269 research outputs found

    Solving Modal Equations of Motion with Initial Conditions Using MSC/NASTRAN DMAP

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    By utilizing MSC/NASTRAN DMAP (Direct Matrix Abstraction Program) in an existing NASA Lewis Research Center coupled loads methodology, solving modal equations of motion with initial conditions is possible using either coupled (Newmark-Beta) or uncoupled (exact mode superposition) integration available within module TRD1. Both the coupled and newly developed exact mode superposition methods have been used to perform transient analyses of various space systems. However, experience has shown that in most cases, significant time savings are realized when the equations of motion are integrated using the uncoupled solver instead of the coupled solver. Through the results of a real-world engineering analysis, advantages of using the exact mode superposition methodology are illustrated

    Solving modal equations of motion with initial conditions using MSC/NASTRAN DMAP. Part 1: Implementing exact mode superposition

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    Within the MSC/NASTRAN DMAP (Direct Matrix Abstraction Program) module TRD1, solving physical (coupled) or modal (uncoupled) transient equations of motion is performed using the Newmark-Beta or mode superposition algorithms, respectively. For equations of motion with initial conditions, only the Newmark-Beta integration routine has been available in MSC/NASTRAN solution sequences for solving physical systems and in custom DMAP sequences or alters for solving modal systems. In some cases, one difficulty with using the Newmark-Beta method is that the process of selecting suitable integration time steps for obtaining acceptable results is lengthy. In addition, when very small step sizes are required, a large amount of time can be spent integrating the equations of motion. For certain aerospace applications, a significant time savings can be realized when the equations of motion are solved using an exact integration routine instead of the Newmark-Beta numerical algorithm. In order to solve modal equations of motion with initial conditions and take advantage of efficiencies gained when using uncoupled solution algorithms (like that within TRD1), an exact mode superposition method using MSC/NASTRAN DMAP has been developed and successfully implemented as an enhancement to an existing coupled loads methodology at the NASA Lewis Research Center

    Comparison between Intravitreal Injection of Ranibizumab and Bevacizumab as Preoperative Measure for Diabetic Vitrectomy

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    Purpose: In order to examine the parameters of surgical operation between intravitreal bevacizumab and ranibizumab as adjuvant therapy before pars plana vitrectomy in proliferative diabetic retinopathy. Patients & methods:A randomized clinical study on 68 eyes, the patients are classified into two groups, group A (n = 34), and group B (n =34), both groups injected by anti-vascular endothelial growth factor before vitrectomy operation, group A injected by Bevacizumab and group B injected by Ranibizumab, the duration between injection and the operation was 3-6 days, the basic data of each patient include vision, type of DM, duration of DM, level of HbA1c, during the operation we record the following parameters diathermy application number, breaks, bleeding, bottle height, and type of tamponade. Results: The mean BCVA was improved from base line to post- operative in both groups without statistically difference between the groups p value =0.231, diathermy application was one application in 30.3% in group A and 32.4% in group B, and two applications in 15.2% in group A and 2.9% in group B. break was one break in 23.5% in group A and 20.6% in group B. two breaks in 2.9% in each group. Bleeding was in 16 cases in group A and 17 cases in group B. tamponade was silicon in 58.8% in group A and 52.9% in group B, fluid tamponade was 38.3% in group A and 44.2% in group B, air tamponade was one case in each group. without statistical difference between groups. Conclusion: When administered preoperatively during a diabetic vitrectomy procedure, there is no difference between bevacizumab and ranibizumab

    Enhanced Convolutional Neural Network for Non-Small Cell Lung Cancer Classification

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    Lung cancer is a common type of cancer that causes death if not detectedearly enough. Doctors use computed tomography (CT) images to diagnoselung cancer. The accuracy of the diagnosis relies highly on the doctor\u27sexpertise. Recently, clinical decision support systems based on deep learningvaluable recommendations to doctors in their diagnoses. In this paper, wepresent several deep learning models to detect non-small cell lung cancer inCT images and differentiate its main subtypes namely adenocarcinoma,large cell carcinoma, and squamous cell carcinoma. We adopted standardconvolutional neural networks (CNN), visual geometry group-16 (VGG16),and VGG19. Besides, we introduce a variant of the CNN that is augmentedwith convolutional block attention modules (CBAM). CBAM aims to extractinformative features by combining cross-channel and spatial information.We also propose variants of VGG16 and VGG19 that utilize a supportvector machine (SVM) at the classification layer instead of SoftMax. Wevalidated all models in this study through extensive experiments on a CTlung cancer dataset. Experimental results show that supplementing CNNwith CBAM leads to consistent improvements over vanilla CNN. Resultsalso show that the VGG variants that use the SVM classifier outperform theoriginal VGGs by a significant margin

    The effect of strict state measures on the epidemiologic curve of COVID-19 infection in the context of a developing country : a simulation from Jordan

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    COVID-19 has posed an unprecedented global public health threat and caused a significant number of severe cases that necessitated long hospitalization and overwhelmed health services in the most affected countries. In response, governments initiated a series of non-pharmaceutical interventions (NPIs) that led to severe economic and social impacts. The effect of these intervention measures on the spread of the COVID-19 pandemic are not well investigated within developing country settings. This study simulated the trajectories of the COVID-19 pandemic curve in Jordan between February and May and assessed the effect of Jordan’s strict NPI measures on the spread of COVID-19. A modified susceptible, exposed, infected, and recovered (SEIR) epidemic model was utilized. The compartments in the proposed model categorized the Jordanian population into six deterministic compartments: suspected, exposed, infectious pre-symptomatic, infectious with mild symptoms, infectious with moderate to severe symptoms, and recovered. The GLEAMviz client simulator was used to run the simulation model. Epidemic curves were plotted for estimated COVID-19 cases in the simulation model, and compared against the reported cases. The simulation model estimated the highest number of total daily new COVID-19 cases, in the pre-symptomatic compartmental state, to be 65 cases, with an epidemic curve growing to its peak in 49 days and terminating in a duration of 83 days, and a total simulated cumulative case count of 1048 cases. The curve representing the number of actual reported cases in Jordan showed a good pattern compatibility to that in the mild and moderate to severe compartmental states. The reproduction number under the NPIs was reduced from 5.6 to less than one. NPIs in Jordan seem to be effective in controlling the COVID-19 epidemic and reducing the reproduction rate. Early strict intervention measures showed evidence of containing and suppressing the disease

    von Willebrand factor levels in the diagnosis of von Willebrand disease: a systematic review and meta-analysis

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    Von Willebrand Disease (VWD) is associated with significant morbidity as a result of excessive mucocutaneous bleeding symptoms. Patients with VWD can experience easy bruising, epistaxis, gastrointestinal and oral cavity bleeding, as well as heavy menstrual bleeding and bleeding after dental work, surgical procedures, and childbirth. Early diagnosis and treatment is important to prevent and treat these symptoms. We systematically reviewed the accuracy of diagnostic tests using different cut-off values of VWF:Ag and platelet-dependent VWF activity assays in the diagnosis of VWD. We searched Cochrane Central, MEDLINE, and EMBASE for eligible studies. Two investigators screened and abstracted data. Risk of bias was assessed using QUADAS-2 and certainty of evidence using the GRADE framework. We pooled estimates of sensitivity and specificity and reported patient important outcomes when relevant. This review included 21 studies that evaluated VWD diagnosis, including the approach to patients with VWF levels that have normalized with age (6 studies), VWF cut-off levels for the diagnosis of Type 1 VWD (9 studies), and platelet-dependent VWF activity/VWF:Ag ratio cut-off levels for the diagnosis of Type 2 VWD (6 studies). The results showed low certainty in the evidence for a net health benefit from reconsidering the diagnosis of VWD versus simply removing the disease in patients with VWF levels that have normalized with age. For the diagnosis of Type 1 VWD, in patients with VWF:A

    Ionization induced by protons on isolated molecules of adenine: theory, modelling and experiment

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    We here report a comparison between semi-empirical and theoretical predictions in terms of differential and total cross sections for proton-induced ionization of isolated adenine molecules. Whereas the first ones are provided by existing analytical models, the second ones are based on two quantum-mechanical models recently developed within the 1st Born and the continuum distorted wave approximation, respectively. Besides, a large set of experimental data is also reported for comparisons. In all kinematical conditions here investigated, we have observed a very good agreement between theory and experiment whereas strong discrepancieswere reported with the semi-empirical models in particular when doubly-differential cross sections are analysed.Fil: Champion, C.. Universite de Bordeaux; FranciaFil: Galassi, Mariel Elisa. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Rosario. Instituto de Física de Rosario (i); ArgentinaFil: Weck, P. F.. University of Nevada Las Vegas. Department of Chemistry and Harry Reid Center for Environmental Studies; Estados UnidosFil: Abdallah, C.. University Saint Joseph. Faculty of Sciences. Department of Physics; LíbanoFil: Francis, Z.. University Saint Joseph. Faculty of Sciences. Department of Physics; Líbano. The Open University. Faculty of Science. Department of Physical Sciences; Reino UnidoFil: Quinto, M. A.. Universite de Bordeaux; FranciaFil: Fojon, Omar Ariel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Rosario. Instituto de Física de Rosario (i); ArgentinaFil: Rivarola, Roberto Daniel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Rosario. Instituto de Física de Rosario (i); ArgentinaFil: Hanssen, Jocelyn. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Rosario. Instituto de Física de Rosario (i); ArgentinaFil: Iriki, Y.. Kyoto University. Department of Nuclear Engineering; JapónFil: Itoh, A.. Kyoto University. Department of Nuclear Engineering; Japó

    Antimicrobial resistance among migrants in Europe: a systematic review and meta-analysis

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    BACKGROUND: Rates of antimicrobial resistance (AMR) are rising globally and there is concern that increased migration is contributing to the burden of antibiotic resistance in Europe. However, the effect of migration on the burden of AMR in Europe has not yet been comprehensively examined. Therefore, we did a systematic review and meta-analysis to identify and synthesise data for AMR carriage or infection in migrants to Europe to examine differences in patterns of AMR across migrant groups and in different settings. METHODS: For this systematic review and meta-analysis, we searched MEDLINE, Embase, PubMed, and Scopus with no language restrictions from Jan 1, 2000, to Jan 18, 2017, for primary data from observational studies reporting antibacterial resistance in common bacterial pathogens among migrants to 21 European Union-15 and European Economic Area countries. To be eligible for inclusion, studies had to report data on carriage or infection with laboratory-confirmed antibiotic-resistant organisms in migrant populations. We extracted data from eligible studies and assessed quality using piloted, standardised forms. We did not examine drug resistance in tuberculosis and excluded articles solely reporting on this parameter. We also excluded articles in which migrant status was determined by ethnicity, country of birth of participants' parents, or was not defined, and articles in which data were not disaggregated by migrant status. Outcomes were carriage of or infection with antibiotic-resistant organisms. We used random-effects models to calculate the pooled prevalence of each outcome. The study protocol is registered with PROSPERO, number CRD42016043681. FINDINGS: We identified 2274 articles, of which 23 observational studies reporting on antibiotic resistance in 2319 migrants were included. The pooled prevalence of any AMR carriage or AMR infection in migrants was 25·4% (95% CI 19·1-31·8; I2 =98%), including meticillin-resistant Staphylococcus aureus (7·8%, 4·8-10·7; I2 =92%) and antibiotic-resistant Gram-negative bacteria (27·2%, 17·6-36·8; I2 =94%). The pooled prevalence of any AMR carriage or infection was higher in refugees and asylum seekers (33·0%, 18·3-47·6; I2 =98%) than in other migrant groups (6·6%, 1·8-11·3; I2 =92%). The pooled prevalence of antibiotic-resistant organisms was slightly higher in high-migrant community settings (33·1%, 11·1-55·1; I2 =96%) than in migrants in hospitals (24·3%, 16·1-32·6; I2 =98%). We did not find evidence of high rates of transmission of AMR from migrant to host populations. INTERPRETATION: Migrants are exposed to conditions favouring the emergence of drug resistance during transit and in host countries in Europe. Increased antibiotic resistance among refugees and asylum seekers and in high-migrant community settings (such as refugee camps and detention facilities) highlights the need for improved living conditions, access to health care, and initiatives to facilitate detection of and appropriate high-quality treatment for antibiotic-resistant infections during transit and in host countries. Protocols for the prevention and control of infection and for antibiotic surveillance need to be integrated in all aspects of health care, which should be accessible for all migrant groups, and should target determinants of AMR before, during, and after migration. FUNDING: UK National Institute for Health Research Imperial Biomedical Research Centre, Imperial College Healthcare Charity, the Wellcome Trust, and UK National Institute for Health Research Health Protection Research Unit in Healthcare-associated Infections and Antimictobial Resistance at Imperial College London

    Global economic burden of unmet surgical need for appendicitis

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    Background: There is a substantial gap in provision of adequate surgical care in many low-and middle-income countries. This study aimed to identify the economic burden of unmet surgical need for the common condition of appendicitis. Methods: Data on the incidence of appendicitis from 170 countries and two different approaches were used to estimate numbers of patients who do not receive surgery: as a fixed proportion of the total unmet surgical need per country (approach 1); and based on country income status (approach 2). Indirect costs with current levels of access and local quality, and those if quality were at the standards of high-income countries, were estimated. A human capital approach was applied, focusing on the economic burden resulting from premature death and absenteeism. Results: Excess mortality was 4185 per 100 000 cases of appendicitis using approach 1 and 3448 per 100 000 using approach 2. The economic burden of continuing current levels of access and local quality was US 92492millionusingapproach1and92 492 million using approach 1 and 73 141 million using approach 2. The economic burden of not providing surgical care to the standards of high-income countries was 95004millionusingapproach1and95 004 million using approach 1 and 75 666 million using approach 2. The largest share of these costs resulted from premature death (97.7 per cent) and lack of access (97.0 per cent) in contrast to lack of quality. Conclusion: For a comparatively non-complex emergency condition such as appendicitis, increasing access to care should be prioritized. Although improving quality of care should not be neglected, increasing provision of care at current standards could reduce societal costs substantially
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