Observations of a Magellanic Corona.

The Large Magellanic Cloud (LMC) and the Small Magellanic Cloud (SMC) are the closest massive satellite galaxies of the Milky Way. They are probably on their first passage on an infalling orbit towards our Galaxy1 and trace the continuing dynamics of the Local Group2. Recent measurements of a high mass for the LMC (Mhalo ≈ 1011.1-11.4 M⊙)3-6 imply that the LMC should host a Magellanic Corona: a collisionally ionized, warm-hot gaseous halo at the virial temperature (105.3-5.5 K) initially extending out to the virial radius (100-130 kiloparsecs (kpc)). Such a corona would have shaped the formation of the Magellanic Stream7, a tidal gas structure extending over 200° across the sky2,8,9 that is bringing in metal-poor gas to the Milky Way10. Here we show evidence for this Magellanic Corona with a potential direct detection in highly ionized oxygen (O+5) and indirectly by means of triply ionized carbon and silicon, seen in ultraviolet (UV) absorption towards background quasars. We find that the Magellanic Corona is part of a pervasive multiphase Magellanic circumgalactic medium (CGM) seen in many ionization states with a declining projected radial profile out to at least 35 kpc from the LMC and a total ionized CGM mass of log10(MH II,CGM/M⊙) ≈ 9.1 ± 0.2. The evidence for the Magellanic Corona is a crucial step forward in characterizing the Magellanic group and its nested evolution with the Local Group.

Telesimulation to Improve Critical Decision-Making in Prehospital Airway Management: A Feasibility Study.

OBJECTIVES: Telesimulation, in which learners and evaluators use technology to connect remotely to simulation-based learning activities, is effective for skills and decision-making review. Historical models in which learners are colocated with the simulation equipment have inherent issues, especially for emergency medical services (EMS) providers. This feasibility study placed the evaluators in the simulation center, whereas the learners were at a distance steering the scenario evolution through telehealth technologies. METHODS: Volunteer EMS providers across South Carolina with varying levels of training and experience completed difficult airway management scenarios focused on clinical decision making. The program consisted of pre- and postexperience examinations, a lecture, and increasingly complicated simulations using high-fidelity mannequins that were facilitated by local trainers under the direction of remote trainees. Audio and video content, including vital signs and cardiac monitoring, were live streamed. Participants worked in two-person teams with lead providers on each scenario clinically assessing and managing cases of anaphylaxis. Data were collected from the simulations using Laerdal software, as well as examination and survey results. RESULTS: A total of 24 participants completed all of the elements of the training. Trends toward improvement in times to bag-mask ventilation and initial epinephrine administration were noted. Average cognitive test scores increased by 9.6%, and learners reported improved comfort with simulation (75%, P ≥ 0.0001) and videoconferencing (83%, P ≥ 0.0001). They also reported high degrees of comfort with intubation (73.3%) following the training. CONCLUSIONS: This method of telesimulation appears to be a viable addition to continuing EMS education and may address access issues for some providers.

Efficacy of bolus-dose epinephrine to manage hypotension in the prehospital setting.

PURPOSE: Hypotension in the Emergency Department (ED) and the prehospital setting has been associated with significant morbidity and mortality. Limited literature exists exploring the utilization of intravenous (IV) bolus-dose epinephrine (BDE) by Emergency Medical Services (EMS). METHODS: A retrospective review evaluated patients transported to an academic medical center who had received IV BDE by a single urban EMS system from 2016 to 2020. The primary outcome was to assess the influence IV BDE had on systolic blood pressure (SBP). Secondary objectives were to assess changes in heart rate (HR), the impact of dose variability on SBP, and the incidence of severe hypertension (SBP > 220 mmHg). RESULTS: A total of 55 patients who received 96 administrations of IV BDE were included in the analysis. The most common individual dose was 10 µg (76.0%) and 45.5% received multiple doses. The median weight-based dose of BDE was 0.14 µg/kg. A significant increase in SBP (median 14.0 mmHg) was noted among all patients following BDE administration compared with baseline (p < 0.001). No significant difference was found in HR following BDE compared with baseline (p = 0.375). Those that received a BDE dose >10 µg were noted to have a significantly greater rise in SBP than those that received 10 µg (30.0 mmHg vs. 11.0 mmHg; p = 0.022). Similarly, patients that received a dose ≥0.2 µg/kg had a significantly greater increase in SBP compared with those that received <0.2 µg/kg (30.0 mmHg vs. 10.0 mmHg; p = 0.048). There were no incidences of severe hypertension following therapy. CONCLUSION: The utilization of IV BDE in the prehospital setting for acute hypotension resulted in a significant rise in SBP. A dose-response relationship was noted both in terms of a flat-based dose and a weight-based dose, with higher doses yielding a greater change in SBP. Additional investigations are necessary to further explore the most appropriate dose of this agent in this setting and its influence, if any, on clinical outcomes.

Hurricane Impact on Emergency Services and Use of Telehealth to Support Prehospital Care.

The impact of hurricanes on emergency services is well-known. Recent history demonstrates the need for prehospital and emergency department coordination to serve communities during evacuation, storm duration, and cleanup. The use of telehealth applications may enhance this coordination while lessening the impact on health-care systems. These applications can address triage, stabilization, and diversion and may be provided in collaboration with state and local emergency management operations through various shelters, as well as during other emergency medical responses.

Public CPR and AED Knowledge: An Opportunity for Educational Outreach in South Carolina.

OBJECTIVES: Sudden cardiac arrest (SCA) remains a significant cause of morbidity and mortality, and the key to increased survival is emergent bystander intervention. A growing body of evidence has shown that timely bystander-initiated cardiopulmonary resuscitation (CPR) and defibrillation are significantly correlated with an increased likelihood of survival. Despite these demonstrated benefits, bystanders perform these interventions in less than half of witnessed SCA cases. We hypothesized that the level of public CPR and automated external defibrillator (AED) knowledge may be limited and may play a role in the likelihood of intervening. METHODS: A convenience survey of potential bystanders to SCA was conducted in a high-traffic shopping center to estimate the overall knowledge level of CPR and AED usage and determine general attitudes toward intervening in the setting of SCA. Concurrently with the survey, professional emergency responders offered free bystander compression-only CPR and AED training on location. RESULTS: The majority of survey respondents expressed a willingness to perform the aforementioned interventions when asked directly. Results, however, indicate that although 69% of respondents consider themselves to have a general knowledge of CPR, only 18% spontaneously mentioned CPR when presented with a hypothetical SCA scenario. In addition, only 2.2% mentioned defibrillation, and 63% indicated that they would not know how to locate a public access AED when needed. Of the individuals who participated in both the survey and the training, all of them indicated that they were more likely to intervene in an SCA after receiving the training. CONCLUSIONS: Our findings suggest that future public outreach efforts should target the current CPR and AED knowledge gap. They also indicate that free, brief trainings offered at public events are a feasible way to increase the knowledge and skills of potential bystanders to SCA.

Myasthenic Crisis In Pregnancy.

This case reviews the management of a 27-year-old pregnant female in myasthenic crisis. She presented to the emergency department in respiratory distress refractory to standard therapy, necessitating airway and ventilatory support and treatment with plasmapheresis. Myasthenic crisis in the setting of pregnancy is rare and presents unique management challenges for emergency physicians.

High power microwave source with a three dimensional printed metamaterial slow-wave structure.

For over the last decade, the concept of metamaterials has led to new approaches for considering the interaction of radiation with complex structures. However, practical manifestations of such a device operating at high power densities have proven difficult to achieve due to the resonant nature of metamaterials and the resultant high electric fields, which place severe constraints on manufacturing the slow wave structures. In this paper, we describe the first experimental manifestation of a high power microwave device utilizing a metallic slow wave structure (metamaterial-like) fabricated using additive manufacturing. The feasibility of utilizing additive manufacturing as a technique for building these relatively complicated structures has thus been demonstrated. The MW class microwave source operates in the C-band and shows frequency tunablility with electron beam voltage. The basic electromagnetic characteristics of this device, the construction using additive manufacturing, and the basic performance as a microwave oscillator are considered. Due to the tunable nature of the device, it shows promise not only as an oscillator but also as a microwave amplifier. Therefore, the dispersive characteristics and a discussion of the anticipated gain is included as it relates to an amplifier configuration.

Apparatus for generating quasi-free-space microwave-driven plasmas.

An apparatus for generating quasi-free-space microwave-driven plasmas has been designed, constructed, and tested. The plasma is driven by a multi-kW, ∼5 GHz microwave beam focused at the center of a vacuum chamber using a Koch-type metal plate lens. Sustained plasma discharges have been generated in argon at pressures ranging from 150 to 200 mTorr, at beam power levels ranging from 5 to 10 kW, and at gas flow rates of approximately 200 SCCM.

Nonlinear transmission line based electron beam driver.

Gated field emission cathodes can provide short electron pulses without the requirement of laser systems or cathode heating required by photoemission or thermionic cathodes. The large electric field requirement for field emission to take place can be achieved by using a high aspect ratio cathode with a large field enhancement factor which reduces the voltage requirement for emission. In this paper, a cathode gate driver based on the output pulse train from a nonlinear transmission line is experimentally demonstrated. The application of the pulse train to a tufted carbon fiber field emission cathode generates short electron pulses. The pulses are approximately 2 ns in duration with emission currents of several mA, and the train contains up to 6 pulses at a frequency of 100 MHz. Particle-in-cell simulation is used to predict the characteristic of the current pulse train generated from a single carbon fiber field emission cathode using the same technique.

Alpha(1)-adrenoceptor stimulation directly induces growth of vascular wall in vivo.

Previous studies suggesting that norepinephrine is directly trophic for the vascular wall have been confounded by concomitant hemodynamic disturbances. Herein, a microcatheter connected to an osmotic minipump was implanted adjacent to the rat carotid for 2-wk perivascular suffusion of agents at systemic levels ~1,000 times below the threshold for altering arterial pressure. Norepinephrine decreased lumen and adventitial areas and circumference by 10, 14, and 5%, respectively (all P < 0.05); a nonsubtype-specific alpha(1)-adrenoceptor (AR) antagonist had no effect. When begun at the time of balloon injury, 2-wk norepinephrine increased lumen loss by 45%, increased neointimal area by 64% and collagen content by 33%, and reduced vessel circumference by 5% (all P < 0.05). alpha(1)-AR antagonists decreased neointimal area by 33% (all P < 0.05). alpha(1)A-AR antagonist reduced lumen loss by 70%, neointimal area by 54%, circumference decline by 84%, and adventitial thickening by 87% (all P < 0.05), whereas alpha(1B)-, alpha(1D)-, alpha(2)- and beta-AR antagonists were without effect. These are the first in vivo studies demonstrating that norepinephrine is directly trophic for the vascular wall and augments injury-induced intimal lesion growth.