120 research outputs found

    High-Performance Inverse Artificial Neural Network Controller for Asynchronous Motor Control

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    Induction motor (IM) is considered one of the most important machines in industrial applications, which requires precise and effective control of its behavior in order to improve its performance. In this paper, three control strategies based on the development of inverse artificial neural networks (IANNs) were proposed in order to control the current (Ias), electromagnetic torque (Ce), and speed (Wr) of an asynchronous machine IM. These inverse artificial neural networks have been learned from conventional control system (PI controller and vector control) data using MATLAB software. Comparison between the responses of both the classical controller and the IANNs showed the ability and effectiveness of the latter in precisely controlling the three properties of the asynchronous motor, and it also achieved better dynamic motor behavior, speed without overtaking, and good load disturbance rejection, which proves the high performance of these developed IANNs

    Dose Conversion Ratio in Hemodialysis Patients Switched from Darbepoetin Alfa to PEG-Epoetin Beta: AFFIRM Study

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    INTRODUCTION: There is limited information published on switching erythropoiesis-stimulating agent (ESA) treatment for anemia associated with chronic kidney disease (CKD) from darbepoetin alfa (DA) to methoxy polyethylene glycol-epoetin beta (PEG-Epo) outside the protocol of interventional clinical studies. AFFIRM (Aranesp Efficiency Relative to Mircera) was a retrospective, multi-site, observational study designed to estimate the population mean maintenance dose conversion ratio [DCR; dose ratio achieving comparable hemoglobin level (Hb) between two evaluation periods] in European hemodialysis patients whose treatment was switched from DA to PEG-Epo. METHODS: Eligible patients had received hemodialysis for ≥12 months and DA for ≥7 months. Data were collected from 7 months before until 7 months after switching treatment. DCR was calculated for patients with Hb and ESA data available in both evaluation periods (EP; Months 1 and 2 were defined as the pre-switch EP, and Months 6 and 7 as the post-switch EP). Red blood cell transfusions pre- and post-switch were quantified. RESULTS: Of 302 patients enrolled, 206 had data available for DCR analysis. The geometric mean DCR was 1.17 (95% CI 1.05, 1.29). Regression analysis indicated a non-linear relationship between pre- and post-switch ESA doses; DCR decreased with increasing pre-switch DA dose. The geometric mean weekly ESA doses were 24.1 μg DA in the pre-switch EP and 28.6 μg PEG-Epo in the post-switch EP. Mean Hb was 11.5 g/dL in the pre-switch EP and 11.4 g/dL in the post-switch EP. There were 16 transfusions and 34 units transfused in the pre-switch period, versus 48 transfusions and 95 units transfused post-switch. Excluding patients receiving a transfusion within 90 days of or during either EP, the DCR was 1.21 (95% CI 1.09, 1.35). CONCLUSION: In these hemodialysis patients switched from DA to PEG-Epo the DCR was 1.17 and 1.21 after accounting for the effect of transfusions. The number of transfusions and units transfused increased approximately threefold from the pre-switch to the post-switch period

    The Impact of Goal-Directed Fluid Therapy in Prolonged Major Abdominal Surgery on Extravascular Lung Water and Oxygenation: A Randomized Controlled Trial

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    BACKGROUND: A growing interest had been paid to goal-directed fluid therapy (GDT) in abdominal surgery; however, its impact on the respiratory profile was not well investigated. AIM: We evaluated the impact of GDT on postoperative extravascular lung water and oxygenation after prolonged major abdominal surgery. METHODS: A randomised, controlled study was conducted in Kasr Alainy hospital from April 2016 till December 2017 including 120 adult patients scheduled for prolonged major abdominal surgery. Patients were randomised into either GDT group (n = 60) who received baseline restricted fluid therapy (2 mL/Kg/hour) which is guided by stroke volume variation, or control group (n = 60) who received standard care. Both study groups were compared according to hemodynamic data, fluid requirements, lung ultrasound score, and PaO2/fraction of inspired oxygen ratio (P/F ratio), RESULTS: Intraoperatively, GDT group received less volume of fluids and showed higher intraoperative mean arterial pressure compared to the control group. Postoperatively, lung ultrasound score was lower, and P/F ratio was higher in the GDT group compared to the control group. The number of patients who showed a significant postoperative increase in LUS was higher in the control group 44 (73%) patients versus 14 (23%) patients, P < 0.001). CONCLUSIONS: Using stroke volume variation for guiding fluid therapy in prolonged, major abdominal operations were associated with better hemodynamic profile, less intraoperative fluid administration, lower extravascular lung water and better oxygenation compared to standard care

    Preservation of Anemia Control and Weekly ESA Dosage After Conversion from PEG-Epoetin Beta to Darbepoetin Alfa in Adult Hemodialysis Patients: The TRANSFORM Study

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    INTRODUCTION: There is scant real-world information on switching treatment for anemia associated with chronic kidney disease (CKD) from methoxy polyethylene glycol-epoetin beta (PEG-Epo) to darbepoetin alfa (DA). TRANSFORM was a multi-center, observational study designed to describe the time course of hemoglobin (Hb) concentration (primary outcome measure) and other parameters of clinical management of anemia in European hemodialysis patients in clinical practice before and after a switch from PEG-Epo to DA. METHODS: Eligible subjects were adult patients with CKD dialyzed at European dialysis centers for ≥26 weeks and treated with PEG-Epo for ≥14 weeks immediately prior to being switched to DA and no earlier than January 2011. Erythropoiesis-stimulating agent doses and Hb values were recorded for the 14-week pre-switch and 26-week post-switch periods. RESULTS: Of the 1,027 eligible patients enrolled at 42 hemodialysis centers in 7 European countries, 785 were included in analyses. Mean (95% confidence interval [CI]) Hb was generally stable: 11.19 (11.11, 11.26), 11.48 (11.40, 11.57), and 11.29 (11.20, 11.37) g/dL at month −1 pre-switch and months 3 and 6 post-switch, respectively. The geometric mean (95% CI) PEG-Epo dose at month −1 was 27.4 (26.0, 28.8) µg/week; DA dose was 29.4 (27.9, 30.9), 23.3 (21.9, 24.9), and 25.6 (24.1, 27.1) µg/week at months 1, 4, and 6, respectively. The geometric mean (95% CI) dose ratio at switching was 1.06 (1.01, 1.11). When stratifying by dose-ratio categories <0.8, 0.8–1.2, and >1.2 at switching, mean DA dose and Hb converged within narrow ranges by month 6 post-switch: 23.9–27.0 µg/week and 11.1–11.5 g/dL, respectively. Hb excursions <10 g/dL were less frequent post-switch versus pre-switch. CONCLUSION: Mean Hb values remained within a narrow range following switching from PEG-Epo to DA in this population of hemodialysis patients. Time trends of mean Hb and DA dose indicate that physicians titrated DA doses post-switch, to attain Hb concentrations comparable to those attained pre-switch with PEG-Epo. FUNDING: Amgen (Europe) GmbH, Zug, Switzerland. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1007/s12325-014-0161-5) contains supplementary material, which is available to authorized users

    The road from development to approval: evaluating the body of evidence to confirm biosimilarity

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    Biosimilars are products that contain a similar version of the active substance of an already authorized original biologic medicinal product (reference medicinal product). Their development requires special consideration, as similarity to the reference agent needs to be established through a comprehensive comparability exercise. Given the complex nature of these agents, minor structural differences may emerge, but the process of biosimilarity determination is designed to ascertain that the nature and impact of these differences are not clinically significant. Determination of biosimilarity should follow quality-by-design principles, which provide a deep understanding of the product development process, guided by pre-defined objectives, process control and risk management. Compared with novel biologic development, biosimilar development places greater emphasis on establishing preclinical quality characteristics. Determination of comparability of quality characteristics includes assessment of physicochemical properties, biological activity, immunochemical properties, purity, impurity and quantity, with appropriate in vivo pharmacology studies being conducted thereafter. Head-to-head comparisons are then conducted to determine pharmacokinetic and pharmacodynamic characteristics, and efficacy, safety and tolerability in phase I and phase III clinical studies. Post-approval risk management requirements include implementation of pharmacovigilance systems and risk management through, for example, the conduct of pharmacoepidemiological studies. There are several biosimilars used in the field of rheumatology that are available in the European Union, or in development, that offer the potential to increase affordability/accessibility of biological treatment. The role of these agents in rheumatology will be determined by the confidence placed in them by rheumatologists. These prescribers should expect high-quality data evaluated by an extensive assessment process.status: publishe

    A Methodology to Build a Framework for Collaboration Performance Assessment in PSS Delivery

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    Heuristic algorithms for two-machine job shop problem under availability constraints on one machine: makespan minimization

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    International audienceWe discuss the two-machine job shop scheduling problem with availability constraints on one machine for maximum completion time (makespan) minimization. We consider the problem when unavailability periods are planned in advance and operations are non-preemptive. Firstly, some propositions considering Jackson’s rule under availability constraints are introduced. Then, we provide polynomial-time algorithm based on Jackson’s rule and an iterated local search tabu based algorithm exploiting the optimality of Jackson’s rule between each two consecutive availability periods to solve the problem. Finally, we present some experimental results
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