Purpose of Review Coronavirus disease of 2019 (COVID-19) is a cause of significant morbidity and mortality worldwide. While cardiac injury has been demonstrated in critically ill COVID-19 patients, the mechanism of injury remains unclear. Here, we review our current knowledge of the biology of SARS-CoV-2 and the potential mechanisms of myocardial injury due to viral toxicities and host immune responses. Recent Findings A number of studies have reported an epidemiological association between history of cardiac disease and worsened outcome during COVID infection. Development of new onset myocardial injury during COVID-19 also increases mortality. While limited data exist, potential mechanisms of cardiac injury include direct viral entry through the angiotensinconverting enzyme 2 (ACE2) receptor and toxicity in host cells, hypoxia-related myocyte injury, and immune-mediated cytokine release syndrome. Potential treatments for reducing viral infection and excessive immune responses are also discussed. Summary COVID patients with cardiac disease history or acquire new cardiac injury are at an increased risk for in-hospital morbidity and mortality. More studies are needed to address the mechanism of cardiotoxicity and the treatments that can minimize permanent damage to the cardiovascular system.
Using published guidelines, 29% of female collegiate athletes in this study were classified into moderate- or high-risk categories using the Female Athlete Triad Cumulative Risk Assessment Score. Moderate- and high-risk athletes were more likely to subsequently sustain a BSI; most BSIs were sustained by cross-country runners.
ABSTRACT:Composites that incorporate a conductive filler into an ethylene-octene (EO) elastomer matrix were evaluated for DC electrical and mechanical properties. Comparing three types of fillers (carbon fiber, low structure carbon black, and high structure carbon black), it was found that the composite with high structure carbon black exhibited a combination of properties not generally achievable with this type of filler in an elastomeric matrix. A decrease in resistivity at low strains is unusual and has only been reported previously in a few instances. Reversibility in the resistivity upon cyclic deformation is a particularly unusual feature of EO with high structure carbon black. The mechanical and electrical performance of the high structure carbon black composites at high strains was also impressive. Mechanical reinforcement in accordance with the Guth model attested to good particle-matrix adhesion. The EO matrix also produced composites that retained the inherent high elongation of the unfilled elastomer even with the maximum amount of filler (30% by volume). The EO matrix with other conducting fillers did not exhibit the exceptional properties of EO with high structure carbon black. Composites with carbon fiber and low structure carbon black did not maintain good mechanical properties, generally exhibited an increase in resistivity with strain, and exhibited irreversible changes in both mechanical and electrical properties after extension to even low strains. An explanation of the unusual properties of EO with high structure carbon black required unique features of both filler and the matrix. The proposed model incorporates the multifunctional physical crosslinks of the EO matrix and dynamic filler-matrix bonds.
Despite consistent declines in rates of cigarette use among adolescents in the last five years, rates of marijuana use have remained constant, with marijuana being the most widely used illegal drug among adolescents. More work is needed to understand how social norms, perceived risks and benefits, and social media messaging impact use of marijuana. This study compared perceptions and social norms related to marijuana, blunts and cigarettes. Additionally, we assessed how perceptions related to social norms, risks and benefits, and exposure to pro- versus anti-marijuana messaging is related to use. Participants were 786 adolescents from Southern and Northern California (36.7% male, 63.3% females; mean age = 16.1 years; SD = 1.6). Participants came from diverse ethnic backgrounds, with 207 (26.61%) White, 171 (21.98%) Asian/Pacific Islander, 232 (29.82%) Hispanic, and 168 (21.59%) other. Results indicated that marijuana and blunts were consistently perceived as more socially acceptable and less risky than cigarettes (p<0.01). Participants who reported that their friends used marijuana had a 27% greater odds of using marijuana themselves. Further, seeing messages about the good things or benefits of marijuana use was associated with a 6% greater odds of use [OR 1.06 (CI 1.00, 1.12)]. This study's findings offer a number of important public health implications, particularly as states move towards legalization of marijuana for recreational use. As this occurs, states need to take adolescents’ perceptions of risks, benefits, social norms, and peer influences into account as they implement strategies to reduce youth use of marijuana and blunts.
Both sport type and Triad risk factors influence BMD. Athletes in low-impact and nonimpact sports and athletes with low BMI and oligomenorrhea/amenorrhea are at highest risk for reduced BMD.
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