Epitaxial graphene growth on cubic silicon carbide on silicon with high temperature neutron reflectometry: an operando study.

The growth of graphene on silicon carbide on silicon offers a very attractive route towards novel wafer-scale photonic and electronic devices that are easy to fabricate and can be integrated in silicon manufacturing. Using a Ni/Cu catalyst for the epitaxial growth of graphene has been successful in the mitigation of the very defective nature of the underlying silicon carbide on silicon, leading to a consistent graphene coverage over large scales. A more detailed understanding of this growth mechanism is warranted in order to further optimise the catalyst composition, preferably via the use of operando characterization measurements. Here, we report in situ neutron reflectometry measurements of (Ni, Cu)/SiC films on silicon wafers, annealed from room temperature to 1100 °C, which initiates graphene formation at the buried (Ni, Cu)/SiC interface. Detailed modelling of the high temperature neutron reflectometry and corresponding scattering length density profiles yield insights into the distinct physical mechanisms within the different temperature regimes. The initially smooth solid metallic layers undergo intermixing and roughening transitions at relatively low temperatures below 500 °C, and then metal silicides begin to form above 600 °C from interfacial reactions with the SiC, releasing atomic carbon. At the highest temperature range of 600-1100 °C, the low neutron scattering length density at high temperature is consistent with a silicon-rich, liquid surface phase corresponding to molten nickel silicides and copper. This liquid catalyst layer promotes the liquid-phase epitaxial growth of a graphene layer by precipitating the excess carbon available at the SiC/metal interface.

Gender and socioecological level differences in stakeholders' perceptions of athlete attrition factors in an Australian high-performance pathway system.

OBJECTIVES: This study aimed to build on previous work by the authors. It examines how socioecological level and gender influence high-performance sport system (HPSS) stakeholders' perspectives of the relative importance and feasibility to address athlete attrition factors within an Australian high-performance pathway system (HPPS). DESIGN: Mixed methods. METHODS: Sub-analysis was conducted of rating data from 30 participants who had contributed to identifying 83 statements in 13 clusters in a previous Concept Mapping study. The 13 clusters were statistically analysed in 'R' using cumulative link mixed models (CLMMs) to determine differences in perceived importance and feasibility between 1) socioecological levels, and 2) genders. RESULTS: Mean ratings for 11 and three of the 13 clusters were statistically significantly different between at least two of the five socioecological levels, for importance and feasibility, respectively. Athletes had the largest variation in mean ratings from the most (athlete health 4.59), to least (performance potential 2.83) important cluster, when compared to the other four socioecological levels. There were statistically significant differences between the ratings between genders (Men/Women) for two clusters for each rating scale: Importance: 'athlete health' (M3.33:W3.84 [p 0.012]); 'performance potential' (M3.35:W2.57; [p 0.001]), Feasibility: 'abuse and mismanagement of health' (M2.97:W3.68; [p 0.000]) and 'athlete health' (M2.54:W3.33; [p 0.000]). CONCLUSIONS: This study highlights the need to implement more robust athlete attrition monitoring protocols. It also highlights the importance of listening to youth athletes' voices, and enabling equal gender representation to ensure holistically tailored environments are created to retain talented athletes in high-performance pathway programmes.

Stakeholder insights into athlete attrition in the high-performance pathway.

OBJECTIVES: Primary: To gain a system-wide perspective on factors leading to athlete attrition from a high-performance sport system (HPSS). Secondary: To identify what a sample of system-wide stakeholders and past athletes value as the most important and feasible attrition factors to address to retain talented athletes. DESIGN: Mixed-methods. METHODS: Concept mapping was used for qualitative data collection and quantitative data analysis. Sixty-one participants including: (i) past athletes from an Australian state sporting institute; (ii) their families; and (iii) internal and external stakeholders to a HPSS who supported past athletes. RESULTS: Participants brainstormed 83 unique statements (i.e. attrition factors) that were mapped into 13 clusters of attrition factors following multidimensional scaling and hierarchical cluster analysis performed on the participants sorting data: 'abuse and mismanagement of health'; 'athlete health'; 'limited support/resourcing'; 'coaching'; 'inconsistent processes'; 'financial and career support'; 'pathway structure'; 'organisational dynamics'; 'competitive stress'; 'performance potential'; 'challenges with selection and transition'; 'psychological state'; and 'competing non-sport priorities'. 'Abuse and mismanagement of health' had the highest mean importance (3.76 out of 5) and feasibility (3.31) rating. The 13 clusters were further grouped into four overarching domains: 'sport system policy, structure and processes'; 'pathway structure, transition and support'; 'individual athlete health and capability'; and 'whole-of-life demands and priorities'. The domain 'sport system policy, structure and processes' contained the most important and feasible clusters. CONCLUSIONS: Macro (system-level) and micro (intrapersonal and interpersonal) level athlete attrition factors should be considered together. Athlete health was considered the most important athlete retention issue to address.

What Contributes to Athlete Performance Health? A Concept Mapping Approach.

BACKGROUND: In high-performance sport, athlete performance health encompasses a state of optimal physical, mental, and social wellbeing related to an athlete's sporting success. The aim of this study was to identify the priority areas for achieving athlete performance health in Australia's high-performance sport system (HPSS). METHODS: Participants across five socioecological levels of Australia's HPSS were invited to contribute to this study. Concept mapping, a mixed-methods approach incorporating qualitative and quantitative data collection, was used. Participants brainstormed ideas for what athlete performance health requires, sorted the ideas into groups based on similar meaning and rated the importance, and ease of achieving each idea on a scale from 1 (not important/easiest to overcome) to 5 (extremely important/hardest to overcome). RESULTS: Forty-nine participants generated 97 unique statements that were grouped into 12 clusters following multidimensional scaling and hierarchical cluster analysis. The three clusters with highest mean importance rating were (mean importance rating (1-5), mean ease of overcoming (1-5)): 'Behavioral competency' (4.37, 2.30); 'Collaboration and teamwork' (4.19, 2.65); 'Valuing athlete wellbeing' (4.17, 2.77). The 12 clusters were grouped into five overarching domains: Domain one-Performance health culture; Domain two-Integrated strategy; Domain three-Operational effectiveness; Domain four-Skilled people; Domain five-Leadership. CONCLUSION: A diverse sample of key stakeholders from Australia's HPSS identified five overarching domains that contribute to athlete performance health. The themes that need to be addressed in a strategy to achieve athlete performance health in Australia's HPSS are 'Leadership', 'Skilled people', 'Performance health culture', 'Operational effectiveness', and 'Integrated strategy'.

Does ankle tape improve proprioception acuity immediately after application and following a netball session? A randomised controlled trial.

OBJECTIVES: To assess whether ankle tape applied by a Sport and Exercise Physiotherapist (SEP) or self-applied by the athlete results in a change in proprioception and whether it is maintained during a netball session. DESIGN: Randomised controlled trial. SETTING: Australian Institute of Sport. PARTICIPANTS: 53 pre-elite netball athletes. MAIN OUTCOME MEASURES: Athlete proprioception was assessed using the Active Movement Extent Discrimination Apparatus (AMEDA) on four occasions for each taping condition: 1) pre-tape, 2) post-tape, 3) post-netball & 4) post-netball no-tape. RESULTS: Mixed effect linear models were used for analysis. A significant increase in proprioception was observed when self-tape: 0.022 (95% CI: [-0.000 - 0.044], p = 0.05), and SEP tape: 0.034 (95% CI: [0.012-0.055], p < 0.01), were initially applied. These improvements were maintained during a netball session for both, self-taping: 0.01 (95% CI: [-0.01 - 0.02], p = 0.45) and SEP-taping: <0.01 (95% CI: [-0.02 - 0.01], p = 0.56). Results also indicate there was no significant difference between taping conditions (ß = -0.001, 95% CI: [-0.02 - 0.02], p = 0.90). CONCLUSIONS: Proprioception improves and is maintained during a netball session with either SEP or self-applied taping.

A prospective study of health problems at the 2018 17/U and 19/U Australian National Netball Championships with comparison of surveillance methodology.

OBJECTIVE: To investigate the incidence, site, nature and cause of injuries sustained during and four weeks following the 2018 Australian National Netball Championships (ANNC's) using medical attention and self-report surveillance tools. DESIGN: Prospective cohort study. METHOD: Injuries were recorded prospectively using medical attention and self-report data collection methods. One hundred and ninety-two athletes competed at the 2018 ANNC's with 96 athletes in each age group (17/U & 19/U). RESULTS: There were 103 medical attention injuries sustained by 80 athletes resulting in an incidence rate of 89.4 per 1000 player hours. The most frequently recorded medical attention injury diagnoses across both age groups were lateral ankle ligament sprain (n=14, 13.6%), foot blisters (n=11, 10.7%), and lumbar pain (n=10, 9.7%). Ankle sprains (n=4), anterior cruciate ligament (ACL) ruptures (n=3) and concussion (n=3) recorded as the highest sports incapacity injuries. The self-report data collection revealed that 46 (27.2%) athletes arrived at the tournament with an existing self-reported injury/illness and 57 (39.3%) athletes had a self-reported injury/illness at the conclusion of the ANNC (RR 1.44 95%CI 1.05-1.99, p=0.030). CONCLUSION: There are no recent studies reporting injury rates specifically in pre-elite netball players. This study found an incidence rate of 89.4 per 1000 player hours. Ankle sprains are the highest medical attention and sports-incapacity injury in pre-elite netball athletes. Foot blisters and low back pain also feature in the highest medical attention injuries and ACL rupture and concussion were high sports incapacity injuries at the ANNC's. Finally, combining both the medical attention and self-report injury/illness data collection methods identified more injuries/illnesses than the use of one method alone.

Injury prevention strategies specific to pre-elite athletes competing in Olympic and professional sports - A systematic review.

OBJECTIVES: To describe and evaluate injury prevention interventions for pre-elite athletes who compete in an Olympic or professional sport. DESIGN: Systematic review. METHODS: This review was prospectively registered (PROSPERO CRD42017065083) and a systematic electronic search was conducted in May 2017. The following inclusion criteria were applied: (1) studies including and analysing data specific to pre-elite athletes (determined by the T3/T4 levels of the FTEM model); (2) featured injury prevention interventions; (3) provided sufficient data related to injury such that the effect can be analysed e.g. injury rates, incidence, prevalence, injury rate ratios; (4) featured randomised and non-randomised controlled trials or prospective cohorts. RESULTS: A total of 13,480 articles were retrieved with 121 titles identified and 11 studies satisfying the inclusion criteria. No studies demonstrated a low risk of bias. Four different interventions were identified: exercise (n=7, 64%), psychological (n=2, 18%), equipment (n=1, 9%), nutrition (n=1, 9%). Of the seven exercise interventions, four showed a protective effect and three found no significant effect, providing conflicting evidence. Caution is advised due to high risk of bias, low intervention reporting and minimal evidence for implementation planning in all seven studies. CONCLUSIONS: There is limited evidence from level 2 and 3 studies suggesting exercise and psychology interventions may prevent injury in pre-elite athletes. There is an absence of evidence to support the use of equipment and nutrition interventions in pre-elite athletes. There is a need for quality research designs confirming the clinical impact of existing injury prevention interventions for pre-elite athletes.

Paradoxical Bactericidal Effects of Hydrophobic Lung Surfactant Proteins and Their Peptide Mimics Using Liposome Molecular Trojan.

Lung surfactant, besides alveolar stability, also provides defence against pathogens by surfactant proteins (SP), SP-A and SP-D. The hydrophobic proteins SP-B and SP-C enhance surface activity. An unusual and paradoxical effect of bovine LS and synthetic model LS with SP-B/-C was bactericidal to Staphylococcus aureus and Escherichia coli. Bacterial proliferation were investigated with bovine lung surfactant extract (BLES), dipalmitoylphosphatdylcholine, palmitooleylglycerol, in combination with SP-B/-C using standard microbiological colony forming unit (CFU) counts and structural imaging. BLES and other surfactant-SP-B/-C mixtures inhibit bacterial growth in the concentration range of 0 -7.5 mg/mL, at > 10 mg/mL paradoxical growth of both the bacterial species suggest antibiotic resistance. The lipid only LS have no effect on bacterial proliferation. Smaller peptide mimics of SP-B or SP-B1-25, were less efficient than SP-Cff. Ultra structural studies of the bacterial CFU using electron and atomic force microscopy suggest some membrane damage of S. aereus at inhibitory concentration of BLES, and some structural alteration of E. coli at dividing zones, suggesting utilization and incorporation of surfactant lipid species by both bacteria. The results depicted from in vitro studies are also in agreement with protein-protein interactions obtained from PatchDock, FireDock and ClasPro algorithm. The MD-simulation decipher a small range fluctuation of gyration radius of the LS proteins and their peptide mimics. The studies have alarming implications in the use of high dosages (100 mg/mL/kg body weight) of exogenous surfactant for treatment of respiratory distress syndrome, genetic knock-out abnormalities associated with these proteins, and the novel roles played by SP-B/C as bactericidal agents.