Capturing dynamical correlations using implicit neural representations.

Understanding the nature and origin of collective excitations in materials is of fundamental importance for unraveling the underlying physics of a many-body system. Excitation spectra are usually obtained by measuring the dynamical structure factor, S(Q, ω), using inelastic neutron or x-ray scattering techniques and are analyzed by comparing the experimental results against calculated predictions. We introduce a data-driven analysis tool which leverages 'neural implicit representations' that are specifically tailored for handling spectrographic measurements and are able to efficiently obtain unknown parameters from experimental data via automatic differentiation. In this work, we employ linear spin wave theory simulations to train a machine learning platform, enabling precise exchange parameter extraction from inelastic neutron scattering data on the square-lattice spin-1 antiferromagnet La2NiO4, showcasing a viable pathway towards automatic refinement of advanced models for ordered magnetic systems.

Impacts of United States Medical Licensing Examination Step 1 Scoring Change on Emergency Medicine Applicant Screening.

BACKGROUND: The U.S. Medical Licensing Examination (USMLE) Step 1 has been used as a screening tool for residency selection. In February 2020, Step 1 numerical scoring changed to pass/fail. OBJECTIVE: Our aim was to survey emergency medicine (EM) residency program attitudes towards the new Step 1 scoring change and to identify important applicant screening factors. METHODS: A 16-question survey was distributed through the Council of Residency Directors in Emergency Medicine listserv from November 11 through December 31, 2020. Given the Step 1 scoring change, the survey questioned the importance of EM rotation grades, composite standardized letters of evaluation (cSLOEs), and individual standardized letters of evaluation, using a Likert scale. Descriptive statistics of demographic characteristics and selection factors were performed along with a regression analysis. RESULTS: Of the 107 respondents, 48% were program directors, 28% were assistant or associate program directors, 14% were clerkship directors, and 10% were in other roles. Sixty (55.6%) disagreed with pass/fail Step 1 scoring change and, of those, 82% believed that numerical scoring was a good screening tool. The cSLOEs, EM rotation grades, and interview were the most important selection factors. Residencies with 50 or more residents had 5.25 odds (95% CI 1.25-22.1; p = 0.0018) of agreeing with pass/fail scoring and those who ranked cSLOEs as the most important selection factor had 4.90 odds (95% CI 1.125-21.37; p = 0.0343) of agreeing with pass/fail scoring. CONCLUSIONS: Most EM programs disagree with pass/fail scoring of Step 1 and will most likely use Step 2 score as a screening tool. The cSLOEs, EM rotation grades, and interview are considered the most important selection factors.

The Knowledge Gap: Mentorship in Emergency Medicine Residency.

STUDY OBJECTIVE: Studies of mentorship in emergency medicine show that mentored residents are twice as likely to describe their career preparation as excellent as compared to nonmentored peers. There has been significant interest in the mentor-mentee relationship in medicine; however, there is minimal guidance and published literature specific to emergency medicine residents. METHODS: In this narrative review, we described the emergency medicine mentor-mentee relationship, discussed alternatives to the traditional dyadic model, and highlighted current barriers to effective mentorship. We conducted a structured literature review to identify relevant published articles regarding the mentoring of emergency medicine residents. Additional studies from general mentoring literature were included based on relevancy. RESULTS: We identified 39 studies in emergency medicine literature based on our search criteria. Additional studies from general medicine literature were included based on relevancy to this review. Based on the limited available literature, we recommend maximizing the resident mentoring relationship by developing formal mentoring programs, supporting the advancement of women and underrepresented minority mentors, and moving toward team mentoring, including peer, near-peer, and collaborative mentorship. The development of a mentoring network is a logical strategy for residents to work with a diverse group of individuals to maximize benefits in multiple areas. CONCLUSION: Alternative approaches to the traditional and hierarchal dyadic mentoring style (eg, team mentoring) are effective methods that residencies may promote to increase effective mentoring. Future efforts in mentoring emergency medicine residents emphasize these strategies, which are increasingly beneficial given the constraints and use of technology highlighted by the COVID-19 pandemic.

Ketamine is not associated with more post-intubation hypotension than etomidate in patients undergoing endotracheal intubation.

INTRODUCTION: Emergency department (ED) patients undergoing emergent tracheal intubation often have multiple physiologic derangements putting them at risk for post-intubation hypotension. Prior work has shown that post-intubation hypotension is independently associated with increased morbidity and mortality. The choice of induction agent may be associated with post-intubation hypotension. Etomidate and ketamine are two of the most commonly used agents in the ED, however, there is controversy regarding whether either agent is superior in the setting of hemodynamic instability. The goal of this study is to determine whether there is a difference in the rate of post-intubation hypotension who received either ketamine or etomidate for induction. Additionally, we provide a subgroup analysis of patients at pre-existing risk of cardiovascular collapse (identified by pre-intubation shock index (SI) > 0.9) to determine if differences in rates of post-intubation hypotension exist as a function of sedative choice administered during tracheal intubation in these high-risk patients. We hypothesize that there is no difference in the incidence of post-intubation hypotension in patients who receive ketamine versus etomidate. METHODS: A retrospective cohort study was conducted on a database of 469 patients having undergone emergent intubation with either etomidate or ketamine induction at a large academic health system. Patients were identified by automatic query of the electronic health records from 1/1/2016-6/30/2019. Exclusion criteria were patients <18-years-old, tracheal intubation performed outside of the ED, incomplete peri-intubation vital signs, or cardiac arrest prior to intubation. Patients at high risk for hemodynamic collapse in the post-intubation period were identified by a pre-intubation SI > 0.9. The primary outcome was the incidence of post-intubation hypotension (systolic blood pressure < 90 mmHg or mean arterial pressure < 65 mmHg). Secondary outcomes included post-intubation vasopressor use and mortality. These analyses were performed on the full cohort and an exploratory analysis in patients with SI > 0.9. We also report adjusted odds ratios (aOR) from a multivariable logistic regression model of the entire cohort controlling for plausible confounding variables to determine independent factors associated with post-intubation hypotension. RESULTS: A total of 358 patients were included (etomidate: 272; ketamine: 86). The mean pre-intubation SI was higher in the group that received ketamine than etomidate, (0.97 vs. 0.83, difference: -0.14 (95%, CI -0.2 to -0.1). The incidence of post-intubation hypotension was greater in the ketamine group prior to SI stratification (difference: -10%, 95% CI -20.9% to -0.1%). Emergency physicians were more likely to use ketamine in patients with SI > 0.9. In our multivariate logistic regression analysis, choice of induction agent was not associated with post-intubation hypotension (aOR 1.45, 95% CI 0.79 to 2.65). We found that pre-intubation shock index was the strongest predictor of post-intubation hypotension. CONCLUSION: In our cohort of patients undergoing emergent tracheal intubation, ketamine was used more often for patients with an elevated shock index. We did not identify an association between the incidence of post-intubation hypotension and induction agent between ketamine and etomidate. Patients with an elevated shock index were at higher risk of cardiovascular collapse regardless of the choice of ketamine or etomidate.

Pronounced interplay between intrinsic phase-coexistence and octahedral tilt magnitude in hole-doped lanthanum cuprates.

Definitive understanding of superconductivity and its interplay with structural symmetry in the hole-doped lanthanum cuprates remains elusive. The suppression of superconductivity around 1/8th doping maintains particular focus, often attributed to charge-density waves (CDWs) ordering in the low-temperature tetragonal (LTT) phase. Central to many investigations into this interplay is the thesis that La1.875Ba0.125CuO4 and particularly La1.675Eu0.2Sr0.125CuO4 present model systems of purely LTT structure at low temperature. However, combining single-crystal and high-resolution powder X-ray diffraction, we find these to exhibit significant, intrinsic coexistence of LTT and low-temperature orthorhombic domains, typically associated with superconductivity, even at 10 K. Our two-phase models reveal substantially greater tilting of CuO6 octahedra in the LTT phase, markedly buckling the CuO2 planes. This would couple significantly to band narrowing, potentially indicating a picture of electronically driven phase segregation, reminiscent of optimally doped manganites. These results call for reassessment of many experiments seeking to elucidate structural and electronic interplay at 1/8 doping.

Diagnosing Achilles Tendon Rupture with Ultrasound in Patients Treated Surgically: A Systematic Review and Meta-Analysis.

BACKGROUND: Achilles tendon rupture is a common injury with increasing incidence due to the rising popularity of high-velocity sports, continued physical activity of the aging American population, and use of fluoroquinolones and steroid injections. The diagnosis can often be missed or delayed, with up to 20% misdiagnosed, most commonly as an ankle sprain. OBJECTIVE: The aim of our study was to systematically evaluate the reported sensitivity, specificity, and likelihood ratios of ultrasound for detecting Achilles tendon rupture in patients who were treated surgically. METHODS: In January 2020, we performed a literature search of MEDLINE and EMBASE databases to identify eligible articles according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Inclusion criteria were original studies with at least five patients, which reported data on the sonographic diagnosis of Achilles tendon rupture (complete or partial) compared to surgery as the reference standard. RESULTS: A total of 15 studies with 808 patients were included in the primary analysis. The sensitivity of ultrasound for detecting complete Achilles tendon ruptures was 94.8% (95% confidence interval [CI] 91.3-97.2%), specificity was 98.7% (95% CI 97.0-99.6%), positive likelihood ratio was 74.0 (95% CI 31.0-176.8), and negative likelihood ratio was 0.05 (95% CI 0.03-0.09), in patients who underwent surgical treatment. CONCLUSIONS: The results from our study suggested that a negative ultrasound result may have the potential to rule out a complete, as well as a partial, Achilles tendon rupture.

Reproducibility of FDG PET/CT image-based cancer staging and standardized uptake values with simulated reduction of injected FDG dose or acquisition time.

18F-fluorodeoxyglucose (FDG) PET/CT is widely used for oncologic imaging. This study aimed to evaluate, using data simulation, if reduction of injected FDG dose or PET acquisition time could be technically feasible when utilizing a sensitive commercial PET/CT imaging system, without sacrificing image quality, image-based staging accuracy, or standardized uptake value (SUV) accuracy. De-identified, standard of care oncologic FDG PET/CT datasets from 83 adults with lymphoma, lung carcinoma or breast carcinoma were retrospectively analyzed. All images had been acquired using clinical standard dose and acquisition time on a single PET/CT system. The list mode datasets were retrospectively software reprocessed to achieve undersampling of counts, thus simulating the effect of shorter PET acquisition time or lower injected FDG dose. The simulated reduced-count images were reviewed and compared with full-count images to assess and compare qualitative (subjective image quality, stage stability) and semi-quantitative (image noise, SUVmax stability, signal-to-noise and contrast-to-noise ratios within index lesions driving cancer stage) parameters. While simulated reduced-count images had measurably greater noise, there appeared to be no significant loss of image-based staging accuracy nor SUVmax reproducibility down to simulated FDG dose of 0.05 mCi/kg at continuous bed motion rate of 1.1 mm/sec. This retrospective simulation study suggests that a modest reduction of either injected FDG dose or emission scan time might be feasible in this limited oncologic population scanned on a single PET/CT system. Verification of these results with prospectively acquired images using actual low injected FDG activity and/or short imaging time is recommended.

Teaching Rapid Assessment Skills in Triage for the Emergency Medicine Clerkship.

BACKGROUND: Rapidly assessing an undifferentiated patient and developing a gestalt for "sick vs. not sick" is a core component of emergency medicine (EM). Developing this skill requires clinical experience and pattern recognition, which can be difficult to attain during a typical EM clerkship. OBJECTIVE: We developed a novel approach to teaching medical students rapid assessment skills in the emergency department (ED) by implementing a teaching shift in triage. METHODS: Fourth-year medical students in our EM clerkship in fall 2019 were scheduled one shift in triage with a dedicated teaching attending. The students evaluated patients under direct supervision, discussed their immediate differential diagnosis, and proposed an initial workup. The attending gave real-time feedback using a standardized direct observation tool. Students completed an electronic pre and post survey (5-point Likert scale) to assess their comfort level in the following areas: performing a rapid triage assessment, determining "sick vs. not sick", performing a focused physical examination, developing a targeted differential diagnosis, and ordering an initial diagnostic workup. RESULTS: Twenty-one students participated in the triage shifts. There was a significant improvement in self-assessed comfort with performing a rapid triage assessment, mean pre 2.76 and post 4.43 (p < 0.0001). There were also significant improvements in the four other survey areas (p < 0.004 or less). CONCLUSIONS: A teaching shift in triage can increase medical students' self-assessed rapid assessment skills for patients in the ED. Benefits to the teaching attending included the opportunity to perform direct observation, give real-time feedback, and identify real-time teaching moments.

Large Cerebellar Stroke in a Young COVID-19-Positive Patient: Case Report.

BACKGROUND: Coronavirus disease 2019 (COVID-19), caused by the novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), most frequently presents with respiratory symptoms, such as fever, dyspnea, shortness of breath, cough, or myalgias. There is now a growing body of evidence that demonstrates that severe SARS-CoV-2 infections can develop clinically significant coagulopathy, inflammation, and cardiomyopathy, which have been implicated in COVID-19-associated cerebrovascular accidents (CVAs). CASE REPORT: We report an uncommon presentation of a 32-year-old man who sustained a large vessel cerebellar stroke associated with a severe COVID-19 infection. He presented with a headache, worse than his usual migraine, dizziness, rotary nystagmus, and dysmetria on examination, but had no respiratory symptoms initially. He was not a candidate for thrombolytic therapy or endovascular therapy and was managed with clopidogrel, aspirin, and atorvastatin. During hospital admission he developed COVID-19-related hypoxia and pneumonia, but ultimately he was discharged to home rehabilitation. WHY SHOULD AN EMERGENCY PHYSICIAN BE AWARE OF THIS?: We present this case to increase awareness among emergency physicians of the growing number of reports of neurologic and vascular complications, such as ischemic CVAs, in otherwise healthy individuals who are diagnosed with SARS-CoV-2 infection. A brief review of the current literature will help elucidate possible mechanisms, risk factors, and current treatments for CVA associated with SARS-CoV-2.

A BERIBERI UNHEALTHY LATTE: ENCEPHALOPATHY AND SHOCK FROM SEVERE NUTRITIONAL DEFICIENCY.

BACKGROUND: Thiamine deficiency is an uncommon cause of severe illness in the United States that can lead to significant morbidity because of high-output cardiac failure, peripheral neuropathy, and permanent neurologic impairment. We report the case of a middle-aged woman with extreme malnutrition caused by complications of Roux-en-Y gastric bypass (RYGB) surgery who presented with signs and symptoms of severe thiamine deficiency and septic shock. CASE REPORT: A 43-year-old woman who had undergone RYGB surgery and who had multiple complications presented to the emergency department with agitation, confusion, and lethargy. The physical examination revealed an obtunded woman appearing much older than her reported age with significant peripheral edema. She was hypoxemic, hypotensive, and febrile. The initial laboratory analysis revealed a serum lactate level above the measurable limit, a normal thyroid-stimulating hormone, and elevated levels of troponin and brain natriuretic peptide. A transthoracic echocardiogram showed high-output heart failure. The patient's family later revealed that for the past year her diet had consisted almost exclusively of frozen blended lattes. High doses of thiamine and folate were started. Her shock, hyperlactatemia, and respiratory failure resolved by hospital day 3 and her encephalopathy resolved soon thereafter. Why Should an Emergency Physician be Aware of This?: Thiamine deficiency is a rare but reversible cause of shock, heart failure, and encephalopathy. Identifying patients who are at risk for severe nutritional deficiencies may aid in more rapid treatment with relatively benign medications with little downside, in this case high-dose vitamin B1, and ultimately improve patient-oriented outcomes such as mortality, morbidity, and hospital length of stay.

Anomalous vortex liquid in charge-ordered cuprate superconductors.

The interplay between charge order and d-wave superconductivity in high-[Formula: see text] cuprates remains an open question. While mounting evidence from spectroscopic probes indicates that charge order competes with superconductivity, to date little is known about the impact of charge order on charge transport in the mixed state, when vortices are present. Here we study the low-temperature electrical resistivity of three distinctly different cuprate families under intense magnetic fields, over a broad range of hole doping and current excitations. We find that the electronic transport in the doping regime where long-range charge order is known to be present is characterized by a nonohmic resistivity, the identifying feature of an anomalous vortex liquid. The field and temperature range in which this nonohmic behavior occurs indicates that the presence of long-range charge order is closely related to the emergence of this anomalous vortex liquid, near a vortex solid boundary that is defined by the excitation current in the [Formula: see text] 0 limit. Our findings further suggest that this anomalous vortex liquid, a manifestation of fragile superconductivity with a suppressed critical current density, is ubiquitous in the high-field state of charge-ordered cuprates.

Predicting Progression to Septic Shock in the Emergency Department Using an Externally Generalizable Machine-Learning Algorithm.

STUDY OBJECTIVE: Machine-learning algorithms allow improved prediction of sepsis syndromes in the emergency department (ED), using data from electronic medical records. Transfer learning, a new subfield of machine learning, allows generalizability of an algorithm across clinical sites. We aim to validate the Artificial Intelligence Sepsis Expert for the prediction of delayed septic shock in a cohort of patients treated in the ED and demonstrate the feasibility of transfer learning to improve external validity at a second site. METHODS: This was an observational cohort study using data from greater than 180,000 patients from 2 academic medical centers between 2014 and 2019, using multiple definitions of sepsis. The Artificial Intelligence Sepsis Expert algorithm was trained with 40 input variables at the development site to predict delayed septic shock (occurring greater than 4 hours after ED triage) at various prediction windows. We then validated the algorithm at a second site, using transfer learning to demonstrate generalizability of the algorithm. RESULTS: We identified 9,354 patients with severe sepsis, of whom 723 developed septic shock at least 4 hours after triage. The Artificial Intelligence Sepsis Expert algorithm demonstrated excellent area under the receiver operating characteristic curve (>0.8) at 8 and 12 hours for the prediction of delayed septic shock. Transfer learning significantly improved the test characteristics of the Artificial Intelligence Sepsis Expert algorithm and yielded comparable performance at the validation site. CONCLUSION: The Artificial Intelligence Sepsis Expert algorithm accurately predicted the development of delayed septic shock. The use of transfer learning allowed significantly improved external validity and generalizability at a second site. Future prospective studies are indicated to evaluate the clinical utility of this model.

A Case of Covid-19 Diagnosed at Home With Portable Ultrasound and Confirmed With Home Serology Test.

BACKGROUND: The coronavirus disease 2019 (COVID-19) pandemic has pushed us to find better ways to accurately diagnose what can be an elusory disease, preferably in a way that limits exposure to others. The potential for home diagnosis and monitoring could reduce infectious risk for other patients and health care providers, limit use of finite hospital resources, and enable better social distancing and isolation practices. CASE REPORT: We report a case of an otherwise healthy emergency physician diagnosed with COVID-19 at home using portable ultrasound, pulse oximetry, and antibody testing. Her clinical picture and typical lung findings of COVID-19 on ultrasound, combined with a normal echocardiogram and negative deep vein thrombosis study, helped inform her diagnosis. She then monitored her clinical course using pulse oximetry, was able to self-isolate for 4 weeks, and had an uneventful recovery. Her diagnosis was confirmed with a positive IgG antibody test after 3 weeks. CONCLUSIONS: Novel times call for novel solutions and our case demonstrates one possible path for home diagnosis and monitoring of COVID-19. The tools used, namely ultrasound and pulse oximetry, should be familiar to most emergency physicians. Ultrasound in particular was helpful in eliminating other potential diagnoses, such as pulmonary embolus.

Phenytoin Toxicity After Transjugular Intrahepatic Portosystemic Shunt (TIPS).

BACKGROUND: Transjugular intrahepatic portosystemic shunt (TIPS) alters portal blood flow and may impact drug metabolism and bioavailability. However, little evidence has been published to provide guidance on medication alterations after TIPS procedures. CASE REPORT: We report a patient who developed phenytoin toxicity requiring a prolonged readmission after a TIPS procedure. It is likely that the TIPS procedure altered phenytoin metabolism and led to toxicity in this patient. Phenytoin is an antiepileptic drug that is primarily eliminated by hepatic metabolism. It is possible that phenytoin toxicity may occur after TIPS, and that decreased dose requirements may be a durable effect of the procedure. WHY SHOULD AN EMERGENCY PHYSICIAN BE AWARE OF THIS?: TIPS is now the most common portal hypertension decompressive procedure performed by interventional radiologists and has become the primary portosystemic shunt (surgical or percutaneous) performed in the United States. Patients with a history of TIPS procedures commonly present to tertiary- and quaternary-care emergency departments with complex clinical presentations. Greater familiarity with the potential effects of TIPS on drug metabolism may help emergency physicians prevent adverse drug effects and optimize clinical outcomes.

Predicting progression to septic shock in the emergency department using an externally generalizable machine learning algorithm.

OBJECTIVE: Machine-learning (ML) algorithms allow for improved prediction of sepsis syndromes in the ED using data from electronic medical records. Transfer learning, a new subfield of ML, allows for generalizability of an algorithm across clinical sites. We aimed to validate the Artificial Intelligence Sepsis Expert (AISE) for the prediction of delayed septic shock in a cohort of patients treated in the ED and demonstrate the feasibility of transfer learning to improve external validity at a second site. METHODS: Observational cohort study utilizing data from over 180,000 patients from two academic medical centers between 2014 and 2019 using multiple definitions of sepsis. The AISE algorithm was trained using 40 input variables at the development site to predict delayed septic shock (occurring greater than 4 hours after ED triage) at varying prediction windows. We then validated the AISE algorithm at a second site using transfer learning to demonstrate generalizability of the algorithm. RESULTS: We identified 9354 patients with severe sepsis of which 723 developed septic shock at least 4 hours after triage. The AISE algorithm demonstrated excellent area under the receiver operating curve (>0.8) at 8 and 12 hours for the prediction of delayed septic shock. Transfer learning significantly improved the test characteristics of the AISE algorithm and yielded comparable performance at the validation site. CONCLUSIONS: The AISE algorithm accurately predicted the development of delayed septic shock. The use of transfer learning allowed for significantly improved external validity and generalizability at a second site. Future prospective studies are indicated to evaluate the clinical utility of this model.

Multisystem Inflammatory Syndrome in Children (MIS-C) in an Adolescent that Developed Coronary Aneurysms: A Case Report and Review of the Literature.

BACKGROUND: A small subset of pediatric patients develop a rare syndrome associated with Coronavirus Disease 2019 (COVID-19) infection called multisystem inflammatory syndrome in children (MIS-C). This syndrome shares characteristics with Kawasaki disease. CASE REPORT: A 15-year-old girl presented to our Emergency Department (ED) with fevers and malaise. She was diagnosed on her initial visit with an acute viral syndrome and discharged with a COVID polymerase chain reaction test pending, which was subsequently negative. She returned 3 days later with persistent fever, conjunctivitis, and a symmetric targetoid rash over her palms. She had no adenopathy, but her erythrocyte sedimentation rate and C-reactive protein were both significantly elevated at 90 mm/h and 19.61 mg/dL, respectively. The patient was then transferred to the regional children's hospital due to a clinical suspicion for MIS-C, and subsequent COVID-19 immunoglobulin G testing was positive. She had been empirically started on intravenous immunoglobulin in addition to 81 mg aspirin daily. Initial echocardiograms showed mild dilatation of the left main coronary artery, and on repeat echocardiogram, a right coronary artery aneurysm was also identified. Oral prednisone therapy (5 mg) was initiated and the patient was discharged on a continued prednisone taper. WHY SHOULD AN EMERGENCY PHYSICIAN BE AWARE OF THIS?: We present a case of a 15-year-old girl who presented to the ED with MIS-C who developed coronary aneurysms despite early therapy, to increase awareness among emergency physicians of this emerging condition.