Properties of short polystyrene chains confined between two Gold surfaces through a combined Density Functional Theory and classical Molecular Dynamics approach

The properties of atactic short-chain polystyrene films confined between two parallel gold surfaces at a temperature of 503 K are investigated using a combination of density functional theory calculations and classical atomistic simulations. A classical Morse-type potential, used to describe the interaction between the polymer and the gold surface, was parameterized based on the results of density functional calculations. Several polystyrene films were studied, with thicknesses ranging from around 1-10 nm. The structural, conformational and dynamical properties of the films were analysed and compared to the properties of the bulk polystyrene systems. The dynamics of the polystyrene close to the surface was found to be significantly slower than in the bulk

Hierarchical multiscale modeling of polymer-solid interfaces: atomistic to coarse-grained description, and structural and conformational properties of polystyrene-gold systems

A hierarchical simulation approach was developed in order to study polystyrene films sandwiched between two parallel Au(111) surfaces. The coarse-grained potentials describing the interaction of polystyrene with the gold surface were developed systematically using constrained all-atom molecular simulations of a styrene trimer on the Au(111) surface. The model was validated by studying a 5 nm film of short (10mer) polystyrene chains using all-atom and coarse-grained molecular dynamics simulations. The density, structure and conformational properties of coarse-grained films were found to be in excellent agreement with all-atom ones. The coarse-grained model was then used to study the structural and conformational properties of roughly 10 nm and 20 nm thick films with 10, 50, 100 and 200mer chains. The width of the interphase region of the polymer films is property specific. The density profiles reached the bulk value around 1.5 nm from the interface, for all chain lengths. An estimate of the width of the interphase region based on the conformation tensor profile indicates that the interphase width is proportional to the square root of the chain length (number of monomers) and for 200mer chains the interphase width is approximately 6-9 nm

Experiments on near-wall structure of three-dimensional boundary layers

Investigations of three-dimensional turbulent boundary layers have shown basic differences between two- and three-dimensional flows. These differences can significantly impact the modeling of three-dimensional flows since many flow models are based on results from two-dimensional boundary layers. In many cases the shear stress vector direction has been shown to lag relative to the direction of the mean velocity gradient as the cross flow grows downstream. Coincidence of these vectors is necessary for a scalar eddy viscosity modeling assumption. A second effect is a reduction in magnitude of the shear stress and/or the shear stress to turbulence energy ratio, a(sub 1). This reduction has been observed in several experiments. Recent numerical simulations also indicate wall-layer structural differences between two- and three-dimensional boundary layers. The differences in structure between two- and three-dimensional boundary layers was also addressed in the experiment of Littell & Eaton. The experiment used two-point correlations to investigate the vortical structures in a three dimensional boundary layer on a spinning disk. It was found that each sign of longitudinal vortex is equally likely to exist, but one sign of vorticity is associated with a structure which is better at producing ejections. The goal of the current investigation is to study the structure of the inner layers. Among other questions, the differences between the effects deduced from the three-dimensional flow simulations and the effects seen in experiments can be examined. The research concentrates on the structure of the wall-layer through flow visualization and direct turbulence measurements down to y(+) = 5

Development of a Survey Instrument to Explore the Characteristics of Australian Private Physiotherapy Practitioners’ Interprofessional Interactions

Background: Interprofessional collaboration is a complex process defined by the relationships and interactions between health practitioners from diverse professional backgrounds. Although the benefits of a collaborative health workforce are widely acknowledged, it is currently poorly understood to what extent private physiotherapy practitioners engage in interprofessional collaboration as a part of their clinical practice, and whether they consider to be adequately trained in this area. Information regarding the frequency, modes of communication, and perceived level of satisfaction associated with private physiotherapy practitioners’ interprofessional interactions is also limited. Purpose: The aim of this paper is to describe the development of a survey instrument that can be used to explore the characteristics of Australian private physiotherapy practitioners’ interprofessional interactions. Methods: A multiphase process was used to develop the survey instrument. The research team conducted a literature search which resulted in the generation of 34 individual survey items. After the initial pool of survey items was developed, three experienced physiotherapists were invited to review the items. The draft survey instrument was then subject to online testing with private physiotherapy practitioners to evaluate the utility of the instrument. Results: All three physiotherapists invited to review the initial pool of survey items provided written feedback to the research team. Following revision, five private physiotherapy practitioners participated in pilot testing the survey instrument. Pilot testing revealed that approximately 10 minutes was required to complete the online survey. Conclusions: The final survey instrument has 29 questions in six sections with categorical, Likert and free text response options and can be used to explore the characteristics of Australian private physiotherapy practitioners’ interprofessional interactions. Information obtained from future research projects utilising this survey may guide the development of effective interventions aimed at enhancing the nature and quality of clinical interactions between private physiotherapy practitioners and other health practitioners working in Australia

Development of a survey instrument to explore the characteristics of Australian private physiotherapy practitioners’ interprofessional interactions

Background: Interprofessional collaboration is a complex process defined by the relationships and interactions between health practitioners from diverse professional backgrounds. Although the benefits of a collaborative health workforce are widely acknowledged, it is currently poorly understood to what extent private physiotherapy practitioners engage in interprofessional collaboration as a part of their clinical practice, and whether they consider to be adequately trained in this area. Information regarding the frequency, modes of communication, and perceived level of satisfaction associated with private physiotherapy practitioners’ interprofessional interactions is also limited. Purpose: The aim of this paper is to describe the development of a survey instrument that can be used to explore the characteristics of Australian private physiotherapy practitioners’ interprofessional interactions. Methods: A multiphase process was used to develop the survey instrument. The research team conducted a literature search which resulted in the generation of 34 individual survey items. After the initial pool of survey items was developed, three experienced physiotherapists were invited to review the items. The draft survey instrument was then subject to online testing with private physiotherapy practitioners to evaluate the utility of the instrument. Results: All three physiotherapists invited to review the initial pool of survey items provided written feedback to the research team. Following revision, five private physiotherapy practitioners participated in pilot testing the survey instrument. Pilot testing revealed that approximately 10 minutes was required to complete the online survey. Conclusions: The final survey instrument has 29 questions in six sections with categorical, Likert and free text response options and can be used to explore the characteristics of Australian private physiotherapy practitioners’ interprofessional interactions. Information obtained from future research projects utilising this survey may guide the development of effective interventions aimed at enhancing the nature and quality of clinical interactions between private physiotherapy practitioners and other health practitioners working in Australia

Regulating Micromobility: Examining Transportation Equity and Access

This paper evaluates the various ways cities have or are attempting to address e-scooter usage equity concerns, with a focus on Atlanta, Georgia as compared to Austin, Texas; Charlotte, North Carolina; Los Angeles, California; and Portland, Oregon. The cities were evaluated by the laws in effect at the time of coding, which occurred during the project period of October through December 2019. To explore how existing laws and regulations affect access to e-scooters, this research was guided by the following overarching questions: How equitable is access to e-scooters? How can equitable access to e-scooters be improved? How can a data-driven approach be used to craft inclusive and effective micromobility regulations for Atlanta, Georgia, and other cities nationwide

Regulating Micromobility: Examining Transportation Equity and Access

This paper evaluates the various ways cities have or are attempting to address e-scooter usage equity concerns, with a focus on Atlanta, Georgia as compared to Austin, Texas; Charlotte, North Carolina; Los Angeles, California; and Portland, Oregon. The cities were evaluated by the laws in effect at the time of coding, which occurred during the project period of October through December 2019. To explore how existing laws and regulations affect access to e-scooters, this research was guided by the following overarching questions: How equitable is access to e-scooters? How can equitable access to e-scooters be improved? How can a data-driven approach be used to craft inclusive and effective micromobility regulations for Atlanta, Georgia and other cities nationwide

Interfacial concentration effect facilitates heterogeneous nucleation from solution

Crystal nucleation from solution plays an important role in environmental, biological, and industrial processes and mainly occurs at interfaces, although the mechanisms are not well understood. We performed nucleation experiments on glycine aqueous solutions and found that an oil−solution interface dramatically accelerates glycine nucleation compared to an air−solution interface. This is surprising given that nonpolar, hydrophobic oil (tridecane) would not be expected to favor heterogeneous nucleation of highly polar, hydrophilic glycine. Molecular dynamics simulations found significantly enhanced vs depleted glycine concentrations at the oil−solution vs air−solution interfaces, respectively. We propose that this interfacial concentration effect facilitates heterogeneous nucleation, and that it is due to dispersion interactions. This interface effect is distinct from previously described mechanisms, including surface functionalization, templating, and confinement and is expected to be present in a wide range of solution systems. This work provides new insight that is essential for understanding and controlling heterogeneous nucleation

Elucidating lithium-ion and proton dynamics in anti-perovskite solid electrolytes

All-solid-state Li-ion batteries are currently attracting considerable research attention as they present a viable opportunity for increased energy density and safety when compared to conventional liquid electrolyte-based devices. The Li-rich anti-perovskite Li3−xOHxCl has generated recent interest as a potential solid electrolyte material, but its lithium and proton transport capabilities as a function of composition are not fully characterised. In this work, we apply a combination of ab initio molecular dynamics and 1H, 2H and 7Li solid-state NMR spectroscopy to study the mobility of lithium ions and protons in Li3−xOHxCl. Our calculations predict a strongly exothermic hydration enthalpy for Li3OCl, which explains the ease with which this material absorbs moisture and the difficulty in synthesising moisture-free samples. We show that the activation energy for Li-ion conduction increases with increasing proton content. The atomistic simulations indicate fast Li-ion diffusion but rule out the contribution of long-range proton diffusion. These findings are supported by variable-temperature solid-state NMR experiments, which indicate localised proton motion and long-range Li-ion mobility that are intimately connected. Our findings confirm that Li3−xOHxCl is a promising solid electrolyte material for all-solid-state Li-ion batteries

Effects of multiple concussions on retired National Hockey League players

The purpose of this study was to understand the meanings and lived experiences of multiple concussions in professional hockey players using hermeneutic, idiographic, and inductive approaches within an interpretative phenomenological analysis. The interviewer was an athlete who had suffered multiple concussions, and the interviewees were five former National Hockey League athletes who had retired due to medically diagnosed concussions suffered during their careers. The men discussed the physical and psychological symptoms they experienced as a result of their concussions and how the symptoms affected their professional careers, personal relationships, and quality of life. The former professional athletes related these symptoms to the turmoil that is ever present in their lives. These findings are of interest to athletes, coaches, sport administrators, family members, sport psychology practitioners, and medical professionals, as they highlight the severity of shortand long-term effects of concussions