The relation between (bio-)chemical, morphological, and mechanical properties of thermally processed carrots as influenced by high-pressure pretreatment condition

Thermal texture evolution kinetics (90–110 °C) of nonpretreated and high-pressure pretreated (HP = 400 MPa, 60 °C, 15 min) carrots were determined using a multiparameter approach (cutting, compression). Alcohol Insoluble Residues (AIR) were extracted before and after thermal processing of the samples and the degree of methylation (DM) was estimated. The β-elimination kinetics of the water soluble pectin extract from the AIR was studied and related to the changes in material properties. Morphological changes and tissue-failure characteristics were monitored. The mechanical properties were strongly dependent on the processing temperature and the DM of the samples. Texture degradation rate constants were independent of the texture measurement method. Increasing temperature accelerated the β-elimination reaction (k _b) and the thermosoftening (k _x) rates, but pretreatment condition slowed down the rates. Interestingly, a strong correlation (r > 0.99) between k _b and k _x occurred. Thermal processing resulted in cell-wall thickening accompanied by a transition from cell rupture to cell separation, a process retarded by pretreatment condition.     

Students' estimates of the prevalence of drug use: Evidence for a false consensus effect.

False consensus, or the tendency to overestimate the extent to which others share one's own attitudes and behaviors, was investigated in a study of 348 university students classified as non-drug users, cannabis-only users, or amphetamine+cannabis users. Participants estimated the prevalence of cannabis and amphetamine use among students. Cannabis and amphetamine users made significantly higher estimates of cannabis use among students than did nonusers, whereas amphetamine users gave significantly higher estimates of amphetamine use than nonusers and cannabis-only users. Correlations between estimates of use among friends and other students were significantly positive for both drugs. The results suggest that students are motivated to overestimate the commonality of their own position on drug use and that their estimates may also be influenced by selective exposure. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Life on the line: Job demands, perceived co-worker support for safety, and hazardous work events.

The present study of 334 United Kingdom trackside workers tested an interaction hypothesis. We hypothesized, drawing on the job demands-resources framework, that perceived support for safety (from senior managers, supervisors, and coworkers) as job resources would weaken the relationship between higher job demands and more frequent hazardous work events. Consistent with social impact theory, we predicted that perceived coworker support for safety would be particularly influential when trackside workers faced higher job demands. Moderated multiple regression showed that, of all three sources of perceived support for safety, perceived coworker support for safety was most important for keeping employees safe in the face of high job demands. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effect of prepartum vaccination with K99 Escherichia coli vaccine on maternal and calf blood antibody concentration and calf health

One hundred and two dry, pregnant Holstein cows were identified alternately as vaccinated or nonvaccinated (Group 0) animals. Vaccinated cows were scheduled for vaccination at 6 and 3 wk prior to expected calving date with Vicogen, a commercial vaccine produced for the prevention of calf scours caused by enteropathogenic Escherichia coli that possess the K99 antigen. Group 1 included cows that were less than 6 wk from freshening when the experiment started and, therefore, received only one vaccination and cows that received two vaccinations with less than 5 days between the second vaccination and freshening. Those cows with interval between the second vaccination and parturition greater than 5 days were classified as Group 2. Soon after birth, each calf was given 2 liters of colostrum from its dam. For at least 3 days, and longer when available, calves from control cows received pooled colostrum from control cows and calves from vaccinated cows received pooled colostrum from vaccinated cows. Anti-K99 antibody titers were determined by an agglutination test on blood from cows and calves and on colostrum. Other measurements were made by standard procedures. Results from Groups 0, 1, and 2 were cow blood titer at freshening 21, 355, 306; calf total plasma protein at 24 h of age 6.45, 6.31, 6.22; calf packed cell volume at 24 h of age 32.9, 30.0, 30.2; calf blood titer at 24 h of age 34, 762, 1114; colostrum titer 74, 1637, 3404. For 93 calves, mortality was 10.6, 11.1, and 7.1%.(ABSTRACT TRUNCATED AT 250 WORDS)     

CYP2D6 allelic frequencies in young-onset Parkinson's disease

Parkinson's disease (PD) is thought to develop as a result of interactions between genetic susceptibility factors and environmental exposures. One candidate gene is CYP2D6, which codes for the debrisoquine 4-hydroxylase cytochrome P450. Impairment of debrisoquine 4-hydroxylase activity has been associated with an increased risk of PD in patients with younger age at disease onset. Genotyping studies in patients with an older age at onset have reported modest increases in risk associated with the CYP2D6 B and A alleles; however, the risk for young-onset PD has not been adequately evaluated. We designed a case-control study to investigate the role of nonfunctional CYP2D6 allelic risk factors for young-onset PD in a sizable patient population and compared the distributions of CYP2D6 genotypes between young-onset ( < or = 51 years) PD patients (n = 108) and controls (n = 236). In contrast with the results from genotyping studies conducted among patients with an older age at onset, there were no significant differences in CYP2D6 allelic frequencies between young-onset PD cases and controls. The frequency of the B allele was slightly lower in the young-onset PD cases than in the controls (0.14 versus 0.20) (X2 = 2.66, p = 0.10). The presence of one or more B alleles was not associated with an increased risk of young-onset PD (odds ratio 0.58; 95% CI 0.33 to 1.00), nor was the presence of one or more nonfunctional alleles (i.e., A, B, D, and D2) (odds ratio 0.68; 95% CI 0.41 to 1.13). This study suggests that the young-onset PD population may differ from the older-onset population with respect to risk factors.     

Psychometric evaluation of the Multidimensional Assessment of Fatigue Scale for use with pregnant and postpartum women.

Although fatigue is a common experience for pregnant women and new mothers, few measures of fatigue have been validated for use with this population. To address this gap, the authors assessed psychometric properties of the Multidimensional Assessment of Fatigue (MAF) scale, which was used in 2 independent samples of pregnant women. Results indicated that the psychometric properties of the scale were very similar across samples and time points. The scale possesses a high level of internal consistency, has good convergent validity with measures of sleep quality and depression, and discriminates well from a measure of social support. Contrary to previous evaluations of the MAF, data strongly suggest that the scale represents a unidimensional construct best represented by a single factor. Results indicate that the MAF is a useful measure of fatigue among pregnant and postpartum women. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Leader--member exchange, differentiation, and psychological contract fulfillment: A multilevel examination.

Prior integrations of the leader-member exchange (LMX) and psychological contract literatures have not clarified how within-group LMX differentiation influences employees' attitudes and behaviors in the employment relationship. Therefore, using a sample of 278 members and managers of 31 intact work groups at 4 manufacturing plants, the authors examined how LMX operating at the within-group level (relative LMX, or RLMX) and the group level influenced perceptions of psychological contract fulfillment and employee-level outcomes. Controlling for individual-level perceptions of LMX quality, results indicated a positive relationship between RLMX and fulfillment, which was strengthened as group-level variability in LMX quality increased. Perceptions of fulfillment mediated the relationship between RLMX and performance and sportsmanship behaviors. The importance of conceptualizing LMX as simultaneously operating at multiple levels is highlighted. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Comparison of species sensitivity distributions derived from interspecies correlation models to distributions used to derive water quality criteria

Species sensitivity distributions (SSD) require a large number of measured toxicity values to define a hazard level protective of multiple species. This investigation comprehensively evaluated the accuracy of SSDs generated from toxicity values predicted from interspecies correlation estimation (ICE) models. ICE models are log-log correlations of multiple chemical toxicity values for a pair of species that allow the toxicity of multiple species to be predicted from a single measured acute toxicity value for a surrogate species. ICE SSDs were generated using four surrogate species (fathead minnow, Pimephales promelas; rainbow trout, Oncorhynchus mykiss; sheepshead minnow, Cyprinodon varigatus; and water flea, Daphnia magna). ICE-based hazard concentrations (HC5s) from the 5th percentile of the log-logistic distribution of toxicity values were compared to HC5s determined from the acute toxicity of 55 chemicals from the United States Environmental Protection Agency Ambient Water Quality Criteria (AWQC). Measured fish and invertebrate acute toxicity data and HC5s from the AWQC data sets were compared to ICE-based HC5s. Surrogate species choice was found to be an important consideration in developing predictive HC5s. These results illustrated that fish predict fish betterthan invertebrates and D. magna predicted invertebrates better than most fish. For example, a mixed model of predicted fish and invertebrates from fathead minnow and D. magna as surrogate species provided predictive relationships with an average factor of 3.0 (+/- 6.7) over 7 orders of toxic magnitude and several chemical classes (HC5(predicted)/HC5(measured)). The application of ICE models is recommended as a valid approach for generating SSDs and hazard concentrations for chemicals with limited toxicity data.