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1.
Isotactic polypropylene and ethylene-1-hexene copolymers containing 32 and 57 mol% of 1-hexene copolymers blends (i-PP/EH32 and i-PP/EH57) were prepared by solution blending, precipitating followed by drying and hot pressing. The two blends were subject to investigation on structure and mechanical properties of these blends under uniaxial drawing. The i-PP/EH32 and i-PP/EH57 represented the immiscible and miscible blends, respectively. The tensile stresses and strains at breaking point of i-PP/EH57 were remarkably higher than those of i-PP/EH32 at room temperature. From wide-angle X-ray diffraction (WAXD) measurement, it was observed that the orientation of crystallites occurred early and then propagated gradually up to about drawing ratio 8 because chains of EH57 copolymer were incorporated into the amorphous regions between lamellae of i-PP. In the WAXD patterns of i-PP/EH57, the oriented spot reflections coexsisted with unoriented ring reflections up to draw ratio higher than in pure i-PP. On the other hand, the two-phase structure was observed from TEM and AFM in i-PP/EH32, and on the drawing, separation at the interface between two-phase was observed in i-PP/EH32 even at the low strain.  相似文献   
2.
BACKGROUND: Amino acids are promising feedstocks for the chemical industry due to their chemical functionality. They can be obtained by the hydrolysis of potentially inexpensive protein streams such as the byproduct of biofuel production. However, individual amino acids are required before they can be used for the further production of chemicals. Here, the separation of L‐aspartic acid (Asp) and L‐glutamic acid (Glu) mixture, which can be isolated from protein hydrolysis solutions at low pH or from electrodialysis of complex amino acid mixtures, was studied. RESULTS: Glu was converted into L‐pyroglutamic acid (pGlu) which can be separated from the mixture of Asp and Glu due to its higher solubility in water. The conversion was carried out under aqueous or melt conditions. Under aqueous conditions, the conversion was studied as a factor of time, temperature and the amount of Glu. The conversion was specific with high yield and not effected by Asp. After pGlu was separated from Asp and residual Glu by solubility difference, it can be transferred back to Glu through hydrolysis. CONCLUSION: The conversion of Glu to pGlu is specific and can be applied to separation Asp and Glu for their use in the production of bio‐based chemicals. Copyright © 2012 Society of Chemical Industry  相似文献   
3.
Within the concept of the replacement of fossil with biobased resources, bacterial polyhydroxybutyrate (PHB) can be obtained from volatile fatty acids (VFAs) from agro‐food waste streams and used as an intermediate toward attractive chemicals. Here we address a crucial step in this process, the conversion of PHB to methyl crotonate (MC), which can be converted via cross‐metathesis with ethylene to methyl acrylate and propylene, two important monomers for the plastics industry. The conversion of PHB to MC proceeds via a thermolysis of PHB to crotonic acid (CA), followed by an esterification to MC. At pressures below 18 bar, the thermolysis of PHB to CA is the rate‐determining step, where above 18 bar, the esterification of CA to MC becomes rate limiting. At 200°C and 18 bar, a full conversion and 60% selectivity to MC is obtained. This conversion circumvents processing and application issues of PHB as a polymer and allows PHB to be used as an intermediate to produce biobased chemicals. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42462.  相似文献   
4.
E. E. Cooper and T. J. Wojan (2000) applied the categorical-coordinate relations distinction to faces on the basis of a finding that two-eyes-up versus one-eye-up distortions had opposite effects in between-class (face normality) and within-class (face identity) tasks. However, Cooper and Wojan failed to match amount of metric change between their 2 deviation types and tested only 1 deviation level. In the present study, eyeheight was shifted (e.g., both eyes up or both eyes down vs. one eye up and one eye down) parametrically (11 levels) and normality and identity ratings obtained. There was no evidence of categorical changes in perception where these would have been predicted by Cooper and Wojan's theory. In all cases, the relationship between physical and perceived distortion followed Fechner's law. Differences across distortion types in Fechner threshold (the minimum deviation altering perceived normality or identity) are explained in terms of the variability associated with different dimensions in face space. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
5.
Pomegranate juice is well known for its health beneficial compounds. This study was undertaken to investigate changes in the major chemical composition in arils and peels during fruit maturation in two Israeli commercial accessions, ‘Wonderful’ and ‘Rosh-Hapered.’ In both accessions, the levels of total phenolic, antioxidant activity and hydrolysable tannins were reduced in the peels during maturation, while the anthocyanin level increased. The results show that the sugar content in the aril juice increased in both accessions while the levels of acidity and of citric acid decreased. However, these two accessions differed in other parameters in the aril juice, i.e., while the antioxidant and total phenolic contents significantly decreased in ‘Rosh-Hapered’, these changes were not observed in ‘Wonderful’. The anthocyanin level, however, increased in ‘Wonderful’ but did not change in ‘Rosh-Hapered.’ This knowledge could help establish the optimum harvest date ensuring the maximum nutritional properties of pomegranates.  相似文献   
6.
Heating of intact cassava leaves causes liberation of hydrogen cyanide. This phenomenon appears to be caused by β-glucosidase-catalysed decomposition of the cyanogenic glycosides linamarin and lotaustralin. Because of these losses, many previously determined values for total nitrogen in cassava (and other cyanogenic plants) are probably in error as plant materials used for Kjeldahl determinations are often dried at 70–90°C. Liberation of cyanide from intact cassava leaves by heating at 80°C is more complete than liberation by the homogenisation methods commonly used. Homogenisation of cassava leaf tissues with liquid nitrogen or dry ice gives somewhat lower values, and these materials are often not readily available in areas where cassava is studied. The basis of a relatively simple procedure for the isolation of hydrogen cyanide from cassava leaves is suggested.  相似文献   
7.
Assessed the home environments and mother-child interactions of a language-delayed group and a matched control group of normal preschool children using the Caldwell Inventory of Home Stimulation (CIHS). 20 language-delayed children were defined by a discrepancy between their Stanford-Binet, language-based, IQ score and their Leiter, non-language-based, IQ score, and by a language evaluation. Children in both groups were distributed across all socioeconomic strata. The language-delayed group had significantly lower scores in 5 of the 6 subcategories of the CIHS. Greatest differences were found in the involvement and responsiveness of the mother and in her avoidance of restriction and punishment. Low CIHS scores were found through the socioeconomic strata, indicating that language delay had a stronger influence on mother-child relationships than did socioeconomic factors. (39 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
8.
Everyday patterns of interaction can strengthen or undermine bonds between family members. This naturalistic observation study focused on an understudied facet of family life: opportunities for interaction among dual-earner family members after work and family members’ responses to these opportunities. Thirty dual-earner couples and their children were observed and video-recorded in their homes throughout two weekday afternoons and evenings. Two interaction opportunities were analyzed: (1) the behavior of family members toward a parent returning home from work and (2) the physical proximity of family members throughout the evening. Three main findings emerged. Women, who tended to return home before men, were greeted with positive behavior and reports of the day’s information from family members. Men, in contrast, returned home later in the day and received positive behavior or no acknowledgment from family members distracted by other activities. Throughout the evening, mothers spent more time with children whereas fathers spent more time alone. Couples were seldom together without their children. The implications of observed interaction patterns and the contribution of naturalistic observation methods to the study of family relationships are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
9.
Pseudoazurin, a low molecular weight protein containing a singletype I copper, functions as an electron donor to a copper-containingnitrite reductase (NIR) in a denitrifying bacterium Alcaligenesfaecalis S-6. To elucidate the proteinprotein interaction betweenthese two copper-containing proteins, each of nine out of 13lysine residues on the surface of pseudoazurin were independentlyreplaced by alanine or aspartate, and the effects of the mutationson the interaction with NIR, as well as the physicochemicalproperties of pseudoazurin, were analyzed. All of the mutatedpseudoazurins showed optical spectra and oxidation-reductionpotentials almost identical to those of wildtype pseudoazurin,suggesting that none of the replacements of these lysine residuesaffected the environment around the type I copper site. Kineticanalysis of electron transfer between mutated pseudoazurinsand NIR reveals that the lysine mutations have very little effecton the rate of electron transfer to NIR, but substitution atresidues 10, 38, 57 and 77, all close to the copper site, substantiallydecreases the affinity of pseudoazurin for NIR. This suggeststhat pseudoazurin interacts with NIR through the region closeto the type I copper site. The refined X-ray structures of Lys38Aspand Lys10Asp/Lys38Asp show that the molecular structure hasindeed changed little. A new space group is observed for theLys109Ala mutant crystal. Crystal packing interactions changefor the Lys10Asp/Lys38Asp mutant but remain the same for Lys38Aspand Lys59Ala mutants.  相似文献   
10.
Discusses 3 aspects of the relationship between the infant and the world: the macrosystem, or the world's view of the infant; the microsystem of family, which concerns the infant's impact on the world; and the infant's processing of the world. Research on the history of childrearing is presented to illustrate how the current North American world view of the infant has contributed to the acceptance of erroneous theories of parent–infant bonding. The impact of new parenthood on women and men is reviewed, and ways in which infants process and make sense of the world are discussed. Research on infant visual habituation is reviewed with special attention to the prediction of childhood intelligence test scores from infant posthabituation preferences for novelty. (French abstract) (83 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
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