The performance of surfactant mixtures at low temperatures

Optimising detergency at lower temperatures is of increasing interest due to environmental and economic factors, and requires a greater understanding of the effects of temperature on the adsorption of surfactant mixtures at interfaces. The adsorption properties of surfactant mixtures and biosurfactant/surfactant mixtures have been studied at room temperatures and at temperatures below ambient using surface tension and neutron reflectivity measurements. For the ternary surfactant mixture of octaethylene monododecyl ether, C12E8, sodium dodecyl 6-benzene sulfonate, LAS, and sodium dioxyethylene glycol monododecyl sulfate, SLES, the surface tension at the air-water interface increases with decreasing temperature. In contrast, there is a notable reduction in the increase in the surface tension with a decrease in temperature from 25 °C to 10 °C for the 5 component rhamnolipid/surfactant mixture of the mono-rhamnose, R1, and di-rhamnose, R2, with C12E8/LAS/SLES. The associated neutron reflectivity data for the ternary C12E8/LAS/SLES mixture and the significant observation is that the 3, 4, and 5-component mixtures containing rhamnolipids in conjunction with the other surfactants show changes in composition and adsorbed amounts of the individual components which are close to the experimental error. However the significant observation is that the neutron reflectivity data indicate that the improved surface tension tolerance at lower temperatures is associated with the dominance of the rhamnolipid adsorption in such mixtures. Hence the introduction of the rhamnolipids provides a tolerance to the adverse effects associated with reduced temperatures, and a potential for improved detergency at relatively low temperatures

Using behavior-analytic implicit tests to assess sexual interests among normal and sex-offender populations

The development of implicit tests for measuring biases and behavioral predispositions is a recent development within psychology. While such tests are usually researched within a social-cognitive paradigm, behavioral researchers have also begun to view these tests as potential tests of conditioning histories, including in the sexual domain. The objective of this paper is to illustrate the utility of a behavioral approach to implicit testing and means by which implicit tests can be built to the standards of behavioral psychologists. Research findings illustrating the short history of implicit testing within the experimental analysis of behavior are reviewed. Relevant parallel and overlapping research findings from the field of social cognition and on the Implicit Association Test are also outlined. New preliminary data obtained with both normal and sex offender populations are described in order to illustrate how behavior-analytically conceived implicit tests may have potential as investigative tools for assessing histories of sexual arousal conditioning and derived stimulus associations. It is concluded that popular implicit tests are likely sensitive to conditioned and derived stimulus associations in the history of the test-taker rather than 'unconscious cognitions', per se

Validation of the Voice Handicap Index by Assessing Equivalence of European Translations

OBJECTIVE: We aimed to assess the equivalence of translations of the Voice Handicap Index (VHI). PATIENTS AND METHODS: Confirmatory factor analysis was used to assess equivalence of the US version and several translations including (1) Dutch, (2) Flemish Dutch (Belgium), (3) UK English, (4) French, (5) German, (6) Italian, (7) Portuguese and (8) Swedish. VHI questionnaires were gathered from 1,281 subjects. Patients were classified into 11 voice lesion categories. Patients with incomplete response (4%) and patients within voice lesion categories with small numbers were excluded from further analyses, leaving a cohort of 1,052 patients from 8 countries. RESULTS: The internal consistency of the VHI proved to be good. Confirmatory factor analysis across countries revealed that a 3-factor fixed measurement model best fitted the data; the 3 subscales appeared to highly intercorrelated, especially in the US data. The underlying structure of the VHI was also equivalent regarding various voice lesions, but distinct groups were recognized with respect to the height of the VHI scores, indicating that various voice lesions lead to a diversity of voice problems in daily life. CONCLUSION: The US VHI and the translations appeared to be equivalent, which means that the results from studies from the various included countries can be compared

Item reduction of the Voice Handicap Index (VHI) based on European translations.

Objective: Constructing an internationally applicable short-scale of the Voice Handicap Index (VHI). Methods: Subjects were 1,052 patients with 5 different types of voice disorder groups from Belgium, France, Sweden, Germany, Italy, The Netherlands, Portugal, and the USA. Different 9- and 12-item subsets were selected from the 30 VHI items using (1) the first factor of an unrotated factor analysis (narrow range subsets) and (2) the first three factors after promax rotation (broad range subsets). Country-specific subsets were selected to test deviations from the international subsets. For all subsets, reliability was investigated using Cronbach’s alphas and correlations with the total VHI. Validity was investigated using regression on voice disorder groups. All analyses were performed for the total and for all country-specific subject samples. Results: Reliability was high for all item subsets. It was lower for the international compared to the country-specific subsets and for the broad range compared to the narrow range subsets. Validity was best for the broad range subsets. Validity was better for the international than for the country-specific subsets. For all statistics the 12-item subsets were not essentially better than the 9-item subsets. Conclusion: The international broad range 9-item subset forms a scale which approximates well the total VHI