345 research outputs found

    R PEAK DETERMINATION USING A WDFR ALGORITHM AND ADAPTIVE THRESHOLD

    Get PDF
    The determination of the R peak position in the ECG signal helps physicians not only to know the heart rate per minute, but also to monitor the patient’s health related to heart disease. This paper proposes a system to accurately determine the R peak position in the ECG signal. The system consists of a pre-processing block for filtering out noise using a WDFR algorithm and highlighting the amplitude of the R peak and a threshold value is calculated for determining the R peak. In this research, the MIT-BIH ECG dataset with 48 records are used for evaluation of the system. The results of the SEN, +P, DER and ACC parameters related to the system quality are 99.70%, 99.59%, 0.70% and 99.31%, respectively. The obtained performance of the proposed R peak position determination system is very high and can be applied to determine the R peak of the ECG signal measuring devices in practice

    Breath Figure Patterns in the Oxidation of Boron Nitride

    Full text link
    Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/66276/1/j.1551-2916.2008.02480.x.pd

    Multifactorial Evolutionary Algorithm For Clustered Minimum Routing Cost Problem

    Full text link
    Minimum Routing Cost Clustered Tree Problem (CluMRCT) is applied in various fields in both theory and application. Because the CluMRCT is NP-Hard, the approximate approaches are suitable to find the solution for this problem. Recently, Multifactorial Evolutionary Algorithm (MFEA) has emerged as one of the most efficient approximation algorithms to deal with many different kinds of problems. Therefore, this paper studies to apply MFEA for solving CluMRCT problems. In the proposed MFEA, we focus on crossover and mutation operators which create a valid solution of CluMRCT problem in two levels: first level constructs spanning trees for graphs in clusters while the second level builds a spanning tree for connecting among clusters. To reduce the consuming resources, we will also introduce a new method of calculating the cost of CluMRCT solution. The proposed algorithm is experimented on numerous types of datasets. The experimental results demonstrate the effectiveness of the proposed algorithm, partially on large instance

    Optimization of Rough Self-Propelled Rotary Turning Parameters in terms of Total Energy Consumption and Surface Roughness

    Get PDF
    The self-propelled rotary tool turning (SPRT) process is an economic and effective solution for machining difficult-to-cut materials. This work optimized SPRT parameters, including the inclination angle (A), depth of cut (D), feed rate (f), and turning speed (V) to decrease the total energy consumption (TE) and surface roughness (SR). The turning experiments of the hardened AISI 4150 steel were executed to obtain the experimental data, while the regression method was applied to develop the TE and SR correlations. The entropy method and quantum-behaved particle swarm optimization (QPSO) were utilized to select the weights and optimal factors. The results indicated that the optimal A, D, f, and V were 34 deg., 0.40 mm, 0.47 mm/rev., and 177 m/min, respectively, while the TE and SR were saved by 9.7% and 35.4%, respectively. The f and V were found to be the most effective parameters, followed by the D and A. The outcomes provide valuable data to determine optimal SPRT factors for minimizing energy consumption and maximizing machining quality.The optimizing technique could be applied to solve other issues for different SPRT operations

    DEVELOPMENT AND EVALUATION OF ORAL SUSTAINED-RELEASE RANITIDINE DELIVERY SYSTEM BASED ON BACTERIAL NANOCELLULOSE MATERIAL PRODUCED BY KOMAGATAEIBACTER XYLINUS

    Get PDF
    Objective: The short biological half-life (2-3 h) and low bioavailability (50 %) of ranitidine (RAN) following oral administration favor the development of a controlled release system. This study was aimed to develop and in vitro evaluate oral sustained-release RAN delivery system based on the bacterial nanocellulose material (BNM) produced by Komagataeibacter xylinus (K. xylinus) from selected culture media. Methods: BNMs are biosynthesized by K. xylinus in the standard medium (SM) and coconut water (CW). RAN was loaded in BNMs by the absorption method. The structural and physicochemical properties of BNMs and BNMs-RAN were evaluated via swelling behavior, FTIR, and FESEM techniques. Moreover, the effect of BNMs on RAN release profile and release kinetics was analyzed and evaluated. Results: The amount of loaded RAN or entrapment efficacy for BNM-CW is higher than for BNM-SM. The BNM-SM-RAN and BNM-CW-RAN exhibited a decreased initial burst release system followed by a prolonged RAN release up to 24 h in relation to the commercial tablets containing RAN. The RAN release from these formulations was found higher in the SGF medium than that of in SIF medium. RAN released from these formulations was found to follow the Korsmeyer-Peppas model and diffusion sustained drug release mechanism. The sustained release of RAN from BNM-SM-RAN was slower than for RAN from BNM-CW-RAN, but the mechanism of sustained RAN release was the same. Conclusion: Oral sustained-release RAN delivery system based on BNMs was successfully prepared and evaluated for various in vitro parameters. The biopolymers like BNM-SM and BNM-CW could be utilized to develop oral sustained RAN release dosage form

    Multi-Response Optimization of the Flat Burnishing Process with a High-Stiffness Tool in terms of Surface Characteristics

    Get PDF
    In this work, the surface roughness (SR), surface hardness (SH), and the thickness of the affected layer (TL) of the multi-roller flat burnishing process are optimized.The parameter inputs are the tool rotational speed (S), burnishing depth (D), and feed rate (f). The flat burnishing tool having three rollers was utilized to facilitate burnishing trials. The Kriging models of performances are proposed regarding inputs.The CRITIC method and Crow Search Algorithm (CSA) were employed to select weights and optimality. The optimizing outcomes indicated that the optimal values of the S, f, and D were 912 rpm, 150 mm/min, and 0.12 mm, respectively. The improvements in the SR, SH, and TL were 33.3%, 26.9%, and 48.6%, respectively. The SR was primarily influenced by the f, followed by the D and S, respectively. The SH and TL were primarily influenced by the D, followed by the S and f, respectively. The optimal data could be applied to the practical multi-roller burnishing process to improve surface properties for flat surfaces. The Kriging models and CSA could be efficiently utilized to solve complex issues for burnishing operations and other machining processes

    Einfluss verschiedener Zellpopulationen auf die Bildung Freier-Radikal-Spezies während der hyperakuten Abstossung der xenoperfundierten Rattenleber.

    Get PDF
    Die hyperakute Abstossung stellt die unmittelbarste Hürde für die Leber-Xenotransplantation dar. Das Ziel dieser Arbeit war es die Bedeutung verschiedener Zellpopulationen für die Bildung von freien Radikalen während der hyperakuten Abstossung der xenotransplantierten Leber zu untersuchen. Wir befassten uns mit der Frage ob es einen Zusammenhang zwischen der FR-Freisetzung und der hyperakuten Abstossung gibt und welche Zellpopulationen hauptverantwortlich für den oxidativen Schaden während der hyperakuten Abstossung sind. In einem etablierten Xenoperfusions-System wurden Rattenlebern mit Perfusaten bestehend aus gezielt-isolierten Zellgruppen reperfundiert. Hierbei evaluierten wir ein Leukozytenfiltersystem und wendeten zur Thrombozytengewinnung ein validiertes Separations/Zentrifugationsprotokoll an. Sowohl die physiologische Zusammensetzung der Perfusate, als auch die physiologische Funktion der Zellen konnten durch Coulter Counter, P-Selektin Flowzytometrie und histologische Untersuchungen gewährleistet werden. Zur Erfassung der FR-Produktion, wurden die Lipidperoxidation, NO Abbauprodukte anhand der Griess–Reaktion, Peroxynitrikonzentration und der antioxidative Status mittels Glutathionkonzentration analysiert. Durch die Verwendung dieser Messmethoden, ließen sich freie Radikale nicht direkt messen und mögliche Zwischenprodukte oder Reaktionsschritte nicht vollständig erfassen, aber die Bestimmung derer stabilen Endprodukte bot uns die Möglichkeit auch ohne Hinzufügen von Chemikalien in das Perfusionssystem ein umfassendes Bild des oxidativen Stresses zu erfassen. Die Organfunktion wurde mittels der Galleproduktion und der Freisetzung von Leberenzyme kontrolliert. Der Potaldruck war ein wichtiger Messparameter für die Makrohämodynamik. Nach Ende der Perfusion wurden Gewebeproben zur histologischen Aufarbeitung mit der HE-, Esterase- und Komplementfärbung zum Nachweis der hyperakuten Abstossungsreaktion entnommen. Folgende Ergebnisse konnten wir zusammenfassend aus unseren Daten gewinnen: In unserem Modell der perfundierten Rattenleber gab es einen signifikanten Unterschied bezüglich der Freisetzung von ROS/RNS zwischen der isogenen und xenogenen Reperfusion mit Vollblut. In den xenogen perfundierten Gruppen hatten wir trotz Zeichen einer Komplementaktivierung, d.h. einer hyperakuten Abstossung, in den Versuchsgruppen mit geringen FR-Konzentrationen eine Reduktion der Leberschäden beobachtet. Wir konnten daraus folgern, die ROS-Bildung im engen Zusammenhang mit der Leberfunktion, dem Zellschaden und der hyperakuten Abstoßungsreaktion stand. Wir konnten in unserem Modell nun erstmals zeigen, dass die Aktivierung des Komplementsystems nur bei gleichzeitiger Anwesenheit von Leukozyten zur Freisetzung von radikalen Stickstoff- und Sauerstoffspezies führt, die dann wiederum die Schädigung des Gewebes und die Dysfunktion des Transplantates verursachen. Es gab signifikante Unterschiede zwischen den untersuchten Zellpopulationen hinsichtlich der Freisetzung von FR in unserem Xenotransplantations-Modell. Unsere Daten weisen darauf hin, dass in der Frühphase der hyperakuten Abstossung weder Erythrozyten noch Thrombozyten oder Hepatozyten eine große Rolle in der Freisetzung von FR spielen. Es ließen sich in den Erythrozyten-und Thrombozytengruppen keine signifikanten Unterschiede zur isogen perfundierten Kontrollgruppe finden. Hauptsächlich für den oxidativen Schaden - also Freisetzung von ROS und RNS - verantwortlich waren in unserem Modell die Leukozyten und in einem geringeren Maße die Kupfferzellen, aber nur in Kombination mit den Leukozyten. Die Leukozytendepletion durch die Filtration wirkte am protektivsten auf die Organfunktion, wogegen die Depletion von KC, nur die ROS-Freisetzung reduzierte, aber keinen protektiven Einfluss auf den Grad der hyperakute Abstossung und Organschädigung hatte. Die Anwesenheit von KC dagegen scheinen NO abzufangen und wirken bezüglich RNS protektiv. Unsere Daten tragen zu dem Verständnis der frühen Vorgänge und insbesondere der Rolle der Freien Radikale während der hyperakuten Abstossung in der Xenotransplantation der Leber bei. Eine Inhibierung oder Modulation der ROS-Freisetzung könnte eine viel versprechende Basis für einen therapeutischen Ansatz der hyperakuten Abstossung darstellen. Inwieweit eine gezielte pharmakologische Hemmung der Leukozytenaktivität und der Einsatz von FR spezifischen Scavengern zu einer Verminderung der hyperakuten Abstoßung von Xenotransplantaten bewirken können, bleibt Inhalt künftiger Untersuchungen

    Globally Convergent Coderivative-Based Generalized Newton Methods in Nonsmooth Optimization

    Full text link
    This paper proposes and justifies two globally convergent Newton-type methods to solve unconstrained and constrained problems of nonsmooth optimization by using tools of variational analysis and generalized differentiation. Both methods are coderivative-based and employ generalized Hessians (coderivatives of subgradient mappings) associated with objective functions, which are either of class C1,1\mathcal{C}^{1,1}, or are represented in the form of convex composite optimization, where one of the terms may be extended-real-valued. The proposed globally convergent algorithms are of two types. The first one extends the damped Newton method and requires positive-definiteness of the generalized Hessians for its well-posedness and efficient performance, while the other algorithm is of {the regularized Newton type} being well-defined when the generalized Hessians are merely positive-semidefinite. The obtained convergence rates for both methods are at least linear, but become superlinear under the semismooth^* property of subgradient mappings. Problems of convex composite optimization are investigated with and without the strong convexity assumption {on smooth parts} of objective functions by implementing the machinery of forward-backward envelopes. Numerical experiments are conducted for Lasso problems and for box constrained quadratic programs with providing performance comparisons of the new algorithms and some other first-order and second-order methods that are highly recognized in nonsmooth optimization.Comment: arXiv admin note: text overlap with arXiv:2101.1055
    corecore