Use of sol-gels as solid matrixes for simultaneous multielement determination by radio frequency glow discharge optical emission spectrometry: determinations of suspended particulate matter

A new approach for the analysis of particulate matter by radio frequency glow discharge optical emission spectrometry (rf-GD-OES) is described. Dispersion of the particles in a sol-gel sample matrix provides a convenient means of generating a thin film suitable for sputter-sampling into the discharge. Acid-catalyzed sol-gel glasses synthesized from tetramethyl orthosilicate were prepared and spun-cast on glass substrates. The resultant thin films on glass substrates were analyzed to determine the discharge operating conditions and resultant sputtering characteristics while a number of optical emission lines of the film components were monitored. Slurries of powdered standard reference materials NIST SRM 1884a (Portland Cement) and NIST SRM 2690 (Coal Fly Ash) dispersed in the sols were cast into films in the same manner. Use of the sol-gels as sample matrixes allows for background subtraction through the use of analytical blanks and may facilitate the generation of calibration curves via readily synthesized, matrix-matched analytical standards in solids analysis. Detection limits were determined for minor elements via the RSDB method to be in the range of 1-10 microg/g in Portland Cement and Coal Fly Ash samples for the elements Al, Fe, Mg, S, and Si. Values for Ca were in the range of 15-35 microg/g. This preliminary study demonstrates the possibility of incorporating various insoluble species, including ceramics and geological specimens in powder form, into a solid matrix for further analysis by either rf-GD-OES or MS.     

Self- and supervisory perspectives on age and work attitudes and performance.

Person- and context-oriented definitions of age were used to predict 3 sets of work outcomes: work attitudes, performance ratings, and reports of developmental practices. The 5 age measures included employee chronological age, employee subjective age (i.e., self-perceptions of age), and social age (i.e., others' perceptions of age), as well as self- and supervisors' perceptions of the employee's relative age (i.e., compared with the employee's work group). The study assessed (1) the relationships among the age measures, (2) the additive relationships among the age measures that predicted work outcomes, and (3) the interactive relationships among the age measures that predicted work outcomes. Each prediction received some support except for number (2). Furthermore, many of the age–work-outcome relationships were replicated in the managerial sample. Implications for the use of alternative age measures are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Review of Leadership for older adults: Aging with purpose and passion.

Reviews the book, Leadership for older adults: Aging with purpose and passion by Sandra A. Cusack and Wendy J. A. Thompson (see record 1999-02171-000). While this is an interesting book, holding promise and providing suggestions for those who wish to take on leadership roles, or for those who work with others who might be encouraged to seek such roles, it also raises many questions about the process of who gets to be leaders of whom and how we can empower those traditionally seen as not worthy of such positions in organizations. The authors state that their book is intended to be used by "dedicated professionals and voluntary leaders" and for anyone who "shares the belief in the infinite possibilities of old age and wants to make a difference" (p.xvii). (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Design and evaluation of an obedience training program for mothers of preschool children.

Conducted a training program in a clinic playroom to teach 24 mothers to use the principles of contingent social reinforcement to increase their preschool child's obedience. During the training, E relayed commands to the mother, cued her to reinforce her child, and reinforced the mother from behind a 1-way vision screen using a "bug-in-the-ear" device. As a group, the mothers' contingent use of maternal proximity and verbal reinforcement improved significantly as a result of the training program. Children's obedience to their mothers' verbal commands was improved as well. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Raters Who Pursue Different Goals Give Different Ratings.

J. N. Cleveland and K. R. Murphy (1992) suggested that phenomena such as rater errors and interrater disagreements could be understood in terms of differences in the goals pursued by various raters. We measured 19 rating goals of students at the beginning of a semester, grouped them into scales, and correlated these with teacher evaluations collected at the end of the semester. We found significant multiple correlations, both within classes and in an analysis of the pooled sample (adjusting for instructor mean differences, incremental R2 = .08). Measures of rating goals obtained after raters had observed a significant proportion of ratee performance accounted for variance (incremental R2 = .07) not accounted for by measures of goals obtained at the beginning of the semester. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The Diagnostic Inventory for Screening Children: Psychometric, factor, and validity analyses.

Reviews normative data from 571 Ss for the Diagnostic Inventory for Screening Children (DISC) developed by J. A. Amdur et al (1988). Concurrent and construct validity of the DISC are also reported, based on data from 40 children who were referred to community agencies for assessment of developmental delays and workers from the agencies. Reliability data indicate substantial agreement and stability within the DISC. Validity data shows that the DISC was more likely to lead to a referral than the Denver Developmental Screening Test or the Stanford-Binet Intelligence Test—Third Edition. Factor analyses indicate that a common factor model with 1 factor was a good fit to most age groups, especially those under age 3 yrs. Limitations of the DISC are discussed. (French abstract) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Durability of wood flour‐plastic composites exposed to accelerated freeze–thaw cycling. II. High density polyethylene matrix

This study examined the durability of extruded HDPE/wood‐flour composites exposed to 15 accelerated cycles of water submersion, freezing, and thawing, according to ASTM standard D6662. The durability of both maple and pine composites was assessed by testing the flexural properties and density. Mercury intrusion porosimetry and scanning electron microscopy were also used to evaluate the interfacial adhesion between the matrix and wood flour before and after exposure to accelerated freeze–thaw cycling. Freeze–thaw actions had no apparent effect on the density of the composites after exposure, regardless of the wood species. However, these actions led to moisture uptake, which decreased the interfacial adhesion and increased the pore size and quantity in the composites, which resulted in a significant loss in flexural properties. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 100: 35–39, 2006     

Starch affecting anti-staling agents and their function in freestanding and pan-baked bread

Anti-staling agents with different mechanisms were added to a normal white wheat bread to investigate the relation between bread staling, amylopectin retrogradation and water-related properties (i.e. water content and distribution between crumb and crust). Bread was baked both as pan-baked and freestanding loaves. The anti-staling agents maltogenic α-amylase, distilled monoglyceride and lipase had a direct influence on starch retrogradation, whereas gluten and waxy wheat flour diluted the amylopectin content or changed the ratio between amylose and amylopectin. The degree of staling was measured as the firmness and springiness, together with two new methods, crumbliness and cutability. In addition, the degrees of amylopectin retrogradation and amylose–lipid complex formation were analyzed by differential scanning calorimetry, and the water content, water loss and water migration were measured. The addition of α-amylase improved most staling parameters, although the changes were not as large as expected. Furthermore, monoglyceride and lipase increased the formation of amylose–lipid complexes, but only lipase gave better results regarding the specific volume and firmness. Increased amylose–lipid complex formation was seen to increase water migration from crumb to crust. Adding 10% waxy wheat flour appeared to lead to a slight overall improvement i.e. lower water migration and better cutability. Adding gluten or 3% waxy wheat flour only improved the specific volume. The method of baking the loaves, i.e. freestanding or pan-baked, had a greater influence than the anti-staling agents, which shows that bread quality is not always improved by starch affecting anti-staling agents without process changes.     

Some physico-chemical properties of nine commercial or semi-commercial whey protein concentrates, isolates and fractions

Summary The physico-chemical properties are reported for a group of whey protein powders prepared on a commercial or semi-commercial scale by three companies and chemically characterized as described elsewhere (Holt et al ., 1999). The dependence of the apparent β-lactoglobulin % on the recovered % showed that the nine samples could be placed in three distinct groups with β-lactoglobulin weight % of 70.9 ± 1.1 (Group 1), 62.0 ± 3.4 (Group 2) and 39.5 ± 4.9 (Group 3). Measurements by ¹H-NMR spectroscopy, on 3 of the samples confirmed that the native fold still predominated in the β-lactoglobulin. β-lactoglobulin could be crystallized from all the powders and the normal space group and cell dimensions were determined for the 8 samples that gave crystals of good enough quality for X-ray studies. Differential scanning microcalorimetry of samples dispersed in a phosphate buffer showed a clear difference between Goups 1 and 2 with a more prominent peak due to α-lactalbumin in the Group 2 samples. Light scattering and size exclusion chromatography showed that two types of aggregates were present to a variable extent in all the samples and after a heat treatment, the larger aggregates tended to predominate in Group 2. The rheology measurements, also made in the phosphate buffer, showed a difference of gel stiffness during heat treatment between the Group 1 and Group 2 samples with the exception of the BORCwpc+ sample. Within each group, gel stiffness increased with the degree of lactoslylation of the β-lactoglobulin. Interfacial measurements on samples dispersed in water presented a more complex pattern of behaviour although surface tension measurements at the air water interface of the Group 2 samples showed a two-step pattern of surface tension decrease with time, compared to a single step pattern in the Group 1 samples.