52 research outputs found

    Optimal Adaptive Output Regulation of Uncertain Nonlinear Discrete-Time Systems using Lifelong Concurrent Learning

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    This Paper Addresses Neural Network (NN) based Optimal Adaptive Regulation of Uncertain Nonlinear Discrete-Time Systems in Affine Form using Output Feedback Via Lifelong Concurrent Learning. First, an Adaptive NN Observer is Introduced to Estimate Both the State Vector and Control Coefficient Matrix, and its NN Weights Are Adjusted using Both Output Error and Concurrent Learning Term to Relax the Persistency Excitation (PE) Condition. Next, by Utilizing an Actor-Critic Framework for Estimating the Value Functional and Control Policy, the Critic Network Weights Are Tuned Via Both Temporal Different Error and Concurrent Learning Schemes through a Replay Buffer. the Actor NN Weights Are Tuned using Control Policy Errors. to Attain Lifelong Learning for Performing Effectively during Multiple Tasks, an Elastic Weight Consolidation Term is Added to the Critic NN Weight Tuning Law. the State Estimation, Regulation, and the Weight Estimation Errors of the Observer, Actor and Critic NNs Are Demonstrated to Be Bounded When Performing Tasks by using Lyapunov Analysis. Simulation Results Are Carried Out to Verify the Effectiveness of the Proposed Approach on a Vander Pol Oscillator. Finally, Extension to Optimal Tracking is Given Briefly

    The first experience of ex-vivo lung perfusion (EVLP) in Iran: An effective method to increase suitable lung for transplantation

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    Background: Although lung transplantation is a well-accepted treatment for end-stage lung diseases patients, only 15-20 of the brain-dead donors' lungs are usable for transplantation. This results in high mortality of candidates on waiting lists. Ex-vivo lung perfusion (EVLP) is a novel method for better evaluation of a potential lung for transplantation. Objective: To report the first experience of EVLP in Iran. Methods: The study included a pig in Vienna Medical University, Vienna, Austria, and 4 humans in Masih Daneshvari Hospital, Tehran, Iran. All brain-dead donors from 2013 to 2015 in Tehran were evaluated for EVLP. Donors without signs of severe chest trauma or pneumonia, with poor oxygenation were included. Results: An increasing trend in difference between the pulmonary arterial pO2 and left atrial pO2, an increasing pattern in dynamic lung compliance, and a decreasing trend in the pulmonary vascular resistance, were observed. Conclusion: The initial experience of EVLP in Iran was successful in terms of important/critical parameters. The results emphasize on some important considerations such as precisely following standard lung harvesting and monitoring temperature and pressure. EVLP technique may not be a cost-effective option for low-income countries at first glance. However, because this is the only therapeutic treatment for end-stage lung disease, it is advisable to continue working on this method to find alternatives with lesser costs

    Оценка насыщения кислородом как показателя для интубации трахеи у пациентов с COVID-19: проспективное когортное исследование

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       Background. Since the beginning of COVID-19 pandemic, the importance of clinical criteria for tracheal intubation in critically ill patients with respiratory failure became more noteworthy, especially in resource limitations. The objective was to evaluate the importance of hemoglobin oxygen saturation as a criterion for tracheal intubation in patients with COVID-19.   Materials and methods. This is a multi-center, prospective, observational cohort study. We included 117 patients with COVID-19 who needed respiratory support between March to June 2021. Patients were intubated by the protocol of each institution participating in the study and the anesthesiologist’s clinical judgement. Signs of respiratory failure, methods of respiratory support and patient outcome were recorded.   Results. Among 117 studied cases, 100 patients had hemoglobin oxygen saturation of 60–90 % in whom 58 were intubated. During hospitalization, 56 intubated patients and 14 non-intubated patients died (96.6 % Vs. 33.3 %).   Conclusion. Arterial blood hemoglobin oxygen saturation of 60–90 could not be the correct key to unlock the problem of intubation decision in patients with COVID-19. Therefore, hemoglobin oxygen saturation should not be solely regarded as an indication for intubation in COVID-19.    Введение. С началом пандемии COVID-19 возросла значимость клинических критериев для интубации трахеи у тяжелобольных пациентов с дыхательной недостаточностью, особенно в условиях ограниченных ресурсов.   Цель – оценить важность показателя насыщения гемоглобина кислородом как критерия для интубации трахеи у пациентов с COVID-19.   Материалы и методы. Многоцентровое проспективное обсервационное когортное исследование, включившее 117 пациентов с COVID-19, которые нуждались в респираторной поддержке в период с марта по июнь 2021 г. Пациенты были интубированы в соответствии с протоколом каждого участвовавшего в исследовании учреждения и клиническим заключением анестезиолога. Регистрировали признаки дыхательной недостаточности, методы респираторной поддержки и результаты лечения пациентов.   Результаты. Из 117 случаев у 100 пациентов насыщение гемоглобина кислородом составило 60–90 %, 58 из них были интубированы. Во время госпитализации 56 интубированных пациентов и 14 неинтубированных пациентов умерли (96,6 % против 33,3 %).   Заключение. Насыщение гемоглобина артериальной крови кислородом в пределах 60–90 % не может быть ключом к решению проблемы интубации у пациентов с COVID-19 и, следовательно, само по себе не может быть подходящим критерием для принятия решения об интубации

    The first experience of ex-vivo lung perfusion (EVLP) in Iran: An effective method to increase suitable lung for transplantation

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    Background: Although lung transplantation is a well-accepted treatment for end-stage lung diseases patients, only 15-20 of the brain-dead donors' lungs are usable for transplantation. This results in high mortality of candidates on waiting lists. Ex-vivo lung perfusion (EVLP) is a novel method for better evaluation of a potential lung for transplantation. Objective: To report the first experience of EVLP in Iran. Methods: The study included a pig in Vienna Medical University, Vienna, Austria, and 4 humans in Masih Daneshvari Hospital, Tehran, Iran. All brain-dead donors from 2013 to 2015 in Tehran were evaluated for EVLP. Donors without signs of severe chest trauma or pneumonia, with poor oxygenation were included. Results: An increasing trend in difference between the pulmonary arterial pO2 and left atrial pO2, an increasing pattern in dynamic lung compliance, and a decreasing trend in the pulmonary vascular resistance, were observed. Conclusion: The initial experience of EVLP in Iran was successful in terms of important/critical parameters. The results emphasize on some important considerations such as precisely following standard lung harvesting and monitoring temperature and pressure. EVLP technique may not be a cost-effective option for low-income countries at first glance. However, because this is the only therapeutic treatment for end-stage lung disease, it is advisable to continue working on this method to find alternatives with lesser costs

    International Consensus Statement on Rhinology and Allergy: Rhinosinusitis

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    Background: The 5 years since the publication of the first International Consensus Statement on Allergy and Rhinology: Rhinosinusitis (ICAR‐RS) has witnessed foundational progress in our understanding and treatment of rhinologic disease. These advances are reflected within the more than 40 new topics covered within the ICAR‐RS‐2021 as well as updates to the original 140 topics. This executive summary consolidates the evidence‐based findings of the document. Methods: ICAR‐RS presents over 180 topics in the forms of evidence‐based reviews with recommendations (EBRRs), evidence‐based reviews, and literature reviews. The highest grade structured recommendations of the EBRR sections are summarized in this executive summary. Results: ICAR‐RS‐2021 covers 22 topics regarding the medical management of RS, which are grade A/B and are presented in the executive summary. Additionally, 4 topics regarding the surgical management of RS are grade A/B and are presented in the executive summary. Finally, a comprehensive evidence‐based management algorithm is provided. Conclusion: This ICAR‐RS‐2021 executive summary provides a compilation of the evidence‐based recommendations for medical and surgical treatment of the most common forms of RS
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