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1.
Composition of the Seed Oil of Clustered Elder (Sambucus racemosa L.) The seeds of clustered elder (Sambucus racemosa L.) contain 28% of an oil. Its separation to groups of components was carried out by adsorption chromatography. Single groups of substances were further analysed by TLC and GLC in combination with physico-chemical methods (IR and MS). Thus the following substances were found and identified: n-alkanes (C17–C33), 2-methyl- and 3-methylalkanes, squalene, a mixture of esters, triglycerides, β-sitosterol, campesterol and a mixture of diglycerides. The conditions for the separation of esters by silica gel column chromatography were also found. The mixture of esters was thus separated into a group of aliphatic wax esters (C34–C44) and four groups of esters of steroidal alcohols (mainly β-sitosterol and campesterol) with aliphatic unsaturated acids (predominantly C18:1, C18:2 and C18:3). In the triglycerides representing the main fraction of the oil (93%), the acids C16:0, C18:1, C18:2 and C18:3 are present. The same acids were also found in diglycerides.  相似文献   
2.
Objective: To examine the contribution of social-cognitive factors (self-efficacy and affect) in predicting long-term physical activity in a sample of older adults (N = 174). Design: A prospective design assessed physical activity and psychosocial variables at 2 and 5 years following a 6-month randomized, controlled exercise trial. Main Outcome Measures: The primary outcome variable was self-reported physical activity, with previous behavior, self-efficacy, and affect assessed as determinants of physical activity. Results: Covariance modeling analyses indicated that physical activity at Year 2 was the strongest predictor of physical activity at 5-year follow-up. Both self-efficacy and affect at Year 2 were also associated with physical activity at Year 5, as was original treatment condition. Variables accounted for 35% of the variance in Year 5 activity. Conclusion: Older adults with higher levels of physical activity, more positive affect, and higher self-efficacy at Year 2 were more likely to continue to be active at Year 5. This study is one of the longest follow-ups of exercise behavior in older adults and has implications for structuring environments to maximize the maintenance of physical activity. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
3.
It was demonstrated previously that replication of plasmids derived from bacteriophage lambda (so-called lambda plasmids) is inhibited in wild-type Escherichia coli cells starved for isoleucine and arginine whereas it proceeds under the same conditions in relA mutants. Since replication of other replicons during the stringent or relaxed response depends on the nature of the deprived amino acid, we investigated replication of lambda plasmids in E. coli relA+ and relA- strains starved for different amino acids. We found that replication of lambda plasmids is generally inhibited during the stringent, but not relaxed, response. Differences between cells starved for different amino acids, although reproducible, were not dramatic. Amino acid starvation was previously proposed as a method for amplification of lambda plasmid DNA in vivo. We found that during amino acid limitation lambda plasmids replicate more extensively in the relA mutants than during amino acid starvation. The efficiency of plasmid DNA amplification was found to be dependent on the kind of limited amino acid; in relA- bacteria limited for leucine we observed about 10-fold plasmid amplification. Some lambda plasmid replication was also found under these conditions in the relA+ host. The mechanism of the stringent control of lambda plasmid DNA replication has already been proposed. Here the possible mechanism of the regulation of lambda plasmid replication during amino acid limitation is presented.  相似文献   
4.
Objective: This longitudinal, observational study examined changes in physical activity and symptoms as correlates of changes in functional limitations and disability across a 6-month period among individuals with multiple sclerosis (MS). Method: Individuals with MS wore an accelerometer for a 7-day period and completed a battery of measures including the Godin Leisure-Time Exercise Questionnaire (Godin & Shephard, 1985), Symptom Inventory (Schwartz, Vollmer, & Lee, 1999), MS-Related Symptom Checklist (Gulick, 1989), and abbreviated Late-Life Function and Disability Inventory (McAuley, Konopack, Motl, Rosengren, & Morris, 2005) at baseline (n = 292) and 6-month follow-up (n = 276). The data were analyzed using panel analysis with latent variables in AMOS 16.0. Results: The standardized coefficients indicated that (a) change in physical activity was associated with residual change in function (β = .22), (b) change in symptoms was associated with residual changes in both function (β = –.29) and disability (γ = –.15), and (c) change in function was associated with residual change in disability (β = .20). Conclusion: Our findings indicate that change in physical activity is associated with change in disability through a pathway that is consistent with Nagi’s (1976) Disablement Model and its extension in individuals with MS. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
5.
Firefighters’ self-contained breathing apparatus (SCBA) protects the respiratory system during firefighting but increases the physiological burden. Extended duration SCBA (>30 min) have increased air supply, potentially increasing the duration of firefighting work cycles. To examine the effects of SCBA configuration and work cycle (length and rest), 30 firefighters completed seven trials using different SCBA and one or two bouts of simulated firefighting following work cycles common in the United States. Heart rate, core temperature, oxygen consumption, work output and self-reported perceptions were recorded during all activities. Varying SCBA resulted in few differences in these parameters. However, during a second bout, work output significantly declined while heart rates and core temperatures were elevated relative to a single bout. Thirty seven per cent of the subjects were unable to complete the second bout in at least one of the two-bout conditions. These firefighters had lower fitness and higher body mass than those who completed all assigned tasks.

Practitioner Summary: The effects of extended duration SCBA and work/rest cycles on physiological parameters and work output have not been examined. Cylinder size had minimal effects, but extended work cycles with no rest resulted in increased physiological strain and decreased work output. This effect was more pronounced in firefighters with lower fitness.  相似文献   

6.
The absence of longitudinal data about correlates of physical activity during adolescence has hindered the identification of key mediator variables that can be targeted by interventions. Building on the authors' previous report of a cross-sectional analysis, this study compared barriers self-efficacy and perceived behavioral control as predictors of change in 2 levels of physical activity across a 1-year period among a sample of Black and White adolescent girls (N = 1,038). Self-efficacy did not predict change in either moderate or vigorous physical activity. In contrast, perceived behavioral control exhibited a longitudinal, independent relationship with change in vigorous physical activity. The authors concluded that perceived behavioral control is an independent predictor of change in vigorous physical activity levels across a 1-year period among a sample of Black and White adolescent girls and warrants study as a potential mediator variable in interventions designed to increase or maintain physical activity. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
7.
Social physique anxiety (SPA) based on Hart, Leary, and Rejeski's (1989) Social Physique Anxiety Scale (SPAS) was originally conceptualized to be a unidimensional construct. Empirical evidence on the factorial validity of the SPAS has been contradictory, yielding both one- and two-factor models. The two-factor model, which consists of separate factors associated with positively and negatively worded items, has stimulated an ongoing debate about the dimensionality and content of the SPAS. The present study employed confirmatory factor analysis (CFA) to examine whether the two-factor solution to the 12-item SPAS was substantively meaningful or a methodological artifact. Results of the CFAs, which were performed on responses from four different samples (Eklund, Kelley, and Wilson, 1997; Eklund, Mack, and Hart, 1996), supported the existence of a single substantive SPA factor underlying responses to the 12-item SPAS. There were, in addition, method effects associated with the negatively worded items that could be modeled to achieve good fit. Therefore, it was concluded that a single substantive factor and a non-substantive method effect primarily related to the negatively worded items best represented the 12-item SPAS.  相似文献   
8.
Objective: Quality of life (QOL) is compromised among individuals with multiple sclerosis (MS). Physical activity has been positively associated with QOL, but little is known about the factors that explain and/or confound the relationship in those with MS. On the basis of a social-cognitive perspective and previous research, the authors tested the hypothesis that physical activity would be indirectly associated with QOL through a mediated pathway that included self-efficacy and functional limitations, after controlling for perceived social support. Participants: Participants were 196 individuals with a definite diagnosis of MS living in the Midwest region of the United States who completed a battery of questionnaires and wore a pedometer and accelerometer for a 7-day period. Results: Covariance modeling analyses indicated that physical activity was indirectly associated with QOL through a pathway that included self-efficacy and functional limitations, and the pattern of relationships was independent of the perception of social support. Conclusions: The findings support physical activity as a possible modifiable behavior for mitigating reductions of QOL in those with MS and suggest that a social-cognitive model aids in the understanding of physical activity's relationships with QOL. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
9.
Structural equation modeling was used to evaluate components within the theories of reasoned action (TRA), planned behavior (TPB), and self-efficacy (SET) for understanding moderate and vigorous physical activity among 1,797 Black and White adolescent girls. Modest to strong support was provided for components of TPB and SET; weak support was provided for components of TRA. Perceived behavioral control was related to vigorous physical activity. Self-efficacy was related to moderate and vigorous physical activity, and it accounted for the effect of intention on physical activity. The observed relationships were similar between Black and White girls. Self-efficacy and perceived behavioral control are independent influences on physical activity among Black and White adolescent girls and warrant study as potential mediators in physical activity interventions. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
10.
Acquiescence, the tendency to agree with statements regardless of content, is often a concern when administering self-report instruments. While there is evidence to support acquiescence as a response style, this reporting tendency may be related to personality factors of individuals. Using a sample of 757 adults, we investigated the Rosenberg Self-Esteem Scale for acquiescence response tendencies by applying the Rasch partial credit model. Results suggested that favorable (i.e., Agree or Strongly Agree) responses were more frequent for the positively worded items than for negatively worded items. Second, the relationship between acquiescence and seven additional personality measures was examined overall and by sex. Among females, acquiescence was correlated with personality measures measuring perceptions by others, whereas acquiescence among males was related to exhibition types of behaviors.  相似文献   
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