Anatomy of an American football game: Player-to-player contact before, during and after an NFL game in context of the 2020 COVID-19 pandemic.

OBJECTIVES: To quantify levels of potential exposure to SARS-CoV-2 surrounding a typical professional American football game, with a focus on interactions on-field between teammates and opposing players before, during, and immediately after competition. METHODS: We examined across-Club consecutive interactions ≥2 minutes within 6 feet [1.8 meters] between athletes on opposing Clubs for all 2020 NFL regular season games (n = 256). Cumulative interaction was measured for a representative subset (n = 119; 46%) of games. Wearable proximity tracking devices (Kinexon) were used to measure distance and duration of interactions; these data were combined with game schedule and Club rosters for analyses. Frequency and per-game mean, median, interquartile range for consecutive interactions ≥2/≥5 minutes and cumulative interactions ≥5/≥15 were described overall and stratified by pre-game, in-game, and post-game. RESULTS: Of the 1964 distinct player-to-opponent contacts ≥2 minutes in NFL regular season games, the majority (n = 1,699; 87%) were fewer than 5 minutes in consecutive length. Among the mean 7.7 distinct contacts ≥2 minutes with opponents each game (median = 4; IQR = 2, 8), very few were ≥5 consecutive minutes at any point (mean = 1.0; median = 0; IQR = 0, 0). Most (n = 849; 43.2%) distinct contacts were pre-game, 546 (27.8%) were during competition, and 569 (29%) were post-game. In games where cumulative interactions were analyzed, there was an average of 17.1 player/opponent interactions with cumulative exposure ≥5 minutes (median = 12; IQR = 4, 30), almost all of which occurred during competition. CONCLUSION: There is limited and short contact between and among competing players in professional American football. In the setting of infectious disease such as the COVID-19 pandemic, a robust prevention program integrating masking, distancing, hygiene, and ventilation when off-field can be created to minimize on- and off-field exposures, which effectively reduces transmission risk in outdoors and/or well-ventilated stadium settings.

Battlefield Acupuncture Versus Standard Pharmacologic Treatment of Low Back Pain in the Emergency Department: A Randomized Controlled Trial.

BACKGROUND: Battlefield acupuncture (BFA) offers a novel analgesic option that avoids the need for pharmacologic interventions with problematic side effect profiles. OBJECTIVE: To compare BFA with standard pharmacologic interventions to treat patients in the emergency department (ED) with low back pain. METHODS: We conducted a nonblinded randomized controlled trial of a convenience sample of adults presenting to an urban tertiary care ED with a chief complaint of low back pain. We randomized subjects to undergo either BFA or the control arm in which they received standard pharmacologic therapies at the discretion of their treating clinician. The primary outcome was mean pain reduction measured on a 100-mm visual analogue scale (VAS) from enrollment to 30-40 min postintervention. Secondary outcomes included the Back Pain Functional Scale (BPFS; scores range from 0-60) measured at 30-40 min postintervention and again at 48-72 h postintervention. RESULTS: We enrolled 52 subjects with 26 randomized to each arm. The mean decrease in pain VAS was 33.4 mm among patients undergoing BFA vs. 21.5 mm in the control arm (effect size difference 12.0 mm [95% confidence interval {CI} 0.1-23.8 mm]). The median improvement in the BPFS score at 48-72 h postintervention was 12.0 among patients undergoing BFA vs. 8.0 in the control arm (effect size difference 4 [95% CI -9.0 to 16.0]). There were no adverse events. CONCLUSIONS: BFA shows promise for further study as an alternative to standard pharmacologic interventions among adults presenting to the ED with low back pain. © 2021 Elsevier Inc.

Tailored semiconductors for high-harmonic optoelectronics.

The advent of high-harmonic generation in gases 30 years ago set the foundation for attosecond science and facilitated ultrafast spectroscopy in atoms, molecules, and solids. We explore high-harmonic generation in the solid state by means of nanostructured and ion-implanted semiconductors. We use wavelength-selective microscopic imaging to map enhanced harmonic emission and show that the generation medium and the driving field can be locally tailored in solids by modifying the chemical composition and morphology. This enables the control of high-harmonic technology within precisely engineered solid targets. We demonstrate customized high-harmonic wave fields with wavelengths down to 225 nanometers (ninth-harmonic order of 2-micrometer laser pulses) and present an integrated Fresnel zone plate target in silicon, which leads to diffraction-limited self-focusing of the generated harmonics down to 1-micrometer spot sizes.

A Case of Brachiocephalic Fistula Steal and the Emergency Physician's Approach to Hemodialysis Arteriovenous Fistula Complications.

BACKGROUND: Chronic kidney disease is common in the United States, with many patients maintained on hemodialysis (HD). The process of HD requires vascular access through an arteriovenous (AV) fistula, AV graft, or central venous catheter. Today, as a result of the National Kidney Foundation's "Fistula First" initiative, nearly 55% of HD patients utilize an AV fistula. As there is significant morbidity and mortality associated with fistula placement and recurrent fistula cannulation, emergency physicians must be equipped to recognize and treat fistula complications. OBJECTIVE: To detail a case study of vascular insufficiency (vascular steal) presenting to an emergency department (ED) and provide an evidence-based approach to the emergency assessment and management of HD AV fistula complications. DISCUSSION: A 66-year-old man presented to the ED with left upper extremity pain, paresthesias, and loss of grip strength of 1-week duration 15 days after placement of left upper extremity brachiocephalic fistula. He was diagnosed with dialysis access-associated steal syndrome and taken to the operating room for revision. Patients with HD fistulas may experience several complications, including vascular insufficiency, hemorrhage, infection, stenosis, thrombosis, aneurysms, or pseudoaneurysms. Emergency physicians must be able to identify these complications and deliver timely treatment. CONCLUSIONS: A comprehensive understanding of the appropriate management of AV fistula complications is paramount for the emergency physician. Early recognition and treatment of vascular insufficiency resulting from fistula creation, fistula hemorrhage, fistula infection, stenosis, thrombosis, and aneurysms or pseudoaneurysms is vital to reducing the morbidity and mortality associated with HD.

A Wireless, Passive Load Cell based on Magnetoelastic Resonance.

A wireless, battery-less load cell was fabricated based on the resonant frequency shift of a vibrating magnetoelastic strip when exposed to an AC magnetic field. Since the vibration of the magnetoelastic strip generated a secondary field, the resonance was remotely detected with a coil. When a load was applied to a small area on the surface of the magnetoelastic strip via a circular rod applicator, the resonant frequency and amplitude decreased due to the damping on its vibration. The force sensitivity of the load cell was controlled by changing the size of the force applicator and placing the applicator at different locations on the strip's surface. Experimental results showed the force sensitivity increased with a larger applicator placing near the edge of the strip. The novelty of this load cell is not only its wireless passive nature, but also the controllability of the force sensitivity.

SPR imaging-based salivary diagnostics system for the detection of small molecule analytes.

Saliva is an underused fluid with considerable promise for biomedical testing. Its potential is particularly great for monitoring small-molecule analytes since these are often present in saliva at concentrations that correlate well with their free levels in blood. We describe the development of a prototype diagnostic device for the rapid detection of the antiepileptic drug (AED) phenytoin in saliva. The multicomponent system includes a hand-portable surface plasmon resonance (SPR) imaging instrument and a disposable microfluidic assay card.

Compact, high performance surface plasmon resonance imaging system.

We report the construction and characterization of a new compact surface plasmon resonance imaging instrument. Surface plasmon resonance imaging is a versatile technique for detection, quantification and visualization of biomolecular binding events which have spatial structure. The imager uses a folded light path, wide-field optics and a tilted detector to implement a high performance optical system in a volume 7 in. x 4 in. x 2 in. A bright diode light source and an image detector with fast frame rate and integrated digital signal processor enable real-time averaging of multiple images for improved signal-to-noise ratio. Operating angle of the imager is adjusted by linear translation of the light source. Imager performance is illustrated using resolution test targets, refractive index test solutions, and competition assays for the antiepileptic drug phenytoin. Microfluidic flowcells are used to enable simultaneous assay of three sample streams. Noise level of refractive index measurements was found to decrease proportional to the square root of the number of pixels averaged, reaching approximately 5 x 10(-7) refractive index units root-mean-square for 160 x 120 pixels image regions imaged for 1s. The simple, compact construction and high performance of the imager will allow the device to be readily applied to a wide range of applications.