To determine the effectiveness of coach-led neuromuscular warm-up on reducing lower extremity (LE) injuries in female athletes in a mixed-ethnicity, predominantly low-income, urban population. Design: Cluster randomized controlled trial. Setting: Chicago public high schools. Participants: Of 258 coaches invited to participate, 95 (36.8%) enrolled (1558 athletes). Ninety coaches and 1492 athletes completed the study. Interventions: We randomized schools to intervention and control groups. We trained intervention coaches to implement a 20-minute neuromuscular warm-up. Control coaches used their usual warm-up. Main Outcome Measures: Coach compliance was tracked by self-report and direct observation. Coaches reported weekly athlete exposures (AEs) and LE injuries causing a missed practice or game. Research assistants interviewed injured athletes. Injury rates were compared between the control and intervention groups using 2 and Fisher exact tests. Significance was set at P Ͻ.05. Poisson regression analysis adjusted for clustering and covariates in an athlete subset reporting personal information (n=855; 57.3%). Results: There were 28 023 intervention AEs and 22 925 control AEs. Intervention coaches used prescribed warm-up in 1425 of 1773 practices (80.4%). Intervention athletes had lower rates per 1000 AEs of gradual-onset LE injuries (0.43 vs 1.22, PϽ.01), acute-onset noncontact LE injuries (0.71 vs 1.61, PϽ.01), noncontact ankle sprains (0.25 vs 0.74, P=.01), and LE injuries treated surgically (0 vs 0.17, P=.04). Regression analysis showed significant incidence rate ratios for acute-onset noncontact LE injuries (0.33; 95% CI, 0.17-0.61), noncontact ankle sprains (0.38; 95% CI, 0.15-0.98), noncontact knee sprains (0.30; 95% CI, 0.10-0.86), and noncontact anterior cruciate ligament injuries (0.20; 95% CI, 0.04-0.95). Conclusion: Coach-led neuromuscular warm-up reduces noncontact LE injuries in female high school soccer and basketball athletes from a mixed-ethnicity, predominantly low-income, urban population.

A new generation of red phosphors of complex fluoride matrices activated with Mn has gained a broad interest in getting high color quality and low color temperature of solid-state white light-emitting diodes (WLEDs). However, besides their instability toward moisture, the extremely irregular and nonuniform morphologies of these phosphors have limited their practical industry applications. In the present study, a novel type of KScF:Mn red phosphor with highly regular, uniform, and high color purity was obtained successfully through a facile coprecipitation route under mild conditions. The crystal structure was identified with aids of the powder X-ray diffraction, Rietveld refinement, and density functional theory calculations. The prototype crystallizes in the space group Fm3 m with a cubic structure, and the lattice parameters are fitted well to be a = b = c = 8.4859(8) Å and V = 611.074(2) Å. The Mn ions occupy Sc sites and locate at the centers of the distorted ScF octahedrons. A wide band gap of approximately 6.15 eV can provide sufficient space to accommodate impurity energy levels. Unlike most other Mn ion-activated fluoride phosphors, the as-prepared KScF:Mn phosphors demonstrate highly uniform and regular morphologies with shapes transforming from cube to octahedron with increasing Mn ion concentration. Under blue light excitation, the as-prepared KScF:Mn sample exhibits intense sharp-line red fluorescence (the strongest peak located at 631 nm) with high color purity. An excellent recovery in luminescence upon heating and cooling processes implies high stability of KScF:Mn. Furthermore, a warm WLED fabricated with blue GaN chips merged with the mixture of KScF:Mn and the well-known commercial YAG:Ce yellow phosphors exhibits wonderful color quality with lower correlated color temperature (3250 K) and higher color-rendering index ( R = 86.4). These results suggest that the KScF:Mn phosphor possesses stupendous potentiality for practical applications.

With the repaid development of NIR pc-LED, it is urgent to develop novel NIR phosphor with broadband emission, strong luminescence and high thermal stability. Here, three isotypic garnet fluorides Na3X2Li3F12...

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