal of food science》2012,77(1):C115-C120
The study focused on characterizing the 10 major Moroccan cultivars to acknowledge the quality and bioactive compounds of the fruits. The following determinations were assessed: pomegranate fruit maturity index, which truly defines juice taste, as well as organic acids and sugar contents, total phenols, and antioxidant activity of pomegranate juice. The cultivar per se (genotype) behaved as the most influencing factor conditioning pomegranate sugar and organic acids profiles, antioxidant activity, and total phenolics. The assessment of pomegranate chemical compositions implies the great potential of Moroccan cultivars for both fresh market and fruit processing. In fact, the \"Hamde\" sour cv. seems particularly suitable for juice production because of its high phenolics content. Additionally, the presence of bioactive compounds in pomegranate juices may encourage their consumption for potential health benefits. PRACTICAL APPLICATION: The cultivar per se (genotype) behaved as the most influencing factor conditioning pomegranate sugar and organic acids profiles, antioxidant activity, and total phenolics. Given the divergence observed on bioactive compounds concentrations and antioxidant activity among evaluated cultivars, the genotype factor should be considered as the most influencing factor in future breeding programs to enhance the synthesis of beneficial bioactive compounds. 相似文献
996.
Carmen Marín Pablo Pérez‐Martínez Javier Delgado‐Lista Purificación Gómez Fernando Rodríguez Elena María Yubero‐Serrano Antonio García‐Ríos Antonio Camargo Francisco Pérez‐Jiménez José López‐Miranda 《Molecular nutrition & food research》2011,55(2):328-335
Scope : Insulin resistance, a condition associated with type 2 diabetes mellitus, results from the interaction of environmental and genetic factors. The aim of this study was to explore the influence of the G972R polymorphism at the insulin receptor substrate 1 gene on insulin sensitivity in a healthy young population. Furthermore, we examined whether the presence of this single nucleotide polymorphism (SNP; GR or GG) interacts with dietary fat to modulate insulin sensitivity. Methods and results : Fifty‐nine healthy volunteers consumed three diets during 4 wk each following a randomized crossover design: a saturated fatty acid diet, a low‐fat and high carbohydrate (CHO) diet or a MUFA diet. For each diet, we investigated peripheral insulin sensitivity with the insulin suppression test. Steady‐state plasma glucose and plasma‐free fatty acids concentrations were significantly lower in GR subjects after the intake of a CHO diet, than did homozygous GG subjects (p<0.05). However, no differences were observed after consuming the two other diets. Conclusions : Insulin sensitivity increased in GR subjects for the G972R polymorphism at the insulin receptor substrate 1 gene locus, after intake of a CHO diet. Increased knowledge of how these and other genes influence insulin sensitivity should increase the understanding of personalized nutrition. 相似文献
997.
Gabriela T Pérez Pablo D Ribotta María E Steffolani Alberto E León 《Journal of the science of food and agriculture》2008,88(3):455-463
BACKGROUND: Gluten and soy proteins interact as a consequence of dough mixing; however, there is no evidence of the effect of soy protein on gluten depolymerization. The aim of this study was to assess the depolymerizing effect of soy protein on gluten network after mixing and resting of mixed doughs. Therefore, the changes in glutenin macropolymer (GMP) content, protein composition and free sulfhydryl content were evaluated. RESULTS: The protein profile from gluten–soybean blends, obtained by multistacking SDS‐PAGE, showed differences when compared to gluten profile. Soy and gluten proteins were extracted together with SDS buffer, which showed that soy proteins remained associated to insoluble wheat proteins even after hand‐washing the dough to obtain gluten. GMP content was determined to analyze the effect of soy protein on GMP gel formation. Protein content of GMP obtained from flour mixes and doughs was increased by inactive soy flour because soy proteins became insoluble and precipitated together with GMP. Active soy flour decreased GMP content due to gluten depolymerization. CONCLUSION: Soy proteins were associated to wheat protein through physical interaction and covalent and non‐covalent bonds during mixing and resting. These interactions produced large and medium‐size polymers. This fact increased SDS solubility of insoluble gluten proteins, producing a weakening of the gluten network. Physicochemical status of soy protein in the product had a great influence on how wheat–soy proteins interact. Copyright © 2007 Society of Chemical Industry 相似文献
998.
999.
1000.
Birgit Scholz Sabine Guth Karl‐Heinz Engel Pablo Steinberg 《Molecular nutrition & food research》2015,59(7):1339-1352
Hypercholesterolemia is an important risk factor for the development of cardiovascular diseases. Dietary intake of phytosterols/phytostanols and their fatty acid esters results in a reduction of the LDL and total plasma cholesterol levels. Therefore, these constituents are added to a broad spectrum of foods. As in the case of cholesterol, thermo‐oxidative treatment of phytosterols may result in the formation of phytosterol oxidation products (POPs), i.e. keto‐, hydroxy‐, and epoxy‐derivatives. This review summarizes and evaluates the current knowledge regarding POPs in the light of the potentially increasing dietary exposure to these constituents via the consumption of foods enriched with phytosterols/phytostanols and their esters. Data on the occurrence of POPs and approaches to assess the potential intake of POPs resulting from the consumption of enriched foods are described. The knowledge on the uptake of POPs and the presently available data on the impact of the consumption of enriched foods on the levels of POPs in humans are discussed. Biological effects of POPs, such as potential proatherogenic properties or the loss of the cholesterol‐lowering effects compared to nonoxidized phytosterols, are discussed. Finally, knowledge gaps are outlined and recommendations for further research needed for a safety assessment of POPs are presented. 相似文献