324 research outputs found
Superconductivity in the YIr2Si2 and LaIr2Si2 Polymorphs
We report on existence of superconductivity in YIr2Si2 and LaIr2Si2 compounds
in relation to crystal structure. The two compounds crystallize in two
structural polymorphs, both tetragonal. The high temperature polymorph (HTP)
adopts the CaBe2Ge2-structure type (space group P4/nmm) while the low
temperature polymorph (LTP) is of the ThCr2Si2 type (I4/mmm). By studying
polycrystals prepared by arc melting we have observed that the rapidly cooled
samples retain the HTP even at room temperature (RT) and below. Annealing such
samples at 900C followed by slow cooling to RT provides the LTP. Both, the HTP
and LTP were subsequently studied with respect to magnetism and
superconductivity by electrical resistivity, magnetization, AC susceptibility
and specific heat measurements. The HTP and LTP of both compounds respectively,
behave as Pauli paramagnets. Superconductivity has been found exclusively in
the HTP of both compounds below Tsc (= 2.52 K in YIr2Si2 and 1.24 K in
LaIr2Si2). The relations of magnetism and superconductivity with the electronic
and crystal structure are discussed with comparing experimental data with the
results of first principles electronic structure calculations
Association Between Sensation-Seeking Behaviors and Concussion-Related Knowledge, Attitudes, Perceived Norms, and Care-Seeking Behaviors among Collegiate Student-Athletes
There are limited data connecting personality and behavioral tendencies and traits related to concussion care-seeking/disclosure behaviors and minimal research exists surrounding the relationship between risky behaviors, sensation-seeking, and concussion-related outcomes. This study examined the association between sensation-seeking and a student-athlete’s concussion-related knowledge, attitudes, perceived social norms, and concussion care-seeking/disclosure behaviors (intention to disclose concussion symptoms, perceived control over symptom disclosure, self-removal from play due to concussion symptoms, continued play with concussion symptoms, and disclosure of all concussions at the time of injury). The current study utilized a retrospective cohort of collegiate student-athletes at a single National Collegiate Athletic Association Division I institution. Separate multivariable linear regression models estimating mean differences (MD) and 95% Confidence Intervals (CI) estimated the association between sensation-seeking and concussion knowledge, concussion attitudes, and perceived social norms. Separate multivariable binomial regression models estimating adjusted prevalence ratios (PR) and 95%CI estimated the association between sensation-seeking and intention to disclose concussion symptoms, perceived control over symptom disclosure, self-removal from play due to concussion symptoms, continued play with concussion symptoms, and disclosure of all concussions at the time of injury. All models were adjusted for sex, sport participation, and concussion history. Higher sensation-seeking was significantly associated with less favorable concussion attitudes (adjusted MD = -1.93; 95%CI = -3.04,-0.83), less favorable perceived social norms surrounding concussion (adjusted MD = -1.39; 95%CI = -2.06,-0.72), and continuing to play while experiencing concussion symptoms (adjusted PR = 1.50; 95%CI = 1.10, 2.06). Student-athletes with increased sensation-seeking could be at risk for failing to disclose a concussion, decreasing athlete safety and resulting in less optimal care post-injury. Results will inform future theory-based concussion education programs which consider behavioral tendencies and traits as well as sport culture to promote concussion care-seeking/disclosure and individualized interventions based on risky behavior engagement
Dehydration and Performance on Clinical Concussion Measures in Collegiate Wrestlers
The effects of dehydration induced by wrestling-related weight-cutting tactics on clinical concussion outcomes, such as neurocognitive function, balance performance, and symptoms, have not been adequately studied
The Precaution Adoption Process Model in Describing Emergency Action Plan Adoption
Purpose: The purpose of this study was to identify the ability of the Precaution Adoption Process Model (PAPM) to classify athletic trainers (ATs) and athletic directors (ADs) readiness to act with regards to adopting an emergency action plan (EAP), and describe factors influencing PAPM stages. Method: We used a cross-sectional questionnaire design to evaluate readiness to act for developing an EAP among ATs and ADs working in United States high schools. The PAPM is a participant-driven model to identify someone’s readiness to act or change and has seven stages: Unaware, Unengaged, Undecided, Decided not to Act, Decided to Act, Acting and Maintaining. Prevalence ratios (PRs) with 95% confidence intervals (95% CI) were calculated. Results: A majority of ATs and ADs reported maintaining an EAP in their secondary school (AT “Maintaining” = 84.4%, AD “Maintaining” = 68.7%). ADs were more likely to be staged as “Decided not to Act” (PR=0.14, 95% CI= 0.05, 0.41) for the development of an EAP compared to ATs. ATs were more likely to be staged as “Maintaining” (PR=1.23, 95% CI = 1.16, 1.30) for the development of an EAP compared to ADs. Conclusions: The PAPM appears to be able to classify AT and AD readiness to act with adoption of an EAP. However, statistical modeling struggles to identify predictors for the various stages. Future research should aim to use the PAPM stages in the development of tailored interventions
Athletic Administrators Report of Emergency Action Plan Adoption in Secondary School Athletics: The Influence of Athletic Training Services
This study describes the emergency action plan (EAP) adoption in secondary school athletics reported by athletic administrators in the United States. Utilizing best-practice criteria, a questionnaire assessed athletic administrators’ knowledge and adoption of an EAP in their athletics program. A majority of athletic administrators reported having an EAP; however, the EAP often lacked the necessary components to be compliant with best-practice guidelines. Further, access to an athletic trainer was associated with increased EAP adoption and adopting a venue specific EAP. Athletic administrators should utilize these data to facilitate improved policy adoption and management of athletics programs
Pedestrian Safety Among High School Runners: a Case Series
Background: Participation in high school cross-country and track has increased over the last few decades. At the same time, the rate of pedestrian-involved motor vehicle crashes (MVCs) has also increased. In the context of organized sport, pedestrian safety among runners is often not highlighted, despite the risk of catastrophic injury. Purpose: To describe incidents of pedestrian-involved MVCs involving student athletes captured by the National Center for Catastrophic Sport Injury Research (NCCSIR) at the University of North Carolina at Chapel Hill. Study Design: Case series. Level of Evidence: Level 5. Methods: This study utilized surveillance data from the NCCSIR from 2011 to 2020. It presents descriptive statistics, including frequencies and percentages, detailed summaries, and a Haddon Matrix. Results: There were 8 incidents involving 11 student athletes, resulting in 9 fatalities. Of these, 5 cases occurred in the afternoon or early evening, 4 occurred in the Fall, and 6 occurred in a rural area. Haddon Matrix analyses of case descriptions indicate schools should implement a runner safety program for all new runners and ensure that runner safety measures are included in emergency action plans. Conclusion: Runner-related MVCs are relatively rare, but tragic, incidents. Pedestrian safety measures should be incorporated into school-sponsored practices and training runs. Clinical Relevance: Pedestrian safety should be incorporated into runner safety and injury prevention efforts
Reporting of Concussion Symptoms By a Nationwide Survey of United States Parents of Middle School Children
This cross-sectional study assessed concussion symptom knowledge of parents of middle school (MS) children (aged 10–15 years) through a free-response item that solicited concussion symptoms and compared findings to a pre-validated scale-based measure. A self-administered online questionnaire was sent to a panel of randomly selected United States residents who were recruited by a third-party company, aged ≥ 18 years, and identified as parents of MS children. Via a free-response item, parents listed what they believed were concussion symptoms. Multiple sections later, parents identified potential concussion symptoms via a scale measure, which featured 25 items (22 actual symptoms, three distractor symptoms) with three response options: yes, no, maybe. Free-response item responses were coded into specific symptoms. The 1062 eligible parents that provided complete data commonly identified the symptoms of dizziness (90.2%), blurred vision (87.4%), and balance problems (86.4%) on the scale-based measure. However, these and other symptoms were less commonly identified via the free-response item (dizziness: 44.4%; blurred vision: 16.5%; balance problems: 3.5%). Concussion symptoms commonly reported via the scale-based measure were reported less frequently within the free-response item. Future research must explore strategies to help clinicians working with parents and their children to measure and assess concussion symptom reporting and knowledge
Association of Blood Biomarkers With Acute Sport-Related Concussion in Collegiate Athletes: Findings From the NCAA and Department of Defense CARE Consortium
Importance:
There is potential scientific and clinical value in validation of objective biomarkers for sport-related concussion (SRC).
Objective:
To investigate the association of acute-phase blood biomarker levels with SRC in collegiate athletes.
Design, Setting, and Participants:
This multicenter, prospective, case-control study was conducted by the National Collegiate Athletic Association (NCAA) and the US Department of Defense Concussion Assessment, Research, and Education (CARE) Consortium from February 20, 2015, to May 31, 2018, at 6 CARE Advanced Research Core sites. A total of 504 collegiate athletes with concussion, contact sport control athletes, and non-contact sport control athletes completed clinical testing and blood collection at preseason baseline, the acute postinjury period, 24 to 48 hours after injury, the point of reporting being asymptomatic, and 7 days after return to play. Data analysis was conducted from March 1 to November 30, 2019.
Main Outcomes and Measures:
Glial fibrillary acidic protein (GFAP), ubiquitin C-terminal hydrolase-L1 (UCH-L1), neurofilament light chain, and tau were quantified using the Quanterix Simoa multiplex assay. Clinical outcome measures included the Sport Concussion Assessment Tool-Third Edition (SCAT-3) symptom evaluation, Standardized Assessment of Concussion, Balance Error Scoring System, and Brief Symptom Inventory 18.
Results:
A total of 264 athletes with concussion (mean [SD] age, 19.08 [1.24] years; 211 [79.9%] male), 138 contact sport controls (mean [SD] age, 19.03 [1.27] years; 107 [77.5%] male), and 102 non-contact sport controls (mean [SD] age, 19.39 [1.25] years; 82 [80.4%] male) were included in the study. Athletes with concussion had significant elevation in GFAP (mean difference, 0.430 pg/mL; 95% CI, 0.339-0.521 pg/mL; P < .001), UCH-L1 (mean difference, 0.449 pg/mL; 95% CI, 0.167-0.732 pg/mL; P < .001), and tau levels (mean difference, 0.221 pg/mL; 95% CI, 0.046-0.396 pg/mL; P = .004) at the acute postinjury time point compared with preseason baseline. Longitudinally, a significant interaction (group × visit) was found for GFAP (F7,1507.36 = 16.18, P < .001), UCH-L1 (F7,1153.09 = 5.71, P < .001), and tau (F7,1480.55 = 6.81, P < .001); the interaction for neurofilament light chain was not significant (F7,1506.90 = 1.33, P = .23). The area under the curve for the combination of GFAP and UCH-L1 in differentiating athletes with concussion from contact sport controls at the acute postinjury period was 0.71 (95% CI, 0.64-0.78; P < .001); the acute postinjury area under the curve for all 4 biomarkers combined was 0.72 (95% CI, 0.65-0.79; P < .001). Beyond SCAT-3 symptom score, GFAP at the acute postinjury time point was associated with the classification of athletes with concussion from contact controls (β = 12.298; 95% CI, 2.776-54.481; P = .001) and non-contact sport controls (β = 5.438; 95% CI, 1.676-17.645; P = .005). Athletes with concussion with loss of consciousness or posttraumatic amnesia had significantly higher levels of GFAP than athletes with concussion with neither loss of consciousness nor posttraumatic amnesia at the acute postinjury time point (mean difference, 0.583 pg/mL; 95% CI, 0.369-0.797 pg/mL; P < .001).
Conclusions and Relevance:
The results suggest that blood biomarkers can be used as research tools to inform the underlying pathophysiological mechanism of concussion and provide additional support for future studies to optimize and validate biomarkers for potential clinical use in SRC
Emergent Access to the Airway and Chest in American Football Players
American football has the highest rate of fatalities and catastrophic injuries of any US sport. The equipment designed to protect athletes from these catastrophic events challenges the ability of medical personnel to obtain neutral spine alignment and immobilization during airway and chest access for emergency life-support delivery
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