547 research outputs found

    Type Iax SNe as a few-parameter family

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    We present direct spectroscopic modeling of five Type Iax supernovae (SNe) with the one dimensional Monte Carlo radiative transfer code TARDIS. The abundance tomography technique is used to map the chemical structure and physical properties of the SN atmosphere. Through via fitting of multiple spectral epochs with self-consistent ejecta models, we can then constrain the location of some elements within the ejecta. The synthetic spectra of the best-fit models are able to reproduce the flux continuum and the main absorption features in the whole sample. We find that the mass fractions of IGEs and IMEs show a decreasing trend toward the outer regions of the atmospheres using density profiles similar to those of deflagration models in the literature. Oxygen is the only element, which could be dominant at higher velocities. The stratified abundance structure contradicts the well-mixed chemical profiles predicted by pure deflagration models. Based on the derived densities and abundances, a template model atmosphere is created for the SN Iax class and compared to the observed spectra. Free parameters are the scaling of the density profile, the velocity shift of the abundance template, and the peak luminosity. The results of this test support the idea that all SNe Iax can be described by a similar internal structure, which argues for a common origin of this class of explosions.Comment: 21 pages, 7 tables, 16 figures, accepted by MNRA

    A Three-dimensional Printed Low-cost Anterior Shoulder Dislocation Model for Ultrasound-guided Injection Training.

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    Anterior shoulder dislocations are the most common, large joint dislocations that present to the emergency department (ED). Numerous studies support the use of intraarticular local anesthetic injections for the safe, effective, and time-saving reduction of these dislocations. Simulation training is an alternative and effective method for training compared to bedside learning. There are no commercially available ultrasound-compatible shoulder dislocation models. We utilized a three-dimensional (3D) printer to print a model that allows the visualization of the ultrasound anatomy (sonoanatomy) of an anterior shoulder dislocation. We utilized an open-source file of a shoulder, available from embodi3D® (Bellevue, WA, US). After approximating the relative orientation of the humerus to the glenoid fossa in an anterior dislocation, the humerus and scapula model was printed with an Ultimaker-2 Extended+ 3D® (Ultimaker, Cambridge, MA, US) printer using polylactic acid filaments. A 3D model of the external shoulder anatomy of a live human model was then created using Structure Sensor®(Occipital, San Francisco, CA, US), a 3D scanner. We aligned the printed dislocation model of the humerus and scapula within the resultant external shoulder mold. A pourable ballistics gel solution was used to create the final shoulder phantom. The use of simulation in medicine is widespread and growing, given the restrictions on work hours and a renewed focus on patient safety. The adage of see one, do one, teach one is being replaced by deliberate practice. Simulation allows such training to occur in a safe teaching environment. The ballistic gel and polylactic acid structure effectively reproduced the sonoanatomy of an anterior shoulder dislocation. The 3D printed model was effective for practicing an in-plane ultrasound-guided intraarticular joint injection. 3D printing is effective in producing a low-cost, ultrasound-capable model simulating an anterior shoulder dislocation. Future research will determine whether provider confidence and the use of intraarticular anesthesia for the management of shoulder dislocations will improve after utilizing this model

    Fully Ir(iii) tetrazolate soft salts: the road to white-emitting ion pairs

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    The first examples of anionic Ir(iii) bis-tetrazolate complexes and their combination with a cationic Ir(iii)tetrazole derivative forming "fully tetrazolate" Ir(iii) based soft salts as O2-sensitive white emitters are described herein

    Targeting divalent metal cations with Re(I) tetrazolato complexes

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    © 2015 The Royal Society of Chemistry. In order to exploit their potential as versatile luminescent sensors, four new Re(i)-tetrazolato complexes with the general formula fac-[Re(CO)3(diim)(L)], where diim is 2,2'-bipyridine (bipy) or 1,10-phenanthroline (phen) and L- is either the anion 5-(2'-pyridyl)tetrazolato (2-PTZ-) or 5-(2'-quinolyl)tetrazolato (2-QTZ-), were prepared and fully characterized. In all cases, the regioselective coordination of the Re(i) center through the N2 atom of the tetrazolato ring was observed. This particular feature ensures the availability of the diiminic (N^N) site that was systematically incorporated into the structure of the 2-PTZ- and 2-QTZ- ligands for further coordination with metal cations. Such a diimine-type coordination mode was preliminarily tested by using the mononuclear Re(i) complexes as N^N ligands for the preparation of two [(N^N)Cu(POP)] cationic species, where POP is the chelating diphosphine bis[2-(diphenylphosphino)phenyl]ether. The X-ray structures of the resulting Re(i)-Cu(i) dyads revealed that the Re(i) mononuclear complexes effectively behaved as chelating N^N ligands with respect to the [Cu(POP)]+ fragment, the coordination of which also resulted in significant modification of the Re(i)-centered luminescence. With these data in hand, the luminescent sensing abilities of the four new Re(i) tetrazolato complexes were screened with respect to divalent metal ions of toxicological and biological importance such as Zn(ii), Cd(ii) and Cu(ii). The interaction of the Re(i) complexes with Zn(ii) and Cd(ii) was witnessed by the evident blue shift (??max = 22-36 nm) of the emission maxima, which was also accompanied by a significant elongation of the emission lifetimes. On the contrary, the addition of the cupric ion caused substantial quenching of the radiative processes originating from the Re(i) luminophores

    Diagnosis and Monitoring of White Coat Hypertension in Pregnancy:an ISSHP Consensus Delphi Procedure

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    BACKGROUND: There is no accepted definition or standardized monitoring for white coat hypertension in pregnancy. This Delphi procedure aimed to reach consensus on out-of-office blood pressure (BP) monitoring, and white coat hypertension diagnostic criteria and monitoring. METHOD: Relevant international experts completed three rounds of a modified Delphi questionnaire. For each item, the predefined cutoff for group consensus was ≥70% agreement, with 60% to 70% considered to warrant reconsideration at the subsequent round, and <60% considered insufficient to warrant consideration. RESULTS: Of 230 experts, 137 completed the first round and 114 (114/137, 83.2%) completed all three. For out-of-office BP monitoring, there was consensus that home BP monitoring (HBPM) should be chosen; instructions given, pairs of BP values taken, opportunity given for women to qualify values they do not regard as valid, and BP considered evaluated when ≥25% of values are above a cutoff. For HBPM, BP should be taken at least 2 to 3 d/wk, at minimum in the morning; however, many factors may affect frequency and timing. Experts endorsed a clinic BP <140/90 mm Hg as normal. While not reaching consensus, most agreed that HBPM values should be lower than clinic BP. Among those, HBPM <135/85 mm Hg was considered normal. There was consensus that white coat hypertension warrants: HBPM at least 1 d/wk before 20 weeks, 2 to 3 d/wk after 20 weeks or if persistent hypertension develops, and symptom monitoring (ie, headache, visual symptoms, and right upper quadrant/epigastric pain). CONCLUSIONS: Consensus-based diagnostic criteria and monitoring strategies should inform clinical care and research, to facilitate evaluation of out-of-office BP monitoring on pregnancy outcomes

    Development and internal validation of the multivariable CIPHER (Collaborative Integrated Pregnancy High-dependency Estimate of Risk) clinical risk prediction model

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    Background: Intensive care unit (ICU) outcome prediction models, such as Acute Physiology And Chronic Health Evaluation (APACHE), were designed in general critical care populations and their use in obstetric populations is contentious. The aim of the CIPHER (Collaborative Integrated Pregnancy High-dependency Estimate of Risk) study was to develop and internally validate a multivariable prognostic model calibrated specifically for pregnant or recently delivered women admitted for critical care.Methods: A retrospective observational cohort was created for this study from 13 tertiary facilities across five high-income and six low- or middle-income countries. Women admitted to an ICU for more than 24 h during pregnancy or less than 6 weeks post-partum from 2000 to 2012 were included in the cohort. A composite primary outcome was defined as maternal death or need for organ support for more than 7 days or acute life-saving intervention. Model development involved selection of candidate predictor variables based on prior evidence of effect, availability across study sites, and use of LASSO (Least Absolute Shrinkage and Selection Operator) model building after multiple imputation using chained equations to address missing data for variable selection. The final model was estimated using multivariable logistic regression. Internal validation was completed using bootstrapping to correct for optimism in model performance measures of discrimination and calibration.Results: Overall, 127 out of 769 (16.5%) women experienced an adverse outcome. Predictors included in the final CIPHER model were maternal age, surgery in the preceding 24 h, systolic blood pressure, Glasgow Coma Scale score, serum sodium, serum potassium, activated partial thromboplastin time, arterial blood gas (ABG) pH, serum creatinine, and serum bilirubin. After internal validation, the model maintained excellent discrimination (area under the curve of the receiver operating characteristic (AUROC) 0.82, 95% confidence interval (CI) 0.81 to 0.84) and good calibration (slope of 0.92, 95% CI 0.91 to 0.92 and intercept of −0.11, 95% CI −0.13 to −0.08).Conclusions: The CIPHER model has the potential to be a pragmatic risk prediction tool. CIPHER can identify critically ill pregnant women at highest risk for adverse outcomes, inform counseling of patients about risk, and facilitate bench-marking of outcomes between centers by adjusting for baseline risk

    A review of the methodological features of systematic reviews in maternal medicine

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    Background In maternal medicine, research evidence is scattered making it difficult to access information for clinical decision making. Systematic reviews of good methodological quality are essential to provide valid inferences and to produce usable evidence summaries to guide management. This review assesses the methodological features of existing systematic reviews in maternal medicine, comparing Cochrane and non-Cochrane reviews in maternal medicine. Methods Medline, Embase, Database of Reviews of Effectiveness (DARE) and Cochrane Database of Systematic Reviews (CDSR) were searched for relevant reviews published between 2001 and 2006. We selected those reviews in which a minimum of two databases were searched and the primary outcome was related to the maternal condition. The selected reviews were assessed for information on framing of question, literature search and methods of review. Results Out of 2846 citations, 68 reviews were selected. Among these, 39 (57%) were Cochrane reviews. Most of the reviews (50/68, 74%) evaluated therapeutic interventions. Overall, 54/68 (79%) addressed a focussed question. Although 64/68 (94%) reviews had a detailed search description, only 17/68 (25%) searched without language restriction. 32/68 (47%) attempted to include unpublished data and 11/68 (16%) assessed for the risk of missing studies quantitatively. The reviews had deficiencies in the assessment of validity of studies and exploration for heterogeneity. When compared to Cochrane reviews, other reviews were significantly inferior in specifying questions (OR 20.3, 95% CI 1.1–381.3, p = 0.04), framing focussed questions (OR 30.9, 95% CI 3.7- 256.2, p = 0.001), use of unpublished data (OR 5.6, 95% CI 1.9–16.4, p = 0.002), assessment for heterogeneity (OR 38.1, 95%CI 2.1, 688.2, p = 0.01) and use of meta-analyses (OR 3.7, 95% CI 1.3–10.8, p = 0.02). Conclusion This study identifies areas which have a strong influence on maternal morbidity and mortality but lack good quality systematic reviews. Overall quality of the existing systematic reviews was variable. Cochrane reviews were of better quality as compared to other reviews. There is a need for good quality systematic reviews to inform practice in maternal medicine

    A new method for quantifying anisotropic martensitic transformation strains accumulated during constrained cooling

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    Martensitic phase transformations during welding can play a major role in determining the final residual stresses and they can be anisotropic if the transformation occurs under stress. Traditionally, the Satoh test has been used to quantify the response, but it suffers from the fact that the temperature is not uniform along the specimen length, making it difficult to interpret the data. This shortcoming is overcome in our new experimental method using digital image correlation (DIC) to quantify the temperature dependent evolution of the transformation strain locally both parallel and perpendicular to an applied load, in this case for a high-strength low alloy (HSLA) steel and a tough, low transformation temperature weld consumable designed to mitigate tensile weld residual stresses. The method is able to separate the volumetric component of the transformation strain from the deviatoric transformation plasticity component. The volumetric component is shown to be independent of applied load, while the deviatoric component varies approximately linearly with applied load. For the HSLA steel studied here the method also reveals that the transformation start temperature rises under both tensile and compressive loading, confirming previous work. From a weld modelling viewpoint our method provides sufficient information to include the stress dependency of the anisotropic transformation strain in numerical finite element models of the weld process

    A risk prediction model for the assessment and triage of women with hypertensive disorders of pregnancy in low-resourced settings: the miniPIERS (Pre-eclampsia Integrated Estimate of RiSk) multi-country prospective cohort study.

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    BACKGROUND: Pre-eclampsia/eclampsia are leading causes of maternal mortality and morbidity, particularly in low- and middle- income countries (LMICs). We developed the miniPIERS risk prediction model to provide a simple, evidence-based tool to identify pregnant women in LMICs at increased risk of death or major hypertensive-related complications. METHODS AND FINDINGS: From 1 July 2008 to 31 March 2012, in five LMICs, data were collected prospectively on 2,081 women with any hypertensive disorder of pregnancy admitted to a participating centre. Candidate predictors collected within 24 hours of admission were entered into a step-wise backward elimination logistic regression model to predict a composite adverse maternal outcome within 48 hours of admission. Model internal validation was accomplished by bootstrapping and external validation was completed using data from 1,300 women in the Pre-eclampsia Integrated Estimate of RiSk (fullPIERS) dataset. Predictive performance was assessed for calibration, discrimination, and stratification capacity. The final miniPIERS model included: parity (nulliparous versus multiparous); gestational age on admission; headache/visual disturbances; chest pain/dyspnoea; vaginal bleeding with abdominal pain; systolic blood pressure; and dipstick proteinuria. The miniPIERS model was well-calibrated and had an area under the receiver operating characteristic curve (AUC ROC) of 0.768 (95% CI 0.735-0.801) with an average optimism of 0.037. External validation AUC ROC was 0.713 (95% CI 0.658-0.768). A predicted probability ≥25% to define a positive test classified women with 85.5% accuracy. Limitations of this study include the composite outcome and the broad inclusion criteria of any hypertensive disorder of pregnancy. This broad approach was used to optimize model generalizability. CONCLUSIONS: The miniPIERS model shows reasonable ability to identify women at increased risk of adverse maternal outcomes associated with the hypertensive disorders of pregnancy. It could be used in LMICs to identify women who would benefit most from interventions such as magnesium sulphate, antihypertensives, or transportation to a higher level of care
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