489 research outputs found

    Effect of cell density on thrombin binding to a specific site on bovine vascular endothelial cells.

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    We studied thrombin binding to proliferating and confluent endothelial cells derived from bovine vascular endothelium. [125]thrombin was incubated with nonconfluent or confluent endothelial cells and both the total amount bound and the amount linked in a 77,000-dalton thrombin-cell complex were determined. Approximately 230,000 molecules of thrombin bound per cell in nonconfluent cultures compared to 12,800 molecules per cell in confluent cultures. Approximately 67,7000 thrombin molecules were bound in an apparently covalent complex, Mr = 77,000, with each cell in sparse cultures, whereas only 4,600 thrombin molecules per cell were bound in this complex with confluent cultures. Similar studies with [125I]thrombin and endothelial cells derived from bovine cornea revealed no difference either in the total amount of thrombin bound or in the amount bound in the 77,000-dalton complex using sparse or confluent cultures. When confluent vascular endothelial cultures were wounded, additional cellular binding sites for the 77,000-dalton complex with thrombin appeared within 24 h. A 237% increase in the amount of thrombin bound to these sites was induced by a wound which resulted in a 20% decrease in cell number in the monolayer. There was no significant increase in thrombin binding to other cellular sites at 24 h. These experiments provide evidence that the first change in thrombin binding after injury is an increase in the cellular sites involved in the 77,000-dalton complex, and suggest that thrombin binding to endothelial cells may be important in the vascular response to injury

    Sensitivity Analysis of an Airfoil using Computational Fluid Dynamics

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    In fixed wing aircrafts, the variation of lift coefficient with the angle of attack is a major consideration. This project explores the variation of lift force and lift coefficient of an SD2030 airfoil as a function of the angle of attack, Raynolds number, size of the computational domain, length of the wing, and the fluid mesh size. The problem is modeled using the flow simulation (CFD) module of SolidWorks. The outcome of this sensitivity analysis is compared with available experimental data

    Developing high-frequency equities trading models

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    Thesis (M.B.A.)--Massachusetts Institute of Technology, Sloan School of Management, 2010.Cataloged from PDF version of thesis.Includes bibliographical references (p. 59).The purpose of this paper is to show evidence that there are opportunities to generate alpha in the high frequency environment of the US equity market, using Principal Component Analysis (PCA hereafter) as a basis for short term valuation and market movements prediction. The time frame of trades and holding periods we are analyzing oscillate between one second to as high as 5 minutes approximately. We particularly believe that this time space offers opportunities to generate alpha, given that most of the known quantitative trading strategies are implemented in two different types of time frames: either on the statistical arbitrage typical type of time frames (with valuation horizons and trading periods in the order of days or weeks to maybe even months), or in the purely high frequency environment (with time frames on the order of the milliseconds). On the latter strategies, there is really not much intention to realize equity valuations, but rather to benefit from high frequency market making, which involves not only seeking to earn profit from receiving the bid/ask spread, but also from the transaction rebates offered by the numerous exchanges to those who provide liquidity. We believe that there are more opportunities to capture existing inefficiencies in this arena, and we show how with very simple mathematical and predictive tools, those inefficiencies can be identified and potentially exploited to generate excess returns. The paper describes our underlying intuition about the model we use, which is based on the results of short term PCA's on equity returns, and shows how these results can predict short term future cumulative returns. We randomly selected 50 of the most liquid equities in the S&P 500 index to test our results.by Leandro Rafael Infantino [and] Savion Itzhaki.M.B.A

    Clinging to Discredited Beliefs: The Larger Cognitive Story

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    2000-2020 NHIS Studies: Factors affecting medication adherence rate in the pediatric population with medical complexity

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    Introduction Children with medical complexity belong to a vulnerable patient population group that is defined by the interplay of chronic health conditions, high healthcare utilization, and severe limitations in cognitive and/or physical functioning. Members of this patient population often require a complex management and/or treatment regimen with the use of more than one medication. Pediatric nonadherence in medication can lead to increases in microbial resistance, adverse drug reactions, morbidity, and mortality. The consequences of this medication nonadherence may also cause slower recovery times, increased number of emergency department visits, and hospitalizations, which subsequently substantiates higher medical costs for families along with the healthcare system. General factors for pediatric medical adherence include age, culture, family structure, socioeconomic status, schedule of medication therapy, and taste/formulation of therapy. Continual studies on these medical adherence factors are of the utmost importance to mitigate nonadherence improving quality of life and reducing medical costs. This study examines the variables and confounding factors that may be responsible for the prevalence of nonadherence in this patient population. Methods Twelve primary articles using data collected through the National Health Interview Survey (NHIS) ā€“ focused on medication adherence secondary to medication therapy management (MTM) in the pediatric population across various chronic disease states ā€“were examined and analyzed to collect the variables and factors of interest. Each article in the review was chosen to analyze a national representation of U.S. children between the years 2000-2020. The age perimeter was between ages zero (infants) to eighteen. Results Among the fifteen NHIS papers measuring medication adherence outcomes, three addressed financial and family disparities, three focused on the racial disparitiesā€™ association, and the remaining nine papers address other confounding factors (including but not limited to geographic location, patient education, and healthcare access). Results from the analysis confirmed the influence that racial/ethnic and/or socioeconomic disparities have on the medication adherence rate of the US pediatric population with medical complexity. Conclusion The medication adherence rate is affected by racial and ethnic disparities, financial hardships, socioeconomic status, family background education, poverty status, childrenā€™s health status, quality of patient education, and religious beliefs. This calls for more public health policies to alleviate the financial burden of medication costs, as well as efforts to improve medication education for the caregivers of children with medical complexity population in the U.S. The data-collecting phase of this research reveals the scarcity of studies on this topic ā€“ as reflected in the small number of articles found and reviewed. For a better understanding of the medication adherence rate among the medically complex pediatric population of the U.S., further research on this topic should be conducted

    The impact of medication therapy management services on pediatric patients with medical complexities

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    Introduction Medication Therapy Management (MTM) is a service provided by healthcare providers to ensure the best medical outcomes, particularly for those with multiple chronic conditions. It is often provided for senior populations supported under the Centers for Medicare & Medicaid Services. Studies show that patients provided with MTM services have higher medication adherence rates and experience fewer complications. However, there are few studies on MTM counseling in pediatric populations. In this literature review study, we investigated the potential impact of MTM services for underserved pediatric populations with chronic conditions or disabilities who are likely to benefit from MTM services. Methods A multivariate review analysis was performed. Data was sourced from National Library of Medicine Pubmed and Google Scholar for the collection of primary literature. Inclusion criteria included terms such as pediatric population (patients less than 20 years of age), children with medical complexities or children with disabilities. MTM eligibility, MTM intervention, medication adherence, barriers to adherence were also included in search criteria. The chronic disease states this study included are: epilepsy, cystic fibrosis, leukemia, asthma, and diabetes. Exclusion criteria were the adult population over 20 years old, and ā€˜acute careā€™. Results A total of 17 primary research articles that met the criteria were identified in this literature review study. The articles were sorted into four criteria based on whether they included: children with disabilities, chronic diseases and medical complexities, multiple medication use complications and interventions, and population health disparities. Thirteen articles satisfied children with disabilities as the target population (age less than 18 years old with chronic physical/developmental/behavioral/emotional conditions that require health interventions). Eleven articles satisfied population health disparities: featuring notable differences in opportunities to achieve optimal health experienced by socially disadvantaged populations. Eight articles satisfied medication use complications and interventions, presenting an ongoing need and use of multiple prescriptions. Seven articles represented chronic diseases and medical complexities: chronic conditions with functional limitations lasting more than a year. Conclusion In total, there were seven articles found that discussed MTM service and medication adherence in the special population that required multiple medication therapy. The disease states that were focused on included epilepsy, cystic fibrosis, leukemia, asthma, and diabetes. Of the articles, two had documented MTM services and adherence monitoring for their patient population. The papers demonstrated that patients with chronic diseases, such as asthma and diabetes in adolescents, received benefits from MTM service and an increased rate of medication adherence. Therefore, our review emphasizes the need for further research on the impact of MTM service in a socially vulnerable population
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