Thermal Unfolding of Gelatin in Solids as Affected by the Glass Transition

ABSTRACT: The thermal unfolding or denaturation of solid-state proteins during processing can affect their functionality. This project explored the relation between the glass transition temperature (T_g) and thermal unfolding temperature (T_m) using gelatin as a model system. Freeze-dried gelatin was prepared containing various polyol types at several concentrations. Using differential scanning calorimetry, T_m andT_g were determined. Moisture and polyols (that is, glycerol, xylitol, sorbitol, sucrose, and trehalose) promoted a lowering of both T_g andT_m, the extent of which depended upon the plasticizer type and concentration. For all the data, T_m > T_g, and a plot of T_m against T_g indicated a linear relationship ( R²= 0.95). These results suggest that formulations must be in the rubbery state to have the necessary mobility for hydrogen bond disruption that leads to protein unfolding. Glass transition data should be considered when developing processing parameters for proteinaceous systems.     

Television violence and aggression: The causal effect remains.

Replies to criticisms by G. Becker (1972), R. M. Kaplan (1972), and H. Kay (1972) on the article by L. D. Eron et al (see record 1973-09034-001) concerning television violence and aggression. There is no reason to change the conclusion that early exposure to TV violence probably has a causal influence on aggression in males. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Reduction of human avoidant behavior: A comparison of counterconditioning, expectancy, and cognitive information approaches.

Compared the fear-reducing efficacy of procedures based on 3 major theories that have been proposed to account for the success of systematic desensitization therapy. 33 female and 14 male undergraduates, chosen on the basis of their fear of snakes, were assigned to 1 of 5 groups, and were given 4 individual treatment sessions. Predictions were confirmed in that the outcome measures of the high-expectancy placebo group and the 2 cognitive-coping groups were significantly superior to those of the counterconditioning and no-treatment groups. Thus, the supposition is supported that changes in human avoidant behavior may be attributed to demand and expectancy variables rather than the conditioning of antagonistic responses as has been previously suggested. (18 ref.) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Physicochemical properties of pectins from okra (Abelmoschus esculentus (L.) Moench)

Okra pectin obtained by hot buffer extraction (HBSS) consists of an unusual pectic rhamnogalacturonan I structure in which acetyl groups and alpha galactose residues are substituted on rhamnose residues within the backbone. The okra Chelating agent Soluble Solids (CHSS) pectin consists of slightly different structures since relatively more homogalacturonan is present within the macromolecule and the rhamnogalacturonan I segments carry slightly longer side chains. The rheological properties of both okra pectins were examined under various conditions in order to understand the unusual slimy behaviour of okra pectins. The viscosity of the okra HBSS pectin was 5–8 times higher than the viscosity of the okra CHSS pectin. The okra HBSS pectin showed an elastic behaviour (G′ > G″) over a wide range of frequencies (10⁻¹–10 Hz), at a strain of 10%, while okra CHSS and saponified okra HBSS/CHSS pectin showed predominantly viscous responses (G′ < G″) over the same frequency range. The results suggest that the structural variation within the okra pectins greatly affect their rheological behaviour and it is suggested that acetylation of the pectin plays an important role through hydrophobic associations. Dynamic light scattering was used to study the association behaviour of both okra pectins at low concentration (0.001–0.1% w/w). Results showed that the saponified okra pectins did not exhibit a tendency to aggregate in the concentration range studied, whereas both non saponified samples showed a substantial degree of association. These results suggest that the unusual slimy behaviour of the non saponified samples may be related to the tendency of these pectins to associate, driven by hydrophobic interactions.     

Computer simulation of an industrial computer-aided drafting configuration

The essential first stage in the development of any computer-aided drafting system concerns the analysis of the processes which are to be computerized. The results of a critical analysis of the existing manual procedures establish the range of user requirements, thus these can be mirrored in the computer system. Operational performance characteristics of an industrial system have been simulated by the authors and it is demonstrated that the procedures described have resulted in an optimal system configuration being chosen.     

Age and achievement in psychology: The harmonic mean as a model.

The age at which a psychologist publishes his one most significant work may be modeled by the harmonic mean. The harmonic mean of a psychologist's age at the first and the last publication predicts that age very well. The 2 figures correlated .52 for a sample of 213 eminent contributors from psychology's history. The harmonic mean is not related to degree of eminence, however. Neither is it a function of sex, nationality, variations in normal life span, or the historic period of the individual's activity. Certain deviations from "normalcy" in an academic or research career make it inherently impossible to use the harmonic mean as a predictor. When these deviations are discounted, the harmonic mean accounts for almost 75% of the variance in the actual age of peak achievement. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Multiple Factors in Short-Term Behavioral Control of Protein Intake in Rats.

The availability and concentration of dietary protein was varied in an examination of the nature of the day-to-day intake of protein solutions by 60-day-old male rats. It was found that the rats consumed a remarkably constant absolute amount of protein each day, adjusting overall caloric intake to maintain protein at a roughly constant proportion of total calories. Factors such as the time of access to a protein source or the extent of prior experience with a protein source were seen to influence the overall constancy of protein intake, whereas daily shifts in preference between two available concentrations of protein did not interfere with such short-term control. The mechanism for this behavioral control is likely to be different from mechanisms mediating the conditioned response to dietary protein, as in the response to dietary amino acid imbalance. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Measurement of self-disclosure in encounter groups: A methodological study.

In order to compare the evaluations of self-disclosure from 3 points of view--the sender, the receiver, and a neutral or objective observer--self-rankings and group-rankings of self-disclosure and participation were collected from 11 members (undergraduates) of a weekend encounter group at the end of the last session. After reviewing 10 hrs of tape, 3 independent raters selected a single list of 33 statements, 3 from each, as being the most self-disclosing. J. Block's (1961) Q technique was used to quantify the statements into rank-order form. Rank-order correlations among the self- and group-rankings of self-disclosure and participation were all extremely high, suggesting that these rankings could be used interchangeably in future research. The Q -sort data, however, indicated that the statements judged to be the most self-revealing were produced by Ss who were both self-ranked and group-ranked as low in self-disclosure. Results are interpreted as indicating that the level of analysis of self-disclosure needs to be carefully spelled out, as content analyses yield quite different results from global analyses. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

MIS capacitance and derivative of capacitance,with application to nonparabolic band semiconductors

Theoretical capacitance (C-V) and derivative of capacitance (C′-V) curves for an MIS structure with a semiconductor having a nonparabolic conduction band and a parabolic valence band are calculated for single level trap, uniform and nonuniform surface state distributions. The Kane model is used to describe the nonparabolic conduction band. The effects of varying the hole effective mass, Kane matrix element, temperature, surface state densities (both donor and acceptor types), and the degeneracy factors for the surface states is examined. The computed results are based on Hg_0·8Cd_0·2TeZnS device parameters.     

Application of the dynamic SIMS technique to the study of silicone release coatings

Secondary ion mass spectrometry (SIMS) depth profiling has been used to determine elemental compositions of cured silicone release coatings as well as the location of controlled release additives (CRAs) in the cured polymer matrix. The two CRAs examined were found to be uniformly distributed throughout the matrix with no apparent increase at either the air or adhesive interface. As CRAs are required for tight release, this suggests that a minimum concentration at the surface is necessary but this concentration is not greater than that found in the bulk.