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101.
Study of the aromatic by-products formed from ozonation of anilines in aqueous solution 总被引:6,自引:0,他引:6
Aqueous solutions of aniline and p-chloroaniline were treated with ozone in order to study the reaction and oxidation by-products. Aniline solutions were ozonated at low and high pH, so as to compare both molecular and hydroxyl free radical mechanisms, respectively. The main identified aromatic by-products were nitrobenzene and azobenzene when the experiment was carried out at acid pH. Formation of nitrobenzene, azobenzene, azoxybenzene and 2-pyridine-carboxylic was observed when the ozonation was carried out at basic pH. p-Chloroaniline was treated with ozone only at high pH and the identified by-products were in accordance with those obtained in the ozonation of aniline: p-chloronitrobenzene, 4,4'-dichloroazobenzene and 4-chloro-2-pyridine-carboxylic acid. All the aromatic by-products found were less toxic than the raw materials. The pseudo-first-order constants in aniline concentration were calculated, whilst kinetic in p-chloroaniline concentration could not be adjusted to a first-order reaction. 相似文献
102.
103.
Frank JE Kim TM Nelson EC 《The Joint Commission journal on quality improvement》2002,28(8):451-2, 417
The authors show how an internal grant program can stimulate quality improvement research by providing technical and financial support to clinicians and employees. 相似文献
104.
The influence of adolescents' autonomy and relatedness to parents on romantic relationships was examined longitudinally over 5 years in 76 middle-class African American late adolescents (mean age = 18.43 years). Relatedness to parents in early adolescence led to longer duration and more supportive romantic relationships in late adolescence, but longer duration was concurrently associated with more negative romantic relationships. Cluster analyses yielded 3 profiles of early adolescent autonomy and relatedness; early adolescents who were high in relatedness and low in autonomy to parents in early adolescence reported longer duration romantic relationships in late adolescence than did adolescents who were moderate or high in relatedness and high in autonomy. The implications for romantic development in African American middle-class youth are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
105.
The development of new communication technologies and their applications has opened a broad spectrum of options to promote learning, of which a significant one is CMC – Computer-Mediated Communication. Yet, students use this medium to a relatively small extent. Our premise is that the use of these technologies depends on the level of skills and expertise of the individuals using them. The purpose of this study is to determine whether taking a Computer Literacy and Applications course (CLA) before taking CMC courses has an impact on students' participation in CMC courses and on the effective use of various CMC tools. The sample consisted of 153 students enrolled in CMC courses in the Social Sciences in the Spring 2001/2 and Fall 2002/3 semesters. Participants were divided into two groups: 80 students who had taken CLA, and 73 students who had not. A questionnaire to assess the impact of CLA on participation in CMC courses was administered to the two groups. The results of the study indicate that participation in CMC courses is more intensive in the group that had taken CLA. Based on these findings, we recommend mandating a CLA course, like the one developed at the Open University of Israel (OUI), before taking CMC courses. 相似文献
106.
Experimental inflammatory arthritis (EIA) produced by carrageenan injection provokes a rapid bone remodeling state with cortical and cancellous bone loss. The objective of this study was to determine whether changes in cortical mechanical properties and/or geometry occur in long bones, either near or remote to the site of inflammation. EIA was induced in the right tibio-femoral joint of rabbits over 56 days. The right humerus and right femur from 15 normal and 25 arthritis group animals were excized. Semi-cylindrical specimens of the medial cortical shaft were subjected to non-destructive four-point bending tests. Transverse sections at the four contact sites of the loading jig were photographed and digitized to obtain average cross-sectional area (A) and moment of inertia (I). Moment of inertia and slope of the load/deflection curve permitted calculation of modulus of elasticity (E) for each specimen. Load/time curves were also used to calculate per cent stress remaining in relaxation experiments. Per cent stress remaining, E, A, I and
\sqrt {{\text{I/A}}} (radius of gyration) were examined for differences by bone (humerus, femur) and by treatment (N,A) using two way ANOVA. The induction of inflammatory arthritis did not significantly alter the modulus of elasticity in either the femur or humerus; however, arthritis reduced the moment of inertia from
. This was observed in the femur (near the arthritic joint), but not in the humerus (remote from arthritic joint). Analysis of area and ratio I/A demonstrated that this geometric effect of treatment was due to reduced area without gross cross-sectional shape changes. Per cent stress remaining in the femur (but not in the humerus) was higher in the arthritis specimens than in the normal specimens
. Thus, in this arthritis model, the principal mechanical or geometric effect on cortical bone was reduction of the cross-sectional area and moment of inertia. The viscoelastic relaxation response of bone was also altered, perhaps due to loss of water or collagen degradation. 相似文献
107.
Effects of 3-pentanone and eight low molecular weight aliphatic alcohols and aldehydes identifed in the mixtures of volatiles released byAmaranthus palmeri S. Wats. (AMAPA) residues were determined on germination of onion, carrot, AMAPA, and tomato seeds. Three-day exposures to these volatiles significantly inhibited germination of these assay seeds, and the inhibition was dependent upon exposure time and concentration. Based on the degree of inhibition observed in both time- and concentration-dependent assays, the following activity series was obtained: 2-heptanol > 3-methyl-1-butanol, 1-hexanol > hexanal, 1-pentanol, 3-pentanone, acetaldehyde > ethanol, 2-methyl-1-propanol. The activities of this group of compounds with that of 2-heptanone appear to be additive and related to test compound volatility and hydrophilicity. 2-Heptanol and 2-heptanone also significantly inhibited the germination of other species, including shepherdspurse, soybean, lettuce, alfalfa, common purslane, oats, and lovegrass.Name of companies or commercial products are given solely for the purpose of providing specific information; their mention does not imply recommendation or endorsement by the U.S. Department of Agriculture over others not mentioned. 相似文献
108.
Dynamic control of polymorphic transformation in triglycerides by surfactants: The button syndrome 总被引:2,自引:2,他引:0
Judith Schlichter Aronhime Sara Sarig Nissim Garti 《Journal of the American Oil Chemists' Society》1988,65(7):1144-1150
The kinetics of polymorphic transformations in monoacid saturated triglycerides and the influence caused by the presence of
certain solid surfactants were investigated. Selected emulsifiers can be incorporated at the level of 10 wt% within the triglyceride,
without changing the crystal lattice; on the other hand, their presence affects the heat capacity of the triglyceride and
the NMR relaxation time T1. Following the polymorphic transformation both during aging and during heating in the DSC, it was observed that both the
mechanism and rate of transformation of the triglyceride strongly depend on the kinetic conditions and on its own chemical
structure. In conjunction with these results it also was observed that the effect of the emulsifier is strongly dependent
on the transformation conditions. The kinetic effect of the additive on the solid-solid transformation has been found to be
strictly associated with its hydrophilic moiety structure; a model of molecular incorporation has been proposed which describes
the arrangement of the surfactant molecules parallel to the triglyceride chains and formation of vacancies. The selectivity
of the additive concerning its effect of dynamic controller of polymorphic transformations has been explained by its capacity
to create hydrogen bonds with the neighboring triglycerides, which was called the “Button Syndrome.” The wide range of different
additives and triglycerides used supplied a better understanding of the factors which determine the polymorphic and crystallization
behavior in triglycerides. 相似文献
109.
Do parents have any important long-term effects on the development of their child's personality? This article examines the evidence and concludes that the answer is no. A new theory of development is proposed: that socialization is context-specific and that outside-the-home socialization takes place in the peer groups of childhood and adolescence. Intra- and intergroup processes, not dyadic relationships, are responsible for the transmission of culture and for environmental modification of children's personality characteristics. The universality of children's groups explains why development is not derailed by the wide variations in parental behavior found within and between societies. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
110.
Habit and intention in everyday life: The multiple processes by which past behavior predicts future behavior. 总被引:8,自引:0,他引:8
Past behavior guides future responses through 2 processes. Well-practiced behaviors in constant contexts recur because the processing that initiates and controls their performance becomes automatic. Frequency of past behavior then reflects habit strength and has a direct effect on future performance. Alternately, when behaviors are not well learned or when they are performed in unstable or difficult contexts, conscious decision making is likely to be necessary to initiate and carry out the behavior. Under these conditions, past behavior (along with attitudes and subjective norms) may contribute to intentions, and behavior is guided by intentions. These relations between past behavior and future behavior are substantiated in a meta-analytic synthesis of prior research on behavior prediction and in a primary research investigation. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献