A contribution to the interpretation of polymer viscoelasticity in DMTA testing

Some ideas relevant to the prevailing viscoelasticity interpretations of dynamic mechanical thermal analysis (DMTA) experiments are presented. The main aspect is the inclusion of kinetic energy and inertia as variables, seeing the relaxing mass constantly increasing during strain, assigning inertial variation and not viscosity to energy dissipation. The equations developed make it possible to obtain the values of important viscoelastic properties, under in any experimental condition, with the data taken from previous experiments.     

Phosphorus‐containing poly(ester‐imide)–polydimethylsiloxane copolymers

New phosphorus‐containing poly(ester‐imide)‐polydimethylsiloxane copolymers were prepared by solution polycondensation of 1,4‐[2‐(6‐oxido‐6H‐dibenz < c,e > < 1, 2 > oxaphosphorin‐6‐yl)]naphthalene‐bis(trimellitate) dianhydride with a mixture of an aromatic diamine (1,3‐bis(4‐aminophenoxy)benzene) and α,ω‐bis(3‐aminopropyl)oligodimethylsiloxane of controlled molecular weight, in various ratios. Poly(amic acid) intermediates were converted quantitatively to the corresponding polyimide structures using a solution imidization procedure. The polymers are easily soluble in polar organic solvents, such as N‐methyl‐2‐pyrrolidone and N,N‐dimethylformamide, as well as in less polar solvents such as tetrahydrofuran. They show good thermal stability, the decomposition temperature being above 370 °C. The glass transition temperatures are in the range 165–216 °C. Solutions of the polymers in N‐methyl‐2‐pyrrolidone exhibit photoluminescence in the blue region. Copyright © 2010 Society of Chemical Industry     

Influence of caring youth sport contexts on efficacy-related beliefs and social behaviors.

Understanding what factors influence positive youth development has been advocated by youth development researchers (P. L. Benson, 2006; J. S. Eccles & J. A. Gootman, 2002). Consequently, the purpose of this study was to examine whether perceptions of a caring youth sport context influenced prosocial and antisocial behavior through efficacy-related beliefs, that is, positive and negative affective self-regulatory efficacy (ASRE) and empathic self-efficacy (ESE). Multiethnic youths taking part in summer sport programs (N = 395) completed a questionnaire that measured perceptions of the caring climate, ESE, ASRE, and social behavior. Structural equation modeling was used to test whether ASRE and ESE mediated the relationship between caring and social behaviors. Findings revealed that perceptions of caring positively predicted ASRE and ESE. In turn, positive ASRE positively predicted ESE. Prosocial behaviors were positively linked to ESE, whereas antisocial behaviors were negatively predicted by positive ASRE. The results suggest that caring influences prosocial and antisocial behavior because such contexts develop youths' ability to monitor, manage, and control positive affect, which in turn enhances their belief in their ability to empathize. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

From paper to pixels: A comparison of paper and computer formats in psychological assessment

Internet based data collection methods have many advantages for psychological assessment when compared with more traditional paper formats, including, reduced costs, and greater convenience for both the researcher and the participant. However, prior to the wide-spread adoption of these methods, equivalence with paper tests formats must be established. The present study compared questionnaire data from the computer with that from a traditional paper format in a sample of college students both directly and through an opinion survey. Three types of questionnaires that represent distinct areas commonly assessed in psychological research included: quality of life (SF-36), depression (BDI-II) and personality (NEO). A within-subjects design counterbalanced order across the computer and paper formats. Overall the findings showed no differences for the Neuroticism and Extraversion facts of the NEO, for the BDI and for the subscales and composite scores of the SF-36. Significant differences were found between the paper and computer formats for the Openness, Agreeableness, and Conscientiousness facets of the NEO. Additionally, the computer was perceived to be convenient, user-friendly, comfortable, and secure. Results suggest that a computerized format is an efficient way to conduct quality of life research, especially for the assessment of distress levels and quality of life.     

A randomized controlled trial of cognitive behavioral therapy for adherence and depression (CBT-AD) in HIV-infected individuals.

Objective: To evaluate cognitive-behavioral therapy to enhance medication adherence and reduce depression (CBT-AD) in individuals with HIV. Design: A two arm, randomized, controlled, cross-over trial comparing CBT-AD to enhanced treatment as usual only (ETAU). ETAU, which both groups received, included a single-session intervention for adherence and a letter to the patient's provider documenting her or his continued depression. The intervention group also received 10 to 12 sessions of CBT-AD. Main Outcome Measures: Adherence to antiretroviral therapy as assessed by Medication Event Monitoring Systems (MEMs) and depression as assessed by blinded structured evaluation. Results: At the acute outcome assessment (3-months), those who received CBT-AD evidenced significantly greater improvements in medication adherence and depression relative to the comparison group. Those who were originally assigned to the comparison group who chose to cross over to CBT-AD showed similar improvements in both depression and adherence outcomes. Treatment gains for those in the intervention group were generally maintained at 6- and 12-month follow-up assessments. By the end of the follow-up period, those originally assigned CBT-AD demonstrated improvements in plasma HIV RNA concentrations, though these differences did not emerge before the cross-over, and hence there were not between-groups differences. Conclusions: CBT-AD is a potentially efficacious approach for individuals with HIV struggling with depression and adherence. Replication and extension in larger efficacy trials are needed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Linking business and requirements engineering: is solution planning a missing activity in software product companies?

A strong link between strategy and product development is important, since companies need to select requirements for forthcoming releases. However, in practice, connecting requirements engineering (RE) and business planning is far from trivial. This paper describes the lessons learned from four software product companies that have recognized the need for more business-oriented long-term planning. The study was conducted using the action research approach. We identified five practices that seem to strengthen the link between business decisions and RE. These are (1) explicating the planning levels and time horizons; (2) separating the planning of products’ business goals from R&D resource allocation; (3) planning open-endedly with a pre-defined rhythm; (4) emphasizing whole-product thinking; and (5) making solution planning visible. To support whole-product thinking and solution planning, we suggest that companies create solution concepts. The purpose of the solution concept is to provide a big picture of the solution and guide RE activities.     

Raspberry seed extract effect on the ferroxidase activity of ceruloplasmin isolated from plasma

In this study, the effect of the raspberry seed extract (RSE) on the ferroxidase activity of ceruloplasmin (Cp) isolated from healthy male subject serum was analyzed. The ferroxidase activity of Cp was determined by spectrophotometry using Fe(II) – histidine complex and ferrozine as a chromogenic reagent. The ferroxidase activity of ceruloplasmin was demonstrated in dose-dependent way within the range 22–66 μg/ml. The effect of RSE on Fe(II) concentration, measured as the decrease of Fe(II) concentration in samples and expressed as ΔFe(II), was found to be a dose-dependent within the range 1.20–51.56 μg dm/ml. The ferroxidase activity of Cp was influenced by the RSE within its studied range. However, the addition of the highest concentration of RSE (51.56 μg dm/ml) to the sample containing the highest level of Cp (66 μg/ml) did not affect its ferroxidase activity. It may be suggested that the competition for Fe(II) as the substrate limits the effect of RSE on Cp activity and causes no further changes in Fe(II) elimination.     

Comparison of the Determination of Eight Cholesterol Oxides in Dry�CCured Shoulder by GC�CFID, GC�CMS, and GC Tandem Mass Spectrometry

The analysis of eight cholesterol oxidation products: 7α–hydroxycholesterol, 7β–hydroxycholesterol, α–epoxycholesterol, β–epoxycholesterol, 20α–hydroxycholesterol, cholestanetriol, 25–hydroxycholesterol, and 7–ketocholesterol in dry–cured shoulder was carried out. The extraction of lipids was performed by using the Bligh and Dyer method (1959). Interferences were removed by solid-phase extraction (SPE) in two steps with silica and aminipropylsilica SPE columns. The separation of the eight cholesterol oxidation products was done by gas chromatography, and the detection was performed by flame ionization detection (FID) and mass spectrometry (MS). The results obtained from the use of both systems of detection were compared. The results showed that gas chromatography-mass spectrometry (GC–MS) was the most suitable technique to obtain reliable quantitative data, and significant differences (p < 0.05) between FID and MS determining 7α–hydroxycholesterol, 20α–hydroxycholesterol, and 25–hydroxycholesterol were observed. For the determination of cholesterol oxidation products, it was necessary to apply gas chromatography-tandem mass spectrometry to increase the sensitivity and to avoid interference from other compounds.