The monolayer structure of the branched nonyl phenol oxyethylene glycols at the air-water interface

The structure of the monolayers formed by a group of monodisperse nonyl phenol ethoxylates with para-substituted 1-butylpentyl chains (para-(C4H9)2CHC6H 4(OC2H4)nOH, abbreviated to BNPEn, n = 4, 8, and 12) at the air-water interface has been determined by surface tension measurements and neutron reflection. The critical micellar concentration (cmc) was found to be 1.1 ± 0.3 × 10-5 M for BNPE4, 4.0 ± 0.3 × 10-5 M for BNPE8 and 8.0 ± 0.3 × 10-5 M for BNPE12 and the limiting area per molecule (Acmc) at the cmc to be 46 ± 3, 61 ± 4, and 75 ± 5 Å2, respectively. The values of Acmc are almost identical to those obtained from dodecyl ethoxylates (C12En) for the same size of the headgroups, suggesting that Acmc for these nonionic surfactants is determined by the size of the headgroups and is not affected by the chemical structure of the hydrophobic chains. The thicknesses of the nonyl phenol layers projected onto the surface normal direction were found to be 18 ± 3 Å for BNPE4, 19 ± 3 Å for BNPE8, and 22 ± 3 Å for BNPE12. In all cases they were about twice as thick as the fully extended chain, suggesting a broad distribution of the hydrophobic chain across the layer and hence a strong mixing of the chain with the ethoxylate groups

Perspectives on Age and Continuing Professional Development for Nurses: A Literature Review

The need for nurses to participate in continuing professional development (CPD) is growing to keep abreast of rapid changes in nursing care. Concurrently, the nursing workforce is growing older. Ageing leads to changes in biological, psychological, and social functioning. Little is known about the effects of age-related changes on nurses’ CPD. A literature review was conducted to examine whether and how CPD differs across age groups. A framework with five perspectives on age was used in an attempt to distinguish factors contributing to these age differences. Given the limited research on this topic with respect to nurses, we also included studies of workers in general. The literature search revealed 27 relevant studies. In general, older workers appeared less likely to participate in CPD, when considering formal learning activities and late-career workers (older than 50/55 years). We found no clear age patterns for motivation to participate in CPD, for learning outcomes, and for participation in informal and non-formal learning activities. The study showed that more nuanced results are found when studies distinguish at least three age groups. By using different perspectives of age, a comprehensive overview of age-related factors in CPD was generated and gaps in current research were identified. Recommendations for further research are discussed, such as the need for research on whether the types of learning activities that nurses undertake change with ageing. Keywords: Continuing professional development, Age differences, Nurses, Older workers, Workplace learning, Literature revie