A reverse pathway? Actual and perceived skill proficiency and physical activity

Purpose: Motor skills are considered a prerequisite to physical activity, yet the relationship may be reciprocal and perceived sports competence might mediate associations.
Methods: In 2006/2007, 215 adolescents completed motor skill proficiency (Get Skilled Get Active), perceived sport competence (Physical Self-Perception Profile) and physical activity assessments (Adolescent Physical Activity Recall Questionnaire) as part of the Physical Activity and Skills Study. Using AMOS (Version 7.0), reciprocal relationships were examined between motor skill (object control and locomotor) and moderate to vigorous physical activity (MVPA). Both models were then run in different versions to understand the role of perceived sports competence as a potential mediator.
Results: Mean age was 16.4 yr (SD = 0.6), 51.6% (111/215) were females. A reciprocal relationship between object control and MVPA and a one-way relationship from MVPA to locomotor skill was found. When perceived sports competence was examined as a mediator, the best-fitting model versions explained 16% (R² = 0.16)
MVPA variation, and 30% object control (R² = 0.30), and 12% locomotor skill variation (R² = 0.12) (reverse relationship). Perceived sports competence partially mediates the relationship between object control proficiency and physical activity for both directions and fully mediates the relationship between physical activity and locomotor skill; but only when locomotor skill is the outcome.
Conclusions: If the relationship between object control skill and physical activity is viewed as a ‘‘positive feedback loop,’’ skill development and increasing physical activity should simultaneously be targeted in physical activity interventions. Increasing perceived sport competence should also be an intervention focus.

Role of Jak2/Stat5/Cis pathway components in zebrafish development

By utilizing the zebrafish as a research model, the function of specific cell signalling pathway components in development was investigated. This revealed new roles for the so-called Jak2/Stat5/Cis pathway in blood and sensory organ development, and a conserved prolactin pathway despite divergent functions between species.

Mixed methods evaluation research for a mental health screening and referral clinical pathway

Rationale: This study is an exemplar of mixed method evaluation research for development of a clinical pathway.

Aim: To develop and evaluate an evidence-based, feasible mental health screening and referral clinical pathway for Department of Veterans’ Affairs-funded community nursing care of war veterans and war widows in the Australian context.

Methods: Mixed methods were applied to formulate and clinically evaluate an appropriate pathway. The pathway was applied at urban and rural sites for the nursing care of 97 war veteran and war widow clients. Evaluative data were collected from clients, their informal carers, community nurses, and general practitioners. Chart auditing and pre-post measures were undertaken. Collaboration occurred with an interdisciplinary design team.

Results: The final modified six-page pathway includes use of validated screening tools (Kessler Psychological Distress Scale [K10]) and Alcohol Use Disorder Identification Test, appropriate referral information, directions for support and health-promoting education, and evidence-based guidelines. Implications for Practice: The clinical pathway is a useful, tested, evidence-based guide for generalist community nurses to identify and suitably respond to common mental healthcare needs of war veterans and war widows. The pathway provides outcomes acceptable to clients and their carers, nurses and doctors.

Conclusions: This study provides an evaluated clinical pathway for generalist community nurses to screen for mental health difficulties, make appropriate referrals as required and to support war veteran and war widow clients. However, the study also shows how research can be used to develop and evaluate
practical, evidence-based clinical pathways.

Transcriptional regulation of the yghJ-pppA-yghG-gspCDEFGHIJKLM cluster, encoding the type II secretion pathway in Enterotoxigenic Escherichia coli

The gene cluster gspCDEFGHIJKLM codes for various structural components of the type II secretion pathway which is responsible for the secretion of heat-labile enterotoxin by enterotoxigenic Escherichia coli (ETEC). In this work, we used a variety of molecular approaches to elucidate the transcriptional organization of the ETEC type II secretion system and to unravel the mechanisms by which the expression of these genes is controlled. We showed that the gspCDEFGHIJKLM cluster and three other upstream genes, yghJ, pppA, and yghG, are cotranscribed and that a promoter located in the upstream region of yghJ plays a major role in the expression of this 14-gene transcriptional unit. Transcription of the yghJ promoter was repressed 168-fold upon a temperature downshift from 37°C to 22°C. This temperature-induced repression was mediated by the global regulatory proteins H-NS and StpA. Deletion mutagenesis showed that the promoter region encompassing positions −321 to +301 relative to the start site of transcription of yghJ was required for full repression. The yghJ promoter region is predicted to be highly curved and bound H-NS or StpA directly. The binding of H-NS or StpA blocked transcription initiation by inhibiting promoter open complex formation. Unraveling the mechanisms of regulation of type II secretion by ETEC enhances our understanding of the pathogenesis of ETEC and other pathogenic varieties of E. coli.

The drainage of thin liquid films between solid surfaces

We present measurements of the thickness as a function of time of liquid films as they are squeezed between molecularly smooth mica surfaces. Three Newtonian, nonpolar liquids have been studied: octamethylcyclotetrasiloxane, n-tetradecane, and n-hexadecane. The film thicknesses are determined with an accuracy of 0.2 nm as they drain from ∼1 μm to a few molecular layers. Results are in excellent agreement with the Reynolds theory of lubrication for film thicknesses above 50 nm. For thinner films the drainage is slower than the theoretical prediction, which can be accounted for by assuming that the liquid within about two molecular layers of each solid surface does not undergo shear. In very thin films the continuum Reynolds theory breaks down, as drainage occurs in a series of abrupt steps whose size matches the thickness of molecular layers in the liquid. The presence of trace amounts of water has a dramatic effect on the drainage of a nonpolar liquid between hydrophilic surfaces, causing film rupture which is not observed in the dry liquids.

The 'wimple' : rippled deformation of a fluid drop caused by hydrodynamic and surface forces during thin film drainage

It is well-known that hydrodynamic pressures in a thin draining liquid film can cause inversion of the curvature of a drop or bubble surface as it approaches another surface, creating a so-called “dimple”. Here it is shown that a more complicated rippled shape, dubbed a “wimple”, can be formed if a fluid drop that is already close to a solid wall is abruptly pushed further toward it. The wimple includes a central region in which the film remains thin, surrounded by a ring of greater film thickness that is bounded at the outer edge by a barrier rim where the film is thin. This shape later evolves into a conventional dimple bounded by the barrier rim, which then drains in the normal way. During the evolution from wimple to dimple, some of the fluid in the thicker part of the film ring flows toward the central region before eventually draining in the opposite direction. Although the drop is pressed toward the wall, the central part of the drop moves away from the wall before approaching it again. This is observed even when the inward push is too small to create a wimple.

The influence of surface forces on thin film drainage between a fluid drop and a flat solid

An experiment is described in which a mica surface is driven towards a mercury drop immersed in aqueous electrolyte. Under appropriate conditions, hydrodynamic pressure in the aqueous film creates a classical dimple in the mercury drop. The use of optical interferometry and video recording to monitor the shape of the drop and the thickness of the aqueous film with sub-nanometre resolution yields a high density of precise data showing the formation and evolution of the dimple as the film drains. Variation of electrical potential applied to the mercury phase allows control of the surface forces acting between the drop and the mica surface, so that the effect of surface forces on the film drainage process is highlighted. It is found that the film thickness at the centre of the dimple and the lateral extent of the dimple are not significantly affected by surface forces. On the other hand, the minimum film thickness at the edge of the dimple is sensitive even to weak surface forces. Since this minimum film thickness is a major determinant of the film drainage rate, it is shown that surface forces have an important effect on the overall drainage process.

Thin film drainage : hydrodynamic and disjoining pressures determined from experimental measurements of the shape of a fluid drop approaching a solid wall

Accurate measurements of the shape of a mercury drop separated from a smooth flat solid surface by a thin aqueous film reported recently by Connor and Horn (Faraday Discuss. 2003, 123, 193-206) have been analyzed to calculate the excess pressure in the film. The analysis is based on calculating the local curvature of the mercury/aqueous interface, and relating it via the Young-Laplace equation to the pressure drop across the interface, which is the difference between the aqueous film pressure and the known internal pressure of the mercury drop. For drop shapes measured under quiescent conditions, the only contribution to film pressure is the disjoining pressure arising from double-layer forces acting between the mercury and mica surfaces. Under dynamic conditions, hydrodynamic pressure is also present, and this is calculated by subtracting the disjoining pressure from the total film pressure. The data, which were measured to investigate the thin film drainage during approach of a fluid drop to a solid wall, show a classical dimpling of the mercury drop when it approaches the mica surface. Four data sets are available, corresponding to different magnitudes and signs of disjoining pressure, obtained by controlling the surface potential of the mercury. The analysis shows that total film pressure does not vary greatly during the evolution of the dimple formed during the thin film drainage process, nor between the different data sets. The hydrodynamic pressure appears to adjust to the different disjoining pressures in such a way that the total film pressure is maintained approximately constant within the dimpled region.

Evolution of JAK-STAT pathway components : mechanisms and role in immune system development

Background
Lying downstream of a myriad of cytokine receptors, the Janus kinase (JAK) – Signal transducer and activator of transcription (STAT) pathway is pivotal for the development and function of the immune system, with additional important roles in other biological systems. To gain further insight into immune system evolution, we have performed a comprehensive bioinformatic analysis of the JAK-STAT pathway components, including the key negative regulators of this pathway, the SH2-domain containing tyrosine phosphatase (SHP), Protein inhibitors against Stats (PIAS), and Suppressor of cytokine signaling (SOCS) proteins across a diverse range of organisms.

Results
Our analysis has demonstrated significant expansion of JAK-STAT pathway components co-incident with the emergence of adaptive immunity, with whole genome duplication being the principal mechanism for generating this additional diversity. In contrast, expansion of upstream cytokine receptors appears to be a pivotal driver for the differential diversification of specific pathway components.

Conclusion
Diversification of JAK-STAT pathway components during early vertebrate development occurred concurrently with a major expansion of upstream cytokine receptors and two rounds of whole genome duplications. This produced an intricate cell-cell communication system that has made a significant contribution to the evolution of the immune system, particularly the emergence of adaptive immunity.

Nurses’ advice regarding sterile or clean urinary drainage bags for individuals with a long-term Indwelling urinary catheter

PURPOSE: The purpose of this study was to identify, compare, and explore advice nurses give to community-dwelling long-term indwelling catheter users on the use of sterile or clean urinary drainage bags, and to obtain information that would inform the design of a larger-scale international survey.


SUBJECTS AND SETTINGS: A survey was targeted to nurse members of the International Continence Society (n = 130). Respondents (n = 28; 21.5%) included nurses from Australia, Canada, Belgium, Switzerland, the United Kingdom, and the United States, who specialized in managing incontinence.


METHODS: The project was conducted as a descriptive, exploratory pilot study. Respondents completed an online anonymous survey that was distributed by the International Continence Society. The survey instrument was designed by the investigators and comprised 14 questions with both fixed and open-ended response options.


RESULTS: Most respondents in this survey advised indwelling catheter users to reuse their catheter bags (n = 15; 68%). Factors that influenced advice included concerns about the cost of catheter bags, an evaluation of the individual's infection risk, local and national policies, evidence-based guidelines, users' living arrangements, and their ability to clean the bags. Advice on decontamination methods varied; however, the most commonly recommended cleaning agent was water and vinegar, followed by a sterilizing or bleach solution or dishwashing detergent.


CONCLUSION: Nurses play a key role in educating and supporting indwelling catheter users. Results of this study highlight variability in the advice nurses give to community-dwelling long-term indwelling catheter users about sterile or clean urinary drainage bags. This variability requires further investigation and affirms the need for a larger-scale study that draws on a broader sample of nurses.