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Background: Meningiomas are the most commonly occurring benign intracranial tumors. When presenting with peritumoral brain edema (PTBE), surgical treatment can lead to patient morbidity. This retrospective case series aims to describe the conservative medical management of moderate to large meningiomas with large PTBE. Methods: Patients with suspected meningiomas greater than 2.0cm and edema index greater than 2.0 were identified by screening 3345 MRI scans between 2012-2017. Imaging analysis included MR imaging features of suspected meningiomas and clinical data was gathered from the electronic patient record (patient age, sex, patient symptoms, follow-up duration, and follow-up symptoms). Results: We report on 31 patients who received conservative medical management. Presenting complaints included headache, seizure, weakness; many presented asymptomatically. The average follow-up time was 3.96 years. At the final follow-up appointment, 19 (61%) patients were asymptomatic. Among symptomatic patients, seizures were the most common complaint. There was no mortality reported in our cohort and the average tumor progression was 7.04cm3/year. Conclusions: In this retrospective report of meningioma patients with high edema index, we found that most patients remained asymptomatic or had stable symptoms after at least 1-yr follow up after medical treatment. This study provides insight around the surgical decision-making for meningiomas with large spread of edema.
Introduction: We previously derived (N = 559) and validated (N = 1,100) the 10-item Ottawa Heart Failure Risk Scale (OHFRS), to assist with disposition decisions for patients with acute heart failure (AHF) in the emergency department (ED). In the current study we sought to use a larger dataset to develop a more concise and more accurate risk scale. Methods: We analyzed data from the prior two studies and from a new cohort. For all 3 groups we conducted prospective cohort studies that enrolled patients who required treatment for AHF at 8 tertiary care hospital EDs. Patients were followed for 30 days. The primary outcome was short-term serious outcome (SSO), defined as death within 30 days, intubation or non-invasive ventilation (NIV) after admission, myocardial infarction, or relapse resulting in hospital admission within 14 days. The fully pre-specified logistic regression model with 13 predictors (where age, pCO2, and SaO2 were modeled using spline functions) was fitted to 10 multiple imputation datasets. Harrell's fast stepdown procedure reduced the number of variables. We calculated the potential impact on sensitivity (95% CI) for SSO and hospital admissions, and estimated a sample size of 2,000 patients. Results: The 1,986 patients had mean age 77.3 years, male 54.1%, EMS arrival 41.2%, IV NTG 3.3%, ED NIV 5.4%, admission on initial visit 49.5%. Overall there were 236 (11.9%) SSOs including 61 deaths (3.1%), meaning that current admission practice sensitivity for SSO was only 59.7%. The final HEARTRISK6 scale is comprised of 6 variables (points) (C-statistic 0.68): Valvular heart disease (2) Antiarrhythmic medication (2) ED non-invasive ventilation (3) Creatinine 80–150 (1); ≥150 (3) Troponin ≥3x URL (2) Walk test failed (1). The probability of SSO ranged from 4.8% for a total score of 0 to 62.4% for a score of 10, showing good calibration. Choosing a HEARTRISK6 total point admission threshold of ≥3 would yield sensitivity of 70.8% (95%CI 64.5-76.5) for SSO with a slight decrease in admissions to 47.9%. Choosing a threshold of ≥2 would yield a sensitivity of 84.3% (95%CI 79.0-88.7) but require 66.6% admissions. Conclusion: Using a large prospectively collected dataset, we created a more concise and more sensitive risk scale to assist with admission decisions for patients with AHF in the ED. Implementation of the HEARTRISK6 scale should lead to safer and more efficient disposition decisions, with more high-risk patients being admitted and more low-risk patients being discharged.
Introduction: The treatment of cutaneous abscesses in the Emergency Department (ED) is common. While most sources describe only incision and drainage (I&D) followed by healing through secondary intention, recent literature suggests that primary repair following I&D results in similar rates of healing as well as treatment failures when compared to standard care in the ED. The primary goal of this research project was to describe the variability in practice with respect to self-reported management of abscesses among Canadian ED physicians and explore potential reluctance in adopting primary repair as a management strategy. Methods: An electronic survey was distributed through the Canadian Association of Emergency Physicians (CAEP). Practicing physician members of CAEP were invited to complete the survey. The 9-question survey probed the willingness of physicians to perform primary closure of abscess in the ED as well as factors that dissuade them from performing this type of closure. The primary outcome was the quantification of practice variability among ED physicians with respect to abscess closure in the ED. The data was presented with simple descriptive statistics. Results: 217 surveys were completed out of 1145 eligible physicians. Physicians working at academic centres comprised 53% of responses, with 47% coming from community centres. Over half of responses were from physicians in practice at least ten years (65.9%). The overwhelming majority of physicians indicated that they manage abscesses following I&D by secondary closure (96.3%). The two main concerns dissuading respondents from performing primary closure of abscesses included risk of treatment failure (47.8%) and the procedure not being considered standard of care (36.7%). Despite these concerns, 67.3% of physicians indicated a willingness to perform primary closure if further evidence supported its use. These physicians were most likely to consider primary closure at the head and neck, breast, trunk, and extremities, however, only 1.5% considered primary closure appropriate for perianal or pilonidal abscesses. Conclusion: This study demonstrates that almost all Canadian ED physicians, regardless of experience or practice centre, manage cutaneous abscesses with I&D followed by healing via secondary intention. With increasing evidence supporting the use of primary closure, many physicians may be willing to adopt primary closure as part of the management of cutaneous abscesses in the ED.
Introduction: Acute aortic syndrome (AAS) is a time sensitive aortic catastrophe that is often misdiagnosed. There are currently no Canadian guidelines to aid in diagnosis. Our goal was to adapt the existing American Heart Association (AHA) and European Society of Cardiology (ESC) diagnostic algorithms for AAS into a Canadian evidence based best practices algorithm targeted for emergency medicine physicians. Methods: We chose to adapt existing high-quality clinical practice guidelines (CPG) previously developed by the AHA/ESC using the GRADE ADOLOPMENT approach. We created a National Advisory Committee consisting of 21 members from across Canada including academic, community and remote/rural emergency physicians/nurses, cardiothoracic and cardiovascular surgeons, cardiac anesthesiologists, critical care physicians, cardiologist, radiologists and patient representatives. The Advisory Committee communicated through multiple teleconference meetings, emails and a one-day in person meeting. The panel prioritized questions and outcomes, using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach to assess evidence and make recommendations. The algorithm was prepared and revised through feedback and discussions and through an iterative process until consensus was achieved. Results: The diagnostic algorithm is comprised of an updated pre test probability assessment tool with further testing recommendations based on risk level. The updated tool incorporates likelihood of an alternative diagnosis and point of care ultrasound. The final best practice diagnostic algorithm defined risk levels as Low (0.5% no further testing), Moderate (0.6-5% further testing required) and High ( >5% computed tomography, magnetic resonance imaging, trans esophageal echocardiography). During the consensus and feedback processes, we addressed a number of issues and concerns. D-dimer can be used to reduce probability of AAS in an intermediate risk group, but should not be used in a low or high-risk group. Ultrasound was incorporated as a bedside clinical examination option in pre test probability assessment for aortic insufficiency, abdominal/thoracic aortic aneurysms. Conclusion: We have created the first Canadian best practice diagnostic algorithm for AAS. We hope this diagnostic algorithm will standardize and improve diagnosis of AAS in all emergency departments across Canada.
While most papers on high-entropy alloys (HEAs) focus on the microstructure and mechanical properties for structural materials applications, there has been growing interest in developing high-entropy functional materials. The objective of this paper is to provide a brief, timely review on select functional properties of HEAs, including soft magnetic, magnetocaloric, physical, thermoelectric, superconducting, and hydrogen storage. Comparisons of functional properties between HEAs and conventional low- and medium-entropy materials are provided, and examples are illustrated using computational modeling and tuning the composition of existing functional materials through substitutional or interstitial mixing. Extending the concept of high configurational entropy to a wide range of materials such as intermetallics, ceramics, and semiconductors through the isostructural design approach is discussed. Perspectives are offered in designing future high-performance functional materials utilizing the high-entropy concepts and high-throughput predictive computational modeling.
We present the defect analysis by photoluminescence (PL) spectroscopy of CdSexTe1-x thin films, grown with varying Se content by a co-sputtered deposition method. We observe a peak at 1.203 eV in the CdSexTe1-x film for x = 0.21, which shifts towards higher energies with increase in laser power. This peak was assigned to a donor-to-acceptor (DAP) transition, with a measured j-shift of ∼4.7 meV/decade. Temperature dependent PL intensity measurements confirm that the observed DAP peak involves a shallow defect state of binding energy ∼34.7 meV. In contrast, a free-to-bound (FB) peak at 1.294 eV involving a shallow defect of binding energy ∼18.3 meV was observed in the CdSexTe1-x film for x = 0.14. Additionally, we observe band edge emission at 1.452 eV and 1.448 eV in CdSexTe1-x films for x = 0.14 and x = 0.21 respectively. Our analysis shows that the Se concentration not only changes the band gap energy of the resulting CdSexTe1-x alloy thin film, but also modifies the nature of the dominant observed defect emission.
Monolithic integrated thin film tandem solar cells consisting of a high bandgap perovskite top cell and a low bandgap thin film bottom cell are expected to reach higher power conversion efficiencies (PCEs) with lower manufacturing cost and environmental impacts than the market-dominant crystalline silicon photovoltaics. There have been several demonstrations of 4-terminal and 2-terminal perovskite tandem devices with CuInGaSe2 (CIGS) or CuInSe2 (CIS) and, similar to the other tandem structures, the optimization of this device relies on optimal choice for the perovskite bandgap and thickness. Therefore, further advancement will be enabled by tuning the perovskite absorber to maximize the photocurrent limited by the current match condition. Here, we systematically study the optical absorption and transmission of perovskite thin films with varying absorber band gap. Based on these results, we model the photocurrent generations in both perovskite and CIS subcells and estimate the performances of projected tandem devices by considering the ideally functioning perovskite and CIS device. Our results show that for perovskite layers with 500 nm thickness the optimal bandgap is around 1.6 eV. With these configurations, PCEs above 20% could be achieved by monolithically integrated perovskite/CIS tandem solar cells. Also by modelling the absorption at every layer we calculate the quantum efficiency at each subcell in addition to tracking optical losses.
This article focus on the rigid-liquid coupling dynamics of the spacecraft with arbitrary axisymmetrical tanks with curved walls and top. The carrier velocity potential function was obtained according to the motion equations of a representative point in the tank of spacecraft, and the relative velocity potential function can be expressed as Gauss hypergeometric series. The Hamilton's variational principle was applied to derive the governing equations of liquid sloshing based on the profile of hydrostatic shape of free liquid surface. The dynamic equations of modal coordinates were established through the Galerkin method. The state equations of coupled motion of main rigid platform of the spacecraft were deduced by using the Lagrange's equations in term of general quasi-coordinates. Thruster firing was actuated to the coupled system to analyze the rigid-liquid coupled dynamic behaviors. Computer numerical simulations was carried out to confirm the validity of the method developed in this paper.
Methods of obtaining large grain size and high crystallinity in absorber materials play an important role in fabrication of high-performance methylammonium lead iodide (MAPbI3) perovskite solar cells. Here we study the effect of adding small concentrations of Cd2+, Zn2+, and Fe2+salts to the perovskite precursor solution used in the single-step solution fabrication process. Enhanced grain size and crystallinity in MAPbI3 films were obtained by using 0.1% of Cd2+ or Zn2+in the precursor solution. Consequently, solar cells constructed with Cd- and Zn-doped perovskite films show a significant improvement in device performance. These results suggest that the process may be an effective and facile method to fabricate high-efficiency perovskite photovoltaic devices.
One of the cornerstones in the development of a new feed rationing system for dairy cows must involve a reappraisal of both the concepts and ‘numbers’ adopted in defining the energy requirements for dairy cows. This is particularly important in the present scenario where increasingly high levels of animal output are being achieved from very different animal genotypes to those used in UK dairying 20 - 30 years ago. One of the tasks within the Feed Into Milk (FIM) project was to develop a new system to predict the energy requirements of todays dairy cow. The objective of the present study was to collate all available energy metabolism data with dairy cows in the UK and to develop relationships for describing metabolisable energy (ME) requirement for maintenance (MEm) and efficiency of ME use for lactation (kl) using both existing and new methodologies.
The Feed into Milk (FIM) project in the United Kingdom has developed a Mitscherlich equation from calorimetric data for energy rationing of dairy cattle (Agnew et al., 2004). The objective of the present study was to evaluate this equation using independent data sets obtained in both calorimetric and production studies.
We present highly resolved, annually dated, calibrated proxies for atmospheric circulation from several Antarctic ice cores (ITASE (International Trans-Antarctic Scientific Expedition), Siple Dome, Law Dome) that reveal decadal-scale associations with a South Pole ice-core 10Be proxy for solar variability over the last 600 years and annual-scale associations with solar variability since AD 1720. We show that increased (decreased) solar irradiance is associated with increased (decreased) zonal wind strength near the edge of the Antarctic polar vortex. The association is particularly strong in the Indian and Pacific Oceans and as such may contribute to understanding climate forcing that controls drought in Australia and other Southern Hemisphere climate events. We also include evidence suggestive of solar forcing of atmospheric circulation near the edge of the Arctic polar vortex based on ice-core records from Mount Logan, Yukon Territory, Canada, and both central and south Greenland as enticement for future investigations. Our identification of solar forcing of the polar atmosphere and its impact on lower latitudes offers a mechanism for better understanding modern climate variability and potentially the initiation of abrupt climate-change events that operate on decadal and faster scales.
This paper presents the bed topography of Jakobshavn Isbræ, Greenland, and Byrd Glacier, Antarctica, derived from sounding these glaciers with high-sensitivity radars. To understand the processes causing the speed-up and retreat of outlet glaciers, and to enable the development of next-generation ice-sheet models, we need information on bed topography and basal conditions. To this end, we performed measurements with the progressively improved Multichannel Coherent Radar Depth Sounder/Imager (MCoRDS/I). We processed the data from each antenna-array element using synthetic aperture radar algorithms to improve radar sensitivity and reduce along-track surface clutter. We then applied array and image-processing algorithms to extract the weak bed echoes buried in off-vertical scatter (cross-track surface clutter). At Jakobshavn Isbræ, we observed 2.7 km thick ice ~30 km upstream of the calving front and ~850 m thick ice at the calving front. We also observed echoes from multiple interfaces near the bed. We applied the MUSIC algorithm to the data to derive the direction of arrival of the signals. This analysis revealed that clutter is dominated by the ice surface at Jakobshavn Isbræ. At Byrd Glacier, we found ~3.62 km thick ice, as well as a subglacial trench ~3.05 km below sea level. We used ice thickness information derived from radar data in conjunction with surface elevation data to generate bed maps for these two critical glaciers. The performance of current radars must be improved further by ~15 dB to fully sound the deepest part of Byrd Glacier. Unmanned aerial systems equipped with radars that can be flown over lines spaced as close as 5 m apart in the cross-track direction to synthesize a two-dimensional aperture would be ideal for collecting fine-resolution data over glaciers like Jakobshavn near their grounding lines.
We apply a novel pre-flare tracking of sunspot groups towards improving the estimation of flare onset time by focusing on the evolution of the 3D magnetic field construction of AR 11429. The 3D magnetic structure is based on potential field extrapolation encompassing a vertical range from the photosphere through the chromosphere and transition region into the low corona. The basis of our proxy measure of activity prediction is the so-called weighted horizontal gradient of magnetic field (WGM) defined between spots of opposite polarities close to the polarity inversion line of an active region. The temporal variation of the distance of the barycenter of the opposite polarities is also found to possess potentially important diagnostic information about the flare onset time estimation as function of height similar to its counterpart introduced initially in an application at the photosphere only in Korsós et al. (2015). We apply the photospheric pre-flare behavioural patterns of sunspot groups to the evolution of their associated 3D-constructed AR 11429 as function of height. We found that at a certain height in the lower solar atmosphere the onset time may be estimated much earlier than at the photosphere or at any other heights. Therefore, we present a tool and recipe that may potentially identify the optimum height for flare prognostic in the solar atmosphere allowing to improve our flare prediction capability and capacity.
Auditory verbal hallucinations (AVHs) are one of the most common and severe symptoms of schizophrenia, but the neuroanatomical abnormalities underlying AVHs are not well understood. The present study aims to investigate whether AVHs are associated with cortical thinning.
Participants were schizophrenia patients from four centers across China, 115 with AVHs and 93 without AVHs, as well as 261 healthy controls. All received 3 T T1-weighted brain scans, and whole brain vertex-wise cortical thickness was compared across groups. Correlations between AVH severity and cortical thickness were also determined.
The left middle part of the middle temporal gyrus (MTG) was significantly thinner in schizophrenia patients with AVHs than in patients without AVHs and healthy controls. Inferences were made using a false discovery rate approach with a threshold at p < 0.05. Left MTG thickness did not differ between patients without AVHs and controls. These results were replicated by a meta-analysis showing them to be consistent across the four centers. Cortical thickness of the left MTG was also found to be inversely correlated with hallucination severity across all schizophrenia patients.
The results of this multi-center study suggest that an abnormally thin left MTG could be involved in the pathogenesis of AVHs in schizophrenia.
Background: Patients with poorly controlled diabetes mellitus (DM) often visit the emergency department (ED) for management of hyperglycemic episodes, including diabetic ketoacidosis (DKA) and hyperosmolar hyperglycemic state (HHS). It has been previously reported that risk factors for readmission to the intensive care unit (ICU) in DKA include older age, female sex and the presence of significant comorbidity including sepsis. However, there are no ED-based studies on this topic, particularly in a Canadian setting, and data on outcomes such as recurrent ED visits, hospital or ICU admission after discharge in these patients is lacking. Objectives: The primary objective of this study is to derive and internally validate a clinical risk tool for prognosis of patients presenting with hyperglycemic emergencies to identify those at higher risk of adverse outcomes within 30 days of initial ED presentation. Methods: This will be a multicentre prospective cohort study of eligible consecutive adult patients with an ED diagnosis of hyperglycemia, DKA or HHS. We will include all visits of adult (≥18 years) ED patients with either a known or unknown history of DM and a diagnosis of hyperglycemia (blood glucose >11.0 mmol/L), DKA or HHS. We will include patients with co-morbid diagnoses in addition to hyperglycemia. We will exclude patients: a) with advanced care directives for resuscitation involving refusal of treatment, and b) who are initially assessed at a peripheral hospital and transferred to our sites for ongoing management. Research assistants will then contact the enrolled participants via telephone for follow-up regarding clinical outcomes, including repeat visits to see a health care provider, changes in diabetic medications, and time taken off of work or school. Participants will be followed to determine if they have further ED visits, admissions or ICU admissions after their ED visit for hyperglycemia. Data on missed patients or those who refused consent will be collected to assess for selection/enrolment bias. Statistical considerations: The primary outcome will be an unplanned return ED visit for hyperglycemia within 30 days of initial presentation. Secondary outcomes will include unplanned admission to hospital or ICU for hyperglycemia, or death within 30 days of the index ED visit. Additionally, we hope to characterize patient-important and health-care system outcomes such as time taken off work or school and follow-up visits to see a healthcare provider. We will conduct descriptive statistics on investigations, treatments, disposition and patient-important outcomes. We will perform an initial univariate logistic regression, followed by a multivariate analysis to identify predictor variables associated with adverse events such as recurrent ED visits, and admission to hospital or ICU for hyperglycemia within 30 days. We will include individual patients who have multiple recurrent visits to the ED during the study period and statistically weight for these using generalized estimating equations (GEE), which are used to develop regression models for correlated data that arise from repeated measures of the same individuals over time. Finally, a clinical risk tool will be derived by rounding the beta co-efficients. Internal validation will be conducted using bootstrapping techniques. Importance: ED visits for hyperglycemia significantly affect both the healthcare system overall and the individual patient. The results of this project will assist clinicians to better identify these patients and enable them to intervene either medically or educationally to prevent subsequent visits to the ED. As a result, patients will have improved care, better blood glucose control, and be identified for closer follow-up with a family physician or diabetes specialist. Furthermore, by aiming to reduce the number of recurrent visits, this project may reduce ED utilization and the associated healthcare costs with frequent visits and admissions for hyperglycemia.
Relativistic collisionless shock charged particle acceleration is considered as a possible origin of high-energy cosmic rays. However, it is hard to explore the nature of relativistic collisionless shock due to its low occurring frequency and remote detecting distance. Recently, there are some works attempt to solve this problem by generating relativistic collisionless shock in laboratory conditions. In laboratory, the scheme of generation of relativistic collisionless shock is that two electron–positron pair plasmas knock each other. However, in laboratory, the appropriate pair plasmas have been not generated. The 10 PW laser pulse maybe generates the pair plasmas that satisfy the formation condition of relativistic collisionless shock due to its ultrahigh intensity and energy. In this paper, we study the positron production by ultraintense laser high Z target interaction using numerical simulations, which consider quantum electrodynamics effect. The simulation results show that the forward positron beam up to 1013/kJ can be generated by 10 PW laser pulse interacting with lead target. The estimation of relativistic collisionless shock formation shows that the positron yield satisfies formation condition and the positron divergence needs to be controlled. Our results indicate that the generation of relativistic collisionless shock by 10 PW laser facilities in laboratory is possible.