798 research outputs found
Airloads on bluff bodies, with application to the rotor-induced downloads on tilt-rotor aircraft
The aerodynamic characteristics of airfoils with several flap configurations were studied theoretically and experimentally in environments that simulate a wing immersed in the downwash of a hovering rotor. Special techniques were developed for correcting and validating the wind tunnel data for large blockage effects, and the test results were used to evaluate two modern blockage effects, and the test results were used to evaluate two modern computational aerodynamics codes. The combined computed and measured results show that improved flap and leading-edge configurations can be designed which will achieve large reductions in the downloads of tilt-rotor aircraft, and thereby improve their hover efficiency
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Modeling the Cognitive Mechanisms Linking Autism Symptoms and Anxiety in Adults
Emotional acceptance, alexithymia, and intolerance of uncertainty (IU) contribute to anxiety disorders in neurotypical populations. Their association with anxiety in people diagnosed with autism spectrum disorder (ASD) has not been studied. We aimed to model the contributions of these constructs on the relationship between dimensional measures of autism and anxiety. Participants were 151 adults recruited from 2 sites, including those diagnosed with ASD (n = 76) and a matched comparison group (n = 75). All participants completed a battery of questionnaires measuring core autism symptoms, anxiety, emotional acceptance, alexithymia, and intolerance of uncertainty. Structural equation modeling with mediation was used to examine directional relationships among these variables. Autism symptoms directly predicted less emotional acceptance and increased alexithymia and IU. Alexithymia and acceptance were shown to explain 64% of the effect between autism symptom severity and anxiety level. This suggests that people with ASD experience increased levels of anxiety because they are more likely to react aversively to their emotional experiences, while lacking the ability to identify and understand their emotions. Developing and implementing mindfulness-based interventions aimed at assuaging alexithymia and IU, while increasing emotional acceptance, may be especially helpful in treating anxiety in ASD
Unraveling the Effect of Rh Isolation on Shallow d States of GalliumāRhodium Alloys
In this study, we report the electronic and chemical structure of supported GaRh alloys as model systems for the active phase in supported catalytically active liquid metal solutions (SCALMS). We prepared a series of galliumārhodium samples with different Rh contents and tracked the evolution of the sample topography and surface electronic structure via photoemission spectroscopy in combination with ab initio calculations and electron microscopy. Our results reveal a characteristic shift of the Rh 3d core levels and narrowing and shifting of the Rh 4d derived band with decreasing Rh content. Calculations show that these spectroscopic observations can be explained by the coexistence of isolated Rh atoms in random GaRh alloys and GaRh intermetallic compounds (IMCs). These results contribute to an enhancement of the fundamental understanding of the electronic surface structure of GaRh alloys, which is crucially required for apprehending and thus further exploiting the improved catalytic activity of GaRh SCALMS
Clinical applications of B-type natriuretic peptide (BNP) testing
Many claims have been made in recent years regarding the utility of plasma B-type natriuretic peptide (BNP) concentration measurements in the diagnosis, risk stratification and monitoring of patients with heart failure. This paper summarizes the current evidence and provides guidance for practising clinicians. Overall, plasma BNP testing appears to be of most value in the diagnostic arena, where it is likely to improve the performance of non-specialist physicians in diagnosing heart failure. In clinical practice, BNP testing is best used as a ārule out' test for suspected cases of new heart failure in breathless patients presenting to either the outpatient or emergency care settings; it is not a replacement for echocardiography and full cardiological assessment, which will be required for patients with an elevated BNP concentration. Although work is ongoing in establishing the ānormal' values of BNP, heart failure appears to be highly unlikely below a plasma concentration of 100pg/ml. However, as BNP levels rise with age and are affected by gender, comorbidity and drug therapy, the plasma BNP measurement should not be used in isolation from the clinical contex
Gene expression of INPP5F as an independent prognostic marker in fludarabine-based therapy of chronic lymphocytic leukemia
Chronic lymphocytic leukemia (CLL) is a heterogeneous disease. Various disease-related and patient-related factors have been shown to influence the course of the disease. The aim of this study was to identify novel biomarkers of significant clinical relevance. Pretreatment CD19-separated lymphocytes (n = 237;discovery set) and peripheral blood mononuclear cells (n = 92;validation set) from the REACH trial, a randomized phase III trial in relapsed CLL comparing rituximab plus fludarabine plus cyclophosphamide with fludarabine plus cyclophosphamide alone, underwent gene expression profiling. By using Cox regression survival analysis on the discovery set, we identified inositol polyphosphate-5-phosphatase F (INPP5F) as a prognostic factor for progression-free survival (P<0.001;hazard ratio (HR),1.63;95% confidence interval (CI),1.35-1.98) and overall survival (Po0.001;HR, 1.47;95% CI, 1.18-1.84),regardless of adjusting for known prognostic factors. These findings were confirmed on the validation set, suggesting that INPP5F may serve as a novel, easy-to-assess future prognostic biomarker for fludarabine-based therapy in CLL
Optimizing fluid management in patients with acute decompensated heart failure (ADHF): the emerging role of combined measurement of body hydration status and brain natriuretic peptide (BNP) levels
The study tests the hypothesis that in patients admitted with acutely decompensated heart failure (ADHF), achievement of adequate body hydration status with intensive medical therapy, modulated by combined bioelectrical vectorial impedance analysis (BIVA) and B-type natriuretic peptide (BNP) measurement, may contribute to optimize the timing of patientās discharge and to improve clinical outcomes. Three hundred patients admitted for ADHF underwent serial BIVA and BNP measurement. Therapy was titrated to reach a BNP value of <250Ā pg/ml, whenever possible. Patients were categorized as early responders (rapid BNP fall below 250Ā pg/ml); late responders (slow BNP fall below 250Ā pg/ml, after aggressive therapy); and non-responders (BNP persistently >250Ā pg/ml). Worsening of renal function (WRF) was evaluated during hospitalization. Death and rehospitalization were monitored with a 6-month follow-up. BNP value on discharge of ā¤250Ā pg/ml led to a 25% event rate within 6Ā months (Group A: 17.4%; Group B: 21%, Chi2; n.s.), whereas a value >250Ā pg/ml (Group C) was associated with a far higher percentage (37%). At discharge, body hydration was 73.8Ā Ā±Ā 3.2% in the total population and 73.2Ā Ā±Ā 2.1, 73.5Ā Ā±Ā 2.8, 74.1Ā Ā±Ā 3.6% in the three groups, respectively. WRF was observed in 22.3% of the total. WRF occurred in 22% in Group A, 32% in Group B, and 20% in Group C (PĀ =Ā n.s.). Our study confirms the hypothesis that combined BNP/BIVA sequential measurements help to achieve adequate fluid balance status in patients with ADHF and can be used to drive a ātailored therapy,ā allowing clinicians to identify high-risk patients and possibly to reduce the incidence of complications secondary to fluid management strategies
Appraising and applying evidence about a diagnostic test during a performance-based assessment
BACKGROUND: The practice of Evidence-based Medicine requires that clinicians assess the validity of published research and then apply the results to patient care. We wanted to assess whether our soon-to-graduate medical students could appraise and apply research about a diagnostic test within a clinical context and to compare our students with peers trained at other institutions. METHODS: 4(th )year medical students who previously had demonstrated competency at probability revision and just starting first-year Internal Medicine residents were used for this research. Following an encounter with a simulated patient, subjects critically appraised a paper about an applicable diagnostic test and revised the patient's pretest probability given the test result. RESULTS: The medical students and residents demonstrated similar skills at critical appraisal, correctly answering 4.7 and 4.9, respectively, of 6 questions (p = 0.67). Only one out of 28 (3%) medical students and none of the 15 residents were able to correctly complete the probability revision task (p = 1.00). CONCLUSIONS: This study found that most students completing medical school are able to appraise an article about a diagnostic test but few are able to apply the information from the article to a patient. These findings raise questions about the clinical usefulness of the EBM skills possessed by graduating medical students within the area of diagnostic testing
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