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Sample records for optimized atrioventricular delay

  1. Determination of the optimal atrioventricular and interventricular delays in cardiac resynchronization therapy

    Institute of Scientific and Technical Information of China (English)

    Hongxia NIU; Wei HUA; Shu ZHANG; Fangzheng WANG; Keping CHEN; Xin CHEN

    2005-01-01

    In order to provide the maximum benefit of cardiac resynchronization therapy (CRT), we tried to use an echocardiography method to optimize the atrioventricular and interventricular delay. Methods The study included 6 patients who underwent implantation of biventricular pacemakers for drug-resistant heart failure. Two-dimensional echocardiography and tissue Doppler imaging were carried out before and after the pacemaker implantation. The optimal AV delay was defined as the AV delay resulting in maximum timevelocity integral (TVI) of transmitral filling flow, the longest left ventricular filling time (LVFT) and the minimum mitral regurgitation(MR). The optimal VV delay was defined as the VV delay producing the maximum LV synchrony and the largest aortic TVI. Results CRT was successfully performed in all patients. After pacemaker implantation, an acute improvement in left ventricular ejection fraction (LVEF) was observed from 26.5% to 35%. Meanwhile, the QRS duration decreased from 170ms to 150ms. The optimal AV delay was programmed at 130, 120, 120, 120, 150 and 110ms respectively with heart rate corrected, LVFT significantly lengthened and TVI of MR decreased (non-optimal vs optimal AV delay: LVFT: 469ms vs 523ms; TVI of MR: 16.43cm vs 13.06cm, P<0.05). The optimal VV delay was programmed at 4, 4, 4, 8, 12 and 8ms with LV preactivation respectively. Programming the optimal VV delay increased the aortic TVI from 17.33cm up to 21.42cm (P<0.05). In the septal and lateral wall, peak systolic velocities improved from2.70cm/s to 3.02cm/s (P>0.05) and froml.31cm/s to 2.50cm/s (P<0.05) respectively. The septal-to-lateral delay in peak velocity improved from 56.4ms to 13.3ms after CRT (P<0.01). Conclusions Optimization of AV and VV delays may further enhance the efficacy of CRT. However, there was interindividual variability of optimal values, warranting individual patient examination.

  2. Echocardiographic effects of changing atrioventricular delay in cardiac resynchronization therapy based on displacement

    DEFF Research Database (Denmark)

    Valeur, Nana; Fritz-Hansen, Thomas; Risum, Niels;

    2010-01-01

    In studies showing benefits of cardiac resynchronization therapy (CRT), individual atrioventricular (AV) delays have been optimized using echocardiography. However, the method for AV delay optimization remains controversial.......In studies showing benefits of cardiac resynchronization therapy (CRT), individual atrioventricular (AV) delays have been optimized using echocardiography. However, the method for AV delay optimization remains controversial....

  3. Echocardiographic estimation of acute haemodynamic response during optimization of multisite pace-maker using different pacing modalities and atrioventricular delays

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    Šalinger-Martinović Sonja

    2009-01-01

    Full Text Available Background/Aim. Cardiac resynchronization therapy (CRT improves ventricular dyssynchrony and is associated with an improvement in symptoms, quality of life and prognosis in patients with severe heart failure and intraventricular conduction delay. Different pacing modalities produce variable activation patterns and may be a cause of different haemodynamic changes. The aim of our study was to investigate acute haemodynamic changes with different CRT configurations during optimization procedure. Methods. This study included 30 patients with severe left ventricular systolic dysfunction and left bundle branch block with wide QRS (EF 24.33 ± 3.7%, QRS 159 ± 17.3 ms, New York Heart Association III/IV 25/5 with implanted CRT device. The whole group of patients had severe mitral regurgitation in order to measure dP/dt. After implantation and before discharge all the patients underwent optimization procedure guided by Doppler echocardiography. Left and right ventricular pre-ejection intervals (LVPEI and RVPEI, interventricular mechanical delay (IVD and the maximal rate of ventricular pressure rise during early systole (max dP/dt were measured during left and biventricular pacing with three different atrioventricular (AV delays. Results. After CRT device optimization, optimal AV delay and CRT mode were defined. Left ventricular pre-ejection intervals changed from 170.5 ± 24.6 to 145.9 ± 9.5 (p < 0.001, RVPEI from 102.4 ± 15.9 to 119.8 ± 10.9 (p < 0.001, IVD from 68.1 ± 18.3 to 26.5 ± 8.2 (p < 0.001 and dP/dt from 524.2 ± 67 to 678.2 ± 88.5 (p < 0.01. Conclusion. In patients receiving CRT echocardiographic assessment of the acute haemodynamic response to CRT is a useful tool in optimization procedure. The variability of Doppler parameters with different CRT modalities emphasizes the necessity of individualized approach in optimization procedure.

  4. Influence of the atrio-ventricular delay optimization on the intra left ventricular delay in cardiac resynchronization therapy

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    Nienaber Christoph A

    2006-01-01

    Full Text Available Abstract Background Cardiac Resynchronization Therapy (CRT leads to a reduction of left-ventricular dyssynchrony and an acute and sustained hemodynamic improvement in patients with chronic heart failure. Furthermore, an optimized AV-delay leads to an improved myocardial performance in pacemaker patients. The focus of this study is to investigate the acute effect of an optimized AV-delay on parameters of dyssynchrony in CRT patients. Method 11 chronic heart failure patients with CRT who were on stable medication were included in this study. The optimal AV-delay was defined according to the method of Ismer (mitral inflow and trans-oesophageal lead. Dyssynchrony was assessed echocardiographically at three different settings: AVDOPT; AVDOPT-50 ms and AVDOPT+50 ms. Echocardiographic assessment included 2D- and M-mode echo for the assessment of volumes and hemodynamic parameters (CI, SV and LVEF and tissue Doppler echo (strain, strain rate, Tissue Synchronisation Imaging (TSI and myocardial velocities in the basal segments Results The AVDOPT in the VDD mode (atrially triggered was 105.5 ± 38.1 ms and the AVDOPT in the DDD mode (atrially paced was 186.9 ± 52.9 ms. Intra-individually, the highest LVEF was measured at AVDOPT. The LVEF at AVDOPT was significantly higher than in the AVDOPT-50setting (p = 0.03. However, none of the parameters of dyssynchrony changed significantly in the three settings. Conclusion An optimized AV delay in CRT patients acutely leads to an improved systolic left ventricular ejection fraction without improving dyssynchrony.

  5. Optimisation of atrioventricular delay during exercise improves cardiac output in patients stabilised with cardiac resynchronisation therapy.

    Science.gov (United States)

    Sun, Jing Ping; Lee, Alex Pui-Wai; Grimm, Richard A; Hung, Ming-Jui; Yang, Xing Sheng; Delurgio, David; Leon, Angel R; Merlino, John D; Yu, Cheuk-Man

    2012-01-01

    Atrioventricular (AV) delay in cardiac resynchronisation therapy (CRT) recipients are typically optimised at rest. However, there are limited data on the impact of exercise-induced changes in heart rate on the optimal AV delay and left ventricular function. The authors serially programmed AV delays in 41 CRT patients with intrinsic sinus rhythm at rest and during two stages of supine bicycle exercise with heart rates at 20 bpm (stage I) and 40 bpm (stage II) above baseline. The optimal AV delay during exercise was determined by the iterative method to maximise cardiac output using Doppler echocardiography. Results were compared to physiological change in PR intervals in 56 normal controls during treadmill exercise. The optimal AV delay was progressively shortened (pexercise level (baseline: 123±26 ms vs. stage I: 102±24 ms vs stage II: 70±22 ms, pexercise. A linear inverse relationship existed between optimal AV delays and heart rates in CRT patients (AV delay=241-1.61×heart rate, R2=0.639, pheart rate during exercise, which suggests the need for programming of rate-adaptive AV delay in CRT recipients.

  6. Primary results from the SmartDelay determined AV optimization: a comparison to other AV delay methods used in cardiac resynchronization therapy (SMART-AV) trial: a randomized trial comparing empirical, echocardiography-guided, and algorithmic atrioventricular delay programming in cardiac resynchronization therapy.

    Science.gov (United States)

    Ellenbogen, Kenneth A; Gold, Michael R; Meyer, Timothy E; Fernndez Lozano, Ignacio; Mittal, Suneet; Waggoner, Alan D; Lemke, Bernd; Singh, Jagmeet P; Spinale, Francis G; Van Eyk, Jennifer E; Whitehill, Jeffrey; Weiner, Stanislav; Bedi, Maninder; Rapkin, Joshua; Stein, Kenneth M

    2010-12-21

    one variable that may influence cardiac resynchronization therapy response is the programmed atrioventricular (AV) delay. The SmartDelay determined av optimization: a comparison to other AV delay methods used in cardiac resynchronization therapy (SMART-AV) trial prospectively randomized patients to a fixed empirical AV delay (120 milliseconds), echocardiographically optimized AV delay, or AV delay optimized with SmartDelay, an electrogram-based algorithm. a total of 1014 patients (68% men; mean age, 66 ± 11 years; mean left ventricular ejection fraction, 25 ± 7%) who met enrollment criteria received a cardiac resynchronization therapy defibrillator, and 980 patients were randomized in a 1:1:1 ratio. All patients were programmed (DDD-60 or DDDR-60) and evaluated after implantation and 3 and 6 months later. The primary end point was left ventricular end-systolic volume. Secondary end points included New York Heart Association class, quality-of-life score, 6-minute walk distance, left ventricular end-diastolic volume, and left ventricular ejection fraction. The medians (quartiles 1 and 3) for change in left ventricular end-systolic volume at 6 months for the SmartDelay, echocardiography, and fixed arms were -21 mL (-45 and 6 mL), -19 mL (-45 and 6 mL), and -15 mL (-41 and 6 mL), respectively. No difference in improvement in left ventricular end-systolic volume at 6 months was observed between the SmartDelay and echocardiography arms (P=0.52) or the SmartDelay and fixed arms (P=0.66). Secondary end points, including structural (left ventricular end-diastolic volume and left ventricular ejection fraction) and functional (6-minute walk, quality of life, and New York Heart Association classification) measures, were not significantly different between arms. neither SmartDelay nor echocardiography was superior to a fixed AV delay of 120 milliseconds. The routine use of AV optimization techniques assessed in this trial is not warranted. However, these data do not exclude

  7. Influence of the heart rate and atrioventricular delays on vortex evolution and blood transport inside the left ventricle

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    Hendabadi, Sahar; Martinez-Legazpi, Pablo; Benito, Yolanda; Bermejo, Javier; Del Alamo, Juan Carlos; Shadden, Shawn

    2013-11-01

    Cardiac resynchronization therapy (CRT) is used to help restore coordinated pumping of the ventricles by overcoming delays in electrical conduction due to cardiac disease. This is accomplished by a specialized cardiac pacemaker that is able to adjust the atrioventricular (AV) delay.A major clinical challenge is to adjust the pacing strategy to best coordinate the blood flow mechanics of ventricular filling and ejection. To this end, we have studied the difference in the vortex formation and its evolution inside the left ventricle (LV) for 4 different AV delays in a cohort of patients with implanted pacemakers. A reconstruction algorithm was used to obtain 2D velocity over the apical long-axis view of the LV from color Doppler and B-mode ultrasound data. To study blood transport, we have identified Lagrangian coherent structures to determine moving boundaries of the blood volumes injected to the LV in diastole and ejected to the aorta in systole. In all cases, we have analyzed the differences in filling and ejection patterns and the blood transport during the E-wave and A-wave formation.Finally we have assessed the influence of the AV delay on 2 indices of stasis, direct flow and residence time.The findings shed insight to the optimization of AV delays in patients undergoing CRT. NIH award 5R21HL108268 and grants PIS09/02603 and RD06/0010 from the Plan Nacional de Investigacion Cientifica, Spain.

  8. Cx30.2 enhancer analysis identifies Gata4 as a novel regulator of atrioventricular delay

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    Munshi, Nikhil V.; McAnally, John; Bezprozvannaya, Svetlana; Berry, Jeff M.; Richardson, James A.; Hill, Joseph A.; Olson, Eric N.

    2009-01-01

    Summary The cardiac conduction system comprises a specialized tract of electrically coupled cardiomyocytes responsible for impulse propagation through the heart. Abnormalities in cardiac conduction are responsible for numerous forms of cardiac arrhythmias, but relatively little is known about the gene regulatory mechanisms that control the formation of the conduction system. We demonstrate that a distal enhancer for the connexin 30.2 (Cx30.2, also known as Gjd3) gene, which encodes a gap junction protein required for normal atrioventricular (AV) delay in mice, is necessary and sufficient to direct expression to the developing AV conduction system (AVCS). Moreover, we show that this enhancer requires Tbx5 and Gata4 for proper expression in the conduction system, and Gata4+/- mice have short PR intervals indicative of accelerated AV conduction. Thus, our results implicate Gata4 in conduction system function and provide a clearer understanding of the transcriptional pathways that impact normal AV delay. PMID:19592579

  9. Atrioventricular Conduction Delay in Fetuses Exposed to Anti-SSA/Ro and Anti-SSB/La Antibodies: A Magnetocardiography Study

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    Annette Wacker-Gußmann

    2012-01-01

    Full Text Available Background. The presence of anti-SSA/Ro and anti-SSB/La antibodies during pregnancy is associated with fetal congenital heart block (CHB, which is primarily diagnosed through fetal echocardiography. Conclusive information about the complete electrophysiology of the fetal cardiac conducting system is still lacking. In addition to echocardiography, fetal magnetocardiography (fMCG can be used. fMCG is the magnetic analogue of the fetal electrocardiogram (ECG. Patients and Methods. Forty-eight pregnant women were enrolled in an observational study; 16 of them tested positive for anti-SSA/Ro and anti-SSB/La antibodies. In addition to routine fetal echocardiography, fMCG was used. Fetal cardiac time intervals (fCTIs were extracted from the magnetic recordings by predefined procedures. ECGs in the neonates of the study group were performed within the first month after delivery. Results. The PQ segment of the fCTI was significantly prolonged in the study group (P=0.007, representing a delay of the electrical impulse in the atrioventricular (AV node. Other fCTIs were within normal range. None of the anti-SSA/Ro and/or anti-SSB/La fetuses progressed to a more advanced heart block during pregnancy or after birth. Conclusion. The study identified a low-risk population within antibody positive mothers, where PQ segment prolongation is associated with a lack of progression of the disease.

  10. Novel insights on effect of atrioventricular programming of biventricular pacemaker in heart failure – a case series

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    Rafique Asim M

    2006-10-01

    Full Text Available Abstract Background Echocardiography plays an integral role in the diagnosis of congestive heart failure including measurement of left heart pressure as well as mechanical dyssynchrony. Methods In this report we describe novel therapeutic uses of echo pulsed wave Doppler in atrioventricular pacemaker optimization in patients who had either not derived significant symptomatic benefit post biventricular pacemaker implantation or deteriorated after deriving initial benefit. In these patients atrioventricular optimization showed novel findings and improved cardiac output and symptoms. Results In 3 patients with Cheyne Stokes pattern of respiration echo Doppler showed worsening of mitral regurgitation during hyperpneac phase in one patient, marked E and A fusion in another patient and exaggerated ventricular interdependence in a third patient thus highlighting mechanisms of adverse effects of Cheyne Stokes respiration in patients with heart failure. All 3 patients required a very short atrioventricular delay programming for best cardiac output. In one patient with recurrent congestive heart failure post cardiac resynchronization, mitral inflow pulse wave Doppler showed no A wave until a sensed atrioventricular delay of 190 ms was reached and showed progressive improvement in mitral inflow pattern until an atrioventricular delay of 290 ms. In 2 patients atrioventricular delay as short as 50 ms was required to allow E and A separation and prevent diastolic mitral regurgitation. All patients developed marked improvement in congestive heart failure symptoms post echo-guided biv pacemaker optimization. Conclusion These findings highlight the value of echo-guided pacemaker optimization in symptomatic patients post cardiac resynchronization treatment.

  11. Effects of AV-delay optimization on hemodynamic parameters in patients with VDD pacemakers.

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    Krychtiuk, Konstantin A; Nürnberg, Michael; Volker, Romana; Pachinger, Linda; Jarai, Rudolf; Freynhofer, Matthias K; Wojta, Johann; Huber, Kurt; Weiss, Thomas W

    2014-05-01

    Atrioventricular (AV) delay optimization improves hemodynamics and clinical parameters in patients treated with cardiac resynchronization therapy and dual-chamber-pacemakers (PM). However, data on optimizing AV delay in patients treated with VDD-PMs are scarce. We, therefore, investigated the acute and chronic effects of AV delay optimization on hemodynamics in patients treated with VDD-PMs due to AV-conduction disturbances. In this prospective, single-center interventional trial, we included 64 patients (38 men, 26 women, median age: 77 (70-82) years) with implanted VDD-PM. AV-delay optimization was performed using a formula based on the surface electrocardiogram (ECG). Hemodynamic parameters (stroke volume (SV), cardiac output (CO), heart rate (HR), and blood pressure (BP)) were measured at baseline and follow-up after 3 months using impedance cardiography. Using an ECG formula for AV-delay optimization, the AV interval was decreased from 180 (180-180) to 75 (75-100) ms. At baseline, AV-delay optimization led to a significant increase of both SV (71.3 ± 15.8 vs. 55.3 ± 12.7 ml, p AV delay vs. nominal AV interval, respectively) and CO (5.1 ± 1.4 vs. 3.9 ± 1.0 l/min, p AV-delay optimization in patients treated with VDD-PMs exhibits immediate beneficial effects on hemodynamic parameters that are sustained for 3 months.

  12. Locomotive Assignment Optimization Including Train Delays

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    Sandra Kasalica

    2013-10-01

    Full Text Available Intention– Cyclic locomotive assignment planning is a specific type of organization of locomotive usage, and in fact, it means putting the complete workload to a closed chain, which is repeated periodically. The concept of cyclic locomotive assignment planning type organization in the area of train traction has proven in practice as the best one, but as it is made for in-advance defined timetable and without considering the stochastic nature of the timetable realization process, it leads to incompatibility in using locomotives. Methodology – Methodology defined in this paper contains: research of train delays on the Serbian Railways and Montenegrin Railways networks, analysis of the real system organization of locomotive usage in conditions of train delays, theoretical thesis of solving the problem of optimal cyclic locomotive assignment planning in conditions of train delays, designing of a model with algorithms, preparing the software package, testing the model and program with results, as well as the conclusions drawn from the complete research project. Results– The optimization model of cyclic locomotive assignment planning during the process of making timetable including train delays has been defined. Conclusion –The obtained results have shown as expected, that the larger delays of trains required a larger number of locomotives. However, by using this model it is possible to optimize the required number of locomotives, taking into account the real time delays of trains.

  13. DYNAMIC LABELING BASED FPGA DELAY OPTIMIZATION ALGORITHM

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    吕宗伟; 林争辉; 张镭

    2001-01-01

    DAG-MAP is an FPGA technology mapping algorithm for delay optimization and the labeling phase is the algorithm's kernel. This paper studied the labeling phase and presented an improved labeling method. It is shown through the experimental results on MCNC benchmarks that the improved method is more effective than the original method while the computation time is almost the same.

  14. Whether noninvasive optimization of AV and VV delays improves the response to cardiac resynchronization therapy.

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    Urbanek, Bożena; Chudzik, Michał; Klimczak, Artur; Rosiak, Marcin; Lewek, Joanna; Wranicz, Jerzy Krzysztof

    2013-01-01

    Device optimization is not routinely performed in patients who underwent cardiac resynchronization therapy (CRT) device implantation. Noninvasive optimization of CRT devices by measurement of cardiac output (CO) can be used as a simple method to assess ventricular systolic performance. The aim of this study was to assess whether optimization of atrioventricular (AV) and interventricular (VV) delay can improve hemodynamic response to CRT and whether this optimization should be performed for each patient individually. Twenty patients with advanced heart failure New York Heart Association (NYHA) class III/IV, left ventricular ejection fraction ≤ 35% and left bundle branch block (QRS ≥ 120 ms) in sinus rhythm were evaluated from 24 h to 48 h after implantation of a CRT device by means of impedance cardiography (ICG). CO was first measured at each patient's intrinsic rhythm. Patients then underwent adjustments of AV and VV delay from 80 ms to 140 ms and from -60 ms to +60 ms, respectively in 20 ms increment steps and CO at each setting was measured by ICG. Both AV and VV delays were programmed according to the greatest improvement in CO compared to intrinsic rhythm. There was a statistically signifi cant increase in CO measured at the intrinsic rhythm compared to different AV delay by mean of 21% (3.8 ± 1.0 vs. 4.6 ± 0.1 L/min, p AV/VV delays with left ventricle-preexcitation or simultaneous biventricular pacing caused additional increased CO from intrinsic rhythm by mean of 32.6% (3.8 ± 1.0 vs. 5.04 ± ± 1.0 L/min, p AV/VV setting delays also resulted in improved hemodynamic responses compared to VV factory setting delay. Both AV and VV delay optimization should be performed in clinical practice. Optimal AV delay improved outcome. However, combination of optimized AV/VV delays provided the best hemodynamic response. Optimized AV/VV delays with left ventricle-preexcitation or simultaneous biventricular pacing increased hemodynamic output compared to intrinsic

  15. Atrioventricular Canal Defect

    Science.gov (United States)

    ... doctor See your doctor if you or your child develops signs or symptoms of atrioventricular canal defect. Atrioventricular canal defect occurs before birth when a baby's heart is developing. Some factors, such as Down syndrome, might increase the risk of atrioventricular canal defect. ...

  16. Optimal Control with Time Delays via the Penalty Method

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    Mohammed Benharrat

    2014-01-01

    Full Text Available We prove necessary optimality conditions of Euler-Lagrange type for a problem of the calculus of variations with time delays, where the delay in the unknown function is different from the delay in its derivative. Then, a more general optimal control problem with time delays is considered. Main result gives a convergence theorem, allowing us to obtain a solution to the delayed optimal control problem by considering a sequence of delayed problems of the calculus of variations.

  17. Delay Reduction in Optimized Reversible Multiplier Circuit

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    Mohammad Assarian

    2012-01-01

    Full Text Available In this study a novel reversible multiplier is presented. Reversible logic can play a significant role in computer domain. This logic can be applied in quantum computing, optical computing processing, DNA computing, and nanotechnology. One condition for reversibility of a computable model is that the number of input equate with the output. Reversible multiplier circuits are the circuits used frequently in computer system. For this reason, optimization in one reversible multiplier circuit can reduce its volume of hardware on one hand and increases the speed in a reversible system on the other hand. One of the important parameters that optimize a reversible circuit is reduction of delays in performance of the circuit. This paper investigates the performance characteristics of the gates, the circuits and methods of optimizing the performance of reversible multiplier circuits. Results showed that reduction of the reversible circuit layers has lead to improved performance due to the reduction of the propagation delay between input and output period. All the designs are in the nanometric scales.

  18. Analysis and optimization of delays in networked control systems

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    The minimization problem of time delays in networked control system (NCS) is concered, which is a hot area of such research field. First, some analysis and comments on time-delayed NCS model listed in previous work are given.Then, time delay minimization problem based on average behavior of network queuing delay is presented. Under fixed routing scheme and certain optimization performance indexes, the delay minimization problem is translated into convex optimization problem. And the solution of the delay minimization problems is attained through optimized allocation of flow rates among network links.

  19. Atrioventricular Pacemaker Lead Reversal

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    Mehmet K Aktas, MD

    2007-01-01

    Full Text Available During cardiac surgery temporary epicardial atrial and ventricular leads are placed in case cardiac pacing is required postoperatively. We present the first reported series of patients with reversal of atrioventricular electrodes in the temporary pacemaker without any consequent deleterious hemodynamic effect. We review the electrocardiographic findings and discuss the findings that lead to the discovery of atrioventricular lead reversal.

  20. Effects of AV delay and VV delay on left atrial pressure and waveform in ambulant heart failure patients: insights into CRT optimization.

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    Chan, W Y Wandy; Blomqvist, Andreas; Melton, Iain C; Norén, Kjell; Crozier, Ian G; Benser, Michael E; Eigler, Neal L; Gutfinger, Dan; Troughton, Richard W

    2014-07-01

    We hypothesized that left atrial pressure (LAP) obtained by a permanent implantable sensor is sensitive to changes in cardiac resynchronization therapy (CRT) settings and could guide CRT optimization to improve the response rate. We investigated the effect of CRT optimization on LAP and its waveform parameters in ambulant heart failure (HF) patients. CRT optimization was performed in eight ambulant HF patients, using echocardiography as reference. LAP waveform was acquired at each of eight atrioventricular (AV) intervals and five inter-ventricular (VV) intervals. Selected waveform parameters were also evaluated for their sensitivity to CRT changes and agreement with echocardiography-guided optimal settings. Optimal AV and VV intervals varied considerably between patients. All patients exhibited significant changes in waveform morphology with AV optimization. Optimal AV delay determined from echocardiography ranged between 140 ms and 225 ms. Mean LAP tended to be lower at optimal setting 14 ± 3 mmHg compared to shorter (160 ms) AV settings (P = 0.16). There were clear trends to smaller peak a-wave (P = 0.11) and gentler positive a-slope (P = 0.15) and positive v-slope (P = 0.09) with longer AV delays. Mean LAP and negative v-wave slope correlated well with echo-guided optimal setting, r = 0.91 (P = 0.001) and 0.79 (P = 0.03), respectively. No significant effects on LAP or waveform were seen during VV optimization. LAP and its waveform changes considerably with AV optimization. There is good agreement between echo-guided optimal setting and LAP. LAP could provide an objective guide to CRT optimization. (Clinical Trial Registry information: URL: http://www.clinicaltrials.gov. Unique Identifier: NCT00632372). ©2014 Wiley Periodicals, Inc.

  1. Practice Utilization of Algorithms for Analog Filter Group Delay Optimization

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    K. Hajek

    2007-04-01

    Full Text Available This contribution deals with an application of three different algorithms which optimize a group delay of analog filters. One of them is a part of the professional circuit simulator Micro Cap 7 and the others two original algorithms are developed in the MATLAB environment. An all-pass network is used to optimize the group delay of an arbitrary analog filter. Introduced algorithms look for an optimal order and optimal coefficients of an all-pass network transfer function. Theoretical foundations are introduced and all algorithms are tested using the optimization of testing analog filter. The optimization is always run three times because the second, third and fourth-order all-pass network is used. An equalization of the original group delay is a main objective of these optimizations. All outputs of all algorithms are critically evaluated and also described.

  2. Optimal state estimation over communication channels with random delays

    KAUST Repository

    Mahmoud, Magdi S.

    2013-04-01

    This paper is concerned with the optimal estimation of linear systems over unreliable communication channels with random delays. The measurements are delivered without time stamp, and the probabilities of time delays are assumed to be known. Since the estimation is time-driven, the actual time delays are converted into virtual time delays among the formulation. The receiver of estimation node stores the sum of arrived measurements between two adjacent processing time instants and also counts the number of arrived measurements. The original linear system is modeled as an extended system with uncertain observation to capture the feature of communication, then the optimal estimation algorithm of systems with uncertain observations is proposed. Additionally, a numerical simulation is presented to show the performance of this work. © 2013 The Franklin Institute.

  3. Distributed Optimal Consensus Control for Multiagent Systems With Input Delay.

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    Zhang, Huaipin; Yue, Dong; Zhao, Wei; Hu, Songlin; Dou, Chunxia

    2017-06-27

    This paper addresses the problem of distributed optimal consensus control for a continuous-time heterogeneous linear multiagent system subject to time varying input delays. First, by discretization and model transformation, the continuous-time input-delayed system is converted into a discrete-time delay-free system. Two delicate performance index functions are defined for these two systems. It is shown that the performance index functions are equivalent and the optimal consensus control problem of the input-delayed system can be cast into that of the delay-free system. Second, by virtue of the Hamilton-Jacobi-Bellman (HJB) equations, an optimal control policy for each agent is designed based on the delay-free system and a novel value iteration algorithm is proposed to learn the solutions to the HJB equations online. The proposed adaptive dynamic programming algorithm is implemented on the basis of a critic-action neural network (NN) structure. Third, it is proved that local consensus errors of the two systems and weight estimation errors of the critic-action NNs are uniformly ultimately bounded while the approximated control policies converge to their target values. Finally, two simulation examples are presented to illustrate the effectiveness of the developed method.

  4. Optimal Control Strategies in Delayed Sharing Information Structures

    CERN Document Server

    Nayyar, Ashutosh; Teneketzis, Demosthenis

    2010-01-01

    The $n$-step delayed sharing information structure is investigated. This information structure comprises of $K$ controllers that share their information with a delay of $n$ time steps. This information structure is a link between the classical information structure, where information is shared perfectly between the controllers, and a non-classical information structure, where there is no "lateral" sharing of information among the controllers. Structural results for optimal control strategies for systems with such information structures are presented. A sequential methodology for finding the optimal strategies is also derived. The solution approach provides an insight for identifying structural results and sequential decomposition for general decentralized stochastic control problems.

  5. Leapfrog: Optimal opportunistic Routing in Probabilistically Contacted Delay Tolerant Networks

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    Ming-Jun Xiao; Liu-Sheng Huang; Qun-Feng Dong; An Liu; Zhen-Guo Yang

    2009-01-01

    Delay tolerant networks (DTNs)experience frequent and long lasting network disconnection due to various reasons such as mobility.power management.and scheduling.One primary concern in DTNs is to route messages to keep the end-to-end delivery delay as low as possible.In this paper,we study the single-copy message routing problem and propose an optimal opportunistic routing strategy--Leapfrog Routing--for probabilistically contacted DTNs where nodes encounter or contact in some fixed probabilities.We deduce the iterative computation formulate of minimum expected opportunistic delivery delay from each node to the destination and discover that under the optimal opportunistic routing strategy,messages would be delivered from high-delay node to low-delay node in the leapfrog manner.Rigorous theoretical analysis shows that such a routing strategy is exactly the optimal among all possible ones.Moreover,we apply the idea of Reverse Dijkstra algorithm to design an algorithm.When a destination iS given,this algorithm can determine for each node the routing selection function under the Leapfrog Routing strategy.The computation overhead of this algorithm is only O(n~2) where n is the number of nodes in the network.In addition,through extensive simulations based on real DTN traces,we demonstrate that our algorithm can significantly outperform the previous ones.

  6. Minimizing ventricular pacing by a novel atrioventricular (AV) delay hysteresis algorithm in patients with intact or compromised intrinsic AV conduction and different atrial and ventricular lead locations.

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    Pakarinen, Sami; Toivonen, Lauri

    2013-09-01

    To investigate if an advanced AV search hysteresis (AVSH) algorithm, Ventricular Intrinsic Preference (VIP(™)), reduces the incidence of ventricular pacing (VP) in sinus node dysfunction (SND) with both intact and compromised AV conduction and with intermittent AV block regardless of the lead positions in the right atria and the ventricle. Patients were classified as having intact AV (AVi) conduction if the PR interval was ≤ 210 ms on ECG and 1:1 AV conduction during atrial pacing up to 120 bpm with PR interval ≤ 350 ms. Otherwise the AV conduction was classified as compromised (AVc). Both AVi and AVc patients were randomized to VIP ON or OFF. VIP performed an intrinsic AV conduction search every 30 s for three consecutive atrial cycles with the extension of the sensed and paced AV (SAV/PAV) delays from basic values of 150/200 ms to 300/350 ms. Extended AV intervals were allowed for three cycles when VP occurred before returning to basic AV delays. The primary end-point was %VP at 12 months. Among 389 patients, 30.1% had intact and 69.9% had compromised AV conduction. The mean %VP at 12 months was 9.6% by VIP compared to 51.8% with standard AV settings in patients with AVi (P < 0.0001) and 28.0% versus 78.9% (P < 0.0001) with AVc. With VIP, excessive %VP among most used lead positions was not seen. Conversely, when VIP was off %VP was low only in patients who had leads in the RA septal-RV septal position (23.0%). VIP feature reduces VP both in patients with SND and with intermittent heart block regardless of the lead positions in the right atria and the ventricle.

  7. Remote optimal state estimation over communication channels with random delays

    KAUST Repository

    Mahmoud, Magdi S.

    2014-01-22

    This paper considers the optimal estimation of linear systems over unreliable communication channels with random delays. In this work, it is assumed that the system to be estimated is far away from the filter. The observations of the system are capsulized without time stamp and then transmitted to the network node at which the filter is located. The probabilities of time delays are assumed to be known. The event-driven estimation scheme is applied in this paper and the estimate of the states is updated only at each time instant when any measurement arrives. To capture the feature of communication, the system considered is augmented, and the arrived measurements are regarded as the uncertain observations of the augmented system. The corresponding optimal estimation algorithm is proposed and additionally, a numerical simulation represents the performance of this work. © 2014 The authors. Published by Oxford University Press on behalf of the Institute of Mathematics and its Applications. All rights reserved.

  8. Online Algorithms for Adaptive Optimization in Heterogeneous Delay Tolerant Networks

    Directory of Open Access Journals (Sweden)

    Wissam Chahin

    2013-12-01

    Full Text Available Delay Tolerant Networks (DTNs are an emerging type of networks which do not need a predefined infrastructure. In fact, data forwarding in DTNs relies on the contacts among nodes which may possess different features, radio range, battery consumption and radio interfaces. On the other hand, efficient message delivery under limited resources, e.g., battery or storage, requires to optimize forwarding policies. We tackle optimal forwarding control for a DTN composed of nodes of different types, forming a so-called heterogeneous network. Using our model, we characterize the optimal policies and provide a suitable framework to design a new class of multi-dimensional stochastic approximation algorithms working for heterogeneous DTNs. Crucially, our proposed algorithms drive online the source node to the optimal operating point without requiring explicit estimation of network parameters. A thorough analysis of the convergence properties and stability of our algorithms is presented.

  9. Identification of optimal inspection interval via delay-time concept

    Directory of Open Access Journals (Sweden)

    Glauco Ricardo Simões Gomes

    2016-06-01

    Full Text Available This paper presents an application of mathematical modeling aimed at managing maintenance based on the delay-time concept. The study scenario was the manufacturing sector of an industrial unit, which operates 24 hours a day in a continuous flow of production. The main idea was to use the concepts of this approach to determine the optimal time of preventive action by the maintenance department in order to ensure the greatest availability of equipment and facilities at appropriate maintenance costs. After a brief introduction of the subject, the article presents topics that illustrate the importance of mathematical modeling in maintenance management and the delay-time concept. It also describes the characteristics of the company where the study was conducted, as well as the data related to the production process and maintenance actions. Finally, the results obtained after applying the delay-time concept are presented and discussed, as well as the limitations of the article and the proposals for future research.

  10. Optimal Linear Joint Source-Channel Coding with Delay Constraint

    CERN Document Server

    Johannesson, Erik; Bernhardsson, Bo; Ghulchak, Andrey

    2012-01-01

    The problem of joint source-channel coding is considered for a stationary remote (noisy) Gaussian source and a Gaussian channel. The encoder and decoder are assumed to be causal and their combined operations are subject to a delay constraint. It is shown that, under the mean-square error distortion metric, an optimal encoder-decoder pair from the linear and time-invariant (LTI) class can be found by minimization of a convex functional and a spectral factorization. The functional to be minimized is the sum of the well-known cost in a corresponding Wiener filter problem and a new term, which is induced by the channel noise and whose coefficient is the inverse of the channel's signal-to-noise ratio. This result is shown to also hold in the case of vector-valued signals, assuming parallel additive white Gaussian noise channels. It is also shown that optimal LTI encoders and decoders generally require infinite memory, which implies that approximations are necessary. A numerical example is provided, which compares ...

  11. Prevalence of cardiac dyssynchrony and correlation with atrio-ventricular block and QRS width in dilated cardiomyopathy

    DEFF Research Database (Denmark)

    Anzouan-Kacou, J B; Ncho-Mottoh, M P; Konin, C

    2012-01-01

    Cardiac dyssynchrony causes disorganised cardiac contraction, delayed wall contraction and reduced pumping efficiency. We aimed to assess the prevalence of different types of dyssynchrony in patients with dilated cardiomyopathy (DCM), and to establish the correlation between atrio-ventricular blo...

  12. Constructing optimized binary masks for reservoir computing with delay systems

    Science.gov (United States)

    Appeltant, Lennert; van der Sande, Guy; Danckaert, Jan; Fischer, Ingo

    2014-01-01

    Reservoir computing is a novel bio-inspired computing method, capable of solving complex tasks in a computationally efficient way. It has recently been successfully implemented using delayed feedback systems, allowing to reduce the hardware complexity of brain-inspired computers drastically. In this approach, the pre-processing procedure relies on the definition of a temporal mask which serves as a scaled time-mutiplexing of the input. Originally, random masks had been chosen, motivated by the random connectivity in reservoirs. This random generation can sometimes fail. Moreover, for hardware implementations random generation is not ideal due to its complexity and the requirement for trial and error. We outline a procedure to reliably construct an optimal mask pattern in terms of multipurpose performance, derived from the concept of maximum length sequences. Not only does this ensure the creation of the shortest possible mask that leads to maximum variability in the reservoir states for the given reservoir, it also allows for an interpretation of the statistical significance of the provided training samples for the task at hand.

  13. Angiographic studies of atrioventricular discordance.

    Science.gov (United States)

    Attie, F; Soni, J; Ovseyevitz, J; Muñoz-Castellanos, L; Testelli, M R; Buendia, A

    1980-08-01

    The results and value of conventional and axial angiocardiography were studied in 26 cases of atrioventricular discordance (AVD). The angiographic anatomy of this malformation was analyzed to determine the precise characteristics of atrioventricular and ventriculoarterial connections. The left and right ventricles in atrial situs solitus and levocardia show angiographic features that differ from those seen in atrial situs solitus and dextrocardia. The same differences are found in atrial situs inversus. Regardless of the type of ventriculoarterial connections, the ventricles maintain the same angiographic characteristics. The ventricular septum in AVD in situs solitus and levocardia and situs inversus and dextrocardia has a peculiar orientation. The use of axial angiocardiography facilitates detection and localization of the ventricular septal defect. In cases of malposition of the heart, the conventional frontal view allows visualization of the ventricular septum in all of its length. The axial projection is useful in diagnosing left ventricular outflow tract obstruction.

  14. Atrioventricular Dissociation after Electroconvulsive Therapy

    Directory of Open Access Journals (Sweden)

    Siegfried William Yu

    2011-01-01

    Full Text Available Electroconvulsive therapy (ECT is increasingly used as a treatment for psychiatric disorders. Cardiac effects are the principal cause of medical complications in these patients. We report a case of atrioventricular (AV dissociation that occurred after ECT that was treated with pacemaker implantation. The mechanisms contributing to the onset of AV dissociation in this patient, and the management and rationale for device therapy, in light of the most recent guidelines, are reviewed.

  15. Atrioventricular nodal reentrant tachycardia treatment using novel potential.

    Science.gov (United States)

    Ardashev, Andrey V; Makarenko, Alexandr S; Zhelyakov, Eugeny G; Shavarov, Andrey A

    2010-12-01

    Radiofrequency ablation of atrioventricular nodal reentrant tachycardia is commonly guided by slow and sharp bipolar potentials of the atrioventricular slow nodal pathway. We optimized the morphology of the guiding potential by unipolar mapping of the slow nodal pathway. We identified a novel unipolar dual-component atrial electrogram at the anterior limb of the coronary sinus ostium. The first component was a positive delta-wave type that corresponded to the isoelectric phase on a bipolar electrogram. The second component had fast biphasic morphology and corresponded to the R wave on a bipolar atrial electrogram. Of 104 consecutive patients with typical atrioventricular nodal reentrant tachycardia, 51 were treated with ablation guided by the novel potential, and 53 underwent ablation using the conventional technique. There was no recurrence of tachycardia in any of these patients. In those treated by the novel potential, there was significantly less radiofrequency power applied and a shorter duration of application than in patients treated by the traditional approach. The novel approach to mapping and ablation of the slow nodal pathway in atrioventricular nodal reentrant tachycardia guided by unipolar recording was safe and effective, and comparable to the traditional technique.

  16. Noether's Symmetry Theorem for Variational and Optimal Control Problems with Time Delay

    OpenAIRE

    Frederico, G. S. F.; Torres, D. F. M.

    2012-01-01

    We extend the DuBois-Reymond necessary optimality condition and Noether's symmetry theorem to the time delay variational setting. Both Lagrangian and Hamiltonian versions of Noether's theorem are proved, covering problems of the calculus of variations and optimal control with delays.

  17. The Optimal Sequence of Production Orders, Taking into Account the Cost of Delays

    Directory of Open Access Journals (Sweden)

    Dylewski Robert

    2016-06-01

    Full Text Available In flexible manufacturing systems the most important element in determining the proper course of technological processes, transport and storage is the control and planning subsystem. The key planning task is to determine the optimal sequence of production orders. This paper proposes a new method of determining the optimal sequence of production orders in view of the sum of the costs related to the delayed execution of orders. It takes into account the different unit costs of delays of individual orders and the amount of allowable delays of orders involving no delay costs. The optimum sequence of orders, in the single-machine problem, in view of the sum of the costs of delays may be significantly different from the optimal order, taking into account the sum of delay times.

  18. Local Bifurcations and Optimal Theory in a Delayed Predator-Prey Model with Threshold Prey Harvesting

    Science.gov (United States)

    Tankam, Israel; Tchinda Mouofo, Plaire; Mendy, Abdoulaye; Lam, Mountaga; Tewa, Jean Jules; Bowong, Samuel

    2015-06-01

    We investigate the effects of time delay and piecewise-linear threshold policy harvesting for a delayed predator-prey model. It is the first time that Holling response function of type III and the present threshold policy harvesting are associated with time delay. The trajectories of our delayed system are bounded; the stability of each equilibrium is analyzed with and without delay; there are local bifurcations as saddle-node bifurcation and Hopf bifurcation; optimal harvesting is also investigated. Numerical simulations are provided in order to illustrate each result.

  19. Analysis and optimization of RC delay in vertical nanoplate FET

    Science.gov (United States)

    Woo, Changbeom; Ko, Kyul; Kim, Jongsu; Kim, Minsoo; Kang, Myounggon; Shin, Hyungcheol

    2017-10-01

    In this paper, we have analyzed short channel effects (SCEs) and RC delay with Vertical nanoplate FET (VNFET) using 3-D Technology computer-aided design (TCAD) simulation. The device is based on International Technology Road-map for Semiconductor (ITRS) 2013 recommendations, and it has initially gate length (LG) of 12.2 nm, channel thickness (Tch) of 4 nm, and spacer length (LSD) of 6 nm. To obtain improved performance by reducing RC delay, each dimension is adjusted (LG = 12.2 nm, Tch = 6 nm, LSD = 11.9 nm). It has each characteristic in this dimension (Ion/Ioff = 1.64 × 105, Subthreshold swing (S.S.) = 73 mV/dec, Drain-induced barrier lowering (DIBL) = 60 mV/V, and RC delay = 0.214 ps). Furthermore, with long shallow trench isolation (STI) length and thick insulator thickness (Ti), we can reduce RC delay from 0.214 ps to 0.163 ps. It is about a 23.8% reduction. Without decreasing drain current, there is a reduction of RC delay as reducing outer fringing capacitance (Cof). Finally, when source/drain spacer length is set to be different, we have verified RC delay to be optimum.

  20. Generalized Interconnect Delay Time and Crosstalk Models: I. Applications of Interconnect Optimization Design

    Science.gov (United States)

    Lee, Trent Gwo-Yann; Tseng, Tseung-Yuen; Wong, Shyh-Chyi; Yang, Cheng-Jer; Liang, Mong Song; Cheng, Huang-Chung

    2001-12-01

    New analytical models for estimating the delay time of single line and coupled interconnect for ramp input waveform are derived. The accuracy of the signal delay time and crosstalk noise voltage models for various driver resistances, loading capacitances, and input-ramping rates has also been verified by simulation program with integrated circuit emphasis (SPICE) simulation. Based on the delay and crosstalk models, interconnect optimization design can be discussed thoroughly. The proposed guaranteed-performance interconnect design method is also discussed. These models are useful for performance estimation and layout optimization in VLSI synthesis as well as process optimization in technology development.

  1. Lyapunov Matrices Approach to the Parametric Optimization of a System with Two Delays

    Directory of Open Access Journals (Sweden)

    Duda Jozef

    2016-09-01

    Full Text Available In the paper a Lyapunov matrices approach to the parametric optimization problem of time-delay systems with two commensurate delays and a P-controller is presented. The value of integral quadratic performance index of quality is equal to the value of the Lyapunov functional for the initial function of time-delay system. The Lyapunov functional is determined by means of the Lyapunov matrix.

  2. Determination of Optimal Control Strength of Delayed Feedback Control Using Time Series

    Institute of Scientific and Technical Information of China (English)

    YIN Hua-Wei; LU Wei-Ping; WANG Peng-Ye

    2004-01-01

    @@ We study controlling chaos using time-delayed feedback control based on chaotic time series without prior knowl edge of dynamical systems, and determine the optimal control parameters for stabilizing unstable periodic orbits with maximal stability.

  3. Understanding atrioventricular septal defect: Anatomoechocardiographic correlation

    Directory of Open Access Journals (Sweden)

    Keirns Candace

    2008-06-01

    Full Text Available Abstract Objective Correlate the anatomic features of atrioventricular septal defect with echocardiographic images. Materials and methods Sixty specimen hearts were studied by sequential segmental analysis. Echocardiograms were performed on 34 patients. Specimen hearts with findings equivalent to those of echocardiographic images were selected in order to establish an anatomo-echocardiographic correlation. Results Thirty-three specimen hearts were in situs solitus, 19 showed dextroisomerism, 6 were in situs inversus and 2 levoisomerism. Fifty-eight had a common atrioventricular valve and 2 had two atrioventricular valves. Rastelli types were determined in 21 hearts. Nine were type A, 2 intermediate between A and B, 1 mixed between A and B, 4 type B and 5 type C. Associated anomalies included pulmonary stenosis, pulmonary atresia atrial septal defect, patent ductus arteriosus and anomalous connection of pulmonary veins. Echocardiograms revealed dextroisomerism in 12 patients, situs solitus in 11, levoisomerism in 7 and situs inversus in 4. Thirty-one patients had common atrioventricular valves and three two atrioventricular valves. Rastelli types were established in all cases with common atrioventricular valves; 17 had type A canal defects, 10 type B, 3 intermediate between A and B, 1 mixed between A and B and 3 type C. Associated anomalies included regurgitation of the atrioventricular valve, pulmonary stenosis, anomalous connection of pulmonary veins, pulmonary hypertension and pulmonary atresia. Conclusion Anatomo-echocardiographic correlation demonstrated a high degree of diagnostic precision with echocardiography.

  4. Evolution and scaling of atrioventricular conduction time in mammals. [Pt. 1

    NARCIS (Netherlands)

    Meijler, F.L.; Strackee, J.

    2006-01-01

    Scaling can be defined as the adjustment of a structure, a function, or an organ to the size of the mammalian body. An example is the size of the heart in relation to the size of the body. The duration of the PR interval on the electrocardiogram (atrioventricular delay) in relation to the size of th

  5. Comparative aspects of the dual role of the human atrioventricular node

    NARCIS (Netherlands)

    Meijler, F.L.

    1986-01-01

    As well as transmitting the impulse from the atria to the ventric1es the atrioventricular node has two other important functions namely: (a) synchronisation of atrial and ventricular contractions by a varying delay; and (b) protection of the ventricles from rapid atrial arrhythmias. The relative imp

  6. Wnt signaling regulates atrioventricular canal formation upstream of BMP and Tbx2

    NARCIS (Netherlands)

    Verhoeven, M.C.; Haase, C.; Christoffels, V.M.; Weidinger, G.; Bakkers, J.

    2011-01-01

    In the developing heart, the atrioventricular canal (AVC) is essential for separation and alignment of the cardiac chambers, for valve formation, and serves to delay the electrical impulse from the atria to the ventricles. Defects in various aspects of its formation are the most common form of

  7. Evolution and scaling of atrioventricular conduction time in mammals. [Pt. 2

    NARCIS (Netherlands)

    Meijler, F.L.; Strackee, J.

    2006-01-01

    Changes of the PR interval (atrioventricular delay) in relation to changes of heart size in mammalian species (scaling) confront us with a perplexing lack of understanding of an essential funetion of the heart. The PR interval controls the duration of late diastolic blood flow from the atria to the

  8. Optimal guaranteed cost control for fuzzy descriptor systems with time-varying delay

    Institute of Scientific and Technical Information of China (English)

    Tian Weihua; Zhang Huaguang

    2008-01-01

    Based on the delay-independent rule, the problem of optimal guaranteed cost control for a class of Takagi-Sugeno (T-S) fuzzy descriptor systems with time-varying delay is studied. A linear quadratic cost function is considered as the performance index of the closed-loop system. Sufficient conditions for the existence of guaranteed cost controllers via state feedback are given in terms of linear matrix inequalities (LMIs), and the design of an optimal guaranteed cost controller can be reduced to a convex optimization problem. It is shown that the designed controller not only guarantees the asymptotic stability of the closed-loop fuzzy descriptor delay system, but also provides an optimized upper bound of the guaranteed cost. At last, a numerical example is given to illustrate the effectiveness of the proposed method and the perfect performance of the optimal guaranteed cost controller.

  9. The Effect of a Reconstruction Technique and Heart Rate in the Evaluation of Optimal Trigger Delay Using Multiphase Reconstruction

    Energy Technology Data Exchange (ETDEWEB)

    Cho, Young Jun [Konyang University School of Medicine, Daejeon (Korea, Republic of)

    2008-12-15

    To evaluate the mean optimal trigger delays and the difference between the absolute delay and the relative delay as a function of heart rate, using multiphase reconstruction. A total of 30 patients consecutively underwent a 64-slice MDCT examination. Optimal trigger delays at four planes (the bifurcation of the left main coronary artery, aortic valve, mitral valve and cardiac apex) were measured using multiphase reconstruction based on the absolute and relative delay. For this reason, patients were divided into three groups according to heart rate (group I, < 65 bpm; group II, 65-74 bpm; group III, {>=} 75 bpm), and the mean optimal trigger delays and the difference between the absolute delay and the relative delay were evaluated at the four planes for each group. The mean optimal trigger delay for the relative delay and absolute delay ranged from 46% to 66% and from 327 to 700 msec, respectively. The differences in the mean optimal trigger delay using the relative and the absolute delay at the four planes were 1% and 4 msec (group I), 3% and 27 msec (group II), and 14% and 46 msec (group III). In group III, the difference of the mean optimal trigger delay based on the relative delay, increased significantly compared to the absolute delay (p = 0.040). For the patients analyzed, the results suggest that as the heart rate increased, the mean optimal trigger delays shifted from the mid-diastolic phase to the end-systolic phase and the differences in the mean optimal trigger delay at the four planes were significantly greater for the relative delay.

  10. Comparison of optimal atrioventricular delay in different pacing modes%不同起搏方式房室延迟优化的对比研究

    Institute of Scientific and Technical Information of China (English)

    寿锡凌; 吉海鸣; 陈新义; 崔翰斌; 梁磊; 官功昌; 樊应书

    2005-01-01

    目的观察双腔起搏(DDD)患者不同起搏方式时最佳房室延迟(AVD)的差异.方法对20例置入DDD起搏器的患者经左侧锁骨下静脉插入Swan-Ganz导管,分别测量DDD方式及心房感知心室起搏(VDD)方式下的不同AVD起搏的急性血流动力学效应.结果DDD右心耳起搏优化AVD(149±15ms)比VDD起搏AVD(114±12ms)延长了38±12ms,差异有非常显著性意义(P<0.01).结论双腔起搏时DDD右心耳起搏可使AVD达到最优.

  11. Design of an integrated phase frequency detector with optimal power consumption and delay by using particle swarm optimization algorithm

    Directory of Open Access Journals (Sweden)

    zeinab pourtaheri

    2014-10-01

    Full Text Available here is a growing interest in the optimal design of the phase locked loops, because these circuits are widely used in communication and electronic circuits. Undoubtedly the most important objectives in designing PLLs (phase locked loops are low power consumption and low delay. In this paper, the process of designing and the optimization of PFD (one of the main part in PLLs are proposed by using particle swarm optimization (PSO algorithm. In the proposed method, instead of carrying out the frequent experiments and simulations based on trial and error to achieve the desired parameters of the phase frequency detector, effective variables are sent to the PSO algorithm and optimization process is done by this algorithm. The results show a remarkable ability of this heuristic method to find transistors sizing for optimal power consumption and delay.

  12. Multi-objective optimal design of active vibration absorber with delayed feedback

    Science.gov (United States)

    Huan, Rong-Hua; Chen, Long-Xiang; Sun, Jian-Qiao

    2015-03-01

    In this paper, a multi-objective optimal design of delayed feedback control of an actively tuned vibration absorber for a stochastically excited linear structure is investigated. The simple cell mapping (SCM) method is used to obtain solutions of the multi-objective optimization problem (MOP). The continuous time approximation (CTA) method is applied to analyze the delayed system. Stability is imposed as a constraint for MOP. Three conflicting objective functions including the peak frequency response, vibration energy of primary structure and control effort are considered. The Pareto set and Pareto front for the optimal feedback control design are presented for two examples. Numerical results have found that the Pareto optimal solutions provide effective delayed feedback control design.

  13. On Time Delay Margin Estimation for Adaptive Control and Optimal Control Modification

    Science.gov (United States)

    Nguyen, Nhan T.

    2011-01-01

    This paper presents methods for estimating time delay margin for adaptive control of input delay systems with almost linear structured uncertainty. The bounded linear stability analysis method seeks to represent an adaptive law by a locally bounded linear approximation within a small time window. The time delay margin of this input delay system represents a local stability measure and is computed analytically by three methods: Pade approximation, Lyapunov-Krasovskii method, and the matrix measure method. These methods are applied to the standard model-reference adaptive control, s-modification adaptive law, and optimal control modification adaptive law. The windowing analysis results in non-unique estimates of the time delay margin since it is dependent on the length of a time window and parameters which vary from one time window to the next. The optimal control modification adaptive law overcomes this limitation in that, as the adaptive gain tends to infinity and if the matched uncertainty is linear, then the closed-loop input delay system tends to a LTI system. A lower bound of the time delay margin of this system can then be estimated uniquely without the need for the windowing analysis. Simulation results demonstrates the feasibility of the bounded linear stability method for time delay margin estimation.

  14. Optimal disturbances rejection control for singularly perturbed systems with time-delay

    Institute of Scientific and Technical Information of China (English)

    Zhang Baolin; Tang Gongyou; Zhao Yandong

    2008-01-01

    The optimal control design for singularly perturbed time-delay systems affected by external disturbances is considered. Based on the decomposition theory of singular perturbation, the system is decomposed into a fast subsystem without time-delay and a slow time-delay subsystem with disturbances. The optimal disturbances rejection control law of the slow subsystem is obtained by using the successive approximation approach (SAA) and feedforward compensation method. Further, the feedforward and feedback composite control (FFCC) law for the original problem is developed. The FFCC law consists of linear analytic terms and a time-delay compensation term which is the limit of the solution sequence of the adjoint vector equations. A disturbance observer is introduced to make the FFCC law physically realizable. Numerical examples show that the proposed algorithm is effective.

  15. Lyapunov matrices approach to the parametric optimization of time-delay systems

    Directory of Open Access Journals (Sweden)

    Duda Józef

    2015-09-01

    Full Text Available In the paper a Lyapunov matrices approach to the parametric optimization problem of time-delay systems with a P-controller is presented. The value of integral quadratic performance index of quality is equal to the value of Lyapunov functional for the initial function of the time-delay system. The Lyapunov functional is determined by means of the Lyapunov matrix

  16. Optimization of time-delayed feedback control of seismically excited building structures

    Institute of Scientific and Technical Information of China (English)

    Xue-ping LI; Wei-qiu ZHU; Zu-guang YING

    2008-01-01

    An optimization method for time-delayed feedback control of partially observable linear building structures subjected to seismic excitation is proposed. A time-delayed control problem of partially observable linear building structure under horizontal ground acceleration excitation is formulated and converted into that of completely observable linear structure by using separation principle. The time-delayed control forces are approximately expressed in terms of control forces without time delay. The control system is then governed by Ito stochastic differential equations for the conditional means of system states and then transformed into those for the conditional means of modal energies by using the stochastic averaging method for quasi-Hamiltonian systems. The control law is assumed to be modal velocity feedback control with time delay and the unknown control gains are determined by the modal performance indices. A three-storey building structure is taken as example to illustrate the proposal method and the numerical results are confirmed by using Monte Carlo simulation.

  17. Delay Optimized Architecture for On-Chip Communication

    Institute of Scientific and Technical Information of China (English)

    Sheraz Anjum; Jie Chen; Pei-Pei Yue; Jian Liu

    2009-01-01

    Networks-on-chip (NoC), a new system on chip (SoC) paradigm, has become a great focus of research by many groups during the last few years. Among all the NoC architectures that have been proposed until now, 2D-Mesh has proved to be the best architecture for implementation due to its regular and simple intercon- nection structure. In this paper, we propose a new interconnect architecture called 2D-diagonal mesh (2DDgl-Mesh) for on-chip communication. The 2DDgl- Mesh is almost similar to traditional 2D-Mesh in aspects of cost, area, and implementation, but it can outperform the later in delay. The both architectures are compared by using NS-2 (a network simulator) and CINSIM (a component based interconnection simulator) under the same traffic models and parametric conditions. The results of comparison show that under the proposed architecture, the packets can almost always be routed to their destinations in less time. In addition, our archi- tecture can sometimes perform better than 2D-Mesh in drop ratio for special fixed traffic models.

  18. Echocardiography in evaluating right ventricular function of patients with sick sinus syndrome and atrioventricular delay with perianal abscesson under AAI and DDD pacing modes%病态窦房结综合征伴房室传导延迟AAI与DDD起搏模式右心功能的超声评价

    Institute of Scientific and Technical Information of China (English)

    陈晓栋; 许迪; 丁文波; 沈建平; 娄彬; 于圣永

    2012-01-01

    Objective To explore the right ventricular function of patients with sick sinus syndrome and atrioventricular delay under AAI and DDD pacing modes. Methods Thirty - five sick sinus syndrome combined with I degree atrioventricular block implantation of DDD patients with dual chamber pacemaker were included in the study. The program- controlled instrument was used to change the pacemaker to DDD mode first,and then to AAI mode. Echocardiography was employed to detect parameter changes of patients with two kinds of pacing mode. Results RVPEP RVPEP/RVET and Sm,Tei index of DDD pacing mode were significantly higher than those of AAI pacing mode (P<0. 05). The E/Em of DDD pacing mode was less than that of AAI pacing mode (P<0.05). Conclusion The right cardiac systolic and diastolic function of the patients with AV is better under the AAI mode pacing mode than under the DDD mode pacing mode.%目的 探讨AAI与DDD起搏模式下病态窦房结综合征伴房室传导阻滞患者的右心功能.方法 35例病态窦房结综合征伴Ⅰ度房室传导阻滞植入DDD双腔起搏器患者,先用程控仪将起搏器程控为DDD模式,最后程控为AAI模式.超声心动图检测患者2种起搏模式下的各参数变化情况.结果 DDD起搏模式下的RVPEP、RVPEP/RVET、Sm、Tei指数明显高于AAI起搏模式(P<0 05),E/Em低于AAI起搏模式(P<0.05).结论 AAI起搏模式右心的收缩和舒张功能均优于AV间期优化的DDD起搏模式.

  19. Decomposition Principles and Online Learning in Cross-Layer Optimization for Delay-Sensitive Applications

    CERN Document Server

    Fu, Fangwen

    2008-01-01

    In this paper, we propose a general cross-layer optimization framework in which we explicitly consider both the heterogeneous and dynamically changing characteristics of delay-sensitive applications and the underlying time-varying network conditions. We consider both the independently decodable data units (DUs, e.g. packets) and the interdependent DUs whose dependencies are captured by a directed acyclic graph (DAG). We first formulate the cross-layer design as a non-linear constrained optimization problem by assuming complete knowledge of the application characteristics and the underlying network conditions. The constrained cross-layer optimization is decomposed into several cross-layer optimization subproblems for each DU and two master problems. The proposed decomposition method determines the necessary message exchanges between layers for achieving the optimal cross-layer solution. However, the attributes (e.g. distortion impact, delay deadline etc) of future DUs as well as the network conditions are ofte...

  20. Delay-Constrained Optimized Packet Aggregation in High-Speed Wireless Networks

    Institute of Scientific and Technical Information of China (English)

    Peyman Teymoori; Nasser Yazdani

    2013-01-01

    High-speed wireless networks such as IEEE 802.11n have been introduced based on IEEE 802.11 to meet the growing demand for high-throughput and multimedia applications.It is known that the medium access control (MAC) efficiency of IEEE 802.11 decreases with increasing the physical rate.To improve efficiency,few solutions have been proposed such as Aggregation to concatenate a number of packets into a larger frame and send it at once to reduce the protocol overhead.Since transmitting larger frames eventuates to dramatic delay and jitter increase in other nodes,bounding the maximum aggregated frame size is important to satisfy delay requirements of especially multimedia applications.In this paper,we propose a scheme called Optimized Packet Aggregation (OPA) which models the network by constrained convex optimization to obtain the optimal aggregation size of each node regarding to delay constraints of other nodes.OPA attains proportionally fair sharing of the channel while satisfying delay constrains.Furthermore,reaching the optimal point is guaranteed in OPA with low complexity.Simulation results show that OPA can successfully bound delay and meet the requirements of nodes with only an insignificant throughput penalty due to limiting the aggregation size even in dynamic conditions.

  1. Atrioventricular Septal Defect with Common Atrioventricular Junction Guarded by a Common Valve Consisting of Left Atrioventricular Trifoliate Valve

    Science.gov (United States)

    Krasniqi, Xhevdet; Gashi, Masar; Berisha, Blerim; Pllana, Ejup; Bakalli, Aurora; Abazi, Flora; Koçinaj, Dardan

    2013-01-01

    Introduction: Atrioventricular septal defect with common atrioventricular junction is a rare adult congenital cardiac syndrome. This occurrence with prolonged survival is exceptionally rare. Case report: We present the case of a patient who presented with this defect with common atrioventricular junction who survived to the age of 32. We describe a 32-year-old man with atrioventricular septal defect with common atrioventricular junction guarded by a common valve. His history, clinical course, and anatomic findings are discussed along with the factors which may have contributed to his longevity, which is unique in the medical literature. His management reflected the state of medical knowledge at the time when he presented, and although alternate approaches may have been utilized if the patient presented today. We discuss the findings, frequency, classifi cation, and management of congenital defects. Development of embryonic structure is altered by interaction between genetics and environmental factors toward a rare associated of congenital cardiac defects-complex congenital heart disease. Conclusion: This case demonstrates that patients with very complex congenital cardiac disease may survive to adulthood, presenting challenges in both medical and surgical treatment. PMID:24554809

  2. An iterative symplectic pseudospectral method to solve nonlinear state-delayed optimal control problems

    Science.gov (United States)

    Peng, Haijun; Wang, Xinwei; Zhang, Sheng; Chen, Biaosong

    2017-07-01

    Nonlinear state-delayed optimal control problems have complex nonlinear characters. To solve this complex nonlinear problem, an iterative symplectic pseudospectral method based on quasilinearization techniques, the dual variational principle and pseudospectral methods is proposed in this paper. First, the proposed method transforms the original nonlinear optimal control problem into a series of linear quadratic optimal control problems. Then, a symplectic pseudospectral method is developed to solve these converted linear quadratic state-delayed optimal control problems. Coefficient matrices in the proposed method are sparse and symmetric since the dual variational principle is used, which makes the proposed method highly efficient. Converged numerical solutions with high precision can be obtained after a few iterations due to the benefit of the local pseudospectral method and quasilinearization techniques. In the numerical simulations, other numerical methods were used for comparisons. The numerical simulation results show that the proposed method is highly accurate, efficient and robust.

  3. [Reversible first-degree atrioventricular block due to hyperthyroidism].

    Science.gov (United States)

    Çelebi, Aksüyek Savaş; Amasyalı, Basri

    2017-04-01

    Hyperthyroidism often causes tachyarrhythmia. Reversible atrioventricular block caused by hyperthyroidism is rare occurrence. Presently described is a case of atrioventricular block due to hyperthyroidism and recovery after antithyroid treatment.

  4. Reversible cardiogenic shock caused by atrioventricular junctional rhythm after percutaneous coronary intervention

    Institute of Scientific and Technical Information of China (English)

    Jun Wang; Qi-Gao Zhang; Xiao-Min Cai; Li-Jun Wang; Jian-Bin Gong; Shi-Sen Jiang

    2012-01-01

    An 82-year-old female patient undergoing cardiogenic shock caused by atrioventricular junctional rhythm immediately after percutaneous coronary intervention (PCI) is described. Pharmacotherapy was invalid, and subsequent application of atrial pacing reversed the cardiogenic shock. PCI-related injury of sinuatrial nodal artery leading to acute atrial contractility loss, accompanied by atrioventricular junctional arrhythmia, was diagnosed. We recommend that preoperative risk evaluation be required for multi-risk patients. Likewise, emergent measures should to be established in advance. This case reminds us that atrial pacing can be an optimal management technique once cardiogenic shock has occurred.

  5. Approximate design of optimal tracking controller for time-delay systems

    Institute of Scientific and Technical Information of China (English)

    TANG Gongyou; LI Chao; ZHAO Yandong

    2006-01-01

    Successive approximate design of the optimal tracking controller for linear systems with time-delay is developed. By applying the successive approximation theory of differential equations, the two-point boundary value (TPBV) problem with both time-delay and time-advance terms derived from the original optimal tracking control (OTC) problem is transformed into a sequence of linear TPBV problems without delay and advance terms. The solution sequence of the linear TPBV problems uniformly converges to the solution of the original OTC problem. The obtained OTC law consists of analytic state feedback terms and a compensation term which is the limit of the adjoint vector sequence. The compensation term can be obtained from an iteration formula of adjoint vectors. By using a finite term of the adjoint vector sequence, a suboptimal tracking control law is revealed. Numerical examples show the effectiveness of the algorithm.

  6. Delay-area trade-off for MPRM circuits based on hybrid discrete particle swarm optimization

    Institute of Scientific and Technical Information of China (English)

    Jiang Zhidi; Wang Zhenhai; Wang Pengjun

    2013-01-01

    Polarity optimization for mixed polarity Reed-Muller (MPRM) circuits is a combinatorial issue.Based on the study on discrete particle swarm optimization (DPSO) and mixed polarity,the corresponding relation between particle and mixed polarity is established,and the delay-area trade-off of large-scale MPRM circuits is proposed.Firstly,mutation operation and elitist strategy in genetic algorithm are incorporated into DPSO to further develop a hybrid DPSO (HDPSO).Then the best polarity for delay and area trade-off is searched for large-scale MPRM circuits by combining the HDPSO and a delay estimation model.Finally,the proposed algorithm is testified by MCNC Benchmarks.Experimental results show that HDPSO achieves a better convergence than DPSO in terms of search capability for large-scale MPRM circuits.

  7. AN OPTIMAL REPLENISHMENT POLICY FOR DETERIORATING ITEMS WITH RAMP TYPE DEMAND UNDER PERMISSIBLE DELAY IN PAYMENTS

    Directory of Open Access Journals (Sweden)

    Dr. Sanjay Jain

    2010-10-01

    Full Text Available The aim of this paper is to develop an optimal replenishment policy for inventory models of deteriorating items with ramp type demand under permissible delay in payments. Deterioration of items begins on their arrival in stock.  An example is also presented to illustrate the application of developed model.

  8. Optimal harvesting of a stochastic delay logistic model with Lévy jumps

    Science.gov (United States)

    Qiu, Hong; Deng, Wenmin

    2016-10-01

    The optimal harvesting problem of a stochastic time delay logistic model with Lévy jumps is considered in this article. We first show that the model has a unique global positive solution and discuss the uniform boundedness of its pth moment with harvesting. Then we prove that the system is globally attractive and asymptotically stable in distribution under our assumptions. Furthermore, we obtain the existence of the optimal harvesting effort by the ergodic method, and then we give the explicit expression of the optimal harvesting policy and maximum yield.

  9. Optimal Inventory Policy under Permissible Payment Delay in Fashion Supply Chains

    Directory of Open Access Journals (Sweden)

    Guo Li

    2014-01-01

    Full Text Available This paper investigates a retailer’s optimal inventory cycle and the corresponding time of payment in fashion supply chains where a supplier allows the payment delay. Here according to the established model we first analyze the retailer's reaction, and then find out the retailer’s optimal inventory policy and time of payment to maximize its total profit. Our result shows that it is not always the best choice for retailers of fashion supply chains to choose the discount way to replenish stocks, but the retailer can decide the optimal credit period and inventory cycle. Moreover, numerical examples are provided to illustrate the model’s feasibility and rationality.

  10. Fault detection and optimization for networked control systems with uncertain time-varying delay

    Institute of Scientific and Technical Information of China (English)

    Qing Wang; Zhaolei Wang; Chaoyang Dong; Erzhuo Niu

    2015-01-01

    The observer-based robust fault detection filter design and optimization for networked control systems (NCSs) with uncer-tain time-varying delays are addressed. The NCSs with uncertain time-varying delays are modeled as parameter-uncertain systems by the matrix theory. Based on the model, an observer-based residual generator is constructed and the sufficient condition for the existence of the desired fault detection filter is derived in terms of the linear matrix inequality. Furthermore, a time domain opti-mization approach is proposed to improve the performance of the fault detection system. To prevent the false alarms, a new thresh-old function is established, and the solution of the optimization problem is given by using the singular value decomposition (SVD) of the matrix. A numerical example is provided to il ustrate the effectiveness of the proposed approach.

  11. Observer-based approximate optimal tracking control for time-delay systems with external disturbances

    Science.gov (United States)

    Su, Hao; Tang, Gong-You

    2016-09-01

    This paper proposes a successive approximation design approach of observer-based optimal tracking controllers for time-delay systems with external disturbances. To solve a two-point boundary value problem with time-delay and time-advance terms and obtain the optimal tracking control law, two sequences of vector differential equations are constructed first. Second, the convergence of the sequences of the vector differential equations is proved to guarantee the existence and uniqueness of the control law. Third, a design algorithm of the optimal tracking control law is presented and the physically realisable problem is addressed by designing a disturbance state observer and a reference input state observer. An example of an industrial electric heater is given to demonstrate the efficiency of the proposed approach.

  12. Scheduling for Optimal Rate Allocation in Ad Hoc Networks With Heterogeneous Delay Constraints

    CERN Document Server

    Jaramillo, Juan Jose; Ying, Lei

    2010-01-01

    This paper studies the problem of scheduling in single-hop wireless networks with real-time traffic, where every packet arrival has an associated deadline and a minimum fraction of packets must be transmitted before the end of the deadline. Using optimization and stochastic network theory we propose a framework to model the quality of service (QoS) requirements under delay constraints. The model allows for fairly general arrival models with heterogeneous constraints. The framework results in an optimal scheduling algorithm which fairly allocates data rates to all flows while meeting long-term delay demands. We also prove that under a simplified scenario our solution translates into a greedy strategy that makes optimal decisions with low complexity.

  13. Online network coding for optimal throughput and delay -- the two-receiver case

    CERN Document Server

    Sundararajan, Jay Kumar; Médard, Muriel

    2008-01-01

    For a packet erasure broadcast channel with two receivers, a new coding algorithm is proposed that makes use of feedback to achieve asymptotically optimal queue size at the sender and decoding delay at the receivers, without compromising on throughput. Our coding module is compatible with the drop-when-seen queuing algorithm proposed in earlier work -- Sundararajan et al. (ISIT 2008). Hence, it guarantees that the physical queue size at the sender tracks the backlog in degrees of freedom. In addition, the coding module is throughput optimal and at the same time, also achieves an asymptotically optimal decoding delay of O(1/{1-\\rho}), where \\rho is the load factor. We consider the asymptotics when \\rho tends to 1 from below, with either the arrival rate (\\lambda) or the channel parameter (\\mu) being fixed at a number less than 1.

  14. The Application of Time-Delay Dependent H∞ Control Model in Manufacturing Decision Optimization

    Directory of Open Access Journals (Sweden)

    Haifeng Guo

    2015-01-01

    Full Text Available This paper uses a time-delay dependent H∞ control model to analyze the effect of manufacturing decisions on the process of transmission from resources to capability. We establish a theoretical framework of manufacturing management process based on three terms: resource, manufacturing decision, and capability. Then we build a time-delay H∞ robust control model to analyze the robustness of manufacturing management. With the state feedback controller between manufacturing resources and decision, we find that there is an optimal decision to adjust the process of transmission from resources to capability under uncertain environment. Finally, we provide an example to prove the robustness of this model.

  15. Global stability, periodic solutions, and optimal control in a nonlinear differential delay model

    Directory of Open Access Journals (Sweden)

    Anatoli F. Ivanov

    2010-09-01

    Full Text Available A nonlinear differential equation with delay serving as a mathematical model of several applied problems is considered. Sufficient conditions for the global asymptotic stability and for the existence of periodic solutions are given. Two particular applications are treated in detail. The first one is a blood cell production model by Mackey, for which new periodicity criteria are derived. The second application is a modified economic model with delay due to Ramsey. An optimization problem for a maximal consumption is stated and solved for the latter.

  16. Factors associated with moderate or severe left atrioventricular valve regurgitation within 30 days of repair of incomplete atrioventricular septal defect

    Directory of Open Access Journals (Sweden)

    Marcelo Felipe Kozak

    2015-04-01

    Full Text Available AbstractIntroduction:Left atrioventricular valve regurgitation is the most concerning residual lesion after surgical correction of atrioventricular septal defect.Objective:To determine factors associated with moderate or greater left atrioventricular valve regurgitation within 30 days of surgical repair of incomplete atrioventricular septal defect.Methods:We assessed the results of 51 consecutive patients 14 years-old and younger presenting with incomplete atrioventricular septal defect that were operated on at our practice between 2002 and 2010. The following variables were considered: age, weight, absence of Down syndrome, grade of preoperative left atrioventricular valve regurgitation, abnormalities on the left atrioventricular valve and the use of annuloplasty. The median age was 4.1 years; the median weight was 13.4 Kg; 37.2% had Down syndrome. At the time of preoperative evaluation, there were 23 cases with moderate or greater left atrioventricular valve regurgitation (45.1%. Abnormalities on the left atrioventricular valve were found in 17.6%; annuloplasty was performed in 21.6%.Results:At the time of postoperative evaluation, there were 12 cases with moderate or greater left atrioventricular valve regurgitation (23.5%. The variation between pre- and postoperative grades of left atrioventricular valve regurgitation of patients with atrioventricular valve malformation did not reach significance (P=0.26, unlike patients without such abnormalities (P=0.016. During univariate analysis, only absence of Down syndrome was statistically significant (P=0.02. However, after a multivariate analysis, none of the factors reached significance.Conclusion:None of the factors studied was determinant of a moderate or greater left atrioventricular valve regurgitation within the first 30 days of repair of incomplete atrioventricular septal defect in the sample. Patients without abnormalities on the left atrioventricular valve benefit more of the operation.

  17. Power Optimization of Multimode Mobile Embedded Systems with Workload-Delay Dependency

    Directory of Open Access Journals (Sweden)

    Hoeseok Yang

    2016-01-01

    Full Text Available This paper proposes to take the relationship between delay and workload into account in the power optimization of microprocessors in mobile embedded systems. Since the components outside a device continuously change their values or properties, the workload to be handled by the systems becomes dynamic and variable. This variable workload is formulated as a staircase function of the delay taken at the previous iteration in this paper and applied to the power optimization of DVFS (dynamic voltage-frequency scaling. In doing so, a graph representation of all possible workload/mode changes during the lifetime of a device, Workload Transition Graph (WTG, is proposed. Then, the power optimization problem is transformed into finding a cycle (closed walk in WTG which minimizes the average power consumption over it. Out of the obtained optimal cycle of WTG, one can derive the optimal power management policy of the target device. It is shown that the proposed policy is valid for both continuous and discrete DVFS models. The effectiveness of the proposed power optimization policy is demonstrated with the simulation results of synthetic and real-life examples.

  18. Optimism and positive and negative feelings in parents of young children with developmental delay.

    Science.gov (United States)

    Kurtz-Nelson, E; McIntyre, L L

    2017-07-01

    Parents' positive and negative feelings about their young children influence both parenting behaviour and child problem behaviour. Research has not previously examined factors that contribute to positive and negative feelings in parents of young children with developmental delay (DD). The present study sought to examine whether optimism, a known protective factor for parents of children with DD, was predictive of positive and negative feelings for these parents. Data were collected from 119 parents of preschool-aged children with developmental delay. Two separate hierarchical linear regression analyses were conducted to determine if optimism significantly predicted positive feelings and negative feelings and whether optimism moderated relations between parenting stress and parent feelings. Increased optimism was found to predict increased positive feelings and decreased negative feelings after controlling for child problem behaviour and parenting stress. In addition, optimism was found to moderate the relation between parenting stress and positive feelings. Results suggest that optimism may impact how parents perceive their children with DD. Future research should examine how positive and negative feelings impact positive parenting behaviour and the trajectory of problem behaviour specifically for children with DD. © 2017 MENCAP and International Association of the Scientific Study of Intellectual and Developmental Disabilities and John Wiley & Sons Ltd.

  19. Design and implementation of a delay-optimized universal programmable routing circuit for FPGAs

    Institute of Scientific and Technical Information of China (English)

    Wu Fang; Zhang Huowen; Lai Jinmei; Wang Yuan; Chen Liguang; Duan Lei; Tong Jiarong

    2009-01-01

    This paper presents a universal field programmable gate array (FPGA) programmable routing circuit,focusing primarily on a delay optimization. Under the precondition of the routing resource's flexibility and routability, the number of programmable interconnect points (PIP) is reduced, and a multiplexer (MUX) plus a BUFFER structure is adopted as the programmable switch. Also, the method of offset lines and the method of complementary hanged end-lines are applied to the TILE routing circuit and the I/O routing circuit, respectively. All of the above features ensure that the whole FPGA chip is highly repeatable, and the signal delay is uniform and predictable over the total chip. Meanwhile, the BUFFER driver is optimized to decrease the signal delay by up to 5%. The proposed routing circuit is applied to the Fudan programmable device (FDP) FPGA, which has been taped out with an SMIC 0.18-μm logic 1P6M process. The test result shows that the programmable routing resource works correctly, and the signal delay over the chip is highly uniform and predictable.

  20. An investigation of optimal photomultiplier signal delay method on detector time resolution in positron emission tomography

    Energy Technology Data Exchange (ETDEWEB)

    Aykac, Mehmet, E-mail: aykac2000@yahoo.com [Siemens Medical Systems, Molecular Imaging, Knoxville, TN 37932 (United States); Cho, Sanghee [Siemens Medical Systems, Molecular Imaging, Knoxville, TN 37932 (United States)

    2011-06-11

    Cerium doped fast scintillators such as LSO and LaBr{sub 3} and fast photomultiplier tubes (PMT) have dramatically improved the timing performance of PET scanners in the last several years. Recent developments in high speed electronics brought new opportunities to understand and process the photosensor signals. In this work, a digital time alignment method is introduced and implemented using fast scintillators and photosensors with the combination of high speed digital electronics. A method was tested on a light sharing 13x13 LSO detector and a 310 ps average crystal time resolution was measured against a single LSO reference detector using optimal signal delays based on a digital leading edge (LE) triggering scheme in a 250 ps sampling interval. The improvement with this method was measured to be about 5.2% compared to the no time alignment case. The crystal time resolution improvements against a single LSO reference detector ranged from 2% to 9% after optimal signal delay implementation.

  1. A novel interconnect-optimal repeater insertion model with target delay constraint in 65 nm CMOS

    Institute of Scientific and Technical Information of China (English)

    Zhu Zhang-Ming; Qian Li-Bo; Yang Yin-Tang

    2009-01-01

    Repeater optimization is the key for SOC (System on Chip) interconnect delay design. This paper proposes a novel optimal model for minimizing power and area overhead of repeaters while meeting the target performance of on-chip interconnect lines. It also presents Lagrangian function to find the number of repeaters and their sizes required for minimizing area and power overhead with target delay constraint. Based on the 65 nanometre CMOS technology, the computed results of the intermediate and global lines show that the proposed model can significantly reduce area and power of interconnected lines, and the better performance will be achieved with the longer line. The results compared with the reference paper demonstrate the validity of this model. It can be integrated into repeater design methodology and CAD (computer aided design) tool for interconnect planning in nanometre SOC.

  2. Optimal Financing Order Decisions of a Supply Chain under the Retailer's Delayed Payment

    Directory of Open Access Journals (Sweden)

    Honglin Yang

    2014-01-01

    Full Text Available In real supply chain, a capital-constrained retailer has two typical payment choices: the up-front payment to receive a high discount price or the delayed payment to reduce capital pressure. We compare with the efficiency of optimal decisions of different participants, that is, supplier, retailer, and bank, under both types of payments based on a game equilibrium analysis. It shows that under the equilibrium, the delayed payment leads to a greater optimal order quantity from the retailer compared to the up-front payment and, thus, improves the whole benefit of the supply chain. The numerical simulation for the random demand following a uniform distribution further verifies our findings. This study provides novel evidence that a dominant supplier who actively offers trade credit helps enhance the whole efficiency of a supply chain.

  3. Decentralized Delay Optimal Control for Interference Networks with Limited Renewable Energy Storage

    CERN Document Server

    Huang, Huang

    2012-01-01

    In this paper, we consider delay minimization for interference networks with renewable energy source, where the transmission power of a node comes from both the conventional utility power (AC power) and the renewable energy source. We assume the transmission power of each node is a function of the local channel state, local data queue state and local energy queue state only. In turn, we consider two delay optimization formulations, namely the decentralized partially observable Markov decision process (DEC-POMDP) and Non-cooperative partially observable stochastic game (POSG). In DEC-POMDP formulation, we derive a decentralized online learning algorithm to determine the control actions and Lagrangian multipliers (LMs) simultaneously, based on the policy gradient approach. Under some mild technical conditions, the proposed decentralized policy gradient algorithm converges almost surely to a local optimal solution. On the other hand, in the non-cooperative POSG formulation, the transmitter nodes are non-cooperat...

  4. Series-based approximate approach of optimal tracking control for nonlinear systems with time-delay

    Institute of Scientific and Technical Information of China (English)

    Gongyou Tang; Mingqu Fan

    2008-01-01

    The optimal output tracking control (OTC) problem for nonlinear systems with time-delay is considered.Using a series-based approx-imate approach,the original OTC problem is transformed into iteration solving linear two-point boundary value problems without time-delay.The OTC law obtained consists of analytical linear feedback and feedforward terms and a nonlinear compensation term with an infinite series of the adjoint vectors.By truncating a finite sum of the adjoint vector series,an approximate optimal tracking control law is obtained.A reduced-order reference input observer is constructed to make the feedforward term physically realizable.Simulation exam-pies are used to test the validity of the series-based approximate approach.

  5. Optimal Inventory Policy under Permissible Payment Delay in Fashion Supply Chains

    OpenAIRE

    Guo Li; Yuchen Kang; Mengqi Liu; Zhaohua Wang

    2014-01-01

    This paper investigates a retailer’s optimal inventory cycle and the corresponding time of payment in fashion supply chains where a supplier allows the payment delay. Here according to the established model we first analyze the retailer's reaction, and then find out the retailer’s optimal inventory policy and time of payment to maximize its total profit. Our result shows that it is not always the best choice for retailers of fashion supply chains to choose the discount way to replenish stocks...

  6. Optimal control strategy for an impulsive stochastic competition system with time delays and jumps

    Science.gov (United States)

    Liu, Lidan; Meng, Xinzhu; Zhang, Tonghua

    2017-07-01

    Driven by both white and jump noises, a stochastic delayed model with two competitive species in a polluted environment is proposed and investigated. By using the comparison theorem of stochastic differential equations and limit superior theory, sufficient conditions for persistence in mean and extinction of two species are established. In addition, we obtain that the system is asymptotically stable in distribution by using ergodic method. Furthermore, the optimal harvesting effort and the maximum of expectation of sustainable yield (ESY) are derived from Hessian matrix method and optimal harvesting theory of differential equations. Finally, some numerical simulations are provided to illustrate the theoretical results.

  7. Optimal tuning of a control system for a second-order plant with time delay

    Science.gov (United States)

    Golinko, I. M.

    2014-07-01

    An engineering method for optimizing the parameters of PI and PID controllers for a second-order controlled plant with time delay is considered. An integral quality criterion involving minimization of the control output is proposed for optimizing the control system, which differs from the existing ones in that the effect the control output has on the technological process is taken into account in a correct way. The use of such control makes it possible to minimize the expenditure of material and/or energy resources, to limit the wear, and to increase the service life of the control devices. The unimodal nature of the proposed quality criterion for solving optimal controller tuning problems is numerically confirmed using the optimization theory. A functional correlation between the optimal controller parameters and dynamic properties of a controlled plant is determined for a single-loop control system with the use of calculation methods. The results from simulating the transients in the control system using the proposed and existing functional dependences are compared. The proposed calculation formulas differ from the existing ones by having simple structure, high accuracy of searching for the optimal controller parameters; they allow efficient control to be obtained and can be used for tuning automatic control systems in a wide range of controlled plant dynamic properties. The obtained calculation formulas are recommended for being used by engineers specializing in automation for designing new and optimizing the existing control systems.

  8. A time-delay equation: well-posedness to optimal control

    Directory of Open Access Journals (Sweden)

    Yildirim Kenan

    2016-01-01

    Full Text Available In this paper, well-posedness, controllability and optimal control for a time-delay beam equation are studied. The equation of motion is modeled as a time-delayed distributed parameter system(DPS and includes Heaviside functions and their spatial derivatives due to the finite size of piezoelectric patch actuators used to suppress the excessive vibrations based on displacement and moment conditions. The optimal control problem is defined with the performance index including a weighted quadratic functional of the displacement and velocity which is to be minimized at a given terminal time and a penalty term defined as the control voltage used in the control duration. Optimal control law is obtained by using Maximum principle and hence, the optimal control problem is transformed the into a boundary-, initial and terminal value problem.The explicit solution of the control problem is obtained by eigenfunction expansions of the state and adjoint variables. Numerical results are presented to show the effectiveness and applicability of the piezoelectric control.

  9. Adaptive Transmitter Optimization in Multiuser Multiantenna Systems: Theoretical Limits, Effect of Delays, and Performance Enhancements

    Directory of Open Access Journals (Sweden)

    Samardzija Dragan

    2005-01-01

    Full Text Available The advances in programmable and reconfigurable radios have rendered feasible transmitter optimization schemes that can greatly improve the performance of multiple-antenna multiuser systems. Reconfigurable radio platforms are particularly suitable for implementation of transmitter optimization at the base station. We consider the downlink of a wireless system with multiple transmit antennas at the base station and a number of mobile terminals (i.e., users each with a single receive antenna. Under an average transmit power constraint, we consider the maximum achievable sum data rates in the case of (1 zero-forcing (ZF spatial prefilter, (2 modified zero-forcing (MZF spatial prefilter, and (3 triangularization spatial prefilter coupled with dirty-paper coding (DPC transmission scheme. We show that the triangularization with DPC approaches the closed-loop MIMO rates (upper bound for higher SNRs. Further, the MZF solution performs very well for lower SNRs, while for higher SNRs, the rates for the ZF solution converge to the MZF rates. An important impediment that degrades the performance of such transmitter optimization schemes is the delay in channel state information (CSI. We characterize the fundamental limits of performance in the presence of delayed CSI and then propose performance enhancements using a linear MMSE predictor of the CSI that can be used in conjunction with transmitter optimization in multiple-antenna multiuser systems.

  10. Atrioventricular septal defects among infants in Europe

    DEFF Research Database (Denmark)

    Christensen, Nikolas; Andersen, Helle; Garne, Ester

    2013-01-01

    OBJECTIVE: To describe the epidemiology of chromosomal and non-chromosomal cases of atrioventricular septal defects in Europe. METHODS: Data were obtained from EUROCAT, a European network of population-based registries collecting data on congenital anomalies. Data from 13 registries for the period...... 2000-2008 were included. RESULTS: There was a total of 993 cases of atrioventricular septal defects, with a total prevalence of 5.3 per 10,000 births (95% confidence interval 4.1 to 6.5). Of the total cases, 250 were isolated cardiac lesions, 583 were chromosomal cases, 79 had multiple anomalies, 58...... of pregnancy owing to foetal anomaly. Among the groups, additional associated cardiac anomalies were most frequent in heterotaxia cases (38%) and least frequent in chromosomal cases (8%). Coarctation of the aorta was the most common associated cardiac defect. The 1-week survival rate for live births was 94...

  11. Solvability of some partial functional integrodifferential equations with finite delay and optimal controls in Banach spaces.

    Science.gov (United States)

    Ezzinbi, Khalil; Ndambomve, Patrice

    2016-01-01

    In this work, we consider the control system governed by some partial functional integrodifferential equations with finite delay in Banach spaces. We assume that the undelayed part admits a resolvent operator in the sense of Grimmer. Firstly, some suitable conditions are established to guarantee the existence and uniqueness of mild solutions for a broad class of partial functional integrodifferential infinite dimensional control systems. Secondly, it is proved that, under generally mild conditions of cost functional, the associated Lagrange problem has an optimal solution, and that for each optimal solution there is a minimizing sequence of the problem that converges to the optimal solution with respect to the trajectory, the control, and the functional in appropriate topologies. Our results extend and complement many other important results in the literature. Finally, a concrete example of application is given to illustrate the effectiveness of our main results.

  12. Delay optimization for planar wireless sensor network with N-policy

    Institute of Scientific and Technical Information of China (English)

    陈志刚; 张德宇; 陈龙

    2014-01-01

    In N-policy, the nodes attempt to seize the channel when the number of packets in the buffer approaches N. The performance of N-policy on the energy efficiency is widely studied in the past years. And it is presented that there exists one optimal N to minimize the energy consumption. However, it is noticed that the delay raised by N-policy receives little attention. This work mathematically proves the delay to monotonically increase with increasing N in the collision-unfree channel. For planar network where the near-to-sink nodes burden heavier traffic than the external ones, the data stemming from the latter undergo longer delay. The various-N algorithm is proposed to address this phenomenon by decreasing the threshold N of outer nodes. Without the impacting on the network longevity, the maximum delay among the network has decreased 62.9% by the algorithm. Extensive simulations are given to verify the effectiveness and correctness of our analysis.

  13. Optimal state estimation for networked systems with random parameter matrices, correlated noises and delayed measurements

    Science.gov (United States)

    Caballero-Águila, R.; Hermoso-Carazo, A.; Linares-Pérez, J.

    2015-02-01

    In this paper, the optimal least-squares state estimation problem is addressed for a class of discrete-time multisensor linear stochastic systems with state transition and measurement random parameter matrices and correlated noises. It is assumed that at any sampling time, as a consequence of possible failures during the transmission process, one-step delays with different delay characteristics may occur randomly in the received measurements. The random delay phenomenon is modelled by using a different sequence of Bernoulli random variables in each sensor. The process noise and all the sensor measurement noises are one-step autocorrelated and different sensor noises are one-step cross-correlated. Also, the process noise and each sensor measurement noise are two-step cross-correlated. Based on the proposed model and using an innovation approach, the optimal linear filter is designed by a recursive algorithm which is very simple computationally and suitable for online applications. A numerical simulation is exploited to illustrate the feasibility of the proposed filtering algorithm.

  14. Optimal fractional delay-IIR filter design using cuckoo search algorithm.

    Science.gov (United States)

    Kumar, Manjeet; Rawat, Tarun Kumar

    2015-11-01

    This paper applied a novel global meta-heuristic optimization algorithm, cuckoo search algorithm (CSA) to determine optimal coefficients of a fractional delay-infinite impulse response (FD-IIR) filter and trying to meet the ideal frequency response characteristics. Since fractional delay-IIR filter design is a multi-modal optimization problem, it cannot be computed efficiently using conventional gradient based optimization techniques. A weighted least square (WLS) based fitness function is used to improve the performance to a great extent. FD-IIR filters of different orders have been designed using the CSA. The simulation results of the proposed CSA based approach have been compared to those of well accepted evolutionary algorithms like Genetic Algorithm (GA) and Particle Swarm Optimization (PSO). The performance of the CSA based FD-IIR filter is superior to those obtained by GA and PSO. The simulation and statistical results affirm that the proposed approach using CSA outperforms GA and PSO, not only in the convergence rate but also in optimal performance of the designed FD-IIR filter (i.e., smaller magnitude error, smaller phase error, higher percentage improvement in magnitude and phase error, fast convergence rate). The absolute magnitude and phase error obtained for the designed 5th order FD-IIR filter are as low as 0.0037 and 0.0046, respectively. The percentage improvement in magnitude error for CSA based 5th order FD-IIR design with respect to GA and PSO are 80.93% and 74.83% respectively, and phase error are 76.04% and 71.25%, respectively.

  15. Approximately optimal tracking control for discrete time-delay systems with disturbances

    Institute of Scientific and Technical Information of China (English)

    Gongyou Tang; Huiying Sun; Haiping Pang

    2008-01-01

    Optimal tracking control (OTC) for discrete time-delay systems affected by persistent disturbances with quadratic performance index is considered. By introducing a sensitivity parameter, the original OTC problem is transformed into a series of two-point boundary value (TPBV) problems without time-advance or time-delay terms. The obtained OTC law consists of analytic feedforward and feedback terms and a compensation term which is the sum of an infinite series of adjoint vectors. The analytic feedforward and feedback terms can be found by solving a Riccati matrix equation and two Stein matrix equations. The compensation term can be obtained by using an iteration formula of the adjoint vectors. Observers are constructed to make the approximate OTC law physically realizable. A simulation example shows that the approximate approach is effective in tracking the reference input and robust with respect to exogenous persistent disturbances.

  16. Time-delayed feedback control optimization for quasi linear systems under random excitations

    Institute of Scientific and Technical Information of China (English)

    Xueping Li; Detain Wei; Weiqiu Zhu

    2009-01-01

    A strategy for time-delayed feedback control optimization of quasi linear systems with random excita-tion is proposed. First, the stochastic averaging method is used to reduce the dimension of the state space and to derive the stationary response of the system. Secondly, the control law is assumed to be velocity feedback control with time delay and the unknown control gains are determined by the performance indices. The response of the controlled system is predicted through solving the Fokker-Plank-Kolmogorov equation associated with the averaged It6 equation. Finally, numerical examples are used to illustrate the proposed con-trol method, and the numerical results are confirmed by Monte Carlo simulation.

  17. Distributive Stochastic Learning for Delay-Optimal OFDMA Power and Subband Allocation

    CERN Document Server

    Cui, Ying

    2010-01-01

    In this paper, we consider the distributive queue-aware power and subband allocation design for a delay-optimal OFDMA uplink system with one base station, $K$ users and $N_F$ independent subbands. Each mobile has an uplink queue with heterogeneous packet arrivals and delay requirements. We model the problem as an infinite horizon average reward Markov Decision Problem (MDP) where the control actions are functions of the instantaneous Channel State Information (CSI) as well as the joint Queue State Information (QSI). To address the distributive requirement and the issue of exponential memory requirement and computational complexity, we approximate the subband allocation Q-factor by the sum of the per-user subband allocation Q-factor and derive a distributive online stochastic learning algorithm to estimate the per-user Q-factor and the Lagrange multipliers (LM) simultaneously and determine the control actions using an auction mechanism. We show that under the proposed auction mechanism, the distributive online...

  18. Sixty-four MDCT achieves higher contrast in pancreas with optimization of scan time delay

    Science.gov (United States)

    Stuber, Tina; Brambs, Hans-Jürgen; Freund, Wolfgang; Juchems, Markus S

    2012-01-01

    AIM: To compare different multidetector computed tomography (MDCT) protocols to optimize pancreatic contrast enhancement. METHODS: Forty consecutive patients underwent contrast-enhanced biphasic MDCT (arterial and portal-venous phase) using a 64-slice MDCT. In 20 patients, the scan protocol was adapted from a previously used 40-channel MDCT scanner with arterial phase scanning initiated 11.1 s after a threshold of 150 HU was reached in the descending aorta, using automatic bolus tracking (Protocol 1). The 11.1-s delay was changed to 15 s in the other 20 patients to reflect the shorter scanning times on the 64-channel MDCT compared to the previous 40-channel system (Protocol 2). HU values were measured in the head and tail of the pancreas in the arterial and portal-venous phase. RESULTS: Using an 11.1-s delay, 74.2 HU (head) were measured on average in the arterial phase and 111.2 HU (head) were measured using a 15-s delay (P < 0.0001). For the pancreatic tail, the average attenuation level was 76.73 HU (11.1 s) and 99.89 HU (15 s) respectively (P = 0.0002). HU values were also significantly higher in the portal-venous phase [pancreatic head: 70.5 HU (11.1 s) vs 84.0 HU (15 s) (P = 0.0014); pancreatic tail: 67.45 HU (11.1 s) and 77.18 HU (15 s) using Protocol 2 (P = 0.0071)]. CONCLUSION: Sixty-four MDCT may yield a higher contrast in pancreatic study with (appropriate) optimization of scan delay time. PMID:22900134

  19. Direct SQP-methods for solving optimal control problems with delays

    Energy Technology Data Exchange (ETDEWEB)

    Goellmann, L.; Bueskens, C.; Maurer, H.

    1994-12-31

    The maximum principle for optimal control problems with delays leads to a boundary value problem (BVP) which is retarded in the state and advanced in the costate function. Based on shooting techniques, solution methods for this type of BVP have been proposed. In recent years, direct optimization methods have been favored for solving control problems without delays. Direct methods approximate the control and the state over a fixed mesh and solve the resulting NLP-problem with SQP-methods. These methods dispense with the costate function and have shown to be robust and efficient. In this paper, we propose a direct SQP-method for retarded control problems. In contrast to conventional direct methods, only the control variable is approximated by e.g. spline-functions. The state is computed via a high order Runge-Kutta type algorithm and does not enter explicitly the NLP-problem through an equation. This approach reduces the number of optimization variables considerably and is implementable even on a PC. Our method is illustrated by the numerical solution of retarded control problems with constraints. In particular, we consider the control of a continuous stirred tank reactor which has been solved by dynamic programming. This example illustrates the robustness and efficiency of the proposed method. Open questions concerning sufficient conditions and convergence of discretized NLP-problems are discussed.

  20. Developing an Inspection Optimization Model Based on the Delay-Time Concept

    Directory of Open Access Journals (Sweden)

    Ehsan Nazemi

    2015-01-01

    Full Text Available Infrastructures are considered as important facilities required for every country and society to be able to work properly. Aging and deterioration of such structures during their lifetime are a major concern both for maintenance researchers in the academic world and for the practitioners. This concern is mainly because the deterioration increases the maintenance costs dramatically and lowers the reliability, availability, and safety of the structural system. Preventive maintenance and inspection activities are the most usual means for keeping the structure in a good condition. This paper utilizes the concept of delay-time for developing the optimal inspection policy for deteriorating structures. In the proposed stochastic model, discrete times of inspection activities are taken as the decision variables of an optimization problem, in a way that the obtained aperiodic (nonuniform inspection schedule minimizes the total downtime ratio of the structure. To illustrate the model capabilities, various numerical examples are solved and results are compared with the traditional periodic (uniform inspection policies. The results indicate the substantial reduction in system downtime due to the wisely planned inspection schedule and the appropriate utilization of delay-time concept, which is indeed a powerful framework for inspection optimization problems.

  1. Robust optimization for nonlinear time-delay dynamical system of dha regulon with cost sensitivity constraint in batch culture

    Science.gov (United States)

    Yuan, Jinlong; Zhang, Xu; Liu, Chongyang; Chang, Liang; Xie, Jun; Feng, Enmin; Yin, Hongchao; Xiu, Zhilong

    2016-09-01

    Time-delay dynamical systems, which depend on both the current state of the system and the state at delayed times, have been an active area of research in many real-world applications. In this paper, we consider a nonlinear time-delay dynamical system of dha-regulonwith unknown time-delays in batch culture of glycerol bioconversion to 1,3-propanediol induced by Klebsiella pneumonia. Some important properties and strong positive invariance are discussed. Because of the difficulty in accurately measuring the concentrations of intracellular substances and the absence of equilibrium points for the time-delay system, a quantitative biological robustness for the concentrations of intracellular substances is defined by penalizing a weighted sum of the expectation and variance of the relative deviation between system outputs before and after the time-delays are perturbed. Our goal is to determine optimal values of the time-delays. To this end, we formulate an optimization problem in which the time delays are decision variables and the cost function is to minimize the biological robustness. This optimization problem is subject to the time-delay system, parameter constraints, continuous state inequality constraints for ensuring that the concentrations of extracellular and intracellular substances lie within specified limits, a quality constraint to reflect operational requirements and a cost sensitivity constraint for ensuring that an acceptable level of the system performance is achieved. It is approximated as a sequence of nonlinear programming sub-problems through the application of constraint transcription and local smoothing approximation techniques. Due to the highly complex nature of this optimization problem, the computational cost is high. Thus, a parallel algorithm is proposed to solve these nonlinear programming sub-problems based on the filled function method. Finally, it is observed that the obtained optimal estimates for the time-delays are highly satisfactory

  2. FIDER: A Force-Balance-Based Interconnect Delay Driven Re-Synthesis Algorithm for Data-Path Optimization After Floorplan

    Institute of Scientific and Technical Information of China (English)

    WANG Yunfeng; BIAN Jinian; HONG Xianlong; ZHOU Qiang; WU Qiang

    2007-01-01

    As the feature size of integrated circuits is reduced to the deep sub-micron level or the nanometer level, the interconnect delay is becoming more and more important in determining the total delay of a circuit. Re-synthesis after floorptan is expected to be very helpful for reducing the interconnect delay of a circuit. In this paper,a force-balance-based re-synthesis algorithm for interconnect delay o ptimization after floorplan is proposed. The algorithm optimizes the inter connect delay by changing the operation scheduling and the functional unit allocation andbinding. With this method the number and positions of all functional units are not changed, but some operations are allocated or bound to different units. Preliminary experimental results show that the interconnect wire delays are reduced efficiently without destroying the floorplan performance.

  3. Atrioventricular Dissociation following Blunt Chest Trauma

    Directory of Open Access Journals (Sweden)

    Salim Surani

    2014-01-01

    Full Text Available Blunt chest trauma (BCT is a common clinical presentation seen in emergency departments. Few cases of cardiac conduction abnormalities due to BCT have been reported in the medical literature. This dysrhythmias may present as permanent conduction defects requiring permanent pacemaker or may have temporary conduction abnormalities requiring temporary pacemaker or supportive care. We present the case of a young woman who suffered from BCT after being kicked by a horse with the development of a significant substernal hematoma. She developed temporary atrioventricular block, which was completely resolved with the decrease in the size of the substernal hematoma suffered.

  4. Intermittent Atrioventricular Block following Fingolimod Initiation

    Directory of Open Access Journals (Sweden)

    E. Gialafos

    2014-01-01

    Full Text Available A 47-year-old female patient with multiple sclerosis (MS developed symptomatic intermittent 2nd degree atrioventricular block (AVB of five-hour duration, five hours after the first two doses of fingolimod, that resolved completely. Frequency domain analysis of heart rate variability (HRV revealed increased parasympathetic activity and decreased sympathetic tone, while modified Ewing tests were suggestive of impaired cardiac sympathetic function. We hypothesize that expression of this particular arrhythmia might be related to autonomic nervous system (ANS dysfunction due to demyelinating lesions in the upper thoracic spinal cord, possibly augmented by the parasympathetic effect of the drug.

  5. Tuning of an optimal fuzzy PID controller with stochastic algorithms for networked control systems with random time delay.

    Science.gov (United States)

    Pan, Indranil; Das, Saptarshi; Gupta, Amitava

    2011-01-01

    An optimal PID and an optimal fuzzy PID have been tuned by minimizing the Integral of Time multiplied Absolute Error (ITAE) and squared controller output for a networked control system (NCS). The tuning is attempted for a higher order and a time delay system using two stochastic algorithms viz. the Genetic Algorithm (GA) and two variants of Particle Swarm Optimization (PSO) and the closed loop performances are compared. The paper shows that random variation in network delay can be handled efficiently with fuzzy logic based PID controllers over conventional PID controllers.

  6. Prognostic importance of complete atrioventricular block complicating acute myocardial infarction

    DEFF Research Database (Denmark)

    Aplin, Mark; Engstrøm, Thomas; Vejlstrup, Niels G

    2003-01-01

    Third-degree atrioventricular block after acute myocardial infarction is considered to have prognostic importance. However, its importance in conjunction with thrombolytic therapy and its relation to left ventricular function remains uncertain. This report also outlines an important distinction...... between atrioventricular block in the setting of anterior and inferior wall acute myocardial infarction, with profound clinical and prognostic implications....

  7. Prognostic importance of complete atrioventricular block complicating acute myocardial infarction

    DEFF Research Database (Denmark)

    Aplin, Mark; Engstrøm, Thomas; Vejlstrup, Niels G

    2003-01-01

    Third-degree atrioventricular block after acute myocardial infarction is considered to have prognostic importance. However, its importance in conjunction with thrombolytic therapy and its relation to left ventricular function remains uncertain. This report also outlines an important distinction...... between atrioventricular block in the setting of anterior and inferior wall acute myocardial infarction, with profound clinical and prognostic implications....

  8. The fusion band in V1: a simple ECG guide to optimal resynchronization? An echocardiographic case report

    Directory of Open Access Journals (Sweden)

    Corbucci Giorgio

    2005-09-01

    Full Text Available Abstract Background Patients with left bundle branch block have a preserved right bundle branch conduction and the efficacy of left ventricular pacing could be explained with the fusion between artificial pulse delivered in the left lateral wall and the spontaneous right ventricular activation. Moreover, the efficacy of left ventricular pacing could be enhanced with an optimal timing between the spontaneous right ventricular activation and the left ventricular pulse. Case presentation We evaluated a patient (male, 47 yrs with surgically corrected mitral regurgitation, sinus rhythm and left bundle branch block, heart failure (NYHA class III despite medical therapy and low ejection fraction (25%: he was implanted with a biventricular device. We programmed ventricular pacing only through the left ventricular lead. We defined what we called electrocardiographic "fusion band" as follow: programming OFF the stimulator, we recorded the native electrocardiogram and measured, through the device, the intrinsic atrioventricular interval. Then, atrioventricular interval was progressively shortened by steps of 20 ms down to 100 ms. Twelve leads electrocardiogram was recorded at each step. The fusion band is the range of AV intervals at which surface electrocardiogram (mainly in V1 lead presents an intermediate morphology between the native left bundle branch block (upper limit of the band and the fully paced right bundle branch block (lower limit. The patient underwent echocardiographic examination at each atrioventricular interval chosen inside the fusion band. The following parameters were evaluated: ejection fraction, diastolic filling time, E wave deceleration time, aortic velocity time integral and myocardial performance index. All the echocardiographic parameters showed an improvement inside the fusion band, with a "plateau" behaviour. As the fusion band in this patient ranged from an atrioventricular delay of 200 ms to an atrioventricular delay of 120

  9. Remediation of time-delay effects in tokamak axisymmetric control loops by optimal tuning and robust predictor augmentation

    Energy Technology Data Exchange (ETDEWEB)

    Sondak, D.; Arastoo, R. [Department of Mechanical Engineering and Mechanics, Lehigh University, Bethlehem, PA 18015 (United States); Schuster, E., E-mail: schuster@lehigh.edu [Department of Mechanical Engineering and Mechanics, Lehigh University, Bethlehem, PA 18015 (United States); Walker, M.L. [General Atomics, San Diego, CA 92121 (United States)

    2011-10-15

    It is sometimes incorrectly assumed that, because superconducting tokamaks already have significant intrinsic or imposed sources of control delay, introducing extra delays/lags into the axisymmetric control loops will have negligible detrimental impact on the plasma control. This study exposes and quantifies the detrimental effects imposed by time delays/lags in the control loop in superconducting tokamaks, using as an example the plasma current control and radial position control in a vertically stable circular plasma in the KSTAR tokamak. Delays and lags in the power supplies, data acquisition, and vessel structure are taken into account. Optimal tuning of PID controllers in combination with an ohmic-flux control strategy is proposed as a possible method for remediating the negative effects of time delays/lags. In addition, an augmentation of the control loop by the introduction of a robust predictor has been proposed to improve the performance of the time-delayed closed-loop system when the amount of delay/lag in the loop is unknown. The Nyquist dual locus technique based on the Argument Principle in complex theory is employed to assess stability of the optimally tuned closed-loop system in the presence of time delays.

  10. [Acute atrioventricular block in chronic Lyme disease].

    Science.gov (United States)

    Wagner, Vince; Zima, Endre; Gellér, László; Merkely, Béla

    2010-09-26

    The tick bite transmitted Lyme disease is one of the most common antropozoonosis, about 10 000 new infections are reported in Hungary each year. The progress and clinical presentation can vary, and carditis can occur in later stages. A serologically verified Lyme disease caused third degree atrioventricular block in young male presenting with presyncope. Based on the tick-bites mentioned a few weeks prior to hospital admission, Lyme carditis was considered with the administration of antibiotics and monitor observation. Typical skin lesions were not recognized and laboratory findings showed no pathology. An electrophysiological study recorded a predominant supra-His atrioventricular block. Total regression of conduction could be detected later and the serological tests established an underlying Lyme disease. Currently no definite treatment recommendation is available for the potentially reversible Lyme carditis. The tick bite seemed to be the key on our way to diagnosis; however, serological tests proved the disease to be older than one year. A detailed medical history and serological tests are essential in identifying the cause and pacemaker implantation can be avoided.

  11. Acidosis slows electrical conduction through the atrio-ventricular node

    Directory of Open Access Journals (Sweden)

    Ashley Muir Nisbet

    2014-06-01

    Full Text Available Acidosis affects the mechanical and electrical activity of mammalian hearts but comparatively little is known about its effects on the function of the atrio-ventricular node (AVN. In this study, the electrical activity of the epicardial surface of the left ventricle of isolated Langendorff-perfused rabbit hearts was examined using optical methods. Perfusion with hypercapnic Tyrode’s solution (20% CO2, pH 6.7 increased the time of earliest activation (Tact from 100.5+7.9 to 166.1+7.2ms (n=8 at a pacing cycle length (PCL of 300ms (37oC. Tact increased at shorter PCL, and the hypercapnic solution prolonged Tact further: at 150ms PCL, Tact was prolonged from 131.0+5.2 to 174.9+16.3ms. 2:1 AVN block was common at shorter cycle lengths. Atrial and ventricular conduction times were not significantly affected by the hypercapnic solution suggesting that the increased delay originated in the AVN. Isolated right atrial preparations were superfused with Tyrode’s solutions at pH 7.4 (control, 6.8 and 6.3. Low pH prolonged the atrial-Hisian (AH interval, the effective and functional refractory periods and Wenckebach cycle length significantly. Complete AVN block occurred in 6 out of 9 preparations. Optical imaging of conduction at the AV junction revealed increased conduction delay in the region of the AVN, with less marked effects in atrial and ventricular tissue. Thus acidosis can dramatically prolong the AVN delay, and in combination with short cycle lengths, this can cause partial or complete AVN block and is therefore implicated in the development of brady-arrhythmias in conditions of local or systemic acidosis.

  12. Delay-Optimal Power and Subcarrier Allocation for OFDMA Systems via Stochastic Approximation

    CERN Document Server

    Lau, Vincent K N

    2009-01-01

    In this paper, we consider delay-optimal power and subcarrier allocation design for OFDMA systems with $N_F$ subcarriers, $K$ mobiles and one base station. There are $K$ queues at the base station for the downlink traffic to the $K$ mobiles with heterogeneous packet arrivals and delay requirements. We shall model the problem as a $K$-dimensional infinite horizon average reward Markov Decision Problem (MDP) where the control actions are assumed to be a function of the instantaneous Channel State Information (CSI) as well as the joint Queue State Information (QSI). This problem is challenging because it corresponds to a stochastic Network Utility Maximization (NUM) problem where general solution is still unknown. We propose an {\\em online stochastic value iteration} solution using {\\em stochastic approximation}. The proposed power control algorithm, which is a function of both the CSI and the QSI, takes the form of multi-level water-filling. We prove that under two mild conditions in Theorem 1 (One is the steps...

  13. Optimized energy-delay sub-network routing protocol development and implementation for wireless sensor networks

    Science.gov (United States)

    Fonda, James W.; Zawodniok, Maciej; Jagannathan, S.; Watkins, Steve E.

    2008-08-01

    The development and the implementation issues of a reactive optimized energy-delay sub-network routing (OEDSR) protocol for wireless sensor networks (WSN) are introduced and its performance is contrasted with the popular ad hoc on-demand distance vector (AODV) routing protocol. Analytical results illustrate the performance of the proposed OEDSR protocol, while experimental results utilizing a hardware testbed under various scenarios demonstrate improvements in energy efficiency of the OEDSR protocol. A hardware platform constructed at the University of Missouri-Rolla (UMR), now the Missouri University of Science and Technology (MST), based on the Generation 4 Smart Sensor Node (G4-SSN) prototyping platform is also described. Performance improvements are shown in terms of end-to-end (E2E) delay, throughput, route-set-up time and drop rates and energy usage is given for three topologies, including a mobile topology. Additionally, results from the hardware testbed provide valuable lessons for network deployments. Under testing OEDSR provides a factor of ten improvement in the energy used in the routing session and extends network lifetime compared to AODV. Depletion experiments show that the time until the first node failure is extended by a factor of three with the network depleting and network lifetime is extended by 6.7%.

  14. Two-Channel Transparency-Optimized Control Architectures in Bilateral Teleoperation With Time Delay

    Science.gov (United States)

    Kim, Jonghyun; Chang, Pyung Hun; Park, Hyung-Soon

    2013-01-01

    This paper introduces transparency-optimized control architectures (TOCAs) using two communication channels. Two classes of two-channel TOCAs are found, thereby showing that two channels are sufficient to achieve transparency. These TOCAs achieve a greater level of transparency but poorer stability than three-channel TOCAs and four-channel TOCAs. Stability of the two-channel TOCAs has been enhanced while minimizing transparency degradation by adding a filter; and a combined use of the two classes of two-channel TOCAs is proposed for both free space and constrained motion, which involve switching between two TOCAs for transition between free space and constrained motions. The stability condition of the switched teleoperation system is derived for practical applications. Through the one degree-of-freedom (DOF) experiment, the proposed two-channel TOCAs were shown to operate stably, while achieving better transparency under time delay than the other TOCAs. PMID:23833548

  15. Optimal Placement and Sizing of FACTS Devices to Delay Transmission Expansion

    CERN Document Server

    Frolov, Vladimir; Backhaus, Scott; Bialek, Janusz; Chertkov, Michael

    2016-01-01

    The Transmission System Operators (TSOs) plan to reinforce their transmission grids based on the projected system congestion caused by the increase in future system load, amongst other factors. However, transmission expansion is severely limited in many countries, and especially in Europe, due to many factors such as clearance acquisitions. An alternative is to use Flexible Alternating Current Transmission System (FACTS) devices, thus allowing to delay or avoid much more expensive transmission expansion. These devices are capable of utilizing the existing transmission grid more flexibly. However, the locations and sizing of future FACTS devices must be carefully determined during the planning phase in order to avoid congestion under many representative scenarios of the projected economic growth (of loads). This paper proposes an optimization approach, based on AC Power Flows, to determine suitable locations and sizes of series and shunt FACTS devices. Non-linear, non-convex and multiple-scenario based optimiz...

  16. Canonical Wnt Signaling Regulates Atrioventricular Junction Programming and Electrophysiological Properties

    Science.gov (United States)

    Gillers, Benjamin S; Chiplunkar, Aditi; Aly, Haytham; Valenta, Tomas; Basler, Konrad; Christoffels, Vincent M.; Efimov, Igor R; Boukens, Bastiaan J; Rentschler, Stacey

    2014-01-01

    Rationale Proper patterning of the atrioventricular canal (AVC) is essential for delay of electrical impulses between atria and ventricles, and defects in AVC maturation can result in congenital heart disease. Objective To determine the role of canonical Wnt signaling in the myocardium during AVC development. Methods and Results We utilized a novel allele of β-catenin that preserves β-catenin’s cell adhesive functions but disrupts canonical Wnt signaling, allowing us to probe the effects of Wnt loss of function independently. We show that loss of canonical Wnt signaling in the myocardium results in tricuspid atresia with hypoplastic right ventricle associated with loss of AVC myocardium. In contrast, ectopic activation of Wnt signaling was sufficient to induce formation of ectopic AV junction-like tissue as assessed by morphology, gene expression, and electrophysiologic criteria. Aberrant AVC development can lead to ventricular preexcitation, a characteristic feature of Wolff-Parkinson-White syndrome. We demonstrate that postnatal activation of Notch signaling downregulates canonical Wnt targets within the AV junction. Stabilization of β-catenin protein levels can rescue Notch-mediated ventricular preexcitation and dysregulated ion channel gene expression. Conclusions Our data demonstrate that myocardial canonical Wnt signaling is an important regulator of AVC maturation and electrical programming upstream of Tbx3. Our data further suggests that ventricular preexcitation may require both morphologic patterning defects, as well as myocardial lineage reprogramming, to allow robust conduction across accessory pathway tissue. PMID:25599332

  17. Establishment of control equations and adjoint equations using block-pulse functions for optimal control of linear systems with time delays

    Institute of Scientific and Technical Information of China (English)

    王兴涛

    2002-01-01

    Control equation and adjoint equation are established by using block-pulse functions, which trans-forms the linear time-varying systems with time delays into a system of algebraic equations and the optimal con-trol problems are transformed into an optimization problem of multivariate functions thereby achieving the opti-mal control of linear systems with time delays.

  18. Pilot signal design via constrained optimization with application to delay-Doppler shift estimation in OFDM systems

    DEFF Research Database (Denmark)

    Jing, Lishuai; Pedersen, Troels; Fleury, Bernard Henri

    2013-01-01

    We address the problem of searching for the optimal pilot signal, i.e. pattern and signature, of an orthogonal frequency-division multiplexing (OFDM) system when the purpose is to estimate the delay and Doppler shift under the assumption of a single-path propagation channel. This problem is relev......We address the problem of searching for the optimal pilot signal, i.e. pattern and signature, of an orthogonal frequency-division multiplexing (OFDM) system when the purpose is to estimate the delay and Doppler shift under the assumption of a single-path propagation channel. This problem...

  19. End to End Delay Improvement in Heterogeneous Multicast Network using Genetic Optimization

    Directory of Open Access Journals (Sweden)

    V. Chandrasekar

    2012-01-01

    Full Text Available Problem statement: Multicast is a concept of group communication which refers to transmitting the same data or messages from a source to multiple destinations in the network. This one-to-many group communication is a generalization of the concepts of one-to-one unicast and one-to-all broadcast. To deliver data from the sender to all receivers efficiently, routing plays an important role in multicast communication. In QoS multicast, every receiver must receive the data within their own specified QoS constraints. This becomes challenging especially if the network is a heterogeneous network made up of wired and wireless devices. Approach: This study investigates the performance of Protocol Independent Multicast-Sparse Mode (PIM-SM protocol in a heterogeneous network running an video conferencing application and proposes an enhanced routing protocol using Genetic Optimizing techniques to improve QOS parameters in the wireless part. Results and Conclusion: Extensive simulations were carried out using the proposed technique and existing PIM-SM. The proposed optimization technique not only improves the throughput of the network but also decreased the end to end delay."

  20. Handling packet dropouts and random delays for unstable delayed processes in NCS by optimal tuning of PIλDμ controllers with evolutionary algorithms.

    Science.gov (United States)

    Pan, Indranil; Das, Saptarshi; Gupta, Amitava

    2011-10-01

    The issues of stochastically varying network delays and packet dropouts in Networked Control System (NCS) applications have been simultaneously addressed by time domain optimal tuning of fractional order (FO) PID controllers. Different variants of evolutionary algorithms are used for the tuning process and their performances are compared. Also the effectiveness of the fractional order PI(λ)D(μ) controllers over their integer order counterparts is looked into. Two standard test bench plants with time delay and unstable poles which are encountered in process control applications are tuned with the proposed method to establish the validity of the tuning methodology. The proposed tuning methodology is independent of the specific choice of plant and is also applicable for less complicated systems. Thus it is useful in a wide variety of scenarios. The paper also shows the superiority of FOPID controllers over their conventional PID counterparts for NCS applications.

  1. A TOTP-Based Enhanced Route Optimization Procedure for Mobile IPv6 to Reduce Handover Delay and Signalling Overhead

    Directory of Open Access Journals (Sweden)

    Peer Azmat Shah

    2014-01-01

    Full Text Available Due to the proliferation of handheld mobile devices, multimedia applications like Voice over IP (VoIP, video conferencing, network music, and online gaming are gaining popularity in recent years. These applications are well known to be delay sensitive and resource demanding. The mobility of mobile devices, running these applications, across different networks causes delay and service disruption. Mobile IPv6 was proposed to provide mobility support to IPv6-based mobile nodes for continuous communication when they roam across different networks. However, the Route Optimization procedure in Mobile IPv6 involves the verification of mobile node’s reachability at the home address and at the care-of address (home test and care-of test that results in higher handover delays and signalling overhead. This paper presents an enhanced procedure, time-based one-time password Route Optimization (TOTP-RO, for Mobile IPv6 Route Optimization that uses the concepts of shared secret Token, time based one-time password (TOTP along with verification of the mobile node via direct communication and maintaining the status of correspondent node’s compatibility. The TOTP-RO was implemented in network simulator (NS-2 and an analytical analysis was also made. Analysis showed that TOTP-RO has lower handover delays, packet loss, and signalling overhead with an increased level of security as compared to the standard Mobile IPv6’s Return-Routability-based Route Optimization (RR-RO.

  2. A TOTP-based enhanced route optimization procedure for mobile IPv6 to reduce handover delay and signalling overhead.

    Science.gov (United States)

    Shah, Peer Azmat; Hasbullah, Halabi B; Lawal, Ibrahim A; Aminu Mu'azu, Abubakar; Tang Jung, Low

    2014-01-01

    Due to the proliferation of handheld mobile devices, multimedia applications like Voice over IP (VoIP), video conferencing, network music, and online gaming are gaining popularity in recent years. These applications are well known to be delay sensitive and resource demanding. The mobility of mobile devices, running these applications, across different networks causes delay and service disruption. Mobile IPv6 was proposed to provide mobility support to IPv6-based mobile nodes for continuous communication when they roam across different networks. However, the Route Optimization procedure in Mobile IPv6 involves the verification of mobile node's reachability at the home address and at the care-of address (home test and care-of test) that results in higher handover delays and signalling overhead. This paper presents an enhanced procedure, time-based one-time password Route Optimization (TOTP-RO), for Mobile IPv6 Route Optimization that uses the concepts of shared secret Token, time based one-time password (TOTP) along with verification of the mobile node via direct communication and maintaining the status of correspondent node's compatibility. The TOTP-RO was implemented in network simulator (NS-2) and an analytical analysis was also made. Analysis showed that TOTP-RO has lower handover delays, packet loss, and signalling overhead with an increased level of security as compared to the standard Mobile IPv6's Return-Routability-based Route Optimization (RR-RO).

  3. A Jackson network model and threshold policy for joint optimization of energy and delay in multi-hop wireless networks

    KAUST Repository

    Xia, Li

    2014-11-20

    This paper studies the joint optimization problem of energy and delay in a multi-hop wireless network. The optimization variables are the transmission rates, which are adjustable according to the packet queueing length in the buffer. The optimization goal is to minimize the energy consumption of energy-critical nodes and the packet transmission delay throughout the network. In this paper, we aim at understanding the well-known decentralized algorithms which are threshold based from a different research angle. By using a simplified network model, we show that we can adopt the semi-open Jackson network model and study this optimization problem in closed form. This simplified network model further allows us to establish some significant optimality properties. We prove that the system performance is monotonic with respect to (w.r.t.) the transmission rate. We also prove that the threshold-type policy is optimal, i.e., when the number of packets in the buffer is larger than a threshold, transmit with the maximal rate (power); otherwise, no transmission. With these optimality properties, we develop a heuristic algorithm to iteratively find the optimal threshold. Finally, we conduct some simulation experiments to demonstrate the main idea of this paper.

  4. Optimal Control of a Single Queue with Retransmissions: Delay-Dropping Tradeoffs

    CERN Document Server

    Giovanidis, Anastasios; Buehler, Joerg

    2009-01-01

    A single queue incorporating a retransmission protocol is investigated, assuming that the sequence of per effort success probabilities in the Automatic Retransmission reQuest (ARQ) chain is a priori defined and no channel state information at the transmitter is available. A Markov Decision Problem with an average cost criterion is formulated where the possible actions are to either continue the retransmission process of an erroneous packet at the next time slot or to drop the packet and move on to the next packet awaiting for transmission. The cost per slot is a linear combination of the current queue length and a penalty term in case dropping is chosen as action. The investigation seeks policies that provide the best possible average packet delay-dropping trade-off for Quality of Service guarantees. An optimal deterministic stationary policy is shown to exist, several structural properties of which are obtained. Based on that, a class of suboptimal -policies is introduced. These suggest that it is almost opt...

  5. The optimal control of a new class of impulsive stochastic neutral evolution integro-differential equations with infinite delay

    Science.gov (United States)

    Yan, Zuomao; Lu, Fangxia

    2016-08-01

    In this paper, we introduce the optimal control problems governed by a new class of impulsive stochastic partial neutral evolution equations with infinite delay in Hilbert spaces. First, by using stochastic analysis, the analytic semigroup theory, fractional powers of closed operators, and suitable fixed point theorems, we prove an existence result of mild solutions for the control systems in the α-norm without the assumptions of compactness. Next, we derive the existence conditions of optimal pairs of these systems. Finally, application to a nonlinear impulsive stochastic parabolic optimal control system is considered.

  6. Optimal tracking control for a class of nonlinear discrete-time systems with time delays based on heuristic dynamic programming.

    Science.gov (United States)

    Zhang, Huaguang; Song, Ruizhuo; Wei, Qinglai; Zhang, Tieyan

    2011-12-01

    In this paper, a novel heuristic dynamic programming (HDP) iteration algorithm is proposed to solve the optimal tracking control problem for a class of nonlinear discrete-time systems with time delays. The novel algorithm contains state updating, control policy iteration, and performance index iteration. To get the optimal states, the states are also updated. Furthermore, the "backward iteration" is applied to state updating. Two neural networks are used to approximate the performance index function and compute the optimal control policy for facilitating the implementation of HDP iteration algorithm. At last, we present two examples to demonstrate the effectiveness of the proposed HDP iteration algorithm.

  7. Optimization of group delay response of (apodized) tapered fiber Bragg grating by shaping taper transition and apodization window

    Science.gov (United States)

    Markowski, Konrad; Jedrzejewski, Kazimierz; Osuch, Tomasz

    2016-09-01

    This article presents implementation of the Simulated Annealing (SA) algorithm for tapered fiber Bragg gratings (TFBGs) design. Particularly, together with well-known Coupled Mode Theory (CMT) and Transfer Matrix Method (TMM) the algorithm optimizes the group delay response of TFBG, by simultaneous shaping of both apodization function and tapered fiber transition profile. Prior to the optimization process, numerical model for TFBG design has been validated. Preliminary results reveal great potential of the SA-based approach and with proper definition of the design criteria may be even applied for optimization of the spectral properties of TFBGs.

  8. Optimal pricing and inventory policies for non-instantaneous deteriorating items with permissible delay in payment: Fuzzy expected value model

    Directory of Open Access Journals (Sweden)

    Hardik N Soni

    2012-04-01

    Full Text Available This study investigates optimal pricing and inventory policies for non-instantaneous deteriorating items with permissible delay in payment. The demand rate is as known, continuous and differentiable function of price while holding cost rate, interest paid rate and interest earned rate are characterized as independent fuzzy variables rather than fuzzy numbers as in previous studies. Under these general assumptions, we first formulated a fuzzy expected value model (EVM and then some useful theoretical results have been derived to characterize the optimal solutions. An efficient algorithm is designed to determine the optimal pricing and inventory policy for the proposed model. The algorithmic procedure is demonstrated by means of numerical examples.

  9. Variable Structure Disturbance Rejection Control for Nonlinear Uncertain Systems with State and Control Delays via Optimal Sliding Mode Surface Approach

    Directory of Open Access Journals (Sweden)

    Jing Lei

    2013-01-01

    Full Text Available The paper considers the problem of variable structure control for nonlinear systems with uncertainty and time delays under persistent disturbance by using the optimal sliding mode surface approach. Through functional transformation, the original time-delay system is transformed into a delay-free one. The approximating sequence method is applied to solve the nonlinear optimal sliding mode surface problem which is reduced to a linear two-point boundary value problem of approximating sequences. The optimal sliding mode surface is obtained from the convergent solutions by solving a Riccati equation, a Sylvester equation, and the state and adjoint vector differential equations of approximating sequences. Then, the variable structure disturbance rejection control is presented by adopting an exponential trending law, where the state and control memory terms are designed to compensate the state and control delays, a feedforward control term is designed to reject the disturbance, and an adjoint compensator is designed to compensate the effects generated by the nonlinearity and the uncertainty. Furthermore, an observer is constructed to make the feedforward term physically realizable, and thus the dynamical observer-based dynamical variable structure disturbance rejection control law is produced. Finally, simulations are demonstrated to verify the effectiveness of the presented controller and the simplicity of the proposed approach.

  10. Triggered non-contrast enhanced MR angiography of peripheral arteries: Optimization of systolic and diastolic time delays for electrocardiographic triggering

    Energy Technology Data Exchange (ETDEWEB)

    Radlbauer, Rudolf, E-mail: rudolf.radlbauer@stpoelten.lknoe.at [MR Physics Group, Department of Radiology, Landesklinikum St. Poelten, Propst Fuehrer Strasse 4, 3100 St. Poelten (Austria); Salomonowitz, Erich, E-mail: erich.salomonowitz@stpoelten.lknoe.at [MR Physics Group, Department of Radiology, Landesklinikum St. Poelten, Propst Fuehrer Strasse 4, 3100 St. Poelten (Austria); Riet, Wilma van der, E-mail: wilma@emric.fr [European MRI Consultancy (EMRIC), 4 rue Gutenberg, 67000 Strasbourg (France); Stadlbauer, Andreas, E-mail: andi@nmr.at [MR Physics Group, Department of Radiology, Landesklinikum St. Poelten, Propst Fuehrer Strasse 4, 3100 St. Poelten (Austria); Department of Neurosurgery, University of Erlangen-Nuremberg, Schwabachanlage 6, 91054 Erlangen (Germany)

    2011-11-15

    The purpose of this study was to determine the optimal systolic and diastolic time delays for electrocardiographic triggering of a non-contrast media enhanced MR angiography using a 3-dimensional fast spin echo sequence in patients suffering from peripheral arterial disease. 12 patients with suspected peripheral arterial disease were examined on a 1.5 T Philips Achieva MR scanner. A cardiac-triggered Volumetric Isotropic T2-weighted fast spin echo sequence was performed using variable trigger delays for systolic and diastolic phase. The signal in the popliteal arteries and anterior tibial arteries of the systolic and diastolic images was measured and optimal delay times for systolic and diastolic phase were determined. Minimum signal to noise ratio (SNR) appears at the time difference {Delta}T = -21 ms on systolic images of the popliteal arteries. In the anterior tibial arteries the minimum SNR is significantly higher and appears at the time difference {Delta}T = -14 ms. Diastolic delay times must be chosen as long or as short as possible depending on heart rate. In peripheral vessels triggered non-contrast MR angiography can yield results which are comparable with contrast enhanced MRA techniques. It is crucial to optimize timing parameters.

  11. A Study on the Analysis and Optimal Control of Linear Time-delay Systems using Fast Haar Transform

    Energy Technology Data Exchange (ETDEWEB)

    Shim, Jae Sun [Samchok National University (Korea, Republic of)

    1998-07-01

    A Haar function method is proposed in this report for the analysis and optimal control of linear time-delay systems, which is based on the Picard`s iterative approximation and fast Haar transformation. In this research, the following results are obtained: 1) The differential and integral equation can be solved by transforming into a simple algebraic equation as it was possible with the usual orthogonal function method: 2) General orthogonal function methods require many calculations of inverse matrices, which are not necessary in this method. Thus, the control problems of linear time-delay systems can be solved much faster and readily. (author). 10 refs., 3 figs., 1 tab.

  12. Power Minimization through Packet Retention in Cognitive Radio Sensor Networks under Interference and Delay Constraints: An Optimal Stopping Approach

    Directory of Open Access Journals (Sweden)

    Amr Y. Elnakeeb

    2016-04-01

    Full Text Available The aim of this article is twofold: First, we study the problem of packets retention in a queue with the aim of minimizing transmission power in delay-tolerant applications. The problem is classified as an optimal stopping problem. The optimal stopping rule has been derived as well. Optimal number of released packets is determined in each round through an Integer Linear Programming (ILP optimization problem. This transmission paradigm is tested via simulations in an interference-free environment leading to a significant reduction in transmission power (at least 55%. Second, we address the problem of applying the scheme of packets retention through the Optimal Stopping Policy (OSP to underlay Cognitive Radio Sensor Networks (CRSNs where strict interference threshold does exist. Simulations proved that our scheme outperforms traditional transmission method as far as dropped packet rate and Average Power per Transmitted Packet (APTP are concerned.

  13. Optimal Register Assignment with Minimum-Path Delay Compensation for Variation-Aware Datapaths

    Science.gov (United States)

    Inoue, Keisuke; Kaneko, Mineo; Iwagaki, Tsuyoshi

    For recent and future nanometer-technology VLSIs, static and dynamic delay variations become a serious problem. In many cases, the hold constraint, as well as the setup constraint, becomes critical for latching a correct signal under delay variations. This paper treats the hold constraint in a datapath circuit, and discusses a register assignment in high level synthesis considering delay variations. Our approach to ensure the hold constraint under delay variations is to enlarge the minimum-path delay between registers, which is called minimum-path delay compensation (MDC) in this paper. MDC can be done by inserting delay elements mainly in non-critical paths of a functional unit (FU). One of our contributions is to show that the minimization of the number of minimum-path delay compensated FUs is NP-hard in general, and it is in the class P if the number of FUs is a constant. A polynomial time algorithm for the latter is also shown in this paper. In addition, an integer linear programming (ILP) formulation is also presented. The proposed method generates a datapath having (1) robustness against delay variations, which is ensured partly by MDC technique and partly by SRV-based register assignment, and (2) the minimum possible numbers of MDCs and registers.

  14. Cascading Delay Risk of Airline Workforce Deployments with Crew Pairing and Schedule Optimization.

    Science.gov (United States)

    Chung, Sai Ho; Ma, Hoi Lam; Chan, Hing Kai

    2017-08-01

    This article concerns the assignment of buffer time between two connected flights and the number of reserve crews in crew pairing to mitigate flight disruption due to flight arrival delay. Insufficient crew members for a flight will lead to flight disruptions such as delays or cancellations. In reality, most of these disruption cases are due to arrival delays of the previous flights. To tackle this problem, many research studies have examined the assignment method based on the historical flight arrival delay data of the concerned flights. However, flight arrival delays can be triggered by numerous factors. Accordingly, this article proposes a new forecasting approach using a cascade neural network, which considers a massive amount of historical flight arrival and departure data. The approach also incorporates learning ability so that unknown relationships behind the data can be revealed. Based on the expected flight arrival delay, the buffer time can be determined and a new dynamic reserve crew strategy can then be used to determine the required number of reserve crews. Numerical experiments are carried out based on one year of flight data obtained from 112 airports around the world. The results demonstrate that by predicting the flight departure delay as the input for the prediction of the flight arrival delay, the prediction accuracy can be increased. Moreover, by using the new dynamic reserve crew strategy, the total crew cost can be reduced. This significantly benefits airlines in flight schedule stability and cost saving in the current big data era. © 2016 Society for Risk Analysis.

  15. Optimal Inventory Planning under Permissible Delay in Payments When a Larger Order Quantity

    Science.gov (United States)

    Hsu, Kuang-Hua; Huang, Hung-Fu; Tu, Yu-Cheng; Huang, Yung-Fu

    In the previous related studies, the inventory replenishment problems under permissible delay in payments are independent of the order quantity. In this study, the restrictive assumption of the trade credit independent of the order quantity is relaxed. This study discusses the inventory policies under permissible delay in payments when a larger order quantity.

  16. Atrioventricular valve replacement in functional single-ventricle patients

    Institute of Scientific and Technical Information of China (English)

    ZHANG Zhong; CEN Jian-zheng; XU Gang; WEN Shu-sheng; CHEN Ji-mei

    2016-01-01

    Background This article summarized the experience of atrioventricular valve replacement operation for functional single ventricle patients whose atrioventricular valve was insufficiency.The follow-up time of operation was arranged from early-to medium-term.Methods From July 2009 to July 2015,there were 40 patients of functional single ventricle receiving the operation of atrioventricular valve replacement,including 23 male and 17 female patients.The age at A-Ⅴ valve replacement was ranged from 6 days to 32 years (the medium age of 9 years),and the body weight ranged from 2.7 to 57 kg (the medium body weight of 21.5 kg).Moreover,the atrioventricular valve replacement was performed on all patients under extracorporeal circulation.Results Atrioventricular valve replacement was performed on 40 patients with function single ventricle in hospital,of which eight (20.0%) died in hospital including two neonate and infant (age range:6 days-2 years old) accounting for 25% (2/8),Among them,seven patients died of low cardiac output syndrome two patients with repeated hypoxemia concurrent infection after operation,and one with bilateral diaphragmatic paralysis and malignant arrhythmia.For the patients suffering the severe perivalvular leakage,there was a reoperation,and the cardiac function before the first operation was class Ⅳ.One patient received heart transplantation finally for severe heart failure after AV valve replacement.For the rest of patients,their cardiac function recovered to class Ⅰ-Ⅱ after operation.Conclusions For function single ventricle patients with atrioventricular valve regurgitation,the mortality rate of atrioventricular valve replacement can be accepted if the operation was indicated.For patients with severe atrioventricular value regurgitation,the result of the operation in the early and medium term was satisfying.Thus,the atrioventricular valve replacement served as a useful treatment for patients diagnosed of A-Ⅴ valve regurgitation and

  17. Morphological aspects of atrioventricular valves in the ostrich (Struthio camelus

    Directory of Open Access Journals (Sweden)

    Marco A. Pereira-Sampaio

    2013-11-01

    Full Text Available Heart anatomy in the ostrich has been reported, but there are few information on the histological features of the atrioventricular valves. Hearts of young ostriches were fixed in 10% formaldehyde for 24 h and dissected to characterize their macroscopic anatomy. Samples of valves were harvested and stained with Mallory’s trichrome, Gomori’s trichrome, and Picro-Sirius red, for later analysis. The right atrioventricular valve consists of a muscle flap with two fixations. The left atrioventricular valve consists of two layers of endocardium with a layer of connective tissue between them. The free border of the tricuspid valve supports a varying number of chordae tendineae. One of the cusps is attached to the septum, while the other two cusps are attached to the opposite wall. The aortic valve, as well as the pulmonary trunk valve, consists of three cusps. The right atrioventricular valve showed up only as a muscle flap of myocardium coated with a thin layer of dense connective tissue, with two fixations. In the connective tissue, we find a predominance of type I collagen fibers and a lesser amount of type III, with a small presence of elastic fibers. The presence of Purkinje fibers were also usual in the valvular subendocardium, suggesting that they directly participate in the transmission of nervous stimulation to the muscle fibers within the valves. The left atrioventricular valve consisted of 3 cusps, a dorsal, a left, and a right.

  18. Optimal guaranteed cost control for an uncertain discrete T-S fuzzy system with time-delay

    Institute of Scientific and Technical Information of China (English)

    Renming WANG; Thierry Marie GUERRA; Juntao PAN

    2009-01-01

    This paper considers the guaranteed cost control problem for a class of uncertain discrete T-S fuzzy systems with time delay and a given quadratic cost function. Sufficient conditions for the existence of such controllers are derived based on the linear matrix inequalities (LMI) approach by constructing a specific nonquadratic Lyapunov-Krasovskii functional and a nonlinear PDC-like control law. A convex optimization problem is also formulated to select the optimal guaranteed cost controller that minimizes the upper bound of the closed-loop cost function. Finally, numerical examples are presented to demonstrate the effectiveness of the proposed approaches.

  19. Brucella Infection Associated with Complete Atrioventricular Block

    Science.gov (United States)

    Bilici, Meki; Demir, Fikri; Yılmazer, Murat Muhtar; Bozkurt, Fatma; Tuzcu, Volkan

    2016-01-01

    Background: The clinical spectrum of Brucella infection is quite diverse and characterized by multi-system involvement. Patients present with myocarditis, endocarditis, or pericarditis. Infective endocarditis is the most common cardiovascular complication in patients with brucellosis. Although conduction abnormalities are seen in cases with endocarditis, they are reported very rarely in the setting of cardiac Brucella infection. Case Report: An eight and a half-year-old male patient was referred to our clinic due to inadequate response to cotrimaxazole plus streptomycin treatment at the 15th day of admission. Although local hospital records on the patient showed a heart rate of 80 bpm, we determined a heart rate of 46 bpm. The electrocardiogram showed complete atrioventricular (AV) block. The average heart rate was determined as 48 bpm with 24-hour Holter electrocardiogram (ECG) monitoring. The echocardiographic examination showed normal-sized heart chambers and the absence of valvular involvement. An agglutination test for brucellosis was found to be positive with a titer of 1/320. High fever, arthralgia, and splenomegaly regressed following doxycycline plus rifampicin therapy, but there was no improvement in the AV block. A permanent pacemaker was implanted because of the detection of an average heart rate of 48 bpm. Conclusion: Because cardiac failure and rhythm abnormalities are reported in the course of Brucella infection and may be associated with significant outcomes, cases with brucellosis should be evaluated carefully in terms of cardiac involvement. This report aims to draw attention to complete AV block as an extremely rare complication of Brucella infection. PMID:27761286

  20. Amplatzer Septal Occluder-induced Transient Complete Atrioventricular Block

    Directory of Open Access Journals (Sweden)

    Shan-Miao Lin

    2007-12-01

    Full Text Available Percutaneous transcatheter atrial septal defect (ASD closure is a widely used technique that has replaced open-heart surgical closure in many centers. The most common implant is the Amplatzer septal occluder which seems to be a highly effective and safe device. However, there are reports of complications associated with its implantation. We report a 9-year-old boy who presented with complete atrioventricular block after undergoing percutaneous closure of a large secundum ASD with an Amplatzer septal occluder. We treated the patient with oral prednisolone. The patient's atrioventricular conduction improved to second-degree Mobitz type 1 block on post-procedure day 24 and first-degree block on day 35. We conclude that patients with Amplatzer septal occluder-induced complete atrioventricular block generally have a good outcome, although it may take several weeks for improvement.

  1. Nearly data-based optimal control for linear discrete model-free systems with delays via reinforcement learning

    Science.gov (United States)

    Zhang, Jilie; Zhang, Huaguang; Wang, Binrui; Cai, Tiaoyang

    2016-05-01

    In this paper, a nearly data-based optimal control scheme is proposed for linear discrete model-free systems with delays. The nearly optimal control can be obtained using only measured input/output data from systems, by reinforcement learning technology, which combines Q-learning with value iterative algorithm. First, we construct a state estimator by using the measured input/output data. Second, the quadratic functional is used to approximate the value function at each point in the state space, and the data-based control is designed by Q-learning method using the obtained state estimator. Then, the paper states the method, that is, how to solve the optimal inner kernel matrix ? in the least-square sense, by value iteration algorithm. Finally, the numerical examples are given to illustrate the effectiveness of our approach.

  2. FPGA implementation of digital constant fraction algorithm with fractional delay for optimal time resolution

    Energy Technology Data Exchange (ETDEWEB)

    Jaeger, Markus, E-mail: jaeger@informatik.uni-leipzig.de [Faculty of Mathematics and Computer Science, University of Leipzig, PF 100920, 04009 Leipzig (Germany); Butz, Tilman, E-mail: butz@physik.uni-leipzig.de [Faculty of Physics and Earth Sciences, University of Leipzig, Linnestr. 5, 04103 Leipzig (Germany)

    2012-05-11

    In a recent development of a fully digital spectrometer for time differential perturbed angular correlations a true constant fraction trigger (CFT) algorithm was implemented that, however, allowed for integer delays, i.e. integer multiples of the sampling interval, only. With a sampling rate of 1 GS/s and BaF{sub 2} scintillators this turned out to be insufficient. Here, we present an extension of the algorithm to fractional delays implemented in field programmable gate arrays (FPGAs). Furthermore, we derive a criterion for the delay for optimum timing based on the steepest slope of the CFT signal. Experimental data are given for LaBr{sub 3}(Ce) scintillators and 511 keV-511 keV prompt coincidences that corroborate the theoretical result.

  3. Guideline of choosing optical delay time to optimize the performance of an interferometry-based in-band OSNR monitor.

    Science.gov (United States)

    Huang, Zhuili; Qiu, Jifang; Wang, Sheng; Ji, Xue; Tian, Ye; Kong, Deming; Yu, Miao; Wu, Jian

    2016-09-15

    We propose and experimentally demonstrate a guideline of choosing optical delay time in an interferometry-based optical signal-to-noise ratio (OSNR) monitor to achieve the optimal monitoring performance by calculating the normalized autocorrelation function of the channel noise. According to the position of the first zero point of the calculated autocorrelation function, the delay time is determined; consequently the OSNR monitoring range up to 29 dB (within an error≤±0.5  dB) is achieved for 112 Gb/s PM-QPSK signal with a channel filter bandwidth of 100 GHz. The experimental results also show that the guideline is applicable to channel filters with different bandwidths and shapes. In simulation, the guideline is proven to be valid in OSNR monitoring for a 28 Gbaud PM-16QAM signal and a 50 Gbaud PM-QPSK signal.

  4. Linear Unbiased Optimal Filter for Discrete-Time Systems with One-Step Random Delays and Inconsecutive Packet Dropouts

    Directory of Open Access Journals (Sweden)

    Jian Ding

    2013-11-01

    Full Text Available This paper is concerned with the linear unbiased minimum variance estimation problem for discrete-time stochastic linear control systems with one-step random delay and inconsecutive packet dropout. A new model is developed to describe the phenomena of the one-step delay and inconsecutive packet dropout by employing a Bernoulli distributed stochastic variable. Based on the model, a recursive linear unbiased optimal filter in the linear minimum variance sense is designed by the method of completing the square. The solution to the linear filter is given by three equations including a Riccati equation, a Lyapunov equation and a simple difference equation. A sufficient condition for the existence of the steady-state filter is given. A simulation shows the effectiveness of the proposed algorithm.    

  5. [Fetal atrioventricular septal defect associated with Patau and Edwards syndromes, as well as trisomy 22].

    Science.gov (United States)

    Cesko, I; Hajdú, J; Marton, T; Tóth-Pál, E; Papp, C; Papp, Z

    1998-05-03

    The atrioventricular septal defect is usually associated with trisomy 21 and it may be observed in the heterotaxia syndromes. Atrioventricular septal defect may be associated with 8p deletion. There are reported cases of familial atrioventricular septal defect. Atrioventicular septal defect is rarely associated with other chromosomal abnormalities. We are reporting three unusual cases of atrioventricular septal defect that were associated with trisomy 13, 18 and 22. This association may be due to effect of genetic loci on the 13, 18 and 22 chromosome which could play the role in the development and fusion of endocardial cushion and atrioventricular septal defect.

  6. Congenital defect of the partial atrioventricular canal with Klinefelter syndrome

    OpenAIRE

    Zhang, Yejing

    2009-01-01

    The case of a 25-year-old man with a partial atrioventricular canal defect (PAVCD) with Klinefelter syndrome is reported here. The patient had Klinefelter syndrome associated with an atrial septal defect and the cleft of the anterior leaflet of the mitral valve.

  7. Atrioventricular conduction after alcohol septal ablation for obstructive hypertrophic cardiomyopathy

    DEFF Research Database (Denmark)

    Axelsson, Anna; Weibring, Kristina; Havndrup, Ole

    2014-01-01

    .1-9.4) after ASA. Patients with high-grade atrioventricular block at follow-up had longer PR intervals at baseline [205 ms (200-230)] than the rest of the cohort [180 ms (140-200), P = 0.004] and a higher incidence of acute complete heart block (63 vs. 15%; P = 0.007) during ASA. A PR interval of at least 200...... ms at baseline was associated with higher prevalence of high-grade atrioventricular block at follow-up (30 vs. 2%; P = 0.0013). The incidence of late-onset complete heart block was 1.5% per year after ASA. CONCLUSION: We found normalized atrioventricular conduction at long-term follow-up, suggesting...... recovery in 6 of 14 patients with a pacemaker implanted in relation to ASA. Permanent atrioventricular conduction abnormalities were associated with baseline PR intervals of at least 200 ms and acute persistent complete heart block during ASA....

  8. "Distal common pathway in atrioventricular node reentrant tachycardia "

    Directory of Open Access Journals (Sweden)

    "Moghaddam M

    2001-06-01

    Full Text Available Anotomical boundary of atrioventricular node reentrant tachycardia (AVNRT is composed of fast and slow pathways right atrium in upper turnaround and common distal pathway in lower turnaround. We performed electophsiologic study (EPS in 152 patients and could show the existence of distal common pathway with decremental conduction properties in approximately 40 patients.

  9. Effects of AV delay programming on ventricular resynchronisation: role of radionuclide ventriculography

    Energy Technology Data Exchange (ETDEWEB)

    Siegrist, Patrick T.; Comte, Nathalie; Holzmeister, Johannes; Suetsch, Gabor; Koepfli, Pascal; Namdar, Mehdi; Duru, Firat; Brunckhorst, Corinna; Scharf, Christoph [Universitiy Hospital Zurich NUK C 32, Cardiovascular Center, Zurich (Switzerland); Kaufmann, Philipp A. [Universitiy Hospital Zurich NUK C 32, Cardiovascular Center, Zurich (Switzerland); University of Zurich, Zurich Center for Integrative Human Physiology, Zurich (Switzerland)

    2008-08-15

    Optimal atrioventricular delay (AVD) setting for cardiac resynchronisation therapy, i.e. biventricular pacing in patients with heart failure, remains a formidable challenge. Thus, the purpose of this study was to evaluate the effects of different AVD on inter- and intra-ventricular resynchronisation using phase histograms of radionuclide ventriculography (RNV). In 17 consecutive patients (mean age 64 {+-} 6 years), RNV was performed 236 {+-} 350 days after pacemaker implantation for cardiac resynchronisation therapy. Images were acquired during atrial pacing at 80 bpm and during biventricular pacing with AVD ranging from 80 to 160 ms. Inter-ventricular dyssynchrony was measured by the delay between the mean phase angles of the left and right ventricles. Intra-ventricular dyssynchrony was measured by the standard deviation (SD) of left ventricular phase histograms. Left ventricular (LV) ejection fraction (EF) was inversely correlated to LV dyssynchrony (SD of LV phase histogram, R = -0.82, p < 0.0001). However, the increase in LVEF by biventricular pacing (mean +4.4 {+-} 4%) showed only modest correlation to the resulting resynchronisation effect (characterised by a -13 {+-} 8 decrease in LV phase histogram SD, R = -0.38, p < 0.0001). RNV is helpful in optimising pacing parameters for resynchronisation therapy. Varying AVD did not have a major impact on intra- or inter-ventricular resynchronisation. Thus, the benefit of AVD-based LVEF optimisation seems to result from atrioventricular resynchronisation. (orig.)

  10. Optimization of the concrete delayed deformations by Kalman filter; Optimisation des deformations differees du beton par filtre de Kalman

    Energy Technology Data Exchange (ETDEWEB)

    Sebastien Massart [CERFACS / URA 1875, 42 Avenue Gaspard Coriolis, 31057 Toulouse Cedex 01, (France)

    2005-07-01

    Imperviousness of French nuclear power plants containments has to secure radioactive products confinement during incident or accident. Temporal evolution of containments is obtained through the numerical model Code Aster that purpose is to detect if some fissure could appear and as a consequence, imperviousness lost. In parallel, sensors are placed all around the containments to follow real time deformations. In this paper, Kalman filter analysis of an extensometer data is used to optimize eight parameters of the numerical model Code Aster. This method allows us to improve the concrete delayed behaviors modelization and supplies uncertainties to the forecast of the containment evolution. (author)

  11. An optimal PID controller via LQR for standard second order plus time delay systems.

    Science.gov (United States)

    Srivastava, Saurabh; Misra, Anuraag; Thakur, S K; Pandit, V S

    2016-01-01

    An improved tuning methodology of PID controller for standard second order plus time delay systems (SOPTD) is developed using the approach of Linear Quadratic Regulator (LQR) and pole placement technique to obtain the desired performance measures. The pole placement method together with LQR is ingeniously used for SOPTD systems where the time delay part is handled in the controller output equation instead of characteristic equation. The effectiveness of the proposed methodology has been demonstrated via simulation of stable open loop oscillatory, over damped, critical damped and unstable open loop systems. Results show improved closed loop time response over the existing LQR based PI/PID tuning methods with less control effort. The effect of non-dominant pole on the stability and robustness of the controller has also been discussed.

  12. The optimal duration and delay of first aid treatment for deep partial thickness burn injuries.

    Science.gov (United States)

    Cuttle, Leila; Kempf, Margit; Liu, Pei-Yun; Kravchuk, Olena; Kimble, Roy M

    2010-08-01

    Using our porcine model of deep dermal partial thickness burn injury, various durations (10min, 20min, 30min or 1h) and delays (immediate, 10min, 1h, 3h) of 15 degrees C running water first aid were applied to burns and compared to untreated controls. The subdermal temperatures were monitored during the treatment and wounds observed weekly for 6 weeks, for re-epithelialisation, wound surface area and cosmetic appearance. At 6 weeks after the burn, tissue biopsies were taken of the scar for histological analysis. Results showed that immediate application of cold running water for 20min duration is associated with an improvement in re-epithelialisation over the first 2 weeks post-burn and decreased scar tissue at 6 weeks. First aid application of cold water for as little as 10min duration or up to 1h delay still provides benefit.

  13. A NOVEL DESIGN OF MULTIPLEXER BASED FULL-ADDER CELL FOR POWER AND PROPAGATION DELAY OPTIMIZATIONS

    Directory of Open Access Journals (Sweden)

    G. RAMANA MURTHY

    2013-12-01

    Full Text Available This paper presents a novel high-speed and high-performance multiplexer based full adder cell for low-power applications. The proposed full adder is composed of two separate modules with identical hardware configurations that generate Sum and Carry signals in a parallel manner. The proposed adder circuit has an advantage in terms of short critical path when compared with various existing previous designs. Comprehensive experiments were performed in various situations to evaluate the performance of the proposed design. Simulations were performed by Microwind 2 VLSI CAD tool for LVS and BSIM 4 for parametric analysis of various feature sizes. The simulation results demonstrate clearly the improvement of the proposed design in terms of lower power dissipation, less propagation delay, less occupying area and low power delay product (PDP compared to other widely used existing full adder circuits.

  14. Defeito completo do septo atrioventricular com cianose Complete repair in total atrioventricular canal defect with cyanosis

    Directory of Open Access Journals (Sweden)

    Carla Tanamati

    2006-09-01

    Full Text Available Os defeitos do septo atrioventricular total (DSAVT representam 4% das mal formações cardíacas e acima de 50% dos defeitos observados na síndrome de Down (SD¹. A apresentação clínica é de insuficiência cardíaca precoce na infância e hipertensão pulmonar por hiperfluxo. Raramente a cianose é observada e sugere hipertensão pulmonar ou associação à tetralogia de Fallot³, dupla via de saída de ventrículo direito², anomalia de Ebstein4, drenagem anômala de cava esquerda persistente em átrio esquerdo (Barbero Marcial, comunicação pessoal. Crianças com SD são particularmente difíceis de avaliação por apresentarem obstrução de vias aéreas superiores, que podem contribuir com o aumento da resistência pulmonar observada no cateterismo cardíaco. A presença de cianose pré-operatória constitui-se um desafio ao tratamento cirúrgico devido ao risco de hipertensão pulmonar irreversível com falência ventricular direita com, a correção dos defeitos intracardíacos.Atrioventricular septal defects account for 4% of congenital cardiac malformations and over 50% of cardiac defects seen in Down syndrome¹. Clinical presentation is marked by congestive heart failure early in infancy. Cyanosis is rarely found in infants and suggests irreversible pulmonary hypertension or associated cardiac defects as tetralogy of Fallot, double outlet right ventricle², Ebstein anomaly³, persistent left superior vena cava draining in the left atrium (Barbero Marcial, personal communication. Children with Down's syndrome is particularly difficult to assess because they often suffer from upper airways obstruction4, which may contribute to the increased pulmonary vascular resistance determined at cardiac catheterization. This association of factors becomes a challenge for operability and, we will report one such case.

  15. Longer Left Ventricular Electric Delay Reduces Mitral Regurgitation After Cardiac Resynchronization Therapy: Mechanistic Insights From the SMART-AV Study (SmartDelay Determined AV Optimization: A Comparison to Other AV Delay Methods Used in Cardiac Resynchronization Therapy).

    Science.gov (United States)

    Chatterjee, Neal A; Gold, Michael R; Waggoner, Alan D; Picard, Michael H; Stein, Kenneth M; Yu, Yinghong; Meyer, Timothy E; Wold, Nicholas; Ellenbogen, Kenneth A; Singh, Jagmeet P

    2016-11-01

    Mitral regurgitation (MR) is associated with worse survival in those undergoing cardiac resynchronization therapy (CRT). Left ventricular (LV) lead position in CRT may ameliorate mechanisms of MR. We examine the association between a longer LV electric delay (QLV) at the LV stimulation site and MR reduction after CRT. QLV was assessed retrospectively in 426 patients enrolled in the SMART-AV study (SmartDelay Determined AV Optimization: A Comparison to Other AV Delay Methods Used in CRT). QLV was defined as the time from QRS onset to the first large peak of the LV electrogram. Linear regression and logistic regression were used to assess the association between baseline QLV and MR reduction at 6 months (absolute change in vena contracta width and odds of ≥1 grade reduction in MR). At baseline, there was no difference in MR grade, LV dyssynchrony, or LV volumes in those with QLV above versus below the median (95 ms). After multivariable adjustment, increasing QLV was an independent predictor of MR reduction at 6 months as reflected by an increased odds of MR response (odds ratio: 1.13 [1.03-1.25]/10 ms increase QLV; P=0.02) and a decrease in vena contracta width (P<0.001). At 3 months, longer QLV (≥median) was associated with significant decrease in LV end-systolic volume (ΔLV end-systolic volume -28.2±38.9 versus -4.9±33.8 mL, P<0.001). Adjustment for 3-month ΔLV end-systolic volume attenuated the association between QLV and 6-month MR reduction. In patients undergoing CRT, longer QLV was an independent predictor of MR reduction at 6 months and associated with interval 3-month LV reverse remodeling. These findings provide a mechanistic basis for using an electric-targeting LV lead strategy at the time of CRT implant. © 2016 American Heart Association, Inc.

  16. Orbit optimization for ASTROD-GW and its time delay interferometry with two arms using CGC ephemeris

    Institute of Scientific and Technical Information of China (English)

    Wang Gang; Ni Wei-Tou

    2013-01-01

    space test of relativity using optical devices optimized for gravitation wave detection (ASTROD-GW) is an optimization of ASTROD to focus on the goal of detection of gravitation waves.The detection sensitivity is shifted 52 times toward larger wavelength compared with that of laser interferometer space antenna (LISA).The mission orbits of the three spacecrafts forming a nearly equilateral triangular array are chosen to be near the Sun-Earth Lagrange points L3,L4,and L5.The three spacecrafis range interferometrically with one another with an arm length of about 260 million kilometers.In order to attain the required sensitivity for ASTROD-GW,laser frequency noise must be suppressed to below the secondary noises such as the optical path noise,acceleration noise,etc.For suppressing laser frequency noise,we need to use time delay interferometry (TDI) to match the two different optical paths (times of travel).Since planets and other solar-system bodies perturb the orbits of ASTROD-GW spacecraft and affect the TDI,we simulate the time delay numerically using CGC 2.7 (here,CGC stands for center for gravitation and cosmology) ephemeris framework.To conform to the ASTROD-GW planning,we work out a set of 20-year optimized mission orbits of ASTROD-GW spacecraft starting at June 21,2028,and calculate the differences in optical path in the first and second generation TDIs separately for one-detector case.In our optimized mission orbits of 20 years,changes of arm lengths are less than 0.0003 AU; the relative Doppler velocities are all less than 3 m/s.All the second generation TDI for one-detector case satisfies the ASTROD-GW requirement.

  17. Orbit optimization for ASTROD-GW and its time delay interferometry with two arms using CGC ephemeris

    Science.gov (United States)

    Wang, Gang; Ni, Wei-Tou

    2013-04-01

    Astrodynamical space test of relativity using optical devices optimized for gravitation wave detection (ASTROD-GW) is an optimization of ASTROD to focus on the goal of detection of gravitation waves. The detection sensitivity is shifted 52 times toward larger wavelength compared with that of laser interferometer space antenna (LISA). The mission orbits of the three spacecrafts forming a nearly equilateral triangular array are chosen to be near the Sun—Earth Lagrange points L3, L4, and L5. The three spacecrafts range interferometrically with one another with an arm length of about 260 million kilometers. In order to attain the required sensitivity for ASTROD-GW, laser frequency noise must be suppressed to below the secondary noises such as the optical path noise, acceleration noise, etc. For suppressing laser frequency noise, we need to use time delay interferometry (TDI) to match the two different optical paths (times of travel). Since planets and other solar-system bodies perturb the orbits of ASTROD-GW spacecraft and affect the TDI, we simulate the time delay numerically using CGC 2.7 (here, CGC stands for center for gravitation and cosmology) ephemeris framework. To conform to the ASTROD-GW planning, we work out a set of 20-year optimized mission orbits of ASTROD-GW spacecraft starting at June 21, 2028, and calculate the differences in optical path in the first and second generation TDIs separately for one-detector case. In our optimized mission orbits of 20 years, changes of arm lengths are less than 0.0003 AU; the relative Doppler velocities are all less than 3 m/s. All the second generation TDI for one-detector case satisfies the ASTROD-GW requirement.

  18. Non-fragile robust optimal guaranteed cost control of uncertain 2-D discrete state-delayed systems

    Science.gov (United States)

    Tandon, Akshata; Dhawan, Amit

    2016-10-01

    This paper is concerned with the problem of non-fragile robust optimal guaranteed cost control for a class of uncertain two-dimensional (2-D) discrete state-delayed systems described by the general model with norm-bounded uncertainties. Our attention is focused on the design of non-fragile state feedback controllers such that the resulting closed-loop system is asymptotically stable and the closed-loop cost function value is not more than a specified upper bound for all admissible parameter uncertainties and controller gain variations. A sufficient condition for the existence of such controllers is established under the linear matrix inequality framework. Moreover, a convex optimisation problem is proposed to select a non-fragile robust optimal guaranteed cost controller stabilising the 2-D discrete state-delayed system as well as achieving the least guaranteed cost for the resulting closed-loop system. The proposed method is compared with the previously reported criterion. Finally, illustrative examples are given to show the potential of the proposed technique.

  19. Growth Trajectory in Children with Trisomy 21 with and without Atrioventricular Septal Defect.

    Science.gov (United States)

    Mackman, Chad A; Loomba, Rohit S; Slicker, Julie; Bartz, Peter J

    2016-07-01

    Trisomy 21 is associated with poor weight gain and atrioventricular septal defects. The impact of atrioventricular septal defects on weight gain in the setting of Trisomy 21 has not previously been described in the recent era. This study aimed to determine if such an association is present. Patients with Trisomy 21 with and without atrioventricular septal defects were identified. Clinical, surgical, and postoperative data were collected were for these patients and then compared between patients. Specifically, weight for age z-scores were compared at various time points in a univariate and multivariate fashion. Effect of timing of surgery in those with an atrioventricular septal defect was also studied. A total of 86 patients were identified, 42 with an atrioventricular septal defect. There was a difference in weight for age z-scores between patients with and without atrioventricular septal defects only at 2 months (P value .038) and 6 months (P value .003) of age. This persisted after multivariate regression which demonstrated atrioventricular septal defects as an independent risk factor. There was no difference noted in weight at 2 years of age in patients undergoing atrioventricular septal defect repair before and 150 days of life. There was a statistically significant, but not clinically relevant, difference in weight between the patients with Trisomy 21 with and without atrioventricular septal defects in our cohort. Those with atrioventricular septal defects required more nutritional intervention, such as gastrostomy tube placement. Timing of repair did not alter outcomes at midterm follow-up. © 2016 Wiley Periodicals, Inc.

  20. Adaptable System Increasing the Transmission Speed and Reliability in Packet Network by Optimizing Delay

    Directory of Open Access Journals (Sweden)

    Zbynek Kocur

    2014-01-01

    Full Text Available There is a great diversity in the transmission technologies in current data networks. Individual technologies are in most cases incompatible at physical and partially also at the link layer of the reference ISO/OSI model. Network compatibility, as the ability to transmit data, is realizable through the third layer, which is able to guarantee the operation of the different devices across their technological differences. The proposed inverse packet multiplexer addresses increase of the speed and reliability of packet transmission to the third layer, and at the same time it increases the stability of the data communication by the regulation of the delay value during the transmission. This article presents implementation of a communication system and its verification in real conditions. The conclusion compares the strengths and weaknesses of the proposed control system.

  1. Delayed image of iodine-123 iomazenil as a relative map of benzodiazepine receptor binding: the optimal scan time

    Energy Technology Data Exchange (ETDEWEB)

    Onishi, Yoshihiro [Nihon Medi-Physics Co. Ltd., Nishinomiya (Japan); Yonekura, Yoshiharu [Fukui Medical School, Fukui (Japan); Tanaka, Fumiko [Kyoto University School of Medicine, Kyoto (Japan); Nishizawa, Sadahiko [Kyoto University School of Medicine, Kyoto (Japan); Okazawa, Hidehiko [Kyoto University School of Medicine, Kyoto (Japan); Ishizu, Koichi [Kyoto University School of Medicine, Kyoto (Japan); Fujita, Toru [Kyoto University School of Medicine, Kyoto (Japan); Konishi, Junji [Kyoto University School of Medicine, Kyoto (Japan); Mukai, Takao [Kyoto College of Medical Technology, Kyoto (Japan)

    1996-11-01

    ``Delayed`` single-photon emission tomograpic (SPET) images after an intravenous bolus injection of iodine-123 iomazenil have been used as a relative map of benzodiazepine receptor binding. We determined the optimal scan time for obtaining such a map and assessed the errors of the map. SPET and blood data from six healthy volunteers and five patients were used. A three-compartment kinetic model was employed in simulation studies and analyses of actual data. The simulation studies suggested that, in the normal brain, the scan time at which a single SPET image best represented the relative receptor binding was 3.0-3.5 h post-injection. This finding was supported by actual data from the volunteers. The simulation studies also suggested that the optimal scan time was not greatly changed by the variability of the input functions, and that the error in the SPET image contrast in the vicinity of the optimal scan time was not increased by changes in the tracer kinetics in the entire brain. The SPET image contrast in the patients at 3.0 h post-injection agreed well with the reference receptor binding estimated by kinetic analysis, with a mean error of 3.6%. These findings support the use of a single SPET image after bolus injection of [{sup 123}I]iomazenil as a relative map of benzodiazepine receptor binding. For this purpose, a SPET scan time of 3.0-3.5 h post-injection is recommended. (orig.). With 5 figs., 1 tab.

  2. Dynamic contrast enhancement of experimental glioma an intra-individual comparative study to assess the optimal time delay.

    Science.gov (United States)

    Engelhorn, Tobias; Schwarz, Marc A; Eyupoglu, Ilker Y; Kloska, Stephan P; Struffert, Tobias; Doerfler, Arnd

    2010-02-01

    The aim of this study was to compare tumor signal and contrast media uptake characteristics on contrast-enhanced T1-weighted sequences at 3 Tesla over 30 minutes after double-dose administration of different contrast agents in an animal model of brain glioma. Nine rats underwent magnetic resonance imaging (MRI) after stereotactic F98 glioma cell implantation before and repetitively for 30 minutes after injection of gadobutrol, gadopentetate, and gadobenate, respectively. Signal-to-noise ratio (SNR) and tumor contrast-to-noise ratio (CNR) were evaluated and MRI-derived tumor volumes were compared to histology. Postcontrast tumor SNR and CNR peaked at 4 minutes after contrast application. While contrast-enhancement within the tumor was fading, tumor volume increased by continuous contrast-uptake of peripheral parts between 4 minutes (137 + or - 29 mm(3), 126 + or - 16 mm(3), 141 + or - 24 mm(3)) and 20 minutes (182 + or - 35 mm(3), 164 + or - 32 mm(3), 191 + or - 25 mm(3)), respectively. At 8 and 12 minutes, 84% and 91% of the tumor volume were definable, respectively. Optimal correlation between MRI-derived tumor volume and histology is achieved by imaging up to 20 minutes after contrast application. At 4 minutes (this delay is mostly used in clinical routine), only 75% of the enhancing tumor volume is assessable. A delay of 8 minutes already reveals 84% of the tumor and seems to be a practical clinical compromise. Copyright 2010 AUR. Published by Elsevier Inc. All rights reserved.

  3. Using AMC and HARQ to Optimize System Capacity and Application Delays in WiMAX Networks

    CERN Document Server

    Adhicandra, Iwan

    2010-01-01

    The IEEE 802.16 technology (WiMAX) is a promising technology for providing last-mile connectivity by radio link due to its high speed data rates, low cost of deployment, and large coverage area. However, the maximum number of channels defined in the current system may cause a potential bottleneck and limit the overall system capacity. The aim of this paper is to compare the impact on system performance of different solutions used to mitigate the impairments due to the radio channel. In particular, taking into account the WiMAX system capacity as well as application delays, the paper presents the simulation results obtained when a static QPSK 1/2 Modulation and Coding Scheme (MCS) is adopted. Then, the study is aimed at evaluating the improvements introduced by the adoption of an adaptive modulation and coding (AMC) and an AMC jointly with Hybrid Automatic Repeat reQuest (HARQ). Results indicate that the best strategy is to use an aggressive AMC table with the HARQ.

  4. Improving perfusion quantification in arterial spin labeling for delayed arrival times by using optimized acquisition schemes

    Energy Technology Data Exchange (ETDEWEB)

    Kramme, Johanna [Fraunhofer MEVIS-Institute for Medical Image Computing, Bremen (Germany); Univ. Bremen (Germany). Faculty of Physics and Electronics; Gregori, Johannes [mediri GmbH, Heidelberg (Germany); Diehl, Volker [Fraunhofer MEVIS-Institute for Medical Image Computing, Bremen (Germany); ZEMODI (Zentrum fuer morderne Diagnostik), Bremen (Germany); Madai, Vince I.; Sobesky, Jan [Charite-Universitaetsmedizin Berlin (Germany). Center for Stroke Research Berlin (CSB); Charite-Universitaetsmedizin Berlin (Germany). Dept. of Neurology; Samson-Himmelstjerna, Frederico C. von [Fraunhofer MEVIS-Institute for Medical Image Computing, Bremen (Germany); Charite-Universitaetsmedizin Berlin (Germany). Center for Stroke Research Berlin (CSB); Charite-Universitaetsmedizin Berlin (Germany). Dept. of Neurology; Lentschig, Markus [ZEMODI (Zentrum fuer morderne Diagnostik), Bremen (Germany); Guenther, Matthias [Fraunhofer MEVIS-Institute for Medical Image Computing, Bremen (Germany); Univ. Bremen (Germany). Faculty of Physics and Electronics; mediri GmbH, Heidelberg (Germany)

    2015-07-01

    The improvement in Arterial Spin Labeling (ASL) perfusion quantification, especially for delayed bolus arrival times (BAT), with an acquisition redistribution scheme mitigating the T1 decay of the label in multi-TI ASL measurements is investigated. A multi inflow time (TI) 3D-GRASE sequence is presented which adapts the distribution of acquisitions accordingly, by keeping the scan time constant. The MR sequence increases the number of averages at long TIs and decreases their number at short TIs and thus compensating the T1 decay of the label. The improvement of perfusion quantification is evaluated in simulations as well as in-vivo in healthy volunteers and patients with prolonged BATs due to age or steno-occlusive disease. The improvement in perfusion quantification depends on BAT. At healthy BATs the differences are small, but become larger for longer BATs typically found in certain diseases. The relative error of perfusion is improved up to 30% at BATs > 1500 ms in comparison to the standard acquisition scheme. This adapted acquisition scheme improves the perfusion measurement in comparison to standard multi-TI ASL implementations. It provides relevant benefit in clinical conditions that cause prolonged BATs and is therefore of high clinical relevance for neuroimaging of steno-occlusive diseases.

  5. Approximate Design of Optimal Disturbance Rejection for Discrete-Time Systems with Multiple Delayed Inputs: Application to a Jacket-Type Offshore Structure

    Directory of Open Access Journals (Sweden)

    Shi-Yuan Han

    2015-01-01

    Full Text Available The study is concerned with problem of optimal disturbance rejection for a class of discrete-time systems with multiple delayed inputs. In order to avoid the two-point boundary value (TPBV problem with items of time-delay and time-advance caused by multiple delayed inputs, the discrete-time system with multiple delayed inputs is transformed into a delay-free system by introducing a variable transformation, and the original performance index is reformulated as a corresponding form without the explicit appearance of time-delay items. Then, the approximate optimal disturbance rejection controller (AODRC is derived from Riccati equation and Stein equation based on the reduced system and reformulated performance index, which is combined with feedback item of system state, feedforward item of disturbances, and items of delayed inputs. Also, the existence and uniqueness of AODRC are proved, and the stability of the closed-loop system is analysed. Finally, numerical examples of disturbance rejection for jacket-type offshore structure and pure mathematical model are illustrated to validate the feasibility and effectiveness of the proposed approach.

  6. Comparison of different invasive hemodynamic methods for AV delay optimization in patients with cardiac resynchronization therapy: Implications for clinical trial design and clinical practice☆☆☆

    Science.gov (United States)

    Whinnett, Zachary I.; Francis, Darrel P.; Denis, Arnaud; Willson, Keith; Pascale, Patrizio; van Geldorp, Irene; De Guillebon, Maxime; Ploux, Sylvain; Ellenbogen, Kenneth; Haïssaguerre, Michel; Ritter, Philippe; Bordachar, Pierre

    2013-01-01

    Background Reproducibility and hemodynamic efficacy of optimization of AV delay (AVD) of cardiac resynchronization therapy (CRT) using invasive LV dp/dtmax are unknown. Method and results 25 patients underwent AV delay (AVD) optimisation twice, using continuous left ventricular (LV) dp/dtmax, systolic blood pressure (SBP) and pulse pressure (PP). We compared 4 protocols for comparing dp/dtmax between AV delays:Immediate absolute: mean of 10 s recording of dp/dtmax acquired immediately after programming the tested AVD,Delayed absolute: mean of 10 s recording acquired 30 s after programming AVD,Single relative: relative difference between reference AVD and the tested AVD,Multiple relative: averaged difference, from multiple alternations between reference and tested AVD. We assessed for dp/dtmax, LVSBP and LVPP, test–retest reproducibility of the optimum. Optimization using immediate absolute dp/dtmax had poor reproducibility (SDD of replicate optima = 41 ms; R2 = 0.45) as did delayed absolute (SDD 39 ms; R2 = 0.50). Multiple relative had better reproducibility: SDD 23 ms, R2 = 0.76, and (p AV delay was LVSBP 2% and LVdp/dtmax 5%, while CRT with pre-determined optimal AVD gave 6% and 9% respectively. Conclusions Because of inevitable background fluctuations, optimization by absolute dp/dtmax has poor same-day reproducibility, unsuitable for clinical or research purposes. Reproducibility is improved by comparing to a reference AVD and making multiple consecutive measurements. More than 6 measurements would be required for even more precise optimization — and might be advisable for future study designs. With optimal AVD, instead of nominal, the hemodynamic increment of CRT is approximately doubled. PMID:23481908

  7. Orbit optimization for ASTROD-GW and its time delay interferometry with two arms using CGC ephemeris

    CERN Document Server

    Wang, G

    2012-01-01

    ASTROD-GW (ASTROD [Astrodynamical Space Test of Relativity using Optical Devices] optimized for Gravitation Wave detection) is an optimization of ASTROD to focus on the goal of detection of gravitation waves. The detection sensitivity is shifted 52 times toward larger wavelength compared to that of LISA. The mission orbits of the 3 spacecraft forming a nearly equilateral triangular array are chosen to be near the Sun-Earth Lagrange points L3, L4 and L5. The 3 spacecraft range interferometrically with one another with arm length about 260 million kilometers. In order to attain the requisite sensitivity for ASTROD-GW, laser frequency noise must be suppressed below the secondary noises such as the optical path noise, acceleration noise etc. For suppressing laser frequency noise, we need to use time delay interferometry (TDI) to match the two different optical paths (times of travel). Since planets and other solar-system bodies perturb the orbits of ASTROD-GW spacecraft and affect the (TDI), we simulate the time ...

  8. Optimal pricing and lot-sizing policies for an economic production quantity model with non-instantaneous deteriorating items, permissible delay in payments, customer returns, and inflation

    DEFF Research Database (Denmark)

    Ghoreishi, Maryam; Mirzazadeh, Abolfazl; Nakhai Kamalabadi, Isa

    2014-01-01

    This article deals with an economic production quantity inventory model for non-instantaneous deteriorating items under inflationary conditions, permissible delay in payments, customer returns, and price- and time-dependent demand. The customer returns are assumed as a function of demand and price....... The effects of time value of money are studied using the Discounted Cash Flow approach. The main objective is to determine the optimal selling price, the optimal length of the production period, and the optimal length of inventory cycle simultaneously such that the present value of total profit is maximized....... An efficient algorithm is presented to find the optimal solution of the developed model. Finally, a numerical example is extracted to solve the presented inventory model using our proposed algorithm, and the effects of the customer returns, inflation, and delay in payments are also discussed....

  9. Coronary sinus and atrioventricular groove avulsion after motor vehicle crash

    Directory of Open Access Journals (Sweden)

    Bradley M Dennis

    2014-01-01

    Full Text Available Simultaneous cardiac and pericardial rupture from blunt chest trauma is a highly lethal combination with rarely reported survival. We report of a case of young patient with a right atrioventricular groove injury, pericardial rupture and a unique description of a coronary sinus avulsion following blunt chest trauma. Rapid recognition of this injury is crucial to patient survival, but traditional diagnostic adjuncts such as ultrasound, echocardiography and computed tomography are often unhelpful. Successful repair of these injuries requires high suspicion of injury, early cardiac surgery involvement of and possible even placement of the patient on cardiopulmonary bypass.

  10. Nitric Oxide Synthase-3 Promotes Embryonic Development of Atrioventricular Valves

    OpenAIRE

    Yin Liu; Xiangru Lu; Fu-Li Xiang; Man Lu; Qingping Feng

    2013-01-01

    Nitric oxide synthase-3 (NOS3) has recently been shown to promote endothelial-to-mesenchymal transition (EndMT) in the developing atrioventricular (AV) canal. The present study was aimed to investigate the role of NOS3 in embryonic development of AV valves. We hypothesized that NOS3 promotes embryonic development of AV valves via EndMT. To test this hypothesis, morphological and functional analysis of AV valves were performed in wild-type (WT) and NOS3(-/-) mice at postnatal day 0. Our data s...

  11. High-septal pacing reduces ventricular electrical remodeling and proarrhythmia in chronic atrioventricular block dogs

    DEFF Research Database (Denmark)

    Winckels, Stephan K G; Thomsen, Morten Bækgaard; Oosterhoff, Peter

    2007-01-01

    This study was designed to analyze the relevance of ventricular activation patterns for ventricular electrical remodeling after atrioventricular (AV) block in dogs.......This study was designed to analyze the relevance of ventricular activation patterns for ventricular electrical remodeling after atrioventricular (AV) block in dogs....

  12. [Complete atrioventricular block as the first clinical manifestation of a tick bite (Lyme disease)].

    Science.gov (United States)

    Bacino, Luca; Gazzarata, Massimo; Siri, Giambattista; Cordone, Stefano; Bellotti, Paolo

    2011-03-01

    A 52-year-old male patient presented to the emergency department because of malaise and frequent dizziness. The ECG revealed high-grade atrioventricular block that required placement of a temporary pacemaker. There were no other abnormalities in physical and echocardiographic examination, and coronary angiography excluded the presence of coronary artery disease. IgM and IgG antibodies against Borrelia were positive, and antibiotic therapy with ceftriaxone at the dose of 2 g/die for 15 days resulted in rapid regression of atrioventricular block. Seven-day ECG recording immediately after discharge and 24h ECG monitoring at 40 days confirmed the total disappearance of atrioventricular block. This represents a case of atrioventricular block as the first manifestation of Borrelia infection (Lyme disease). A prompt diagnosis and antibiotic therapy usually result in complete resolution of atrioventricular block without the need for a permanent pacemaker.

  13. A Flexible Job Shop Scheduling Problem with Controllable Processing Times to Optimize Total Cost of Delay and Processing

    Directory of Open Access Journals (Sweden)

    Hadi Mokhtari

    2015-11-01

    Full Text Available In this paper, the flexible job shop scheduling problem with machine flexibility and controllable process times is studied. The main idea is that the processing times of operations may be controlled by consumptions of additional resources. The purpose of this paper to find the best trade-off between processing cost and delay cost in order to minimize the total costs. The proposed model, flexible job shop scheduling with controllable processing times (FJCPT, is formulated as an integer non-linear programming (INLP model and then it is converted into an integer linear programming (ILP model. Due to NP-hardness of FJCPT, conventional analytic optimization methods are not efficient. Hence, in order to solve the problem, a Scatter Search (SS, as an efficient metaheuristic method, is developed. To show the effectiveness of the proposed method, numerical experiments are conducted. The efficiency of the proposed algorithm is compared with that of a genetic algorithm (GA available in the literature for solving FJSP problem. The results showed that the proposed SS provide better solutions than the existing GA.

  14. Orbit optimization and time delay interferometry for inclined ASTROD-GW formation with half-year precession-period

    CERN Document Server

    Wang, Gang

    2014-01-01

    ASTROD-GW (ASTROD [Astrodynamical Space Test of Relativity using Optical Devices] optimized for Gravitational Wave detection) is a gravitational-wave mission with the aim of detecting gravitational waves from massive black holes, extreme mass ratio inspirals (EMRIs) and galactic compact binaries, together with testing relativistic gravity and probing dark energy and cosmology. Mission orbits of the 3 spacecrafts forming a nearly equilateral triangular array are chosen to be near the Sun-Earth Lagrange points L3, L4 and L5. The 3 spacecrafts range interferometrically with one another with arm length about 260 million kilometers. For 260 times longer arm length, the detection sensitivity of ASTROD-GW is 260 fold better than that of eLISA/NGO in the lower frequency region by assuming the same acceleration noise. Therefore, ASTROD-GW will be a better cosmological probe. In previous papers, we have worked out the time delay interferometry (TDI) for the ecliptic formation. To resolve the reflection ambiguity about ...

  15. Controversies in the Management of Isolated Congenital Atrioventricular Block.

    Science.gov (United States)

    DeNoble, Anna E; Kuller, Jeffrey A; Rhee, Eleanor J

    2015-08-01

    Congenital atrioventricular block (CAVB) affects approximately 2% of fetuses of mothers with anti-Ro or anti-La antibodies, regardless of maternal rheumatologic symptoms. Anti-Ro and anti-La antibodies are antinuclear antibodies commonly found in autoimmune diseases. Congenital atrioventricular block is associated with a relatively high fetal morbidity and mortality, particularly more advanced degrees of block. There is significant controversy surrounding surveillance of anti-Ro/La-positive pregnancies and treatment of fetuses diagnosed with CAVB. Studies of dexamethasone in the treatment of CAVB have yielded conflicting results, with most suggesting only a limited potential benefit in first- and seconddegree CAVB and in cases complicated by fetal hydrops. Larger prospective studies are needed to further evaluate the efficacy of intravenous immunoglobulin in the treatment of CAVB and of intravenous immunoglobulin and hydroxychloroquine in the prevention of CAVB in fetuses of at-risk mothers. Surveillance and treatment regimens should be determined on a case-by-case basis, taking into consideration the degree of CAVB, costs, and potential adverse effects of treatment.

  16. Modified Senning Procedure for Correction of Atrioventricular Discordance With Total Anomalous Pulmonary Venous Return, Atrial Situs Inversus, Dextrocardia, and Bilateral Superior Venae Cavae.

    Science.gov (United States)

    Sebastian, Vinod A; Guleserian, Kristine J; Juraszek, Amy; Kane, Colin; Hamzeh, Rabih; Forbess, Joseph M

    2015-10-01

    The Senning and Mustard baffles remain important techniques for the treatment of congenitally corrected transposition (cc-TGA), isolated ventricular inversion, and D-transposition of the great arteries with delayed presentation. We describe the treatment of an 8-month old infant with atrioventricular discordance, ventriculoarterial concordance, and dextrocardia with atrial situs inversus. A modified Senning procedure was performed through the "left-sided" atrium. Modifications of the Senning and Mustard baffles remain important tools in the treatment of rare conditions like isolated ventricular inversion.

  17. Small-Signal Modeling, Stability Analysis and Design Optimization of Single-Phase Delay-Based PLLs

    DEFF Research Database (Denmark)

    Golestan, Saeed; Guerrero, Josep M.; Vidal, Ana

    2016-01-01

    Generally speaking, designing single-phase phaselocked loops (PLLs) is more complicated than three-phase ones, as their implementation often involves the generation of a fictitious orthogonal signal for the frame transformation. In recent years, many approaches to generate the orthogonal signal...... have been proposed, the simplest perhaps being the transfer delay based method. In the transfer delay based PLL (TD-PLL), the orthogonal signal is generated by delaying the original singlephase signal by T=4 (one-quarter of a period). The phase shift caused by the transfer delay block, however......, will not be exactly 90 under off-nominal grid frequencies, which results in errors in the estimated quantities by the TD-PLL. To alleviate this issue, an improved version of TD-PLL, called the non-frequency dependent TD-PLL (NTD-PLL), has recently been proposed. The NTD-PLL uses another T=4 delay unit in its feedback...

  18. Inter-pulse delay optimization in dual-pulse laser induced breakdown vacuum ultraviolet spectroscopy of a steel sample in ambient gases at low pressure

    Energy Technology Data Exchange (ETDEWEB)

    Jiang, X., E-mail: xi.jiang2@mail.dcu.ie [School of Physical Sciences, Dublin City University, Dublin (Ireland); National Centre for Plasma Science and Technology, Dublin City University, Dublin (Ireland); Hayden, P. [School of Physical Sciences, Dublin City University, Dublin (Ireland); National Centre for Plasma Science and Technology, Dublin City University, Dublin (Ireland); Laasch, R. [Institut fuer Experimentalphysik, Universitat Hamburg, Luruper Chaussee 149, 22761 Hamburg (Germany); Costello, J.T.; Kennedy, E.T. [School of Physical Sciences, Dublin City University, Dublin (Ireland); National Centre for Plasma Science and Technology, Dublin City University, Dublin (Ireland)

    2013-08-01

    Time-integrated spatially-resolved Laser Induced Breakdown Spectroscopy (LIBS) has been used to investigate spectral emissions from laser-induced plasmas generated on steel targets. Instead of detecting spectral lines in the visible/near ultraviolet (UV), as investigated in conventional LIBS, this work explored the use of spectral lines emitted by ions in the shorter wavelength vacuum ultraviolet (VUV) spectral region. Single-pulse (SP) and dual-pulse LIBS (DP-LIBS) experiments were performed on standardized steel samples. In the case of the double-pulse scheme, two synchronized lasers were used, an ablation laser (200 mJ/15 ns), and a reheating laser (665 mJ/6 ns) in a collinear beam geometry. Spatially resolved and temporally integrated laser induced plasma VUV emission in the DP scheme and its dependence on inter-pulse delay time were studied. The VUV spectral line intensities were found to be enhanced in the DP mode and were significantly affected by the inter-pulse delay time. Additionally, the influence of ambient conditions was investigated by employing low pressure nitrogen, argon or helium as buffer gases in the ablation chamber. The results clearly demonstrate the existence of a sharp ubiquitous emission intensity peak at 100 ns and a wider peak, in the multi-microsecond range of inter-pulse time delay, dependent on the ambient gas conditions. - Highlights: • First dual-pulse and ambient gas deep VUV LIBS plasma emission study • Optimization of inter-pulse delay time for vacuum and ambient gas environments • A sharp intensity peak implies optimal inter-pulse delay of 100 ns for all conditions. • A broad peak appears in the microsecond delay range, but only in ambient gases. • Pressure dependence implies a different enhancement process.

  19. Down Syndrome with Complete Atrioventricular Septal Defect, Hypertrophic Cardiomyopathy, and Pulmonary Vein Stenosis.

    Science.gov (United States)

    Mahadevaiah, Guruprasad; Gupta, Manoj; Ashwath, Ravi

    2015-10-01

    The prevalence of congenital heart disease in infants with Down syndrome is 40%, compared with 0.3% in children who have normal chromosomes. Atrioventricular and ventricular septal defects are often associated with chromosomal aberrations, such as in trisomy 21, whereas hypertrophic cardiomyopathy is chiefly thought to be secondary to specific gene mutations. We found only one reported case of congenital hypertrophic cardiomyopathy and atrioventricular septal defect in an infant with Down syndrome. Here, we report atrioventricular septal defect, hypertrophic cardiomyopathy, and pulmonary vein stenosis in a neonate with Down syndrome-an apparently unique combination. In addition, we discuss the relevant medical literature.

  20. Reentry confined to the atrioventricular node: electrophysiologic and anatomic findings.

    Science.gov (United States)

    Sheinman, M M; Gonzalez, R; Thomas, A; Ullyot, D; Bharati, S; Lev, M

    1982-05-01

    A patient with recurrent disabling, paroxysmal supraventricular tachycardia refractory to drug treatment underwent electrophysiologic studies. The paroxysmal supraventricular tachycardia was found to be due to atrioventricular (A-V) nodal reentry. The patient died shortly after surgical His bundle section and detailed anatomic studies were performed. These showed fatty infiltration of the approaches to the sinoatrial node, atrial preferential pathways, and A-V node and common bundle. The A-V node was mechanically damaged and the common His bundle was completely severed. These abnormalities were clearly delineated and there was no evidence of an atrio-His bundle bypass tract to an accessory A-V node. Specifically, the central fibrous body and pars membranacea were defined and no atrial muscular fibers pierced these structures to joint the A-V bundle. It is concluded that paroxysmal supraventricular tachycardia due to A-V nodal reentry can be confined to the A-V node.

  1. Atrioventricular block and wiry hair in Teebi hypertelorism syndrome.

    Science.gov (United States)

    Han, Xiao-Dong; Cox, Vicki; Slavotinek, Anne

    2006-09-15

    We report on a 4 1/2-year-old girl with clinical features of Teebi hypertelorism syndrome (THS), including a prominent forehead with a widow's peak, heavy and broad eyebrows, hypertelorism, long palpebral fissures, ptosis, a thin upper lip, a grooved chin, and a left preauricular cyst. She required a pacemaker for third degree atrioventricular (AV) block, a finding that has not been previously reported in 36 other patients with THS and for which we were unable to identify other causes. We have reviewed the previous reports of THS and note a characteristic facial appearance with hypertelorism, heavy, broad, and arched eyebrows, a thin upper lip with a long and deep philtrum, and a prominent forehead. Structural cardiac defects were present in five patients, implying that cardiac investigations are warranted in patients with a cardiac murmur and a clinical diagnosis of THS.

  2. Rapidly Progressive Atrioventricular Block in a Patient with Sarcoidosis

    Directory of Open Access Journals (Sweden)

    Nagham Saeed Jafar

    2014-01-01

    Full Text Available Cardiac sarcoidosis is a major cause of death in patients with systemic sarcoidosis. Cardiac manifestations are seen in 2.3% of the patients. Atrioventricular (AV block is one of the common manifestations of cardiac sarcoidosis. Other presentations of cardiac involvement include congestive heart failure, ventricular arrhythmias, and sudden cardiac death. The presence of AV block in young patients should raise the suspicion of sarcoidosis. AV block may be the only manifestation and patients may not have clinical evidence of pulmonary involvement. Here we describe a young male presented with exercise induced AV block rapidly progressing to complete heart block with recurrent syncope needing urgent pacemaker implantation. Factors that suggested an infiltrative process included his young age, rapidly progressive conduction abnormalities in the ECG in the absence of coronary disease, and previous history of cutaneous sarcoidosis.

  3. Effect of atrioventricular conduction on heart rate variability

    KAUST Repository

    Ahmad, Talha Jamal

    2011-08-01

    This paper discusses the effect of atrioventricular conduction time (AVCT) on the short-term Heart Rate Variability (HRV) by computing HRV parameters using intervals between the onsets of successive P waves (PP time series) for three groups: normal, arrhythmia and sudden cardiac death (SCD) patients. A very precise wavelet transform based ECG delineator was developed to detect PP, PR and RR time series. Mean PR variation in arrhythmia and SCD group was found to be significantly high as compared to the normal group. It was observed that when PR variations in arrhythmia and SCD cases crossed a certain threshold, RR variability no longer provided a very accurate estimate of HRV. In such cases, PP variability was able to provide a better assessment of HRV. © 2011 IEEE.

  4. Defective Tbx2-dependent patterning of the atrioventricular canal myocardium causes accessory pathway formation in mice

    NARCIS (Netherlands)

    Aanhaanen, W.T.J.; Boukens, B.J.D.; Sizarov, A.; Wakker, V.; de Gier- de Vries, C.; van Ginneken, A.C.; Moorman, A.F.M.; Coronel, R.; Christoffels, V.M.

    2011-01-01

    Ventricular preexcitation, a feature of Wolff-Parkinson-White syndrome, is caused by accessory myocardial pathways that bypass the annulus fibrosus. This condition increases the risk of atrioventricular tachycardia and, in the presence of atrial fibrillation, sudden death. The developmental

  5. Cardiac resynchronization therapy and AV optimization increase myocardial oxygen consumption, but increase cardiac function more than proportionally.

    Science.gov (United States)

    Kyriacou, Andreas; Pabari, Punam A; Mayet, Jamil; Peters, Nicholas S; Davies, D Wyn; Lim, P Boon; Lefroy, David; Hughes, Alun D; Kanagaratnam, Prapa; Francis, Darrel P; Whinnett, Zachary I

    2014-02-01

    The mechanoenergetic effects of atrioventricular delay optimization during biventricular pacing ("cardiac resynchronization therapy", CRT) are unknown. Eleven patients with heart failure and left bundle branch block (LBBB) underwent invasive measurements of left ventricular (LV) developed pressure, aortic flow velocity-time-integral (VTI) and myocardial oxygen consumption (MVO2) at 4 pacing states: biventricular pacing (with VV 0 ms) at AVD 40 ms (AV-40), AVD 120 ms (AV-120, a common nominal AV delay), at their pre-identified individualised haemodynamic optimum (AV-Opt); and intrinsic conduction (LBBB). AV-120, relative to LBBB, increased LV developed pressure by a mean of 11(SEM 2)%, p=0.001, and aortic VTI by 11(SEM 3)%, p=0.002, but also increased MVO2 by 11(SEM 5)%, p=0.04. AV-Opt further increased LV developed pressure by a mean of 2(SEM 1)%, p=0.035 and aortic VTI by 4(SEM 1)%, p=0.017. MVO2 trended further up by 7(SEM 5)%, p=0.22. Mechanoenergetics at AV-40 were no different from LBBB. The 4 states lay on a straight line for Δexternal work (ΔLV developed pressure × Δaortic VTI) against ΔMVO2, with slope 1.80, significantly >1 (p=0.02). Biventricular pacing and atrioventricular delay optimization increased external cardiac work done but also myocardial oxygen consumption. Nevertheless, the increase in cardiac work was ~80% greater than the increase in oxygen consumption, signifying an improvement in cardiac mechanoenergetics. Finally, the incremental effect of optimization on external work was approximately one-third beyond that of nominal AV pacing, along the same favourable efficiency trajectory, suggesting that AV delay dominates the biventricular pacing effect - which may therefore not be mainly "resynchronization". © 2013. Published by Elsevier Ireland Ltd. All rights reserved.

  6. Atrioventricular Conduction Delay in the Second Trimester Measured by Fetal Magnetocardiography

    Directory of Open Access Journals (Sweden)

    Annette Wacker-Gussmann

    2014-01-01

    Full Text Available Introduction. Fetal AV block in SSA/Ro pregnancies is generally not seen before 18-week gestation and onset is rare after 28-week gestation. If complete AV block appears, it is believed to be irreversible. The purpose of the study was to evaluate precise electrophysiological AV conduction from 18-week gestation onwards. Patients and Methods. 21 fetuses of pregnant women with collagen vascular diseases were included in the study group and 59 healthy fetuses served as controls. In addition to fetal echocardiography, fetal magnetocardiography (fMCG was used to investigate precise electrophysiological fetal cardiac time intervals (fCTIs. Results. The PR segment (isoelectric segment between the end of the P wave and the start of the QRS complex was significantly prolonged (P<0.036 2nd trimester, P<0.023 3rd trimester in both trimesters within the study group. In fetuses less than 23-week gestational age, a nearly complete separation was found, where a PR segment of 60 ms or greater completely excluded control fetuses. All other fCTIs did not differ significantly. None of the fetuses progressed to a more advanced heart block. Conclusion. Slight antibody effects in pregnancy, leading to PR segment prolongation, can already be seen from 18-week gestation onwards by fMCG. Serial fetal Doppler echocardiography and additional fMCG can be useful methods to measure early and precise AV conduction time, to achieve best surveillance for these high-risk pregnancies.

  7. Effectiveness of balloon valvuloplasty for palliation of mitral stenosis after repair of atrioventricular canal defects.

    Science.gov (United States)

    Robinson, Joshua D; Marx, Gerald R; Del Nido, Pedro J; Lock, James E; McElhinney, Doff B

    2009-06-15

    Closure of a mitral valve (MV) cleft, small left-sided cardiac structures, and ventricular imbalance all may contribute to mitral stenosis (MS) after repair of atrioventricular canal (AVC) defects. MV replacement is the traditional therapy but carries high risk in young children. The utility of balloon mitral valvuloplasty (BMV) in postoperative MS is not established and may offer alternative therapy or palliation. Since 1996, 10 patients with repaired AVC defects have undergone BMV at a median age of 2.5 years (range 8 months to 14 years), a median of 2 years after AVC repair. At catheterization, the median value of mean MS gradients was 16 mm Hg (range 12 to 22) and was reduced by 34% after BMV. Before BMV, there was mild mitral regurgitation in 9 of 10 patients, which increased to severe in 1 patient. All patients were alive at follow-up (median 5.4 years). Repeat BMV was performed in 4 patients, 10 weeks to 18 months after initial BMV. One patient underwent surgical valvuloplasty; 3 underwent MV replacement 2, 3, and 28 months after BMV. In the 6 patients (60%) with a native MV at most recent follow-up (median 3.2 years), the mean Doppler MS gradient was 9 mm Hg, the median weight had doubled, and weight percentile had increased significantly. In conclusion, BMV provides relief of MS in most patients with repaired AVC defects; marked increases in mitral regurgitation are uncommon. Because BMV can incompletely relieve obstruction and increase mitral regurgitation, it will not be definitive in most patients but will usually delay MV replacement to accommodate a larger prosthesis.

  8. 时滞对逻辑网络优化控制的影响%The Effect of Time Delay on the Optimization Control of Logical Networks

    Institute of Scientific and Technical Information of China (English)

    杨萌; 李睿; 楚天广

    2012-01-01

    分析了包含两种个体的逻辑网络的时滞优化控制.其中第1种被称为机器的个体策略是固定的;第2种被称为人的个体具有自适应性,即能根据系统的整体状态做出策略的调整.以矩阵的半张量积作为逻辑分析的工具,分析了在状态时滞和输入时滞的影响下使人的收益最大的最优控制问题.理论分析显示状态时滞导致最优控制策略的周期长度增加,但人的最大收益值不会改变.最后提出仿真算法,其数值结果与理论结果一致.%This paper investigates the optimal control with time delay of the logical network that consists of two kinds of agents called machine and human, respectively. The former has a fixed strategy whereas the latter can adaptively modify its strategy according to the state of the system. By means of the semi-tensor product of matrix technique* we solve the optimization problem of maximizing the payoff of human in the presence of time delay in states and inputs. The theoretical analysis indicates that the period of the optimal control strategy becomes longer due to the delay in states, but the maximum payoff does not change. We also propose a simulation algorithm. The numerical results thus obtained are in good agreement with the theoretical results.

  9. Atrioventricular node and input pathways: a correlated gross anatomical and histological study of the canine atrioventricular junctional region.

    Science.gov (United States)

    Racker, D K

    1989-07-01

    To determine the architecture of the atrioventricular (AV) junctional region, structures in atrial preparations were correlated to those in serial sections made either parallel or perpendicular to the long axis of the AV node (AVN)/AV bundle complex. The results demonstrated the following for the first time: 1) A right medial atrial wall (MAW) extends anteriorly from the interatrial septum, superior to the interventricular septum (IVS). 2) An atrial interventricular septum (A-IVS) groove is located between the base of the MAW and the crest of the IVS. 3) Three atrionodal bundles converge to form a proximal AV bundle (PAVB), which in turn is contiguous with the AVN. The atrionodal bundles are associated with the MAW or the superomedial and inferolateral margins of the coronory sinus. Terminal portions of the atrionodal bundles and the PAVB reside within the A-IVS groove. The AV bundle was termed distal (DAVB) to avoid confusion. 4) The location of the AVN/DAVB complex topographically is deep to the apex of the septal cusp of the tricuspid valve subjacent to the MAW. Intracardially, the AVN/DAVB complex is within the central fibrous body. Significantly, this study resulted in the first unequivocal demonstration of discrete bundles of myocardial fibers associated with the atrial end of the AV node. Moreover, it appears likely that the atrionodal AV bundles are continuous with the sinoatrial nodal extensions, thereby forming internodal tracts.

  10. Atrioventricular conduction in mammalian species: Hemodynamic and electrical scaling

    NARCIS (Netherlands)

    Meijler, F.L.; Billette, J.; Jalife, J.; Kik, M.J.L.; Reiber, J.H.C.; Stokhof, A.A.; Westenberg, J.J.M.; Wassenaar, C.; Strackee, J.

    2005-01-01

    OBJECTIVES The purpose of this study was to investigate scaling of the duration of late diastolic left ventricular (LV) filling in relation to AV conduction time (delay) (PR interval on the ECG) in mammals. BACKGROUND From mouse to whale, AV delay increases 10-fold, whereas body mass increases one m

  11. Genome-Wide Association Study of Down Syndrome-Associated Atrioventricular Septal Defects.

    Science.gov (United States)

    Ramachandran, Dhanya; Zeng, Zhen; Locke, Adam E; Mulle, Jennifer G; Bean, Lora J H; Rosser, Tracie C; Dooley, Kenneth J; Cua, Clifford L; Capone, George T; Reeves, Roger H; Maslen, Cheryl L; Cutler, David J; Feingold, Eleanor; Sherman, Stephanie L; Zwick, Michael E

    2015-07-20

    The goal of this study was to identify the contribution of common genetic variants to Down syndrome-associated atrioventricular septal defect, a severe heart abnormality. Compared with the euploid population, infants with Down syndrome, or trisomy 21, have a 2000-fold increased risk of presenting with atrioventricular septal defects. The cause of this increased risk remains elusive. Here we present data from the largest heart study conducted to date on a trisomic background by using a carefully characterized collection of individuals from extreme ends of the phenotypic spectrum. We performed a genome-wide association study using logistic regression analysis on 452 individuals with Down syndrome, consisting of 210 cases with complete atrioventricular septal defects and 242 controls with structurally normal hearts. No individual variant achieved genome-wide significance. We identified four disomic regions (1p36.3, 5p15.31, 8q22.3, and 17q22) and two trisomic regions on chromosome 21 (around PDXK and KCNJ6 genes) that merit further investigation in large replication studies. Our data show that a few common genetic variants of large effect size (odds ratio >2.0) do not account for the elevated risk of Down syndrome-associated atrioventricular septal defects. Instead, multiple variants of low-to-moderate effect sizes may contribute to this elevated risk, highlighting the complex genetic architecture of atrioventricular septal defects even in the highly susceptible Down syndrome population.

  12. 模拟滤波器群时延的优化设计%Optimization Design of Analog Filter's Group-delay

    Institute of Scientific and Technical Information of China (English)

    马红梅; 李鹏; 张旭珍

    2011-01-01

    为解决滤波器幅频特性算术对称性和相位平直度之间的矛盾,提出了一种基于极点放置技术和电路改进技术的滤波器优化设计方法,即在网络综合法设计的滤波器电路基础上,利用极点放置技术和电路改进技术对电路结构进行改进,然后用最小二乘法使群时延特性逼近一条直线,同时利用无约束优化算法对整个电路进行优化使幅频特性线性对称.仿真结果表明,该方法能够使滤波器幅频特性算术对称,通带内能得到较好的群时延特性,而且电路结构简单,阶数少,插入损耗低.%As for the contradiction between the filter' s amplitude-frequency characteristic arithmetic symmetry and the phase-frequency straightness,the paper is focus on an optimization design method based on pole placement technique and circuit improvement technique. Improving the circuit designed by network synthesis method,then optimizing the group-delay to a straight line using least square method,and simultaneously the circuit is optimized by unconstrained optimization method to obtain arithmetic symmetrical amplitude-frequency characteristic. The simulation results indicate that the proposed method can get arithmetic symmetrical amplitude-frequency and preferable group delay characteristics in pass-band. The designed circuit has merits of simple structure,less order,and lower insertion loss.

  13. Nitric oxide synthase-3 promotes embryonic development of atrioventricular valves.

    Science.gov (United States)

    Liu, Yin; Lu, Xiangru; Xiang, Fu-Li; Lu, Man; Feng, Qingping

    2013-01-01

    Nitric oxide synthase-3 (NOS3) has recently been shown to promote endothelial-to-mesenchymal transition (EndMT) in the developing atrioventricular (AV) canal. The present study was aimed to investigate the role of NOS3 in embryonic development of AV valves. We hypothesized that NOS3 promotes embryonic development of AV valves via EndMT. To test this hypothesis, morphological and functional analysis of AV valves were performed in wild-type (WT) and NOS3(-/-) mice at postnatal day 0. Our data show that the overall size and length of mitral and tricuspid valves were decreased in NOS3(-/-) compared with WT mice. Echocardiographic assessment showed significant regurgitation of mitral and tricuspid valves during systole in NOS3(-/-) mice. These phenotypes were all rescued by cardiac specific NOS3 overexpression. To assess EndMT, immunostaining of Snail1 was performed in the embryonic heart. Both total mesenchymal and Snail1(+) cells in the AV cushion were decreased in NOS3(-/-) compared with WT mice at E10.5 and E12.5, which was completely restored by cardiac specific NOS3 overexpression. In cultured embryonic hearts, NOS3 promoted transforming growth factor (TGFβ), bone morphogenetic protein (BMP2) and Snail1expression through cGMP. Furthermore, mesenchymal cell formation and migration from cultured AV cushion explants were decreased in the NOS3(-/-) compared with WT mice. We conclude that NOS3 promotes AV valve formation during embryonic heart development and deficiency in NOS3 results in AV valve insufficiency.

  14. Coexistent Types of Atrioventricular Nodal Re-Entrant Tachycardia

    Science.gov (United States)

    Marine, Joseph E.; Latchamsetty, Rakesh; Zografos, Theodoros; Tanawuttiwat, Tanyanan; Sheldon, Seth H.; Buxton, Alfred E.; Calkins, Hugh; Morady, Fred; Josephson, Mark E.

    2015-01-01

    Background— There is evidence that atypical fast–slow and typical atrioventricular nodal re-entrant tachycardia (AVNRT) do not use the same limb for fast conduction, but no data exist on patients who have presented with both typical and atypical forms of this tachycardia. We compared conduction intervals during typical and atypical AVNRT that occurred in the same patient. Methods and Results— In 20 of 1299 patients with AVNRT, both typical and atypical AVNRT were induced at electrophysiology study by pacing maneuvers and autonomic stimulation or occurred spontaneously. The mean age of the patients was 47.6±10.9 years (range, 32–75 years), and 11 patients (55%) were women. Tachycardia cycle lengths were 368.0±43.1 and 365.8±41.1 ms, and earliest retrograde activation was recorded at the coronary sinus ostium in 60% and 65% of patients with typical and atypical AVNRT, respectively. Thirteen patients (65%) displayed atypical AVNRT with fast–slow characteristics. By comparing conduction intervals during slow–fast and fast–slow AVNRT in the same patient, fast pathway conduction times during the 2 types of AVNRT were calculated. The mean difference between retrograde fast pathway conduction during slow–fast AVNRT and anterograde fast pathway conduction during fast–slow AVNRT was 41.8±39.7 ms and was significantly different when compared with the estimated between-measurement error (P=0.0055). Conclusions— Our data provide further evidence that typical slow–fast and atypical fast–slow AVNRT use different anatomic pathways for fast conduction. PMID:26155802

  15. Nitric Oxide Synthase-3 Promotes Embryonic Development of Atrioventricular Valves

    Science.gov (United States)

    Liu, Yin; Lu, Xiangru; Xiang, Fu-Li; Lu, Man; Feng, Qingping

    2013-01-01

    Nitric oxide synthase-3 (NOS3) has recently been shown to promote endothelial-to-mesenchymal transition (EndMT) in the developing atrioventricular (AV) canal. The present study was aimed to investigate the role of NOS3 in embryonic development of AV valves. We hypothesized that NOS3 promotes embryonic development of AV valves via EndMT. To test this hypothesis, morphological and functional analysis of AV valves were performed in wild-type (WT) and NOS3−/− mice at postnatal day 0. Our data show that the overall size and length of mitral and tricuspid valves were decreased in NOS3−/− compared with WT mice. Echocardiographic assessment showed significant regurgitation of mitral and tricuspid valves during systole in NOS3−/− mice. These phenotypes were all rescued by cardiac specific NOS3 overexpression. To assess EndMT, immunostaining of Snail1 was performed in the embryonic heart. Both total mesenchymal and Snail1+ cells in the AV cushion were decreased in NOS3−/− compared with WT mice at E10.5 and E12.5, which was completely restored by cardiac specific NOS3 overexpression. In cultured embryonic hearts, NOS3 promoted transforming growth factor (TGFβ), bone morphogenetic protein (BMP2) and Snail1expression through cGMP. Furthermore, mesenchymal cell formation and migration from cultured AV cushion explants were decreased in the NOS3−/− compared with WT mice. We conclude that NOS3 promotes AV valve formation during embryonic heart development and deficiency in NOS3 results in AV valve insufficiency. PMID:24204893

  16. Nitric oxide synthase-3 promotes embryonic development of atrioventricular valves.

    Directory of Open Access Journals (Sweden)

    Yin Liu

    Full Text Available Nitric oxide synthase-3 (NOS3 has recently been shown to promote endothelial-to-mesenchymal transition (EndMT in the developing atrioventricular (AV canal. The present study was aimed to investigate the role of NOS3 in embryonic development of AV valves. We hypothesized that NOS3 promotes embryonic development of AV valves via EndMT. To test this hypothesis, morphological and functional analysis of AV valves were performed in wild-type (WT and NOS3(-/- mice at postnatal day 0. Our data show that the overall size and length of mitral and tricuspid valves were decreased in NOS3(-/- compared with WT mice. Echocardiographic assessment showed significant regurgitation of mitral and tricuspid valves during systole in NOS3(-/- mice. These phenotypes were all rescued by cardiac specific NOS3 overexpression. To assess EndMT, immunostaining of Snail1 was performed in the embryonic heart. Both total mesenchymal and Snail1(+ cells in the AV cushion were decreased in NOS3(-/- compared with WT mice at E10.5 and E12.5, which was completely restored by cardiac specific NOS3 overexpression. In cultured embryonic hearts, NOS3 promoted transforming growth factor (TGFβ, bone morphogenetic protein (BMP2 and Snail1expression through cGMP. Furthermore, mesenchymal cell formation and migration from cultured AV cushion explants were decreased in the NOS3(-/- compared with WT mice. We conclude that NOS3 promotes AV valve formation during embryonic heart development and deficiency in NOS3 results in AV valve insufficiency.

  17. Pathology of complete atrioventricular block in chronic chagas' myocarditis

    Directory of Open Access Journals (Sweden)

    Zilton A. Andrade

    1988-03-01

    Full Text Available Sclero-atrophy, fibrosis, vascular ectasia, phlebosclerosis and mild non-specific chronic inflammatory changes were observed in variable location and proportion involving the atrioventricular conducting tissue of the heart in five human cases of chronic Chagas' myocarditis associated with complete atrioventricular block. One case presented complete destruction of the A-V conduction system. In three cases the lesions were disseminated all along the conducting tissue but did not cause anywhere a complete disruption in the continuity of the system. The distal portion of the bundle branches were the most damaged sector of the system, exceptfor the fasciculi of the posterior division of the left bundle branch which were relatively preserved. One case exhibited bilateral sclero-atrophy of the bundle branches as the main change; and another showed early and mild fibrocalcific damage of the penetrating portion of the His bundle. The A-V node appeared as the least involved part of the conducting system in the cases studied. Demonstration of the lesions in this series of cases seems important because: a it reveals that complete atrioventriculr block in chronic Chagas' disease results from disseminated lesions and not from focal disruptive change as has been commonly observed in cases of other etiologies; b it shows that chronic inflammation can produce at the end variable and widespread vascular, degenerative andfibrotic alterations within the conducting tissue of the heart, which may lead to its total destruction.O estudo do sistema de condução atrioventricular através cortes seriados completos em cinco casos humanos de miocardite crônica chagásica e bloqueio A-V total revelou a presença de lesões de esclero-atrofia, fibrose, ectasia vascular, fleboesclerose e inflamação crônica inespeclfica envolvendo o sistema de maneira disseminada, mas com distribuição e intensidade variáveis de caso para caso. Em um caso, todo o sistema, do nódulo A

  18. Diseño de Filtros FIR de Retraso Fraccionario Mediante Optimización en Frecuencia Fractional Delay FIR Filter Design using Frequency-Based Optimization

    Directory of Open Access Journals (Sweden)

    J. Díaz-Carmona

    2005-01-01

    Full Text Available En este artículo se describe el diseño en el dominio de la frecuencia de filtros digitales FIR de retraso fraccionario (Fractional Delay Filter, FDF con características de ancho de banda amplio y una resolución fina de retraso. El método de diseño en frecuencia utilizado está basado en optimización con mínimos cuadrados en la aproximación de series de Taylor de la señal de entrada. La propuesta consiste en reducir la complejidad de la optimización en frecuencia al momento de diseñar el FDF. Lo anterior se logra con la combinación de una estructura multirazón (multirate y una estructura Farrow modificada. El filtro resultante presenta como ventajas un número reducido de operaciones por muestra de salida y una reducción notable en la carga computacional de diseño.A frequency domain design method for fractional delay FIR filters (Fractional Delay Filter, FDF with wide bandwidth and fine delay resolution is described. The frequency domain method is based on a least square Taylor series approximation of the input signal. The proposed design method consists of reducing the complexity of the frequency optimization workload in the design of the FDF. This is obtained by the combination of a multirate structure and a modified Farrow structure. The resulting filter has a reduced number of arithmetic operations per output sample and yields a significant reduction in the design computational workload.

  19. Rate-adaptive AV delay and exercise performance following cardiac resynchronization therapy.

    Science.gov (United States)

    Shanmugam, Nesan; Prada-Delgado, Oscar; Campos, Ana Garcia; Grimster, Alex; Valencia, Oswaldo; Baltabaeva, Aigul; Jones, Sue; Anderson, Lisa

    2012-11-01

    Physiological shortening of the atrioventricular (AV) interval with increasing heart rate is well documented in normal human beings and is an established component of dual-chamber pacing for bradycardia. To assess the effect of exercise on optimal AV delay and the impact of a patient-specific rate-adaptive AV delay (RAAVD) on exercise capacity in patients with heart failure following cardiac resynchronization therapy. Phase 1: We performed iterative AV optimization at rest and exercise in 52 cardiac resynchronization therapy patients in atrial-sensed mode (mean age 71.6 ± 9.2 years, 25% females). Phase 2: Subsequently, 20 consecutive volunteers from this group (mean age 69.2 ± 9.6 years, 15% females) underwent cardiopulmonary exercise testing with RAAVD individually programmed ON (RAAVD-ON) or OFF (RAAVD-OFF). Phase 1: In 94% of the patients, there was a marked reduction (mean 50%) in optimal AV delay with exercise. The optimal resting vs exercise AV delay was 114.2 ± 29 ms at a heart rate of 64.4 ± 7.1 beats/min vs 57 ± 31 ms at a heart rate of 103 ± 13 beats/min (P AV delay with exercise, and 3 (6%) showed no change. Phase 2: With RAAVD-ON, significantly better exercise times were achieved (8.7 ± 3.2 minutes) compared with RAAVD-OFF (7.9 ± 3.2 minutes; P = .003), and there was a significant improvement in Vo(2)max (RAAVD-ON 16.1 ± 4.0 vs RAAVD-OFF 14.9 ± 3.7 mL/(kg · min); P = .024). There was a dramatic reduction in optimal AV delay with physiological exercise in the majority of this heart failure cardiac resynchronization therapy cohort. Replicating this physiological response with a programmable RAAVD translated into a 10% improvement in exercise capacity. Copyright © 2012 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.

  20. Local Stabilization of Time-Delay Nonlinear Discrete-Time Systems Using Takagi-Sugeno Models and Convex Optimization

    Directory of Open Access Journals (Sweden)

    Luís F. P. Silva

    2014-01-01

    Full Text Available A convex condition in terms of linear matrix inequalities (LMIs is developed for the synthesis of stabilizing fuzzy state feedback controllers for nonlinear discrete-time systems with time-varying delays. A Takagi-Sugeno (T-S fuzzy model is used to represent exactly the nonlinear system in a restricted domain of the state space, called region of validity. The proposed stabilization condition is based on a Lyapunov-Krasovskii (L-K function and it takes into account the region of validity to determine a set of initial conditions for which the actual closed-loop system trajectories are asymptotically stable and do not evolve outside the region of validity. This set of allowable initial conditions is determined from the level set associated to a fuzzy L-K function as a Cartesian product of two subsets: one characterizing the set of states at the initial instant and another for the delayed state sequence necessary to characterize the initial conditions. Finally, we propose a convex programming problem to design a fuzzy controller that maximizes the set of initial conditions taking into account the shape of the region of validity of the T-S fuzzy model. Numerical simulations are given to illustrate this proposal.

  1. [Atrioventricular defect with 2 valves associated with absence of the pericardium. Report of a case].

    Science.gov (United States)

    Miranda-Chávez, Irma; Muñoz-Castellanos, Luis; Kimura-Hayama, Erick; Vidal-Rojo, Paola; Figueroa-Solano, Javier; de Micheli Serra, Alfredo; Buendía-Hernández, Alfonso

    2013-01-01

    We present a case of a patient with a cardiac malformation that represents a form of embryo-anatomical transition of an atrioventricular septal defect between a 2 valves form to a common valve form. This entity was associated with pericardium absence. Throughout several studies we have precisely established a diagnostic sequence by determining the adequate contribution of each method and we have been able to clear out the proper nomenclature of the atrioventricular cushion defect. Copyright © 2012 Instituto Nacional de Cardiología Ignacio Chávez. Published by Masson Doyma México S.A. All rights reserved.

  2. Tubular hypoplasia of the aorta and right atrioventricular valve dysplasia in a Bulldog.

    Science.gov (United States)

    Robinson, Nicholas A; Armíen, Aníbal G

    2010-07-01

    A Bulldog puppy that died at 1 day of age was presented for postmortem evaluation. Macroscopically, there was marked hypoplasia of the ascending, transverse, and proximal segments of the descending thoracic aorta and almost complete secondary thrombosis of the left ventricle causing a functional stenosis of the left atrioventricular valve. Separately, there was right atrioventricular valve dysplasia with secondary dilation of the right atrium. Microscopically, the left ventricular outflow tract was occluded by chondroid metaplasia, fibrosing recanalization of a left-ventricular thrombus, and isolated Purkinje fiber degeneration and necrosis.

  3. Optimizing the dynamics of a two-cell DC-DC buck converter by time delayed feedback control

    Science.gov (United States)

    Feki, M.; El Aroudi, A.; Robert, B. G. M.; Martínez-Salamero, L.

    2011-11-01

    A study of the dynamical behavior of a two-cell DC-DC buck converter under a digital time delayed feedback control (TDFC) is presented. Various numerical simulations and dynamical aspects of this system are illustrated in the time domain and in the parameter space. Without TDFC, the system may present many undesirable behaviors such as sub-harmonics and chaotic oscillations. TDFC is able to widen the stability range of the system. Optimum values of parameters giving rise to fast response while maintaining stable periodic behavior are given in closed form. However, it is detected that in a certain region of the parameter space, the stabilized periodic orbit may coexist with a chaotic attractor. Boundary between basins of attraction are obtained by means of numerical simulations.

  4. Optimal control of laser plasma instabilities using Spike Trains of Uneven Duration and Delay (STUD pulses) for ICF and IFE

    CERN Document Server

    Afeyan, Bedros

    2012-01-01

    An adaptive method of controlling parametric instabilities in laser produced plasmas is proposed. It involves fast temporal modulation of a laser pulse on the fastest instability's amplification time scale, adapting to changing and unknown plasma conditions. These pulses are comprised of on and off sequences having at least one or two orders of magnitude contrast between them. Such laser illumination profiles are called STUD pulses for Spike Trains of Uneven Duration and Delay. The STUD pulse program includes scrambling the speckle patterns spatially in between the laser spikes. The off times allow damping of driven waves. The scrambling of the hot spots allows tens of damping times to elapse before hot spot locations experience recurring high intensity spikes. Damping in the meantime will have healed the scars of past growth. Another unique feature of STUD pulses on crossing beams is that their temporal profiles can be interlaced or staggered, and their interactions thus controlled with an on-off switch and ...

  5. Optimal control of laser plasma instabilities using Spike Trains of Uneven Duration and Delay (STUD pulses) for ICF and IFE

    Science.gov (United States)

    Afeyan, Bedros; Hüller, Stefan

    2013-11-01

    An adaptive method of controlling parametric instabilities in laser produced plasmas is proposed. It involves fast temporal modulation of a laser pulse on the fastest instability's amplification time scale, adapting to changing and unknown plasma conditions. These pulses are comprised of on and off sequences having at least one or two orders of magnitude contrast between them. Such laser illumination profiles are called STUD pulses for Spike Trains of Uneven Duration and Delay. The STUD pulse program includes scrambling the speckle patterns spatially in between the laser spikes. The off times allow damping of driven waves. The scrambling of the hot spots allows tens of damping times to elapse before hot spot locations experience recurring high intensity spikes. Damping in the meantime will have healed the scars of past growth. Another unique feature of STUD pulses on crossing beams is that their temporal profiles can be interlaced or staggered, and their interactions thus controlled with an on-off switch and a dimmer.

  6. Acute beneficial hemodynamic effects of a novel 3D-echocardiographic optimization protocol in cardiac resynchronization therapy.

    Directory of Open Access Journals (Sweden)

    Carolin Sonne

    Full Text Available BACKGROUND: Post-implantation therapies to optimize cardiac resynchronization therapy (CRT focus on adjustments of the atrio-ventricular (AV delay and ventricular-to-ventricular (VV interval. However, there is little consensus on how to achieve best resynchronization with these parameters. The aim of this study was to examine a novel combination of doppler echocardiography (DE and three-dimensional echocardiography (3DE for individualized optimization of device based AV delays and VV intervals compared to empiric programming. METHODS: 25 recipients of CRT (male: 56%, mean age: 67 years were included in this study. Ejection fraction (EF, the primary outcome parameter, and left ventricular (LV dimensions were evaluated by 3DE before CRT (baseline, after AV delay optimization while pacing the ventricles simultaneously (empiric VV interval programming and after individualized VV interval optimization. For AV delay optimization aortic velocity time integral (AoVTI was examined in eight different AV delays, and the AV delay with the highest AoVTI was programmed. For individualized VV interval optimization 3DE full-volume datasets of the left ventricle were obtained and analyzed to derive a systolic dyssynchrony index (SDI, calculated from the dispersion of time to minimal regional volume for all 16 LV segments. Consecutively, SDI was evaluated in six different VV intervals (including LV or right ventricular preactivation, and the VV interval with the lowest SDI was programmed (individualized optimization. RESULTS: EF increased from baseline 23±7% to 30±8 (p<0.001 after AV delay optimization and to 32±8% (p<0.05 after individualized optimization with an associated decrease of end-systolic volume from a baseline of 138±60 ml to 115±42 ml (p<0.001. Moreover, individualized optimization significantly reduced SDI from a baseline of 14.3±5.5% to 6.1±2.6% (p<0.001. CONCLUSIONS: Compared with empiric programming of biventricular pacemakers

  7. Closure of the zone of apposition at correction of complete atrioventricular septal defect improves outcome.

    Science.gov (United States)

    Wetter, J; Sinzobahamvya, N; Blaschczok, C; Brecher, A M; Grävinghoff, L M; Schmaltz, A A; Urban, A E

    2000-02-01

    Outcome after correction of atrioventricular septal defect depends to a great deal on the postoperative function of the left atrioventricular valve. The related role of the zone of apposition ('cleft') has been debated: should it be closed (bileaflet repair) or should it be left untouched (trileaflet repair)? This study aims to answer the question by comparing the outcome of patients treated according to these two approaches. We reviewed all our patients who underwent repair of complete atrioventricular septal defect from 1984 to 1997 and selected those in whom the closure of the zone of apposition in principle would have been possible. Two groups with similar characteristics were constituted: group I (n=63), where the zone of apposition was deliberately not closed as part of a trileaflet repair (postoperative open zone of apposition) and group II (n=96), where it was electively closed as part of a bileaflet AV valve repair (closed zone of apposition). Since we changed from a trileaflet to a bileaflet repair in 1987, the two groups differ in terms of size and length of follow-up. Outcome was compared with regard to survival and freedom from reoperation for left atrioventricular valve incompetence. Late atrioventricular valve function was evaluated by Echo-Doppler. For statistical analysis, we used Chi-square or Fisher's exact test, the Mann-Whitney test and the log-rank test for comparison of Kaplan-Meier curves. The difference was considered statistically significant with a P-value of 0.05 or less. Early mortality was 9.5% (6/63) in group I and 3.1% (3/96) in group II (P=0.16). Actuarial survival after 1, 4 and 8 years was 80.4, 68.4 and 64.8%, respectively, for group I. Actuarial survival for group II was 94.7, 92.1 and 92.1% (P=0.0002). Freedom from reoperation for left atrioventricular valve regurgitation was 90.2, 85.6 and 77.8% for group I at the same time interval. It was a constant 97.9% for group II (P=0.0016). At reoperation, left atrioventricular valve

  8. Forecasting of DST index from auroral electrojet indices using time-delay neural network + particle swarm optimization

    Science.gov (United States)

    Lazzús, J. A.; López-Caraballo, C. H.; Rojas, P.; Salfate, I.; Rivera, M.; Palma-Chilla, L.

    2016-05-01

    In this study, an artificial neural network was optimized with particle swarm algorithm and trained to predict the geomagmetic DST index one hour ahead using the past values of DST and auroral electrojet indices. The results show that the proposed neural network model can be properly trained for predicting of DST(t + 1) with acceptable accuracy, and that the geomagnetic indices used have influential effects on the good training and predicting capabilities of the chosen network.

  9. Optimal Control of Laser-Plasma Instabilities Using Spike Trains of Uneven Duration and Delay: STUD Pulses

    CERN Document Server

    Afeyan, Bedros

    2013-01-01

    Adaptive methods of laser irradiation of plasmas are proposed consisting of deterministic, `on-off' amplitude modulations in time, and intermittently changing speckle-patterns. These laser pulses consist of a series of picosecond time-scale spikes in a spike train of uneven duration and delay (STUD pulses), in contrast to hydrodynamic-time-scale modulated, multi-nanosecond pulses for laser fusion. Properly designed STUD pulses minimize backscatter and tame any absorptive parametric instability for a given set of plasma conditions, by adjusting the modulation periods, duty cycles and spatial hot-spot-distribution scrambling-rates of the spikes. Traditional methods of beam conditioning are subsumed or surpassed by STUD pulses. In addition, STUD pulses allow an advance in the control of instabilities driven by spatially overlapped laser beams by allowing the spikes of crossing beams to be temporally staggered. When the intensity peaks of one fall within the nulls of its crossing beam, it allows an on-off switch ...

  10. OPTIMAL ORDERING POLICY FOR THE TIME DEPENDENT DETERIORATION WITH ASSOCIATED SALVAGE VALUE WHEN DELAY IN PAYMENTS IS PERMISSIBLE

    Directory of Open Access Journals (Sweden)

    Nita H. Shah *, Poonam Pandey*

    2008-09-01

    Full Text Available In this research article, an attempt is made to develop mathematical model when units in inventory are subject to deterioration with time, and the supplier offers his retailer the credit period to settle the account of the procurement units. The salvage value is associated to the deterioration units. The objective is to minimize the retailer’s total inventory cost. An algorithm is proposed to find optimal ordering policy. A numerical example is given to study the effect of allowable credit period and deterioration on decision variable and the total cost of the retailer.

  11. [Successful selective electrical ablation of the retrograde pathway in atrioventricular nodal reentry tachycardia associated with syncope].

    Science.gov (United States)

    Lukl, J; Cíhalík, C

    1992-01-01

    A 55-year-old man was admitted to the intensive care unit on account of repeatedly occurring syncopes which developed at the peak of physical exertion. The attack was reproduced by exercise on a bicycle ergometer: the patient developed paroxysmal tachycardia with a narrow QRS and a frequency of 160/min leading after 20 sec. to severe hypotension and loss of consciousness. The same tachycardia caused by programmed atrial stimulation caused a drop of tension in the recumbent position by 30 mmHg and after more detailed analysis during electrophysiological examination it was evaluated as atrioventricular nodal reentrant tachycardia. By an electric discharge of 300 J administered by means of a stimulation electrode 7F USCI into the area of the AV node the retrograde conduction through the perinodal rapid pathways was completely interrupted and 1st. degree atrioventricular block developed. Repeated electrophysiological examination and exercise tests on a bicycle ergometer provided evidence of the disappearance of the retrograde pathway and the impossibility to elicit AVNRT. The authors express the view that the rapid perinodal pathway is interrupted in successful cases in both directions and the 1st. degree AV block is due to conduction along a slow pathway and not incidental slowing of conduction along the rapid pathway which is the generally accepted interpretation. Modification of the atrioventricular conduction by interruption of the rapid pathway by fulguration is according to data in the literature and the described patient a method which makes is possible to cure severe atrioventricular nodal reentrant tachycardias.

  12. Electrophysiologic and antiarrhythmic effects of intravenous bisoprolol in atrioventricular nodal reentry tachycardia

    NARCIS (Netherlands)

    vandeVen, LLM; Crijns, HJGM; deMuinck, ED; VanGelder, IC; VanWijk, LM; Lie, KI

    1996-01-01

    Beta-blockade may be useful in the termination and prevention of atrioventricular nodal reentry tachycardia (AVNRT), An electrophysiologic study was performed in 9 patients (4 men and 5 women; mean +/- SD age, 56 +/- 16 years) with documented AVNRT before and after the intravenous administration of

  13. Deterministic model of the canine atrio-ventricular node as a periodically perturbed, biological oscillator

    NARCIS (Netherlands)

    Tweel, I. van der; Herbschleb, J.N.; Borst, C.; Meijler, F.L.

    1986-01-01

    The atrio-ventricular (AV) node may be regarded as a periodically perturbed, biologicaL oscillator. In that case the ventricular response to atrial excitation can be described by a latency-phase curve. The phase is approximated by the time between a QRS-complex and an atrial stimulus S (R-S interval

  14. Cardiovascular magnetics resonance diagnosis of cystic tumor of the atrioventricular node

    Directory of Open Access Journals (Sweden)

    Wang Xuedong

    2009-04-01

    Full Text Available Abstract Late gadolinium enhanced (LGE cardiovascular magnetic resonance (CMR has proven to be the gold standard for viability assessment. LGE CMR is also useful for identifying the nature of cardiac masses or lesions. We report a case of a rare primary cystic tumor of the atrioventricular node, in which CMR proved to be valuable.

  15. Potential additional indicators for pacemaker requirement in isolated congenital atrioventricular block.

    NARCIS (Netherlands)

    Breur, J.M.; Udink ten Cate, F.E.; Kapusta, L.; Boramanand, N.; Cohen, M.I.; Crosson, J.E.; Lubbers, L.J.; Friedman, A.H.; Brenner, J.I.; Vetter, V.L.; Meijboom, E.J.

    2006-01-01

    Low heart rate is the predominantly used indication for pacemaker intervention in patients with isolated congenital atrioventricular block (CAVB). The aim of this study was to compare the difference in heart rates recorded with ECG and Holter monitoring between paced (PM) and nonpaced (NPM) patients

  16. Potential additional indicators for pacemaker requirement in isolated congenital atrioventricular block

    NARCIS (Netherlands)

    J.M.P.J. Breur; F.E.A.U. ten Cate; L. Kapusta; N. Boramanand; M.I. Cohen; J.E. Crosson; L.J. Lubbers; A.H. Friedman; J.I. Brenner; V.L. Vetter; E.J. Meijboom

    2006-01-01

    Low heart rate is the predominantly used indication for pacemaker intervention in patients with isolated congenital atrioventricular block (CAVB). The aim of this study was to compare the difference in heart rates recorded with ECG and Holter monitoring between paced (PM) and nonpaced (NPM) patients

  17. [Exercise-induced atrioventricular block. Significance of the ischemic component. Report of 4 new cases].

    Science.gov (United States)

    Rumoroso, J R; Montes Orbe, P M; Cembellín, J C; Pérez-García, P; González-Liébana, J; Gómez-Varela, S; Bodegas, A; Barrenetxea, J I

    1997-04-01

    We report four new cases of exercise-induced atrio-ventricular block (appearing during treadmill exercise testing). The mechanism was ischemia in two patients and the conduction disturbance disappeared after coronary artery bypass grafting. The literature on this matter is reviewed. Also the etiology, the natural history and management are discussed in these cases.

  18. Longitudinal echocardiographic follow-up in children with congenital complete atrioventricular block

    NARCIS (Netherlands)

    Beaufort-Krol, Gertie C. M.; Leeuwen, Miek J. M. Schasfoort-Van; Stienstra, Ymkje; Bink-Boelkens, Margreet Th. E.

    2007-01-01

    Background: Due to a low heart rate (HR) in children with congenital complete atrioventricular block (CCAVB), a larger stroke volume of the left ventricle (LV) may be expected. If so, end-diastolic (LVEDD) and end-systolic (LVESD) diameters may be enlarged and even dilated cardiomyopathy (DCM) may o

  19. Potential additional indicators for pacemaker requirement in isolated congenital atrioventricular block.

    NARCIS (Netherlands)

    Breur, J.M.; Udink ten Cate, F.E.A.; Kapusta, L.; Boramanand, N.; Cohen, M.I.; Crosson, J.E.; Lubbers, L.J.; Friedman, A.H.; Brenner, J.I.; Vetter, V.L.; Meijboom, E.J.

    2006-01-01

    Low heart rate is the predominantly used indication for pacemaker intervention in patients with isolated congenital atrioventricular block (CAVB). The aim of this study was to compare the difference in heart rates recorded with ECG and Holter monitoring between paced (PM) and nonpaced (NPM) patients

  20. Atrioventricular septal defect : advanced imaging from early development to long-term follow-up

    NARCIS (Netherlands)

    Calkoen, Emmeline E.

    2016-01-01

    The aim of this thesis is to review the current knowledge on atrioventricular septal defect (AVSD) (Part 1), to study the pathogenesis of AVSD (Part 2) and finally to analyze cardiac outcome long-term after AVSD correction (Part 3). Studies are performed with novel imaging techniques. In part 2 it

  1. Exercise capacity in children with isolated congenital complete atrioventricular block: does pacing make a difference?

    NARCIS (Netherlands)

    Blank, A.C.; Hakim, S.; Strengers, J.L.; Tanke, R.B.; Veen, T.A. van; Vos, M.E. de; Takken, T.

    2012-01-01

    The management of patients with isolated congenital complete atrioventricular block (CCAVB) has changed during the last decades. The current policy is to pace the majority of patients based on a variety of criteria, among which is limited exercise capacity. Data regarding exercise capacity in this p

  2. Exercise Capacity in Children With Isolated Congenital Complete Atrioventricular Block : Does Pacing Make a Difference?

    NARCIS (Netherlands)

    Blank, A. Christian; Hakim, Sara; Strengers, Jan L.; Tanke, Ronald B.; van Veen, Toon A.; Vos, Marc A.; Takken, Tim

    2012-01-01

    The management of patients with isolated congenital complete atrioventricular block (CCAVB) has changed during the last decades. The current policy is to pace the majority of patients based on a variety of criteria, among which is limited exercise capacity. Data regarding exercise capacity in this p

  3. Congenital intermittent atrio-ventricular dissociation in tetralogy of Fallot (a case report.

    Directory of Open Access Journals (Sweden)

    Karande S

    1991-01-01

    Full Text Available A case of tetralogy of fallot with congenital intermittent atrioventricular dissociation is reported. A review of standard postgraduate books of cardiology fails to describe this condition, thus showing its extreme rarity. The therapeutic dilemma in treating such a case is also discussed.

  4. Congenital intermittent atrio-ventricular dissociation in tetralogy of Fallot (a case report).

    OpenAIRE

    Karande S; Sheth S; Dalvi B; Lahiri K; Shah M

    1991-01-01

    A case of tetralogy of fallot with congenital intermittent atrioventricular dissociation is reported. A review of standard postgraduate books of cardiology fails to describe this condition, thus showing its extreme rarity. The therapeutic dilemma in treating such a case is also discussed.

  5. Fetal atrioventricular and outflow tract flow velocity waveforms during conducted and blocked supraventricular extrasystoles

    NARCIS (Netherlands)

    K. van der Mooren (K.); J.W. Wladimiroff (Juriy); Th. Stijnen (Theo)

    1992-01-01

    textabstractMaximum flow velocity waveforms at atrioventricular and outflow tract level were studied cross‐sectionally in 19 human fetuses with conducted and/or blocked supraventricular extrasystoles ranging from 25 to 38 weeks of gestation. At outflow tract level, peak systolic velocity and acceler

  6. Mobitz type I atrio-ventricular block in dengue myocarditis, requiring temporary pacing

    Directory of Open Access Journals (Sweden)

    S. de Mel

    2015-01-01

    Full Text Available We present a case of dengue myocarditis related Mobitz type I atrio-ventricular (A-V block. To our knowledge, this is the first report of such a patient requiring pacing. An early response to methylprednisolone suggests the possibility of a therapeutic role for steroids in these patients.

  7. A case of complete atrioventricular block: The use of magnetic resonance imaging conditional pacemakers for diagnosing cardiac sarcoidosis

    Directory of Open Access Journals (Sweden)

    Yosuke Miwa, MD

    2014-04-01

    Full Text Available A 50-year-old man presented to the emergency department with repeated episodes of faintness and exertional dyspnea, and was found to have an atrioventricular (AV block. Chest radiography and transthoracic echocardiography results were normal, without any evidence of heart failure, wall motion abnormalities, interventricular septum thinning, or bilateral hilar lymphadenopathy. A temporary pacemaker was implanted, followed by a permanent pacemaker. Chest computed tomography with contrast enhancement did not show abnormalities, including patent coronary arteries, lymph node adenopathy, and pulmonary abnormalities. Thus, an MRI conditional dual chamber pacemaker and leads were implanted. Six weeks following the implant, a cardiac MRI was performed to test for cardiac sarcoidosis. Although cine imaging showed normal left and right ventricular function, late gadolinium enhancement demonstrated multiple enhanced uptakes. Based on the results of the cardiac MRI, PET, and gallium scintigraphy, the most likely diagnosis was cardiac sarcoidosis. Although no abnormal findings were found on physical examination, blood work, chest radiography, and transthoracic echocardiogram, multiple regions of delayed enhancement were observed in the cardiac MRI. Thus, MRI conditional pacemakers are a useful tool for diagnosing cardiac sarcoidosis and early therapeutic intervention.

  8. Optimal Communication Network-Based H∞ Quantized Control With Packet Dropouts for a Class of Discrete-Time Neural Networks With Distributed Time Delay.

    Science.gov (United States)

    Han, Qing-Long; Liu, Yurong; Yang, Fuwen

    2016-02-01

    This paper is concerned with optimal communication network-based H∞ quantized control for a discrete-time neural network with distributed time delay. Control of the neural network (plant) is implemented via a communication network. Both quantization and communication network-induced data packet dropouts are considered simultaneously. It is assumed that the plant state signal is quantized by a logarithmic quantizer before transmission, and communication network-induced packet dropouts can be described by a Bernoulli distributed white sequence. A new approach is developed such that controller design can be reduced to the feasibility of linear matrix inequalities, and a desired optimal control gain can be derived in an explicit expression. It is worth pointing out that some new techniques based on a new sector-like expression of quantization errors, and the singular value decomposition of a matrix are developed and employed in the derivation of main results. An illustrative example is presented to show the effectiveness of the obtained results.

  9. Optimal Design of the Group Delay Time Equalizer Using the Genetic Algorithm%群延时均衡器的遗传算法优化设计

    Institute of Scientific and Technical Information of China (English)

    马云辉

    2001-01-01

    在已有文献报道中多采用Powell法设计均衡网络,但Powell法是确定性优化方法,结果的好坏与初始点的选择关系密切,并易陷入局部极值点。由于遗传算法是一种全局随机搜索方法,即使定义的适应性函数不可导或不连续,它也可能以很大的概率求得全局最优解,因而在工程领域中将有十分广泛的实际应用前景。将一种新的实数码遗传算法应用到群延时均衡器的设计中,并给出了巴特沃斯滤波器群延时均衡器的设计实例,结果表明提出的方法十分有效。%It has been reported that the equalizer network was designed by Powell method in previous literatures. Since Powell method is a confirmed optimization method, the results, fine or bad, are closely related to the selection of initial points, and it is easy to fall into local optimal solutions. Because the genetic algorithm (GA) is a global stochastic searching method, and even if the defined fitness function is indifferential or uncontinuous, it is also possible to obtain the global optimal solution with a considerable probability. Thus there will be widely practical application in the engineering field. This paper attempts to present a new real coded GA for applying to design group delay time equalizers, and the examples about designing group delay time equalizers of the Butterworth filter are given This method is illustrated very effectively by results.

  10. Rapid parameter optimization of low signal-to-noise samples in NMR spectroscopy using rapid CPMG pulsing during acquisition: application to recycle delays.

    Science.gov (United States)

    Farooq, Hashim; Courtier-Murias, Denis; Soong, Ronald; Masoom, Hussain; Maas, Werner; Fey, Michael; Kumar, Rajeev; Monette, Martine; Stronks, Henry; Simpson, Myrna J; Simpson, André J

    2013-03-01

    A method is presented that combines Carr-Purcell-Meiboom-Gill (CPMG) during acquisition with either selective or nonselective excitation to produce a considerable intensity enhancement and a simultaneous loss in chemical shift information. A range of parameters can theoretically be optimized very rapidly on the basis of the signal from the entire sample (hard excitation) or spectral subregion (soft excitation) and should prove useful for biological, environmental, and polymer samples that often exhibit highly dispersed and broad spectral profiles. To demonstrate the concept, we focus on the application of our method to T(1) determination, specifically for the slowest relaxing components in a sample, which ultimately determines the optimal recycle delay in quantitative NMR. The traditional inversion recovery (IR) pulse program is combined with a CPMG sequence during acquisition. The slowest relaxing components are selected with a shaped pulse, and then, low-power CPMG echoes are applied during acquisition with intervals shorter than chemical shift evolution (RCPMG) thus producing a single peak with an SNR commensurate with the sum of the signal integrals in the selected region. A traditional (13)C IR experiment is compared with the selective (13)C IR-RCPMG sequence and yields the same T(1) values for samples of lysozyme and riverine dissolved organic matter within error. For lysozyme, the RCPMG approach is ~70 times faster, and in the case of dissolved organic matter is over 600 times faster. This approach can be adapted for the optimization of a host of parameters where chemical shift information is not necessary, such as cross-polarization/mixing times and pulse lengths.

  11. Effects of beta-blockade on atrial and atrioventricular nodal refractoriness, and atrial fibrillatory rate during atrial fibrillation in pigs

    NARCIS (Netherlands)

    van den Berg, MP; van de Ven, LLM; Witting, W; Crijns, JGM; Haaksma, J; Bel, KJ; de Langen, CDJ; Lie, KI

    1997-01-01

    Despite their widespread use in atrial fibrillation, the effects of beta-adrenoceptor blockers on atrial and atrioventricular (AV) nodal refractoriness, and atrial fibrillatory rate during atrial fibrillation have been incompletely characterised. In particular, it is unknown whether additional sodiu

  12. A Case of Adult-Onset Acute Rheumatic Fever With Long-Lasting Atrioventricular Block Requiring Permanent Pacemaker Implantation.

    Science.gov (United States)

    Oba, Yusuke; Watanabe, Hiroaki; Nishimura, Yoshioki; Ueno, Shuichi; Nagashima, Takao; Imai, Yasushi; Shimpo, Masahisa; Kario, Kazuomi

    2015-01-01

    A 45-year-old hypertensive Japanese woman presented with epigastric pain on inspiration, fever, complete atrioventricular block and polyarthritis. Her antistreptolysin O levels were markedly elevated. A diagnosis of rheumatic fever was made according to the modified Jones criteria. She was prescribed loxoprofen sodium, which was partially effective for her extracardiac clinical symptoms. However, she had syncope due to complete atrioventricular block with asystole longer than 10 seconds. Consequently, we implanted a permanent pacemaker. Although we prescribed prednisolone, the efficacy of which was limited for the patient's conduction disturbance, the complete atrioventricular block persisted. In our systematic review of 12 similar cases, the duration of complete heart block was always transient and there was no case requiring a permanent pacemaker. We thus encountered a very rare case of adult-onset acute rheumatic fever with persistent complete atrioventricular block necessitating permanent pacemaker implantation.

  13. Anatomia da valva atrioventricular esquerda: I. As cúspides Anatomy of the left atrio-ventricular valve: I. The cusps

    Directory of Open Access Journals (Sweden)

    Antônio B. Prado Fortuna

    1988-12-01

    Full Text Available Os resultados de um estudo anatômico da valva atrioventricular esquerda, realizado em 30 corações aparentemente normais, conservados em formalina, são comparados aos dados da literatura, tendo por objetivo adequar a nomenclatura e os conceitos anatômicos clássicos aos atuais, baseados na ultra-sonografia e na prática cirúrgica corrente. O presente artigo tratará apenas das cúspides, sendo que os demais elementos anatômicos dessa valva atrioventricular esquerda fazem parte de uma "unidade aortoventricular", onde distinguimos a cúspide anterior, em continuidade com o trígono intervalvar e o anel aórtico, e um grupo de cúspides posteriores, em relação com a parede posterior do ventrículo esquerdo. A cúspide anterior está separada do grupo de cúspides posteriores, tanto no polo valvar superior como no inferior, por uma estrutura anatômica bem definida: a "lâmina juncional", superior e inferior, respectivamente. As cúspides do grupo posterior são designadas pela ordem numeral ordinal, a partir da lâmina juncional superior. Esta nomenclatura tem por objetivo destacar a cúspide como unidade funcional da valva e facilitar as referências ecocardiográficas e cirúrgicas, particularmente nos casos em que mais de 3 cúspides posteriores são encontradas.A review of the left atrio-ventricular valve anatomy is compared to a clinical oriented morphological study on 30 normal adult heart, preserved in formalin. The results will be presented in five separated sections: I. The cusps; II. The comissures; III. The chordae tendinae; IV. The papilary muscles; V. The valvar annulus. The present publication will deal with the cusps. The terms "left atrio-ventricular valve" and "cusps" are to be prefered to the more descriptive and traditional "mitral valve" and "leaflets". The anterior cusp, in continuity with the aortic annulus, and a group of posterior cusps, attached to the posterior left wall, are described. An ordinal numerical

  14. Utilization of Electrocardiographic P-wave Duration for AV Interval Optimization in Dual-Chamber Pacemakers.

    Science.gov (United States)

    Sorajja, Dan; Bhakta, Mayurkumar D; Scott, Luis Rp; Altemose, Gregory T; Srivathsan, Komandoor

    2010-09-05

    Empiric programming of the atrio-ventricular (AV) delay is commonly performed during pacemaker implantation. Transmitral flow assessment by Doppler echocardiography can be used to find the optimal AV delay by Ritter's method, but this cannot easily be performed during pacemaker implantation. We sought to determine a non-invasive surrogate for this assessment. Since electrocardiographic P-wave duration estimates atrial activation time, we hypothesized this measurement may provide a more appropriate basis for programming AV intervals. A total of 19 patients were examined at the time of dual chamber pacemaker implantation, 13 (68%) being male with a mean age of 77. Each patient had the optimal AV interval determined by Ritter's method. The P-wave duration was measured independently on electrocardiograms using MUSE® Cardiology Information System (version 7.1.1). The relationship between P-wave duration and the optimal AV interval was analyzed. The P-wave duration and optimal AV delay were related by a correlation coefficient of 0.815 and a correction factor of 1.26. The mean BMI was 27. The presence of hypertension, atrial fibrillation, and valvular heart disease was 13 (68%), 3 (16%), and 2 (11%) respectively. Mean echocardiographic parameters included an ejection fraction of 58%, left atrial index of 32 ml/m(2), and diastolic dysfunction grade 1 (out of 4). In patients with dual chamber pacemakers in AV sequentially paced mode and normal EF, electrocardiographic P-wave duration correlates to the optimal AV delay by Ritter's method by a factor of 1.26.

  15. Electrical Injury-Induced Complete Atrioventricular Block: Is Permanent Pacemaker Required?

    Directory of Open Access Journals (Sweden)

    Osman Beton

    2015-01-01

    Full Text Available A considerable percentage of electrical injuries occur as a result of work activities. Electrical injury can lead to various cardiovascular disorders: acute myocardial necrosis, myocardial ischemia, heart failure, arrhythmias, hemorrhagic pericarditis, acute hypertension with peripheral vasospasm, and anomalous, nonspecific ECG alterations. Ventricular fibrillation is the most common arrhythmia resulting from electrical injury and is the leading cause of death in electrical (especially low voltage alternating current injury cases. Asystole, premature ventricular contractions, ventricular tachycardia, conduction disorders (various degrees of heart blocks, bundle-brunch blocks, supraventricular tachycardia, and atrial fibrillation are the other arrhythmic complications of electrical injury. Complete atrioventricular block has rarely been reported and permanent pacemaker was required for the treatment in some of these cases. Herein, we present a case of reversible complete atrioventricular block due to low voltage electrical injury in a young electrical technician.

  16. Atrium-atrioventricular node block: an unusual complication during catheter ablation of persistent atrial fibrillation

    Institute of Scientific and Technical Information of China (English)

    MIAO Cheng-long; SANG Cai-hua; DONG Jian-zeng; MA Chang-sheng

    2011-01-01

    Ablation of persistent atrial fibrillation is still a challenge for the ablationist. Extensive ablation is required under some conditions and could lead to some unintended complications. Here we report a case of atrium-atrioventricular node block complicating multiple catheter ablation procedures for persistent atrial fibrillation. After extensive ablation, including circumferential pulmonary vein ablation, linear ablation at the left atrial roof, mitral isthmus, atrial septum, cavotricuspid isthmus, and complex fractionated atrial electrogram ablation, conduction obstacle was found, and sinus impulse could not travel from the right atrium, atrial septum and left atrium to atrioventricular node. The case indicated that intensive ablation at some key sites, especially the interatrial septum, should be careful during ablation of atrial fibrillation.

  17. [Innervation of the atrioventricular portion of the interatrial septum in the rat].

    Science.gov (United States)

    Pavlovich, E R

    1984-03-01

    A quantitative electron microscopical investigation has revealed reliable differences in contents of muscular, connective tissue and neural elements in the conductive system, on the one hand (in the atrioventricular node and in the internodal specialized pathways) and in the working myocardium of the inferior third of the interatrial septum, on the other hand. Morphometrical analysis of the neuromuscular interrelations, performed separately for every type of specialized conductive myocytes (II, III) and of working cardiomyocytes of the interatrial septum, reveals some differences in size of the neural fibers and their terminals and in distance between them and myocytes. The synaptic vesicles of the efferent terminals are qualitatively different in all types of the myocytes. The afferent terminals situating near specialized cardiac cells are characterized. Criteria for distinguishing small and large granular vesicles in the terminals are discussed. A suggestion is made that the innervational peculiarities revealed reflect certain specificity in regulation the conduction in the atrioventricular area of the heart.

  18. Atrioventricular block induced by mad-honey intoxication: confirmation of diagnosis by pollen analysis.

    Science.gov (United States)

    Cagli, Kumral Ergun; Tufekcioglu, Omac; Sen, Nihat; Aras, Dursun; Topaloglu, Serkan; Basar, Nur; Pehlivan, Sevil

    2009-01-01

    An unusual type of food poisoning, mad-honey intoxication, can be observed in the Black Sea region of Turkey and various other parts of the world. It can occur after ingestion of grayanotoxin-contaminated honey produced from the nectar of Rhododendron ponticum and other plant species, chiefly of the Ericaceae and Sapindaceae families. Mad-honey intoxication can result in severe cardiac complications, such as complete atrioventricular block. The diagnosis is generally reached on the basis of the patient's history of honey intake. In this report, we describe the case of a patient who had mad-honey-related complete atrioventricular block; in this instance, the diagnosis was confirmed by a pollen analysis of the suspect honey.

  19. Biological Glue Application in Repair of Atrioventricular Groove Rupture: A Case Report

    Directory of Open Access Journals (Sweden)

    Ahmet Baris-Durukan

    2015-10-01

    Full Text Available Atrioventricular groove rupture is a rare, albeit mortal, complication following mitral valve surgery. Avoidance is the best strategy but it cannot fully prevent the occurrence of this complication. Several repair techniques have been described with varying success rates; however, the rarity of the complication precludes consensus about the safest technique.Here we report two cases of posterior atrioventricular groove rupture. Both cases were diagnosed immediately after the cessation of cardiopulmonary bypass. Repair was performed successfully with a technique involving the use of biological glue. The postoperative course was uneventful for both of them. Both cases are well with normally functioning mitral prostheses; one with a follow-up time of 5.5 years and the other 10 months. We believe that the glue provides additional hemostasis and support to the repaired area.

  20. Ablation of left-deviated dual atrioventricular nodal pathway from coronary sinus

    Institute of Scientific and Technical Information of China (English)

    HUANG Wei-bin; HONG Jiang; WANG Yan; ZHOU Fa-guang; ZENG Zhao-pin; GONG Yan; SUN Bao-gui; WANG Le-xin

    2009-01-01

    @@ Atrioventricular nodal reentrant tachycardia (AVNRT) is one of the most common types of paroxysmal supraventricular tachycardia. The mechanism of AVNRT is reentry associated with dual or multiple atrioventricular nodal (AVN) pathways. Typical AVNRT pathways,including fast and slow pathways, are confined in the right atrium. Radiofrequency catheter ablation of the slow pathway, and occasionally the fast pathway, has become the definitive treatment of choice for most symptomatic patients. Besides typical AVNRT, there exists some atypical AVNRT with various manifestations. Several groups have reported successful ablation of the leftward dual AVN pathway from the left side of the heart.1-3 We present one case of left-sided AVN as well as dual AVN pathway. The tachycardia was successfully eliminated by ablation of the slow pathway deep in the coronary sinus.

  1. A Rare Heart Rhythm Problem in Acute Rheumatic Fever: Complete Atrioventricular Block

    Directory of Open Access Journals (Sweden)

    Ayse Kibar

    2014-03-01

    Full Text Available Rheumatic heart disease remains the most important cause of acquired heart disease in children and young adults. Different kinds of rhythm and conduction disturbances may be seen during the course of acute rheumatic fever (ARF. Long PR intervals are found commonly in rheumatic fever, but complete atrioventricular (AV block is an exceptionally rare manifestation. This case report is about a 14 year-old-female patient diagnosed as ARF based on migratory arthralgia and mild carditis who also developed complete heart block on admission. Electrocardiogram on the 3rd day of hospitalization depicts 2nd degree atrioventricular block (Mobitz I combined with PR prolongation. The ECG revealed a normal sinus rhythm with PR prolongation on the 4th day of hospitalization. Rarely, complete AV heart block can occur as a complication of ARF and may develop during the acute phase

  2. Orthodromic atrioventricular reciprocating tachycardia conducted with intraventricular conduction disturbance mimicking ventricular tachycardia in an English Bulldog.

    Science.gov (United States)

    Santilli, Roberto A; Diana, Alessia; Baron Toaldo, Marco

    2012-01-01

    Electrocardiographic tracings of an English Bulldog referred for cardiogenic shock due to an orthodromic atrioventricular reciprocating tachycardia conducted with intraventricular conduction disturbance and mimicking ventricular tachycardia (VT) are presented. At admission the surface ECG showed a wide QRS complex tachycardia (WCT) that was converted to sinus rhythm using manual cardioversion (chest thump). This change revealed pre-existing right bundle branch block, and a final diagnosis of supraventricular tachycardia (SVT) with intraventricular conduction disturbance was made. Electrophysiologic study defined the SVT mechanism as an atrioventricular macroreentrant tachycardia mediated by a single mid-septal accessory pathway. The differentiation between various types of WCT is essential when antiarrhythmic therapy is considered. The surface ECG should be systematically evaluated in order to recognize the characteristic features of SVT and VT. Moreover chest thump procedure can be very helpful in the attempt to convert the rhythm to sinus rhythm and to correctly recognize the underlying arrhythmia.

  3. Atrioventricular block in coronary artery bypass surgery: perioperative predictors and impact on mortality

    Directory of Open Access Journals (Sweden)

    Ricardo Medeiros Piantá

    2015-04-01

    Full Text Available AbstractIntroduction:Disturbances of the cardiac conduction system are frequent in the postoperative period of coronary artery bypass surgery. They are mostly reversible and associated with some injury of the conduction tissue, caused by the ischemic heart disease itself or by perioperative factors.Objective:Primary: investigate the association between perioperative factors and the emergence of atrioventricular block in the postoperative period of coronary artery bypass surgery. Secondary: determine the need for temporary pacing and of a permanent pacemaker in the postoperative period of coronary artery bypass surgery and the impact on hospital stay and hospital mortality.Methods:Analysis of a retrospective cohort of patients submitted to coronary artery bypass surgery from the database of the Postoperative Heart Surgery Unit of the Sao Lucas Hospital of the Pontifical Catholic University of Rio Grande do Sul, using the logistic regression method.Results:In the period from January 1996 to December 2012, 3532 coronary artery bypass surgery were carried out. Two hundred and eighty-eight (8.15% of the total sample patients had atrioventricular block during the postoperative period of coronary artery bypass surgery, requiring temporary pacing. Eight of those who had atrioventricular block progressed to implantation of a permanent pacemaker (0.23% of the total sample. Multivariate analysis revealed a significant association of atrioventricular block with age above 60 years (OR=2.34; CI 95% 1.75-3.12; P<0.0001, female gender (OR=1.37; CI 95% 1.06-1.77; P=0.015, chronic kidney disease (OR=2.05; CI 95% 1.49-2.81; P<0.0001, atrial fibrillation (OR=2.06; CI 95% 1.16-3.66; P=0.014, functional class III and IV of the New York Heart Association (OR=1.43; CI 95% 1.03-1.98; P=0.031, perioperative acute myocardial infarction (OR=1.70; CI 95% 1.26-2.29; P<0.0001 and with the use of the intra-aortic balloon in the postoperative period of coronary artery bypass

  4. Complete paroxysmal atrioventricular block in a 2-year-old girl

    DEFF Research Database (Denmark)

    Holst, Line M; Dixen, Ulrik; Jeppesen, Dorthe L

    2014-01-01

    We present a case of atypical syncope in a 2-year-old, otherwise healthy girl. The patient presented with three episodes of syncope without any precipitating factors and no family history of sudden unexpected death. Holter monitoring revealed 24 events of complete atrioventricular block lasting u...... to 6 seconds. A normal 12-lead electrocardiogram does not necessarily exclude cardiac disease, and Holter monitoring is warranted in children with atypical syncope....

  5. Bloqueo atrioventricular completo y reversible en un paciente con corazón estructuralmente sano

    Directory of Open Access Journals (Sweden)

    Oswaldo Gutiérrez-Sotelo

    2008-06-01

    Full Text Available Se presenta el caso de un paciente joven, deportista, quien presentó un episodio de síncope con pródromo breve, durante ejercicio físico. Se encontró el corazón estructuralmente normal y que durante la prueba de inclinación presentó bloqueo atrioventricular completo, que revirtió rápidamente con la posición de decúbito dorsal.

  6. The anatomy and histology of the atrioventricular conducting system in the hedgehog (Hemiechinus auritus) heart

    OpenAIRE

    NABIPOUR, Abolghasem

    2010-01-01

    This study examined the atrioventricular conducting system in 4 adult male hedgehogs (Hemiechinus auritus). The histological structure of these components was studied using routine histological methods. The AVN was located at the lower and anterior part of the interatrial septum, near the root of the aorta. It was almost oval and consisted of twisted cells. Internodal pathways in the hedgehog heart were not observed, but there were numerous purkinje-like fibers within the myocardium of the at...

  7. Intermittent rate-dependent retrograde conduction over a concealed atrioventricular accessory pathway: what is the mechanism?

    Science.gov (United States)

    Rordorf, Roberto; Vicentini, Alessandro; Petracci, Barbara; Landolina, Maurizio

    2009-02-01

    Intermittent retrograde conduction over an accessory pathway (AP) is quite an uncommon phenomenon. We describe the case of a 60-year-old woman with recurrent episodes of palpitations. Atrioventricular re-entry tachycardia was diagnosed at electrophysiological study. Interestingly, retrograde conduction over the AP was detectable only when ventricular pacing was performed at fast rate. Supernormal retrograde conduction over the AP was considered the most likely explanation of this unusual finding.

  8. Abnormalities of atrioventricular conduction in patients with the Lown-Ganong-Levine syndrome.

    Science.gov (United States)

    Pavlovic, J; Fabián, J; Belán, A

    1978-01-01

    In 18 patients with the Lown-Ganong-Levine syndrome and in 11 control subjects the response of the atrioventricular conduction system to heart rate acceleration by right atrial pacing, and, with the aid of His bundle electrogram, the behaviour of individual levels of the atrioventricular conduction system were studied. At spontaneous sinus rhythm A-H interval was shorter in the patients with the Lown-Ganong-Levine syndrome than in the controls. In the latter the A-H interval became markedly prolonged, up to a Wenckebach-type IInd-degree AV block, already at a minor pacing-induced acceleration of the heart rate, whereas in the patients with the Lown-Ganong-Levine syndrome the atrioventricular propagation of excitation at a 1:1 ratio remained preserved even at substantially higher heart-rate values. On the basis of the responses of the A-H interval to pacing the patients with the Lown-Ganong-Levine syndrome were classed into four types.

  9. The structure of the atrioventricular node in the heart of the female laying ostrich (Struthio camelus).

    Science.gov (United States)

    Parto, P

    2012-02-01

    The electrical impulse for cardiac contraction is generated in the Sinoatrial node (SA node), subsequently spreads to the Atrioventricular node (AV node) and continues in the Atrioventricular bundle (AV bundle). The AV node may not always be present in different avian species and seems to differ in location and contents between species. In this study, the anatomy and histology of the AV node were studied five female adult ostriches (Struthio camelus). Routine paraffin sectioning and transmission electron microscopic method were performed. The study showed that in the ostrich, the AV node is located in the endocardium of the atrial surface of the right atrioventricular valve adjacent to the fibrous ring. The parenchyma of the AV node is formed by small specialized muscle fibres that are spread within a loose connective tissue network. The AV node is not covered by a connective tissue sheath and some arterioles are present. Nerve fibres are seen related to the node. Ultrastructurally, they stain lighter and contain fewer organized myofibrils than usual myocardial cells. The myofibril bundles run parallel to one another and have interspersed mitochondria, which display distinct cristae. The cells have a large euchromatic nucleus with a clear perinuclear area, and they connected by desmosomes. The ostrich is, thus, one of the birds that have the AV node, whose position varies from the other birds. © 2011 Blackwell Verlag GmbH.

  10. Delayed Puberty

    DEFF Research Database (Denmark)

    Kolby, Nanna; Busch, Alexander Siegfried; Juul, Anders

    2017-01-01

    Delayed puberty can be a source of great concern and anxiety, although it usually is caused by a self-limiting variant of the normal physiological timing named constitutional delay of growth and puberty (CDGP). Delayed puberty can, however, also be the first presentation of a permanent condition ...... mineral density) and psychological (e.g., low self-esteem) and underline the importance of careful clinical assessment of the patients.......Delayed puberty can be a source of great concern and anxiety, although it usually is caused by a self-limiting variant of the normal physiological timing named constitutional delay of growth and puberty (CDGP). Delayed puberty can, however, also be the first presentation of a permanent condition...

  11. Delayed fission

    Energy Technology Data Exchange (ETDEWEB)

    Hatsukawa, Yuichi [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

    1997-07-01

    Delayed fission is a nuclear decay process that couples {beta} decay and fission. In the delayed fission process, a parent nucleus undergoes {beta} decay and thereby populates excited states in the daughter. If these states are of energies comparable to or greater than the fission barrier of the daughter, then fission may compete with other decay modes of the excited states in the daughter. In this paper, mechanism and some experiments of the delayed fission will be discussed. (author)

  12. Management of paroxysmal atrioventricular nodal reentrant tachycardia in the critically ill surgical patient.

    Science.gov (United States)

    Kirton, O C; Windsor, J; Wedderburn, R; Gomez, E; Shatz, D V; Hudson-Civetta, J; Komanduri, S; Civetta, J M

    1997-05-01

    Paroxysmal atrioventricular nodal reentrant tachycardia is an infrequently encountered supraventricular arrhythmia that continues to present difficult management problems in the critically ill surgical patient. The purpose of this study was to evaluate the efficacy of a new treatment algorithm involving the sequential administration of different classes of antiarrhythmic agents until conversion to sinus rhythm was achieved. Nonrandomized, consecutive, protocol-driven descriptive cohort. University hospital surgical and trauma intensive care unit (ICU). During an 11-month period, we prospectively evaluated all hemodynamically stable patients who sustained new-onset atrioventricular nodal reentrant tachycardia. Vagal maneuver, followed by the rapid, sequential infusion of antiarrhythmic agents (i.e., adenosine, verapamil, and esmolol, respectively) until the arrhythmia was terminated. Twenty-seven patients (4% of all admissions) were evaluated, including 16 trauma patients (injury Severity Score of 20 +/- 8) and 11 general surgical patients (Acute Physiology and Chronic Health Evaluation II score of 17 +/- 7). Time from ICU admission to onset of atrioventricular nodal reentrant tachycardia was 4.5 +/- 5 days (median 2.5). Arrhythmia termination was achieved in all patients within minutes (mean 13 +/- 10 [SD]). Incremental sequential adenosine administration alone, however, was successful in affecting conversion to sinus rhythm in only 44% of initial episodes of atrioventricular nodal reentrant tachycardia (95% confidence interval 21% to 67%). A total of 14 (52%) patients developed 38 relapses of paroxysmal supraventricular tachycardia in the ICU after initial conversion to sinus rhythm. These relapses required additional antiarrhythmic therapy. Adenosine was only effective in 34% of the relapses (95% confidence interval 17% to 53%). Seven (50%) of these 14 patients developed multiple relapses. However, only two patients were receiving suppressive calcium-channel or

  13. Permissible Delay in Payments

    Directory of Open Access Journals (Sweden)

    Yung-Fu Huang

    2007-01-01

    Full Text Available The main purpose of this paper wants to investigate the optimal retailer's lot-sizing policy with two warehouses under partially permissible delay in payments within the economic order quantity (EOQ framework. In this paper, we want to extend that fully permissible delay in payments to the supplier would offer the retailer partially permissible delay in payments. That is, the retailer must make a partial payment to the supplier when the order is received. Then the retailer must pay off the remaining balance at the end of the permissible delay period. In addition, we want to add the assumption that the retailer's storage space is limited. That is, the retailer will rent the warehouse to store these exceeding items when the order quantity is larger than retailer's storage space. Under these conditions, we model the retailer's inventory system as a cost minimization problem to determine the retailer's optimal cycle time and optimal order quantity. Three theorems are developed to efficiently determine the optimal replenishment policy for the retailer. Finally, numerical examples are given to illustrate these theorems and obtained a lot of managerial insights.

  14. Optimization of cell-wall skeleton derived from Mycobacterium bovis BCG Tokyo 172 (SMP-105) emulsion in delayed-type hypersensitivity and antitumor models.

    Science.gov (United States)

    Miyauchi, M; Murata, M; Fukushima, A; Sato, T; Nakagawa, M; Fujii, T; Koseki, N; Chiba, N; Kashiwazaki, Y

    2012-08-01

    Cell-wall skeleton prepared from Mycobacterium bovis BCG (BCG-CWS) is known as a potent adjuvant and has been shown to possess antitumor activity in many non-clinical and clinical studies. As there are no approved BCG-CWS formulations for cancer therapy, we investigated the potential for cancer immunotherapy of SMP-105, our originally produced BCG-CWS. For optimizing SMP-105 emulsion, we compared the effects of drakeoland squalane-based SMP-105 emulsions on IFN-γ production in rats and evaluated their ability to induce skin reaction in guinea pigs. Both emulsions had the same activity in both experiments. We selected squalane as base material and produced two types of squalane-based formulations (vialed emulsion and pumped emulsion) that can easily be prepared as oil-in-water emulsions. Although the vialed emulsion showed the same pattern of distribution as a usual homogenized emulsion, the pumped emulsion showed more uniform distribution than the other two emulsions. Whereas both emulsions enhanced strong delayed type hypersensitivity (DTH) reaction in a mouse model, the pumped emulsion induced slightly smaller edema. Data on oil droplet size distribution suggest that few micrometer oil droplet size might be appropriate for oil-in-water microemulsion of SMP-105. The antitumor potency of SMP-105 emulsion was stronger than that of some of the launched toll-like receptor (TLR) agonists (Aldara cream, Picibanil, and Immunobladder). Aldara and Picibanil showed limited antitumor effectiveness, while Immunobladder had almost the same effect as SMP-105 at the highest dose, but needed about 10 times the amount of SMP-105. These findings first indicate that SMP-105 has great potential in cancer immunotherapy.

  15. Optimism

    Science.gov (United States)

    Carver, Charles S.; Scheier, Michael F.; Segerstrom, Suzanne C.

    2010-01-01

    Optimism is an individual difference variable that reflects the extent to which people hold generalized favorable expectancies for their future. Higher levels of optimism have been related prospectively to better subjective well-being in times of adversity or difficulty (i.e., controlling for previous well-being). Consistent with such findings, optimism has been linked to higher levels of engagement coping and lower levels of avoidance, or disengagement, coping. There is evidence that optimism is associated with taking proactive steps to protect one's health, whereas pessimism is associated with health-damaging behaviors. Consistent with such findings, optimism is also related to indicators of better physical health. The energetic, task-focused approach that optimists take to goals also relates to benefits in the socioeconomic world. Some evidence suggests that optimism relates to more persistence in educational efforts and to higher later income. Optimists also appear to fare better than pessimists in relationships. Although there are instances in which optimism fails to convey an advantage, and instances in which it may convey a disadvantage, those instances are relatively rare. In sum, the behavioral patterns of optimists appear to provide models of living for others to learn from. PMID:20170998

  16. Optimization

    CERN Document Server

    Pearce, Charles

    2009-01-01

    Focuses on mathematical structure, and on real-world applications. This book includes developments in several optimization-related topics such as decision theory, linear programming, turnpike theory, duality theory, convex analysis, and queuing theory.

  17. Hemodynamic device-based optimization in cardiac resynchronization therapy: concordance with systematic echocardiographic assessment of AV and VV intervals

    Directory of Open Access Journals (Sweden)

    Oliveira MM

    2015-08-01

    Full Text Available Mário M Oliveira, Luisa M Branco, Ana Galrinho, Nogueira da Silva, Pedro S Cunha, Bruno Valente, Joana Feliciano, Ricardo Pimenta, Ana Sofia Delgado, Rui Cruz Ferreira Santa Marta Hospital, Lisbon, Portugal Background: Inappropriate settings of atrioventricular (AV and ventriculo-ventricular (VV intervals can be one of the factors impacting response to cardiac resynchronization therapy (CRT. Optimal concordance of AV and VV intervals between echocardiographic-based assessment and a device-based automatic programming with a hemodynamic sensor was investigated, together with left ventricle (LV reverse remodeling after 6 months of regular automatic device-based optimization.Methods: We evaluated blindly 30 systematic echocardiographic examinations during 6 months in 17 patients (12 men, 64±10 years, in sinus rhythm and New York Heart Association class III; 76% with non-ischemic dilated cardiomyopathy, LV ejection fraction [LVEF] <35%, QRS 130 milliseconds and LV dyssynchrony implanted with the SonRtip lead and a cardioverter-defibrillator device. Dyssynchrony (AV, VV, or intraventricular was evaluated by an experienced operator blinded to the device programming, using conventional echocardiography, tissue synchronization imaging, tissue Doppler imaging, radial strain, and 3D echocardiography.Results: Either no AV or VV dyssynchrony (n=11; 36.7% or a slight septal or lateral delay (n=13; 43.3% was found in most echocardiography examinations (80%. AV or VV dyssynchrony requiring further optimization was identified in one-fifth of the examinations (20%. At 6 months, 76.5% patients were responders with LV reverse remodeling, of which 69% were super-responders (LVEF >40%. A statistically significant increase in LVEF was observed between baseline and 6 months post implant (P<0.01. One patient died from non-cardiac causes.Conclusion: Concordance between echocardiographic methods and device-based hemodynamic sensor optimization was found in most

  18. Correção biventricular em defeito do septo atrioventricular desbalanceado Corrección biventricular en defecto del septo atrioventricular desbalanceado Biventricular repair in unbalanced atrioventricular septal defect

    Directory of Open Access Journals (Sweden)

    Edmar Atik

    2009-04-01

    Full Text Available É apresentada a evolução favorável, após correção operatória biventricular, de criança com 2,5 anos de idade, com defeito do septo atrioventricular desbalanceado, com ventrículo esquerdo (VE pequeno (anel mitral de 10 mm em relação de 0,4 com o anel tricúspide, DDVE de 17 mm, Vd2 VE de 15 ml/m² e relação do índice longitudinal VE/VD de 0,71. Houve desenvolvimento normal do VE, verificado três meses após a operação (anel mitral de 22 mm, em relação de 0,84 com o da valva tricúspide e DDVE de 30 mm. Discutem-se os parâmetros atuais de utilização do ventrículo hipoplásico.Presenta evolución favorable después de corrección operatoria biventricular, de niño con 2,5 años de edad, con Defecto del Septo Atrioventricular Desbalanceado con ventrículo izquierdo (VI pequeño (anillo mitral de 10 mm en relación de 0,4 con el anillo tricúspide, DDVI de 17 mm, Vd2 VI de 15 ml/m2 y relación de ejes longitudinales VI/VD de 0,71. Hubo desarrollo normal del VI, verificado tres meses después de la operación (anillo mitral de 22 mm, en relación de 0,84 con el de la válvula tricúspide y DDVI de 30 mm. Se discuten los parámetros actuales de utilización del ventrículo hipoplásico.We present the case of a 2.5 year-old child with unbalanced atrioventricular septal defect due to a small left ventricle (LV (mitral annulus of 10mm and a 0.4 ratio in relation to the tricuspid annulus, LVDD: 17 mm, LV Vd2: 15 ml/m² and LV/RV long-axis ratio of 0.71; he had a favorable outcome after biventricular surgical repair. Normal LV development was observed three months after the operation (mitral annulus of 22 mm, with a 0.84 ratio in relation to the tricuspid annulus, and LVDD of 30 mm. Current parameters for utilization of the hypoplastic ventricle are discussed.

  19. Cardiac resynchronization therapy and AV optimization increase myocardial oxygen consumption, but increase cardiac function more than proportionally☆

    Science.gov (United States)

    Kyriacou, Andreas; Pabari, Punam A.; Mayet, Jamil; Peters, Nicholas S.; Davies, D. Wyn; Lim, P. Boon; Lefroy, David; Hughes, Alun D.; Kanagaratnam, Prapa; Francis, Darrel P.; I.Whinnett, Zachary

    2014-01-01

    Background The mechanoenergetic effects of atrioventricular delay optimization during biventricular pacing (“cardiac resynchronization therapy”, CRT) are unknown. Methods Eleven patients with heart failure and left bundle branch block (LBBB) underwent invasive measurements of left ventricular (LV) developed pressure, aortic flow velocity-time-integral (VTI) and myocardial oxygen consumption (MVO2) at 4 pacing states: biventricular pacing (with VV 0 ms) at AVD 40 ms (AV-40), AVD 120 ms (AV-120, a common nominal AV delay), at their pre-identified individualised haemodynamic optimum (AV-Opt); and intrinsic conduction (LBBB). Results AV-120, relative to LBBB, increased LV developed pressure by a mean of 11(SEM 2)%, p = 0.001, and aortic VTI by 11(SEM 3)%, p = 0.002, but also increased MVO2 by 11(SEM 5)%, p = 0.04. AV-Opt further increased LV developed pressure by a mean of 2(SEM 1)%, p = 0.035 and aortic VTI by 4(SEM 1)%, p = 0.017. MVO2 trended further up by 7(SEM 5)%, p = 0.22. Mechanoenergetics at AV-40 were no different from LBBB. The 4 states lay on a straight line for Δexternal work (ΔLV developed pressure × Δaortic VTI) against ΔMVO2, with slope 1.80, significantly > 1 (p = 0.02). Conclusions Biventricular pacing and atrioventricular delay optimization increased external cardiac work done but also myocardial oxygen consumption. Nevertheless, the increase in cardiac work was ~ 80% greater than the increase in oxygen consumption, signifying an improvement in cardiac mechanoenergetics. Finally, the incremental effect of optimization on external work was approximately one-third beyond that of nominal AV pacing, along the same favourable efficiency trajectory, suggesting that AV delay dominates the biventricular pacing effect — which may therefore not be mainly “resynchronization”. PMID:24332598

  20. Allelic Interaction between CRELD1 and VEGFA in the Pathogenesis of Cardiac Atrioventricular Septal Defects

    Science.gov (United States)

    Redig, Jennifer K.; Fouad, Gameil T.; Babcock, Darcie; Reshey, Benjamin; Feingold, Eleanor; Reeves, Roger H.; Maslen, Cheryl L.

    2014-01-01

    Atrioventricular septal defects (AVSD) are highly heritable, clinically significant congenital heart malformations. Genetic and environmental modifiers of risk are thought to work in unknown combinations to cause AVSD. Approximately 5–10% of simplex AVSD cases carry a missense mutation in CRELD1. However, CRELD1 mutations are not fully penetrant and require interactions with other risk factors to result in AVSD. Vascular endothelial growth factor-A (VEGFA) is a well-characterized modulator of heart valve development. A functional VEGFA polymorphism, VEGFA c.–634C, which causes constitutively increased VEGFA expression, has been associated with cardiac septal defects suggesting it may be a genetic risk factor. To determine if there is an allelic association with AVSD we genotyped the VEGFA c.–634 SNP in a simplex AVSD study cohort. Over-representation of the c.–634C allele in the AVSD group suggested that this genotype may increase risk. Correlation of CRELD1 and VEGFA genotypes revealed that potentially pathogenic missense mutations in CRELD1 were always accompanied by the VEGFA c.–634C allele in individuals with AVSD suggesting a potentially pathogenic allelic interaction. We used a Creld1 knockout mouse model to determine the effect of deficiency of Creld1 combined with increased VEGFA on atrioventricular canal development. Morphogenic response to VEGFA was abnormal in Creld1-deficient embryonic hearts, indicating that interaction between CRELD1 and VEGFA has the potential to alter atrioventricular canal morphogenesis. This supports our hypothesis that an additive effect between missense mutations in CRELD1 and a functional SNP in VEGFA contributes to the pathogenesis of AVSD. PMID:25328912

  1. Allelic Interaction between CRELD1 and VEGFA in the Pathogenesis of Cardiac Atrioventricular Septal Defects

    Directory of Open Access Journals (Sweden)

    Jennifer K. Redig

    2014-03-01

    Full Text Available Atrioventricular septal defects (AVSD are highly heritable, clinically significant congenital heart malformations. Genetic and environmental modifiers of risk are thought to work in unknown combinations to cause AVSD. Approximately 5–10% of simplex AVSD cases carry a missense mutation in CRELD1. However, CRELD1 mutations are not fully penetrant and require interactions with other risk factors to result in AVSD. Vascular endothelial growth factor-A (VEGFA is a well-characterized modulator of heart valve development. A functional VEGFA polymorphism, VEGFA c.-634C, which causes constitutively increased VEGFA expression, has been associated with cardiac septal defects suggesting it may be a genetic risk factor. To determine if there is an allelic association with AVSD we genotyped the VEGFA c.-634 SNP in a simplex AVSD study cohort. Over-representation of the c.-634C allele in the AVSD group suggested that this genotype may increase risk. Correlation of CRELD1 and VEGFA genotypes revealed that potentially pathogenic missense mutations in CRELD1 were always accompanied by the VEGFA c.-634C allele in individuals with AVSD suggesting a potentially pathogenic allelic interaction. We used a Creld1 knockout mouse model to determine the effect of deficiency of Creld1 combined with increased VEGFA on atrioventricular canal development. Morphogenic response to VEGFA was abnormal in Creld1-deficient embryonic hearts, indicating that interaction between CRELD1 and VEGFA has the potential to alter atrioventricular canal morphogenesis. This supports our hypothesis that an additive effect between missense mutations in CRELD1 and a functional SNP in VEGFA contributes to the pathogenesis of AVSD.

  2. Delayed Random Relays

    CERN Document Server

    Ohira, Toru

    2016-01-01

    We present here a system with collection of random walks relaying a signal in one dimension with a presence of a delay. We are interested in the time for a signal to travel from one end (start) to the other end (finish) of the lined group of random walkers. It is found that there is an optimal number of walkers for the signal to travel fastest if the delay is present. We discuss implications of this model and associated behaviors to physical and biological systems.

  3. Complete atrioventricular block in adult Sjögren's syndrome with anti-Ro autoantibody.

    Science.gov (United States)

    Sung, Myung Jun; Park, Sung-Hoon; Kim, Seong-Kyu; Lee, Young-Soo; Park, Chul-Yeon; Choe, Jung-Yoon

    2011-06-01

    Anti-Ro autoantibody is associated with Sjögren's syndrome (SS), systemic lupus erythematosus (SLE), and neonatal lupus syndrome (i.e., congenital complete heart block in newborns). Generally, the adult atrioventricular (AV) node is believed to be relatively resistant to the scarring effects of anti-Ro/anti-La autoantibodies. However, there have been some reports of adult complete AV block in SS and SLE patients. Here, we report a case of complete heart block in primary SS with anti-Ro autoantibodies, with no other risk factor for the development of heart block, and review their etiological association.

  4. Konno procedure using atrioventricular groove patch plasty after arterial switch operation.

    Science.gov (United States)

    Kosaka, Yoshimichi; Kurosawa, Hiromi; Nagatsu, Masayoshi

    2004-11-01

    A patient with transposition of the great arteries accompanied by Shaher type 9 coronary anatomy experienced the development of progressive neoaortic valvular regurgitation with a small annulus, supravalvular stenosis, and neopulmonary valvular and supravalvular stenoses 15 years after an arterial switch operation. To implant a prosthetic valve clinically adequate in size, the Konno procedure was necessary. However, the right coronary anatomy precluded the original Konno procedure. My colleagues and I accomplished neoaortic anterior annular enlargement in this case by using atrioventricular groove patch plasty without jeopardizing the right coronary artery, and this resulted in a satisfactory outcome.

  5. Optimization of combined delayed neutron and differential die-away prompt neutron signal detection for characterization of spent nuclear fuel assemblies

    Energy Technology Data Exchange (ETDEWEB)

    Blanc, Pauline [Los Alamos National Laboratory; Tobin, Stephen J [Los Alamos National Laboratory; Croft, Stephen [Los Alamos National Laboratory; Menlove, Howard O [Los Alamos National Laboratory; Swinhoe, M [Los Alamos National Laboratory; Lee, T [NON LANL

    2010-12-02

    The Next Generation Safeguards Initiative (NGSI) of the U.S. Department of Energy (DOE) has funded multiple laboratories and universities to develop a means to accurately quantify the Plutonium (Pu) mass in spent nuclear fuel assemblies and ways to also detect potential diversion of fuel pins. Delayed Neutron (DN) counting provides a signature somewhat more sensitive to {sup 235}U than Pu while Differential Die-Away (DDA) is complementary in that it has greater sensitivity to Pu. The two methods can, with care, be combined into a single instrument which also provides passive neutron information. Individually the techniques cannot robustly quantify the Pu content but coupled together the information content in the signatures enables Pu quantification separate to the total fissile content. The challenge of merging DN and DDA, prompt neutron (PN) signal, capabilities in the same design is the focus of this paper. Other possibilities also suggest themselves, such as a direct measurement of the reactivity (multiplication) by either the boost in signal obtained during the active interrogation itself or by the extension of the die-away profile. In an early study, conceptual designs have been modeled using a neutron detector comprising fission chambers or 3He proportional counters and a {approx}14 MeV neutron Deuterium-Tritium (DT) generator as the interrogation source. Modeling was performed using the radiation transport code Monte Carlo N-Particles eXtended (MCNPX). Building on this foundation, the present paper quantifies the capability of a new design using an array of {sup 3}He detectors together with fission chambers to optimize both DN and PN detections and active characterization, respectively. This new design was created in order to minimize fission in {sup 238}U (a nuisance DN emitter), to use a realistic neutron generator, to reduce the cost and to achieve near spatial interrogation and detection of the DN and PN, important for detection of diversion, all within

  6. Atrioventricular septal defects among infants in Europe: a population-based study of prevalence, associated anomalies, and survival

    OpenAIRE

    Christensen, Nikolas; Andersen, Helle; Garne, Ester; Wellesley, Diana; Addor, Marie-Claude; Haeusler, Martin; Khoshnood, Babak; Mullaney, Carmel; Rankin, Judith; Tucker, David

    2017-01-01

    Abstract Objective To describe the epidemiology of chromosomal and non-chromosomal cases of atrioventricular septal defects in Europe. Methods Data were obtained from EUROCAT, a European network of population-based registries collecting data on congenital anomalies. Data from 13 registries for the period 2000-2008 were included. Results There was a total of 993 cases of atrioventricular septal defects, with a total prevalence of 5.3 per 10,000 births (95% confidence interval 4.1 to 6.5). Of t...

  7. Pheochromocytoma-induced atrial tachycardia leading to cardiogenic shock and cardiac arrest: resolution with atrioventricular node ablation and pacemaker placement.

    Science.gov (United States)

    Shawa, Hassan; Bajaj, Mandeep; Cunningham, Glenn R

    2014-12-01

    Pheochromocytoma should be considered in young patients who have acute cardiac decompensation, even if they have no history of hypertension. Atrioventricular node ablation and pacemaker placement should be considered for stabilizing pheochromocytoma patients with cardiogenic shock due to atrial tachyarrhythmias. A 38-year-old black woman presented with cardiogenic shock (left ventricular ejection fraction, cardiogenic shock and cardiac arrest unresolved by the placement of 2 different ventricular assist devices, but that was completely reversed by radiofrequency ablation of the atrioventricular node and the placement of a temporary pacemaker. We present the patient's clinical, laboratory, and imaging findings, and we review the relevant literature.

  8. A case of Kearns-Sayre sindrome with autoimmune thyroiditis and complete atrio-ventricular block.

    Science.gov (United States)

    Berio, A; Piazzi, A

    2006-06-01

    The Kearns-Sayre syndrome, (characterized by its onset before the age of 20 years, chronic ophthalmoplegia, pigmentary retinal degeneration and at least one of the following symptoms: ataxia, heart block and high protein content in the cerebrospinal fluid) is a severe variant of chronic progressive external ophthalmoplegia with frequent rearrangements of the mitochondrial DNA (mtDNA). The aim of this paper is to report a sporadic paediatric case of Kearns-Sayre syndrome with mtDNA heteroplasmic deletion, absence of cytochrome c-oxidase in many muscle fibers, autoimmune thyroiditis, complete atrio-ventricular heart block in which the diagnosis of subclinical hypothyroiditis associated with autoimmune thyroid disease was made. The subclinical hypothyroidism, more severe in the presence of thyroid antibodies, may have contributed to the pathogenesis of cardiovascular disease. We hypothesized that in this patient, predisposed by mitochondrial deletion, anti-thyroid antibodies may have interfered with the mitochondrial function of conduction heart system, causing atrio-ventricular heart block. It seems important to study anti-thyroid antibodies in every case of Kearn-Sayre syndrome, specially if cardiac rhythm disturbances are present.

  9. The Dorsal Mesenchymal Protrusion and the Pathogenesis of Atrioventricular Septal Defects

    Science.gov (United States)

    Burns, Tara; Yang, Yanping; Hiriart, Emilye; Wessels, Andy

    2017-01-01

    Congenital heart malformations are the most common type of defects found at birth. About 1% of infants are born with one or more heart defect on a yearly basis. Congenital Heart Disease (CHD) causes more deaths in the first year of life than any other congenital abnormality, and each year, nearly twice as many children die in the United States from CHD as from all forms of childhood cancers combined. Atrioventricular septal defects (AVSD) are congenital heart malformations affecting approximately 1 in 2000 live births. Babies born with an AVSD often require surgical intervention shortly after birth. However, even after successful surgery, these individuals typically have to deal with lifelong complications with the most common being a leaky mitral valve. In recent years the understanding of the molecular etiology and morphological mechanisms associated with the pathogenesis of AVSDs has significantly changed. Specifically, these studies have linked abnormal development of the Dorsal Mesenchymal Protrusion (DMP), a Second Heart Field-derived structure, to the development of this congenital defect. In this review we will be discuss some of the latest insights into the role of the DMP in the normal formation of the atrioventricular septal complex and in the pathogenesis of AVSDs. PMID:28133602

  10. [Results of surgical therapy of the partial form of persistent common atrioventricular canal (author's transl)].

    Science.gov (United States)

    Morino, F; Possati, F; Calafiore, A M; Santarelli, P; Malara, D; Ottino, G M; de Nunno, T

    1975-01-01

    20 patients with partial form of persistent common atrioventricular canal underwent surgery at the Centro di Cardiochirurgia "A. Blalock", University of Turin, between 1969 and 1974. In each case the treatment of lesions took place in the following order: the repair or replacement (one case) of the mitral valve; the closing with a patch of the atrial septal defect; the repair, in one case, of the tricuspid. The most frequent post-operative complications were arrhythmias, which in two cases consisted of a total atrioventricular block. Only one patient died postoperatively for an acute pulmonary oedema following an imperfect mitral valve correction. Six months after surgery, another patient died from bacterial endocarditis. Thirteen of the eighteen surviving patients showed excellent results at the clinical and/or hemodynamic check; two had fair results and three had poor results. In two cases, mitral insufficiency was hemodynamically aggravated, whilst in another five it disappeared. In eight, a slight apex systolic murmor 1-2/6 persisted, which was not correlated with any radiological or electrocardiographical sign of mitral insufficiency (and for three of these, not even a hemodynamic one). The authors consider that the most difficult problem in surgical therapy for these malformations is still the treatment of mitral lesions.

  11. Defeito do septo atrioventricular forma total associado a tricuspidização da valva atrioventricular esquerda na infância

    Directory of Open Access Journals (Sweden)

    DOBRIANSKYJ Aleksander

    1997-01-01

    Full Text Available Entre maio de 1987 e dezembro de 1996, o reparo do defeito do septo atrioventricular, forma total (DSAVT, com duplo retalho de pericárdio bovino e tricuspidização da valva atrioventricular (VAV esquerda, foi realizado em 34 pacientes consecutivos com mortalidade global de 5 (14,7% pacientes (pac.. Grupo I: abaixo de 6 meses (m com 12 pac. (1 óbito; 8,3%; Grupo II: entre 7m e 12m, com 15 pac. (4 óbitos; 26,6% e Grupo III: entre 1 e 5 anos (a com 7 pac. sem óbitos. Ocorreram 2 óbitos tardios (1 por Insuficiência mitral residual + insuficiência cardíaca congestiva e outro por pneumonia + insuficiência respiratória. Duas crianças receberam implante de marcapasso definitivo (após 45 dias e 4 anos. Nenhum paciente foi reoperado, apesar de mais 2 apresentarem insuficiência da VAV esquerda e 1 VAV direita, controlada clinicamente, e as restantes encontram-se nos graus I e II da New York Heart Association (NYHA. Apesar de 29 pacientes apresentarem peso abaixo de 10 kg, utilizou-se circulação extracorpórea (CEC e hipotermia a 25°C sem parada circulatória total. Iniciou-se o reparo pela zona de "aposição" da VAV única com um ou dois pontos em "x", mantendo tricúspide. Sutura-se o primeiro retalho de pericárdio bovino (PB em forma de "gota", insinuando-o entre as cordas do lado direito do septo; a seguir, sutura-se o segundo retalho, fazendo uma aposição concomitante com a VAV única, septando-se, desta forma, as quatro cavidades. As vantagens desta técnica são: preservação da integridade valvar, maior durabilidade funcional da VAV esquerda, menor possibilidade de reoperação mesmo em pacientes mais jovens e que devem ser preferencialmente operados em torno de 6º mês de vida.

  12. Geometric Time Delay Interferometry

    OpenAIRE

    Vallisneri, Michele

    2005-01-01

    The space-based gravitational-wave observatory LISA, a NASA-ESA mission to be launched after 2012, will achieve its optimal sensitivity using Time Delay Interferometry (TDI), a LISA-specific technique needed to cancel the otherwise overwhelming laser noise in the inter-spacecraft phase measurements. The TDI observables of the Michelson and Sagnac types have been interpreted physically as the virtual measurements of a synthesized interferometer. In this paper, I present Geometric TDI, a new an...

  13. EFFECT OF METOPROLOL ON ATRIAL FIBRILLATORY RATE, ATRIOVENTRICULAR NODAL CONCEALED CONDUCTION, AND VENTRICULAR RESPONSE DURING ATRIAL-FIBRILLATION IN PIGS

    NARCIS (Netherlands)

    VANDENBERG, MP; DELANGEN, CDJ; CRIJNS, HJGM; HAAKSMA, J; BEL, KJ; WESSELING, H; LIE, KI

    1994-01-01

    We wished to elucidate the effect of beta-blockade on fibrillatory rate and atrioventricular (AV) nodal concealed conduction during atrial fibrillation (AF). Subsequent to determination of the effect on atrial functional refractoriness with the extrastimulus technique (basic cycle length 400 ms), th

  14. Transmembrane protein 2 (Tmem2) is required to regionally restrict atrioventricular canal boundary and endocardial cushion development

    NARCIS (Netherlands)

    Smith, K.; Lagendijk, A.K.; Courtney, A.D.; Chen, H.; Paterson, S.; Hogan, B.M.; Wicking, C.; Bakkers, J.

    2011-01-01

    The atrioventricular canal (AVC) physically separates the atrial and ventricular chambers of the heart and plays a crucial role in the development of the valves and septa. Defects in AVC development result in aberrant heart morphogenesis and are a significant cause of congenital heart malformations.

  15. Transmembrane protein 2 (Tmem2) is required to regionally restrict atrioventricular canal boundary and endocardial cushion development

    NARCIS (Netherlands)

    Smith, K.; Lagendijk, A.K.; Courtney, A.D.; Chen, H.; Paterson, S.; Hogan, B.M.; Wicking, C.; Bakkers, J.

    2011-01-01

    The atrioventricular canal (AVC) physically separates the atrial and ventricular chambers of the heart and plays a crucial role in the development of the valves and septa. Defects in AVC development result in aberrant heart morphogenesis and are a significant cause of congenital heart malformations.

  16. Modulation by endothelin-1 of spontaneous activity and membrane currents of atrioventricular node myocytes from the rabbit heart.

    Directory of Open Access Journals (Sweden)

    Stéphanie C Choisy

    Full Text Available BACKGROUND: The atrioventricular node (AVN is a key component of the cardiac pacemaker-conduction system. Although it is known that receptors for the peptide hormone endothelin-1 (ET-1 are expressed in the AVN, there is very little information available on the modulatory effects of ET-1 on AVN electrophysiology. This study characterises for the first time acute modulatory effects of ET-1 on AVN cellular electrophysiology. METHODS: Electrophysiological experiments were conducted in which recordings were made from rabbit isolated AVN cells at 35-37°C using the whole-cell patch clamp recording technique. RESULTS: Application of ET-1 (10 nM to spontaneously active AVN cells led rapidly (within ~13 s to membrane potential hyperpolarisation and cessation of spontaneous action potentials (APs. This effect was prevented by pre-application of the ET(A receptor inhibitor BQ-123 (1 µM and was not mimicked by the ET(B receptor agonist IRL-1620 (300 nM. In whole-cell voltage-clamp experiments, ET-1 partially inhibited L-type calcium current (I(Ca,L and rapid delayed rectifier K(+ current (I(Kr, whilst it transiently activated the hyperpolarisation-activated current (I(f at voltages negative to the pacemaking range, and activated an inwardly rectifying current that was inhibited by both tertiapin-Q (300 nM and Ba(2+ ions (2 mM; each of these effects was sensitive to ET(A receptor inhibition. In cells exposed to tertiapin-Q, ET-1 application did not produce membrane potential hyperpolarisation or immediate cessation of spontaneous activity; instead, there was a progressive decline in AP amplitude and depolarisation of maximum diastolic potential. CONCLUSIONS: Acutely applied ET-1 exerts a direct modulatory effect on AVN cell electrophysiology. The dominant effect of ET-1 in this study was activation of a tertiapin-Q sensitive inwardly rectifying K(+ current via ET(A receptors, which led rapidly to cell quiescence.

  17. Delay of Vehicle Motion in Traffic Dynamics

    CERN Document Server

    Bando, M; Nakanishi, K; Nakayama, A; Bando, Masako; Hasebe, Katsuya; Nakanishi, Ken; Nakayama, Akihiro

    1996-01-01

    We demonstrate that in Optimal Velocity Model (OVM) delay times of vehicles coming from the dynamical equation of motion of OVM almost explain the order of delay times observed in actual traffic flows without introducing explicit delay times. Delay times in various cases are estimated: the case of a leader vehicle and its follower, a queue of vehicles controlled by traffic lights and many-vehicle case of highway traffic flow. The remarkable result is that in most of the situation for which we can make a reasonable definition of a delay time, the obtained delay time is of order 1 second.

  18. Resultados da correção simplificada com enxerto único no defeito septal atrioventricular completo

    Directory of Open Access Journals (Sweden)

    Ana Paula Tagliari

    2013-03-01

    Full Text Available FUNDAMENTO: Desde que Wilcox, em 1997, descreveu uma forma simplificada de correção do Defeito Septal Atrioventricular (DSAV com enxerto único, diversos estudos têm sido realizados comparando-a à técnica com duplo enxerto. OBJETIVO: Relatar os resultados em médio e longo prazos da correção de DSAV completo pela técnica simplificada de enxerto único. MÉTODOS: Estudo retrospectivo de 16 casos consecutivos arrolados entre janeiro de 2001 e dezembro de 2011. A idade média foi 18,31 ± 34,19 meses (2 meses - 11 anos e o peso 7,80 ± 6,12 Kg (3,77 - 25,0 Kg; 6 pacientes eram do sexo masculino e 14 eram portadores de Síndrome de Down. O tempo de seguimento médio foi de 54,97 ± 47,79 meses. RESULTADOS: O tempo médio de circulação extracorpórea foi 74,63 ± 18,48 min (49 - 112 min e o de pinçamento aórtico, de 46,44 ± 11,89 min (34 - 67 min. Foram observados dois óbitos hospitalares (12,5%, ambos por causa cardiovascular. Três pacientes foram reoperados por regurgitação da valva atrioventricular (VA esquerda e dois apresentaram bloqueio atrioventricular (BAV completo com necessidade de implante de marca-passo definitivo. Não houve nenhum caso de obstrução da via de saída do ventrículo esquerdo. Os 14 pacientes sobreviventes permanecem assintomáticos, 10 deles com insuficiência da valva VA esquerda leve (71,42%. CONCLUSÃO: A técnica simplificada com enxerto único para correção de DSAV completo mostrou-se factível, associada à correção adequada dos defeitos e à favorável evolução clínica e ecocardiográfica nos 57,97 meses de seguimento médio avaliados.

  19. Clinical feasibility of exercise-based A-V interval optimization for cardiac resynchronization: a pilot study.

    Science.gov (United States)

    Choudhuri, Indrajit; MacCarter, Dean; Shaw, Rachael; Anderson, Steve; St Cyr, John; Niazi, Imran

    2014-11-01

    One-third of eligible patients fail to respond to cardiac resynchronization therapy (CRT). Current methods to "optimize" the atrio-ventricular (A-V) interval are performed at rest, which may limit its efficacy during daily activities. We hypothesized that low-intensity cardiopulmonary exercise testing (CPX) could identify the most favorable physiologic combination of specific gas exchange parameters reflecting pulmonary blood flow or cardiac output, stroke volume, and left atrial pressure to guide determination of the optimal A-V interval. We assessed relative feasibility of determining the optimal A-V interval by three methods in 17 patients who underwent optimization of CRT: (1) resting echocardiographic optimization (the Ritter method), (2) resting electrical optimization (intrinsic A-V interval and QRS duration), and (3) during low-intensity, steady-state CPX. Five sequential, incremental A-V intervals were programmed in each method. Assessment of cardiopulmonary stability and potential influence on the CPX-based method were assessed. CPX and determination of a physiological optimal A-V interval was successfully completed in 94.1% of patients, slightly higher than the resting echo-based approach (88.2%). There was a wide variation in the optimal A-V delay determined by each method. There was no observed cardiopulmonary instability or impact of the implant procedure that affected determination of the CPX-based optimized A-V interval. Determining optimized A-V intervals by CPX is feasible. Proposed mechanisms explaining this finding and long-term impact require further study. ©2014 Wiley Periodicals, Inc.

  20. Time Delay of CGM Sensors

    Science.gov (United States)

    Schmelzeisen-Redeker, Günther; Schoemaker, Michael; Kirchsteiger, Harald; Freckmann, Guido; Heinemann, Lutz; del Re, Luigi

    2015-01-01

    Background: Continuous glucose monitoring (CGM) is a powerful tool to support the optimization of glucose control of patients with diabetes. However, CGM systems measure glucose in interstitial fluid but not in blood. Rapid changes in one compartment are not accompanied by similar changes in the other, but follow with some delay. Such time delays hamper detection of, for example, hypoglycemic events. Our aim is to discuss the causes and extent of time delays and approaches to compensate for these. Methods: CGM data were obtained in a clinical study with 37 patients with a prototype glucose sensor. The study was divided into 5 phases over 2 years. In all, 8 patients participated in 2 phases separated by 8 months. A total number of 108 CGM data sets including raw signals were used for data analysis and were processed by statistical methods to obtain estimates of the time delay. Results: Overall mean (SD) time delay of the raw signals with respect to blood glucose was 9.5 (3.7) min, median was 9 min (interquartile range 4 min). Analysis of time delays observed in the same patients separated by 8 months suggests a patient dependent delay. No significant correlation was observed between delay and anamnestic or anthropometric data. The use of a prediction algorithm reduced the delay by 4 minutes on average. Conclusions: Prediction algorithms should be used to provide real-time CGM readings more consistent with simultaneous measurements by SMBG. Patient specificity may play an important role in improving prediction quality. PMID:26243773

  1. Inter-pulse delay optimization in dual-pulse laser induced breakdown vacuum ultraviolet spectroscopy of a steel sample in ambient gases at low pressure

    Science.gov (United States)

    Jiang, X.; Hayden, P.; Laasch, R.; Costello, J. T.; Kennedy, E. T.

    2013-08-01

    Time-integrated spatially-resolved Laser Induced Breakdown Spectroscopy (LIBS) has been used to investigate spectral emissions from laser-induced plasmas generated on steel targets. Instead of detecting spectral lines in the visible/near ultraviolet (UV), as investigated in conventional LIBS, this work explored the use of spectral lines emitted by ions in the shorter wavelength vacuum ultraviolet (VUV) spectral region. Single-pulse (SP) and dual-pulse LIBS (DP-LIBS) experiments were performed on standardized steel samples. In the case of the double-pulse scheme, two synchronized lasers were used, an ablation laser (200 mJ/15 ns), and a reheating laser (665 mJ/6 ns) in a collinear beam geometry. Spatially resolved and temporally integrated laser induced plasma VUV emission in the DP scheme and its dependence on inter-pulse delay time were studied. The VUV spectral line intensities were found to be enhanced in the DP mode and were significantly affected by the inter-pulse delay time. Additionally, the influence of ambient conditions was investigated by employing low pressure nitrogen, argon or helium as buffer gases in the ablation chamber. The results clearly demonstrate the existence of a sharp ubiquitous emission intensity peak at 100 ns and a wider peak, in the multi-microsecond range of inter-pulse time delay, dependent on the ambient gas conditions.

  2. Transient complete atrioventricular block in a preterm neonate with congenital myotonic dystrophy: case report.

    Science.gov (United States)

    Kim, Hee Na; Cho, Young Kuk; Cho, Joo Hyun; Yang, Eun Mi; Song, Eun Song; Choi, Young Youn

    2014-06-01

    Congenital myotonic dystrophy (CMD) is an inherited neuromuscular disorder with cardiac rhythm abnormalities that may occur as a child grows. No report has described complete atrioventricular (AV) block detected in a neonate with CMD. We report a floppy infant of 31(+4) weeks gestation with complete AV block at birth, who was diagnosed with CMD by Southern analysis. She recovered from complete AV block 32 hr after temporary transcutaneous pacing was applied. To the best our knowledge, this is the first recorded case of a complete AV block accompanied by CMD during the neonatal period. When a newborn has a complete AV block, the physician should consider the possibility of the CMD and conduct a careful physical examination.

  3. Patologia do bloqueio atrioventricular na cardiomiopatia por depósito de desmina

    Directory of Open Access Journals (Sweden)

    Luiz Alberto Benvenuti

    2012-01-01

    Full Text Available Geralmente, a cardiomiopatia restritiva por deposição de desmina é caracterizada pela restrição ao enchimento diastólico ventricular e por diferentes graus de bloqueio atrioventricular (BAV. Neste relato, são descritas as alterações anatomopatológicas do sistema de condução cardíaco relacionadas ao BAV. O nó sinusal, o nó compacto e o feixe penetrante (feixe de His não apresentavam anormalidades, entretanto, havia extensa fibrose das porções terminais do feixe ramificante e do início dos feixes esquerdo e direito, no topo do septo ventricular. A patogenia dessa substituição fibrosa é provavelmente a mesma que origina a extensa fibrose do miocárdio ventricular contrátil, e permanece por ser elucidada.

  4. O nódulo atrioventricular e o feixe de his no homem

    Directory of Open Access Journals (Sweden)

    C. Magarinos Torres

    1961-09-01

    Full Text Available A demonstração do nódulo atrioventricular e do feixe de His, no coração humano, não oferece dificuldade especial, uma vez que seja seguida a técnica consagrada. A negação da sua existência, feita há cêrca de 20 anos atraz, é atribuível à não observância dêsse cuidado. A documentação apresentada refere-se a um paciente do sexo feminino, de côr branca, com 36 anos de idade, não infectado pelo Schizotrypanum cruzi, cujo coração pesava 310 g, sendo considerado macro e microscòpicamente, normal. Destina-se ela a servir de têrmo de comparação para a que será publicada, oportunamente, sôbre a cardiopatia crônica na doença de Chagas. Confirmamos o que dizem muitos autores quando assinalam a ausência completa de células ganglionares e de nervos, no nódulo atrioventricular, no tronco comum do feixe His e em seus dois ramos, quando observados no homem. Contrasta isso, fortemente, com o que existe, nas mesmas estruturas, no coração dos ungulados. Verificamos, não raramente, continuidade entre fibras musculares do tecido específico, no ramo esquerdo do feixe de His e fibras musculares ventriculares, sendo o ramo esquerdo constituído, em certa proporção, por fibras com caracters intermediários entre fibras musculares ordinárias e fibras de Purkinje (fibras de transição. Algumas vêzes fibras com características das de Purkinie aparecem em grupos musculares do septo ventricular imediatamente adjacentes ao ramo esquerdo, dificultando a demarcação exata daquele ramo. Reproduzimos, textualmente, pontos de mior interêsse, na literatura consultada, quando receavamos que a tradução não pudesse traduzir o pensamento exato do autor ou pudesse dar tal impressão.No particular difficulty was met in the demonstration of the atrioventricular node and bundel of His in the human heart when standard methods such as that described by RÉNON and GÉRAUDEL (posteriorly referred as MAHAIM's method was followed. The figures

  5. Atrioventricular junction (AVJ) motion tracking: a software tool with ITK/VTK/Qt.

    Science.gov (United States)

    Pengdong Xiao; Shuang Leng; Xiaodan Zhao; Hua Zou; Ru San Tan; Wong, Philip; Liang Zhong

    2016-08-01

    The quantitative measurement of the Atrioventricular Junction (AVJ) motion is an important index for ventricular functions of one cardiac cycle including systole and diastole. In this paper, a software tool that can conduct AVJ motion tracking from cardiovascular magnetic resonance (CMR) images is presented by using Insight Segmentation and Registration Toolkit (ITK), The Visualization Toolkit (VTK) and Qt. The software tool is written in C++ by using Visual Studio Community 2013 integrated development environment (IDE) containing both an editor and a Microsoft complier. The software package has been successfully implemented. From the software engineering practice, it is concluded that ITK, VTK, and Qt are very handy software systems to implement automatic image analysis functions for CMR images such as quantitative measure of motion by visual tracking.

  6. [Supra-His complete atrioventricular block in a patient with subclinical hyperthyroidism].

    Science.gov (United States)

    Amasyalı, Basri; Barçın, Cem; Kılıç, Ayhan

    2011-12-01

    Subclinical hyperthyroidism is a difficult entity to diagnose because of silent clinical features and it may be easily underdiagnosed unless it is suspected and thyroid hormone levels are examined. Although atrioventricular (AV) conduction abnormalities such as complete heart block may occasionally be seen in hyperthyroidism, its association with subclinical hyperthyroidism has not been reported previously. We report on a 50-year-old female patient who did not have any systemic or cardiovascular disease or history of drug use that could affect AV conduction and presented with presyncope and complete heart block with narrow QRS complexes. Thyroid function tests showed subclinical hyperthyroidism and an electrophysiological study showed the supra-His level as the site of complete AV block. After initiation of antithyroid treatment (propylthiouracil), the patient's rhythm improved to second-degree AV block on the third day and returned to normal sinus rhythm on the fourth day.

  7. RADIOFREQUENCY CURRENT CATHETER ABLATION OF THE LEFT ATRIOVENTRICULAR ACCESSORY PATHWAYS WITH PAROXYSMAL SUPRAVENTRICULAR TACHYCARDIA

    Institute of Scientific and Technical Information of China (English)

    王静毅; 郭继鸿; 吴益明; 朱继红; 王伟民; 赵红; 刘喜荣; MichaelA.Lee

    1994-01-01

    Seventy patients with left atrioventricular accessory pathways and paroxysmal supraventricular tachycardia (PSVT) underwent radiofrequency catheter ablation (RFCA).The success rate was 94.3%.Among these pa-tients,26 had manifest preexcitation syndrome,and 44 had concealed preexcitation.Eighteen patients with con-cealed preexcitation underwent coronary sinus(CS) pacinga,and delta wave appeared in 15.The keys to successful RFCA were correct positioning of the radiofrequency (RF) catheter tip,A/V amplitude ratio,AV interval(in si-nus rhythm)and VA interval(during SVT or ventricular pacing).After 1-14 months of follow-up,two pa- tients had supraventricular tachycardia(SVT)recurrence.

  8. 时滞积微分系统最优参数选择问题的一致算法%A Unified Computational Approach to Optimal Parameter Selection Problems with Delay Integro-Differential Systems

    Institute of Scientific and Technical Information of China (English)

    孙文兵; 杨立君

    2012-01-01

    文章讨论了带时滞项的积微分系统最优参数选择问题,并利用变分法推导出目标函数的梯度公式,将最优参数选择问题当成最优化问题利用逐步二次规划法(SQP)进行数值求解,并给出具体的算法.%In this paper, an optimal parameter selection problem with delay integro-differential systems was considered.Gradient formulae for the objective function was derived by using variational calculus. With the gradient formulae, the optimal parameter selec- tion problem can be treated as mathematical programming problem applying sequential quadratic programming algorithm (SQP), and a unified computational approach to the problem was given.

  9. TAQUICARDIA POR REENTRADA DEL NODO AURÍCULO-VENTRICULAR / Atrioventricular nodal reentrant tachycardia

    Directory of Open Access Journals (Sweden)

    Jéssica Mirella Mercedes

    2013-01-01

    Full Text Available Resumen La taquicardia por reentrada del nodo aurículo–ventricular representa una parte significativa de las taquiarritmias que los médicos asisten en los servicios de urgencias. Constituye la taquicardia paroxística más frecuente, y es característico que se presente sobre todo en mujeres entre la cuarta y la quinta década de la vida. El diagnóstico puede hacerse con alta fiabilidad mediante el electrocardiograma de superficie y algunos casos complejos o dudosos, mediante los estudios electrofisiológicos. Su tratamiento debe ser dirigido hacia la curación definitiva mediante la técnica de ablación endocavitaria, pero de acuerdo a su disponibilidad o las preferencias del paciente se puede indicar tratamiento farmacológico. En este artículo se resumen las técnicas diagnósticas, los tipos de taquicardia por reentrada intranodal y los principales aspectos del tratamiento. / Abstract Atrioventricular nodal reentrant tachycardia represents a significant part of tachyarrhythmias seen by attending physicians in emergency departments. It is the most common paroxysmal tachycardia, and it occurs primarily in women between their fourth and fifth decades of life. Diagnosis can be made with high reliability by surface electrocardiogram and complex or borderline cases by electrophysiological studies. Its treatment should be aimed towards definitive healing by endocardial ablation technique, but depending on availability or patient preferences drug treatment may be indicated. This article summarizes the diagnostic techniques, types of atrioventricular nodal reentrant tachycardia and major aspects of treatment.

  10. Msx1 and Msx2 are required for endothelial-mesenchymal transformation of the atrioventricular cushions and patterning of the atrioventricular myocardium

    Directory of Open Access Journals (Sweden)

    Maxson Robert E

    2008-07-01

    Full Text Available Abstract Background Msx1 and Msx2, which belong to the highly conserved Nk family of homeobox genes, display overlapping expression patterns and redundant functions in multiple tissues and organs during vertebrate development. Msx1 and Msx2 have well-documented roles in mediating epithelial-mesenchymal interactions during organogenesis. Given that both Msx1 and Msx2 are crucial downstream effectors of Bmp signaling, we investigated whether Msx1 and Msx2 are required for the Bmp-induced endothelial-mesenchymal transformation (EMT during atrioventricular (AV valve formation. Results While both Msx1-/- and Msx2-/- single homozygous mutant mice exhibited normal valve formation, we observed hypoplastic AV cushions and malformed AV valves in Msx1-/-; Msx2-/- mutants, indicating redundant functions of Msx1 and Msx2 during AV valve morphogenesis. In Msx1/2 null mutant AV cushions, we found decreased Bmp2/4 and Notch1 signaling as well as reduced expression of Has2, NFATc1 and Notch1, demonstrating impaired endocardial activation and EMT. Moreover, perturbed expression of chamber-specific genes Anf, Tbx2, Hand1 and Hand2 reveals mispatterning of the Msx1/2 double mutant myocardium and suggests functions of Msx1 and Msx2 in regulating myocardial signals required for remodelling AV valves and maintaining an undifferentiated state of the AV myocardium. Conclusion Our findings demonstrate redundant roles of Msx1 and Msx2 in regulating signals required for development of the AV myocardium and formation of the AV valves.

  11. Stochastic Optimal Preview Control of Active Vehicle Suspension with Time-delay Consideration%考虑控制时滞的车辆主动悬架随机预瞄控制

    Institute of Scientific and Technical Information of China (English)

    宋刚; 许长城

    2013-01-01

    Stochastic preview control with time-delay consideration was investigated for an active vehicle suspension system with look-ahead sensor.The road roughness height was modeled as a filtered white noise stochastic process and the rate of change in the road profile at some distances in front of the vehicle was measured by the look-ahead sensor.The suspension system was optimized by minimizing the performance index containing the mean-square values of body acceleration,suspension rattle space,tire deflection and control force.Only partial state variables were assumed able to be measured and the measurement noises were taken into consideration.Design of the preview compensator that may be called stochastic optimal,output feedback,preview regulator problem with time-delay consideration was reduced to the classical linear quadratic Gaussian (LQG) control problem,by converting the state equations and the performance index into discrete forms and augmenting the state and output vectors.Simulation results demonstrated that time delay should be considered in the stochastic preview control of an active suspension system,especially when large time delay exited.If the suspension system with time delay was controlled by the optimal controller designed with no consideration of time delay,instability in responses might occur and the control effects possibly got worse with preview time increase.%采用随机预瞄控制策略对存在控制时滞的车辆主动悬架系统进行了研究.路面不平度被看作过滤白噪声随机过程,通过安装在车辆前部的预瞄传感器来量测车轮前方一定距离的路面变化信息.在控制器设计中,采用包含车身加速度、悬架动行程、轮胎动位移和控制力加权的连续形式性能指标,假定只有部分状态变量可以量测,而且量测噪声不能忽略.通过将连续形式的状态方程和性能指标进行离散化,并对状态向量和量测向量进行增维,这种考虑控制时滞的基于

  12. Ablation of the atrioventricular node executed after paranodal ablation of the atrioventricular node for the treatment of paroxysmal atrial-ventricular node of reentry tachycardia in conditions of artificial blood circulation

    Directory of Open Access Journals (Sweden)

    Melikulov A.Kh.

    2014-03-01

    Full Text Available In this clinical observation is shown the data of the patient who was previously undergone paranodal ablation of atrial-ventricular junction for the treatment of atrioventricular (AV nodal reentrant tachycardia. Radiofrequency ablation of right lower isthmus for treatment of the paroxysmal form of atrial flutter was made for the patient. Sick sinus node syndrome and paroxysmal form of atrial fibrillation were diagnosed. Then dual-chamber pacemaker was implanted. Antiarrhythmic therapy about the persistent form of atrial fibrillation had no effect. The decision for the implementation of radio frequency modification of atrioventricular connection using right ventriclar access failed because of the lack of verification of the His bundle's spike. Using retrograde access through the aorta we managed to create AV blockade of III degree. Taking into account the fact that in 1990-ies patients with atrioventricular nodal reentrant tachycardia were operated using paranodal ablation of the AV node using extracorporeal circulation, this case has a practical significance when endovascular catheter modification of AV nodal conduction in this category of patients is made.

  13. [Effect of the preparations amiodarone, pexid and CERM-1978 on sinus rhythm and atrioventricular conduction in unanesthetized dogs].

    Science.gov (United States)

    Georgiev, G

    1977-01-01

    The author examined the influence of Amiodarone, Perexiline maliate (Pexid) and the preparation CERM-1978 (Bepiridil) on the sinus rhythm and atrioventriular conduction of trained dogs with preliminary implanted electrodes for electrostimulation of the right atrium under the conditions of chronic experiment. The three preparations in doses of 2,5 and 5 mg/kg of body weight prolonged the refractory period of the atrioventricular zone, estimated by the method of "the maximal atrioventricular frequency". The br dicaric effect was also present, more manifested in a dose of 2.5 mg/kg of body weight. The established negative chrono- and dromotropic action had their maximum 15 minutes after the administration and lasted more than 2 hours.

  14. High-degree atrioventricular block complicating ST-segment elevation myocardial infarction in the era of primary percutaneous coronary intervention

    DEFF Research Database (Denmark)

    Gang, Uffe Jakob Ortved; Hvelplund, Anders; Pedersen, Sune

    2012-01-01

    Primary percutaneous coronary intervention (pPCI) has replaced thrombolysis as treatment-of-choice for ST-segment elevation myocardial infarction (STEMI). However, the incidence and prognostic significance of high-degree atrioventricular block (HAVB) in STEMI patients in the pPCI era has been only...... sparsely investigated. The objective of this study was to assess the incidence, predictors and prognostic significance of HAVB in STEMI patients treated with pPCI....

  15. Novel Calibration Optimization Method for Delay-Control Systems Based on Genetic Algorithm%基于遗传算法的时间决策系统标定优化方法

    Institute of Scientific and Technical Information of China (English)

    熊彦铭; 毛凌; 杨战平

    2012-01-01

    针对由多延时电路并联而成的时间决策系统,提出了新的标定优化方法.综合考虑系统精度和可靠度,将标定问题转换为多目标优化问题,并建立了相应的优化目标函数.利用遗传算法对该问题进行求解,采取自适应交叉和变异策略,改善了遗传算法的收敛性能,仿真算例和工程实际应用表明,新方法具有近似最优的精度和较高的可靠度,具有较高的工程实用价值.%A novel calibration optimization method for delay-control systems is proposed. A multi-objective optimization function, considering both precision and reliability, is introduced to handle the calibration problem. Genetic algorithm (GA) is used to solve the optimization function, in which adaptive crossover and mutation algorithm are applied to improve the convergence performance of GA. Good performance of precision and reliability is demonstrated by numerical results.

  16. Early Correction of Common Atrioventricular Septal Defects: A Single-Center 20-Year Experience.

    Science.gov (United States)

    Vida, Vladimiro L; Tessari, Chiara; Castaldi, Biagio; Padalino, Massimo A; Milanesi, Ornella; Gregori, Dario; Stellin, Giovanni

    2016-12-01

    Over the past 20 years our policy has been to electively repair common atrioventricular canal defects (CAVCD) in patients between 8 and 12 weeks of age. We sought to evaluate the results of our past 20-year experience. From January 1992 to April 2014, 159 consecutive patients underwent CAVCD repair (133 patients had complete CAVCD and 26 patients had a transitional form of CAVCD). Surgical repair was accomplished with a double-patch (n = 137 [86%]) or a modified single patch (n = 22 [14%]) technique. Median age at operation was 96 days (interquartile range [IQR], 73-128 days); 90 patients were younger than 3 months of age. There were 3 operative (1.9%) and 12 late (7.7%) deaths. Median follow-up time after repair was 8.2 years (IQR, 3.6-15 years). Twenty patients (13%) required reoperation-16 (10%) for left atrioventricular valve (LAVV) regurgitation. Reoperation on the LAVV was more frequent in patients with a dysplastic LAVV preoperatively (p = 0.01; odds ratio [OR], 4.2; 95% confidence interval [CI], 1.33-13.5) and in patients who underwent closure for an absent/incomplete cleft at the time of repair (p = 0.01; OR, 5.4; 95% CI, 1.4-21). Late LAVV performance (regurgitation greater than or equal to moderate or the need for reoperation), including late deaths and patients who underwent reoperation, was significantly worse in patients older than 3 months at repair (10 of 83 patients [12%] versus 20 of 73 patients [27%]; hazard ratio [HR], 2.71; 95% CI, 1.19-6.19) and in patients with LAVV dysplasia (19 of 68 patients [28%] versus 11 of 88 patients [12%]; HR, 3; 95% CI, 1.53-8.51). Individualized early repair of CAVCD is safe and beneficial, with good early and long-term results. Copyright © 2016 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.

  17. O efeito da morfina na inibição vagal do coração: demonstração da dupla via do nodo atrioventricular = The effect of morphine on vagal inhibition of the heart: demonstration of dual atrioventricular nodal pathways

    Directory of Open Access Journals (Sweden)

    José Geraldo Pereira da Cruz

    2006-07-01

    Full Text Available A estimulação elétrica do nervo vago diminui a freqüência cardíaca e aumenta o intervalo PQ no eletrocardiograma, podendo ativar a via anterógrada do nodo atrioventricular. Neste experimento é investigada a interação da morfina sobre o controle nervoso parassimpático cardíaco em relação à dupla condução do nodo atrioventricular. Aestimulação do nervo vago induz uma significativa bradicardia e um bloqueio atrioventricular de terceiro grau, com a onda P aparecendo negativa na derivação II. Devido aos efeitos moduladores da anestesia sobre o coração, administração de injeções de morfina induz o aparecimento de onda P positiva através de uma ação inibitória sobre a reentrância do nodo atrioventricular. Tudo sugere a presença de duas vias atrioventriculares, anatômica e funcionalmente distintas.That electrical stimulation of the vagus decreased heart rate and increased the PQ interval in electrocardiogram, consistent with anterograde dual atriventricular conduction. The present experiments were investigating the interaction of the morphine with cardiac parasympathetic nervous control in dual atrioventricular node. Electrical stimulation of the vagus nerve induced significantbradycardia and of third degree atrioventricular block and the P wave appearance was negative in leads II. Because background anesthesia modulates the heart, administered morphine injection the P waves appearance was positive through one inhibitory action on atrioventricular nodal reentry. All suggest the presence of two functionally and anatomically distinct atrioventricular pathways.

  18. Adjoint Vector Method-based Optimal Disturbance Rejection for Multiple-delay Systems%基于伴随向量方法的多延时系统最优扰动抑制

    Institute of Scientific and Technical Information of China (English)

    雷靖; 白雪玲

    2012-01-01

    The paper considers the optimal disturbance rejection problem for continuous-time systems with state, control, and measurement delays. Firstly, the conditions of system transformation are analyzed and the approach is proposed , based on which the original system is transformed into one without delays. Then combining the system and the exosystem to an augmented system, the optimal disturbance rejection control problem is converted to an optimal state regulator problem. The necessity is proved by using Pontryagin minimum principle and the sufficiency is proved applying dynamic programming. The physical unrealization problem of disturbance vector and optimal performance index is solved by defining an adjoint vector. Finally, numerical simulations are made to compare the system responses using some different control laws. The effectiveness and simplicity of the designed control law are demonstrated.%研究包含有状态、控制和测量延时连续系统的最优扰动抑制问题.首先分析并提出了系统转换的方法,将原系统转化为无延时项的连续系统.然后将该系统与扰动系统联立为增广系统,并将最优扰动抑制问题转化为最优状态调节器问题.运用Pontryagin极小值原理证明最优控制的必要性,运用动态规划法证明其充分性;通过定义伴随向量解决了扰动向量和最优性能指标物理不可实现的问题.最后运用数据仿真将几种不同控制律作用下的系统响应作比较,验证所设计控制律的有效性及简易性.

  19. Use-dependent properties of flecainide acetate in accessory atrioventricular pathways.

    Science.gov (United States)

    Goldberger, J; Helmy, I; Katzung, B; Scheinman, M

    1994-01-01

    Flecainide acetate has been shown to have use-dependent properties. The use-dependent properties of flecainide were evaluated in 20 patients (13 men and 7 women, mean age 32 +/- 11 years) with accessory atrioventricular connections. Twenty to 30 stimulus drive trains were introduced in either the atrium or ventricle at progressively faster rates. The range of cycle lengths over which anterograde and retrograde conduction block occurred in the accessory pathway was assessed in the drug-free state and after oral loading with flecainide acetate. The block cycle length index was defined as the shortest cycle length during which 1:1 conduction was maintained in the accessory pathway minus the longest cycle length during which block in the accessory pathway occurred on the second paced beat. In the drug-free state, the (mean +/- SD) anterograde and retrograde block cycle length indexes were 20 +/- 12 and 20 +/- 9 ms, respectively. After flecainide therapy, the anterograde and retrograde block cycle length indexes increased to 80 +/- 33 and 65 +/- 29 ms, respectively (p = 0.002 compared with the drug-free state). The block cycle length index did not correlate with serum flecainide levels, but did correlate with other electrophysiologic markers of drug effect on accessory pathway conduction. The change in the block cycle length index demonstrates that flecainide has a progressive effect on accessory pathway conduction at more rapid rates, consistent with its in vitro use-dependent properties. This index is an excellent marker of drug efficacy.

  20. Occurrence of atrioventricular block during supraventricular tachycardia: What is its possible mechanism?

    Directory of Open Access Journals (Sweden)

    Ho-Shun Cheng

    2014-02-01

    Full Text Available A female patient was admitted to our hospital for catheter ablation arising from paroxysmal supraventricular tachycardia (PSVT. In the laboratory, PSVT (the earliest retrograde atrial activation at the coronary sinus ostium with intermittent atrioventricular (AV block could be induced repeatedly. The tachycardia could be terminated during ventricular pacing without retrograde conduction to the atria. Therefore, orthodromic AV reciprocating tachycardia (AVRT and atrial tachycardia (AT could be ruled out and AV nodal re-entrant tachycardia (AVNRT was subsequently considered. Initial attempts using slow or intermediate AV nodal ablation failed to cure the tachycardia. We considered the possibility of orthodromic AV reciprocating tachycardia (AVRT with AV block occurring during the tachycardia. The tachycardia was successfully terminated during the ablation of the right posteroseptal pathway at the coronary sinus ostium. We hypothesized about the possible explanation that might help to clarify the phenomenon of AV block during SVT in order to provide some guidance to other clinicians confronted with similar patient challenges in the future.

  1. Natural and modified history of complete atrioventricular septal defect--a 17 year study.

    Science.gov (United States)

    Frontera-Izquierdo, P; Cabezuelo-Huerta, G

    1990-01-01

    We reviewed 103 cases of isolated complete atrioventricular septal defect. These cases represented 4.4% of the cases of congenital heart disease diagnosed in our hospital by catheterisation and angiography during 1971-88. Most children (n = 76) had Down's syndrome. Banding of the pulmonary artery was performed in seven cases and complete repair in 67 cases. In the period 1971-82 the complete correction was performed at a mean age of 23 months with a surgical mortality of 88.8%. In the period 1983-8 the mean age at complete correction was 13 months, the mortality 43.2%, and the five year actuarial survival was 46.8%. The 22 patients that survived after complete correction were in functional classes I and II of the New York Heart Association classification. After a mean follow up of 10 years only eight (36%) of the 22 who were followed up and treated medically survived; all had developed pulmonary vascular obstructive disease and were in functional classes III or IV. Our findings stress the importance of early complete surgical repair. PMID:2221969

  2. Polymorphic haplotypes of CRELD1 differentially predispose Down syndrome and euploids individuals to atrioventricular septal defect.

    Science.gov (United States)

    Ghosh, Priyanka; Bhaumik, Pranami; Ghosh, Sujoy; Ozbek, Umut; Feingold, Eleanor; Maslen, Cheryl; Sarkar, Biswanath; Pramanik, Vishmadeb; Biswas, Priyanka; Bandyopadhyay, Biswajit; Dey, Subrata Kumar

    2012-11-01

    To explore the role of CRELD1 variants on congenital heart defects, we sequenced the entire reading frame of CRELD1 in the samples from Kolkata and adjoining areas. Nearly, 400 participants were included in the genetic association study and they were stratified as Down syndrome (DS) with atrioventricular septal defect (AVSD), DS without AVSD, euploid with AVSD, and euploid without AVSD. A significant association was found between AVSD and three polymorphisms, namely rs9878047 (c.1049-129T > C), rs3774207 (c.1119C > T), and rs73118372 (c.1136T > C) among the Down syndrome and euploid individuals. The polymorphism rs73118372, involves a transition (c.1136T > C) that leads to change in amino acid methionine to threonine which alters protein secondary structure as confirmed by the bioinformatics software SOPMA. In addition, two haplotypes, C-T-C and C-T-T, in the order of loci rs9878047-rs3774207-rs73118372 were associated with incidence of AVSD among euploid and Down syndrome, with a slightly higher odds ratio in the later group. We hypothesize that these haplotypes increase the risk of AVSD, and the susceptibility is exacerbated in DS, possibly due to the trisomy 21 genetic background. Moreover, we report for the first time on an interaction between the mutant alleles of rs3774207 and rs73118372 which could disrupt the delicate balance between different CRELD1 isoforms.

  3. Contribution of Copy Number Variation to Down Syndrome-associated Atrioventricular Septal Defects

    Science.gov (United States)

    Ramachandran, Dhanya; Mulle, Jennifer G.; Locke, Adam E.; Bean, Lora J.H.; Rosser, Tracie C.; Bose, Promita; Dooley, Kenneth J.; Cua, Clifford L.; Capone, George T.; Reeves, Roger H.; Maslen, Cheryl L.; Cutler, David J.; Sherman, Stephanie L.; Zwick, Michael E.

    2014-01-01

    Purpose The goal of this study was to identify the contribution of large copy number variants (CNV) to Down syndrome (DS) associated atrioventricular septal defects (AVSD), whose risk in the trisomic population is 2000-fold more compared to general disomic population. Methods Genome-wide CNV analysis was performed on 452 individuals with DS (210 cases with complete AVSD; 242 controls with structurally normal hearts) using Affymetrix SNP 6.0 arrays, making this the largest heart study conducted to date on a trisomic background. Results Large common CNVs with substantial effect sizes (OR>2.0) do not account for the increased risk observed in DS-associated AVSD. In contrast, cases had a greater burden of large rare deletions (p<0.01) and intersected more genes (p<0.007) when compared to controls. We also observed a suggestive enrichment of deletions intersecting ciliome genes in cases compared to controls. Conclusion Our data provide strong evidence that large rare deletions increase the risk of DS-associated AVSD, while large common CNVs do not appear to increase the risk of DS-associated AVSD. The genetic architecture of AVSD is complex and multifactorial in nature. PMID:25341113

  4. An improved in vivo method for atrioventricular node ablation via thoracotomy

    Directory of Open Access Journals (Sweden)

    R.H. MacIver

    2010-02-01

    Full Text Available The atrioventricular (AV node is permanently damaged in approximately 3% of congenital heart surgery operations, requiring implantation of a permanent pacemaker. Improvements in pacemaker design and in alternative treatment modalities require an effective in vivo model of complete heart block (CHB before testing can be performed in humans. Such a model should enable accurate, reliable, and detectable induction of the surgical pathology. Through our laboratory’s efforts in developing a tissue engineering therapy for CHB, we describe here an improved in vivo model for inducing chronic AV block. The method employs a right thoracotomy in the adult rabbit, from which the right atrial appendage may be retracted to expose an access channel for the AV node. A novel injection device was designed, which both physically restricts needle depth and provides electrical information via electrocardiogram interface. This combination of features provides real-time guidance to the researcher for confirming contact with the AV node, and documents its ablation upon formalin injection. While all animals tested could be induced to acute AV block, those with ECG guidance were more likely to maintain chronic heart block >12 h. Our model enables the researcher to reproduce both CHB and the associated peripheral fibrosis that would be present in an open congenital heart surgery, and which would inevitably impact the design and utility of a tissue engineered AV node replacement.

  5. Delayed childbearing.

    Science.gov (United States)

    Francis, H H

    1985-06-01

    In many Western nations, including England and Wales, Sweden, and the US, there is a current trend towards delayed childbearing because of women's pursuit of a career, later marriage, a longer interval between marriage and the 1st birth, and the increasing number of divorcees having children in a 2nd marriage. Wives of men in social classes I and II in England and Wales are, on average, having their 1st child at 27.9 years, 1.6 years later than in 1973, and in social classes IV and V, 1.0 years later than in 1973, at a mean age of 23.7 years. Consequently, the total period fertility rate for British women aged 30-34 years, 35-39 years, and 40 and over increased by 4%, 2%, and 4%, respectively, between 1982-83, in contrast to reductions of 2% and 3%, respectively, in the 15-19 year and 20-24 year age groups, with the 25-29-year-olds remaining static. The average maternal mortality for all parties in England and Wales during 1976-78 was 106/million for adolescents, 70.4/million for 20-24 year-olds, and 1162/million for those aged 40 years and older. The specific obstetric and allied conditions which increase with age are the hypertensive diseases of pregnancy, hemorrhage, pulmonary embolism, abortion, cardiac disease, caesarean section, ruptured uterus, and amniotic fluid embolism. The Swedish Medical Birth Registry of all live births and perinatal deaths since 1973 has shown that the risk of late fetal death is significantly greater in women aged 30-39 years than in those of the same parity and gravidity aged 20-24 years. The risk of giving birth to low birth weight babies preterm and at term and of premature labor are similarly increased. The early neonatal death rate also was increased for primigravidas and nulliparas in the 30-39 year age group but not in parous women. This is, in part, due to the rise in incidence of fetal abnormalities with advancing maternal age because of chromosomal and nonchromosomal anomalies. These also appear to be the cause of the

  6. Delay-dependent observer-based stabilizing controller design for linear multiple state-delayed systems

    Institute of Scientific and Technical Information of China (English)

    Dejin WANG

    2003-01-01

    This article concerns a coupled LMIs approach to delay-dependent observer-based output feedback stabilizing controller design for linear continuous-time systems with multiple state delays. The advantage of our proposed delay-dependent coupled LMIs criterion lies in that: (1) it can optimize one of multiple time delays with others selected properly, and at the same time, the feedback-gain and observer-gain can be obtained, respectively. (2) it is less conservative than the existing delay-independent ones in the literature. Algorithm to solve the coupled LMIs is also given. Numerical examples illustrate the effectiveness of our method.

  7. Functional Capacity of Patients with Pacemaker Due to Isolated Congenital Atrioventricular Block

    Directory of Open Access Journals (Sweden)

    Roberto Márcio de Oliveira Júnior

    2015-01-01

    Full Text Available Background: Isolated congenital atrioventricular block (CAVB is a rare condition with multiple clinical outcomes. Ventricular remodeling can occur in approximately 10% of the patients after pacemaker (PM implantation. Objectives: To assess the functional capacity of children and young adults with isolated CAVB and chronic pacing of the right ventricle (RV and evaluate its correlation with predictors of ventricular remodeling. Methods: This cross-sectional study used a cohort of patients with isolated CAVB and RV pacing for over a year. The subjects underwent clinical and echocardiographic evaluation. Functional capacity was assessed using the six-minute walk test. Chi-square test, Fisher's exact test, and Pearson correlation coefficient were used, considering a significance level of 5%. Results: A total of 61 individuals were evaluated between March 2010 and December 2013, of which 67.2% were women, aged between 7 and 41 years, who were using PMs for 13.5 ± 6.3 years. The percentage of ventricular pacing was 97.9 ± 4.1%, and the duration of the paced QRS complex was 153.7 ± 19.1 ms. Majority of the subjects (95.1% were asymptomatic and did not use any medication. The mean distance walked was 546.9 ± 76.2 meters and was strongly correlated with the predicted distance (r = 0.907, p = 0.001 but not with risk factors for ventricular remodeling. (Arq Bras Cardiol. 2014; [online].ahead print, PP.0-0 Conclusions: The functional capacity of isolated CAVB patients with chronic RV pacing was satisfactory but did not correlate with risk factors for ventricular remodeling.

  8. Primary percutaneous coronary intervention ameliorates complete atrioventricular block complicating acute inferior myocardial infarction

    Directory of Open Access Journals (Sweden)

    Lee SN

    2014-11-01

    Full Text Available Su Nam Lee, You-Mi Hwang, Gee-Hee Kim, Ji-Hoon Kim, Ki-Dong Yoo, Chul-Min Kim, Keon-Woong MoonDepartment of Internal Medicine, St Vincent’s Hospital, The Catholic University of Korea, Suwon, South KoreaObjective: Complete atrioventricular block (CAVB in acute inferior ST-segment elevation myocardial infarction (STEMI is associated with poor clinical outcomes after noninvasive treatment. This study was designed to determine the effect of primary percutaneous coronary intervention (PCI in patients with CAVB complicating acute inferior STEMI, at a single center.Methods: We enrolled 138 consecutive patients diagnosed with STEMI involving the inferior wall; of these, 27 patients had CAVB. All patients received primary PCI. The clinical characteristics, procedural data, and clinical outcomes were compared in patients with versus without CAVB. Results: Baseline clinical characteristics were similar between patients with and without CAVB. Patients with CAVB were more likely to present with cardiogenic shock, and CAVB was caused primarily by right coronary artery occlusion. Door-to-balloon time was similar between those two groups. After primary PCI, CAVB was reversed in all patients. The peak creatinine phosphokinase level, left ventricular ejection fraction and in-hospital mortality rate were similar between the two groups. After a median follow up of 318 days, major adverse cardiac events did not differ between the groups (8.1% in patients without CAVB; 11.1% in patients with CAVB (P=0.702.Conclusion: We conclude that primary PCI can ameliorate CAVB-complicated acute inferior STEMI, with an acceptable rate of major adverse cardiac events, and suggest that primary PCI should be the preferred reperfusion therapy in patients with CAVB complicating acute inferior myocardial infarction. Keywords: major adverse cardiac events, PCI-capable hospital

  9. Functional Capacity of Patients with Pacemaker Due to Isolated Congenital Atrioventricular Block

    Science.gov (United States)

    de Oliveira Júnior, Roberto Márcio; da Silva, Kátia Regina; Kawauchi, Tatiana Satie; Alves, Lucas Bassolli de Oliveira; Crevelari, Elizabeth Sartori; Martinelli, Martino; Costa, Roberto

    2015-01-01

    Background Isolated congenital atrioventricular block (CAVB) is a rare condition with multiple clinical outcomes. Ventricular remodeling can occur in approximately 10% of the patients after pacemaker (PM) implantation. Objectives To assess the functional capacity of children and young adults with isolated CAVB and chronic pacing of the right ventricle (RV) and evaluate its correlation with predictors of ventricular remodeling. Methods This cross-sectional study used a cohort of patients with isolated CAVB and RV pacing for over a year. The subjects underwent clinical and echocardiographic evaluation. Functional capacity was assessed using the six-minute walk test. Chi-square test, Fisher's exact test, and Pearson correlation coefficient were used, considering a significance level of 5%. Results A total of 61 individuals were evaluated between March 2010 and December 2013, of which 67.2% were women, aged between 7 and 41 years, who were using PMs for 13.5 ± 6.3 years. The percentage of ventricular pacing was 97.9 ± 4.1%, and the duration of the paced QRS complex was 153.7 ± 19.1 ms. Majority of the subjects (95.1%) were asymptomatic and did not use any medication. The mean distance walked was 546.9 ± 76.2 meters and was strongly correlated with the predicted distance (r = 0.907, p = 0.001) but not with risk factors for ventricular remodeling. Conclusions The functional capacity of isolated CAVB patients with chronic RV pacing was satisfactory but did not correlate with risk factors for ventricular remodeling. PMID:25387405

  10. Atrioventricular canal defect and associated genetic disorders: new insights into polydactyly syndromes

    Directory of Open Access Journals (Sweden)

    M. Cristina Digilio

    2011-07-01

    Full Text Available Atrioventricular canal defect (AVCD is a common congenital heart defect (CHD, representing 7.4% of all cardiac malformations, considered secondary to an extracellular matrix anomaly. The AVCD is associated with extracardiac defects in about 75% of the cases. In this review we analyzed different syndromic AVCDs, in particular those associated with polydactyly disorders, which show remarkable genotype-phenotype correlations. Chromo - some imbalances more frequently associated with AVCD include Down syndrome, deletion 8p23 and deletion 3p25, while mendelian disorders include Noonan syndrome and related RASopathies, several polydactyly syndromes, CHARGE and 3C (cranio-cerebello-cardiac syndrome. The complete form of AVCD is prevalent in patients with chromosomal imbalances. Additional cardiac defects are found in patients affected by chromosomal imbalances different from Down syndrome. Left-sided obstructive lesions are prevalently found in patients with RASopathies. Patients with deletion 8p23 often display AVCD with tetralogy of Fallot or with pulmonary valve stenosis. Tetralogy of Fallot is the only additional cardiac defect found in patients with Down syndrome and AVCD. On the other hand, the association of AVCD and tetralogy of Fallot is also quite characteristic of CHARGE and 3C syndromes. Heterotaxia defects, including common atrium and anomalous pulmonary venous return, occur in patients with AVCD associated with polydactyly syndromes (Ellis-van Creveld, short rib polydactyly, oral-facial-digital, Bardet-Biedl, and Smith-Lemli-Opitz syndromes. The initial clinical evidence of anatomic similarities between AVCD and heterotaxia in polydactyly syndromes was corroborated and explained by experimental studies in transgenic mice. These investigations have suggested the involvement of the Sonic Hedgehog pathway in syndromes with postaxial polydactyly and heterotaxia, and ciliary dysfunction was detected as pathomechanism for these disorders

  11. Pseudopacemaker syndrome and marked first-degree atrioventricular block: Case report

    Directory of Open Access Journals (Sweden)

    Panić Miloš

    2010-01-01

    Full Text Available Introduction. Pacemaker syndrome consists of the symptoms and signs present in the single chamber (VVI pacemaker patient with electrode placed in the right ventricular apex. It is caused by inadequate timing of atrial and ventricular contractions. Pacemaker syndrome without a pacemaker (or pseudopacemaker syndrome refers to occurrence of symptoms in the presence of marked first-degree atrioventricular (AV block, when P wave is too close to the preceding QRS complex producing the same haemodynamic disturbance as artificial pacemaker cardiac stimulation with retrograde VA conduction. Case Outline. We present the patient with acute inferior myocardial infarction due to late bare metal stent thrombosis, treated with primary pectutaneous coronary intervention. Hospital course was complicated by complete heart block which was treated with temporary pacing. During the stand-by mode of temporary pacing, sinus rhythm with marked first-degree AV block (PQ interval 480 ms was observed while the patients re-experienced the symptoms that were present prior to pacemaker implantation. Temporary pacing was continued for the next 24 hours when spontaneous shorteninig of PQ interval (250-270 ms was noticed; since the patient was asymptomatic during the stand-by mode, the pacemaker electrodes were removed and the patient discharged 11 days after admission. Conclusion. Conduction disturbances, such as the varying degrees of AV blocks, are relatively common in acute inferior myocardial infarction. The first degree AV blok is usually asymptomatic and does not require treatment, unless when it is associated with pseudopacemaker syndrome. In that case, temporary pacing provides haemodynamic stability until conduction system recovers.

  12. Atrioventricular and interventricular groove and septal extension of right sinus of valsalva aneurysm: a rare cause of complete heart block.

    Science.gov (United States)

    Khan, Javaid Arif; Hussain, Mushtaq; Rizvi, Nadeem H; Fehmi, Nadeem; Hussain, Akhtar; Sial, Jawaid A

    2013-10-01

    A 26 years old male presented with vertigo and history of fall. The electrocardiogram revealed 2:1 second-degree heart block and later progression to complete heart block. Transthoracic echocardiography revealed aneurysm at the site of ascending aorta and computed tomographic scan showed an aneurysm of right sinsus of Valsalva extending into right atrioventricular and interventricular groove and causing complete heart block by compression on the conduction system. He also suffered from lymph node tuberculosis. This case report is unique because of rare presentation as complete heart block.

  13. Complete atrioventricular block in an adult with congenitally corrected transposition of the great arteries with interrupted inferior vena cava

    Directory of Open Access Journals (Sweden)

    Namsik Yoon

    2012-01-01

    Full Text Available A 56-year-old man got admitted as he was suffering from dizziness for 3 days. Electrocardiogram (ECG showed complete atrioventricular (AV block with ventricular rhythm of 35/min. We found that he had no inferior vena cava (IVC which drained into right atrium in the middle of temporary pacing lead insertion. Venous drainage into superior vena cava from dilated azygos vein was identified after venogram. Echocardiogram revealed a congenitally corrected transposition of the great arteries (CCTGA. Chest computed tomography (CT angiogram revealed AV and ventriculoarterial discordance with reversed ventricles and interrupted IVC with azygos continuation. DDD pacemaker was implanted via left axillary vein without any problem.

  14. Normalisation of left ventricular systolic function after change from VVI pacing to biventricular pacing in a child with congenital complete atrioventricular block, long-QT syndrome, and congenital muscular dystrophy

    DEFF Research Database (Denmark)

    Ellesøe, Sabrina G; Reimers, Jesper I; Andersen, Henrik

    2013-01-01

    Development of dilated cardiomyopathy in patients with congenital complete atrioventricular block with or without pacemaker is well described. We report a case of dilated cardiomyopathy in a child with congenital complete atrioventricular block, long-QT syndrome, and VVI pacemaker. Temporary pacing...

  15. Delays in the management of retroperitoneal sarcomas

    DEFF Research Database (Denmark)

    Seinen, Jojanneke; Almquist, Martin; Styring, Emelie

    2010-01-01

    at the general practitioner, 36 days at local hospitals, and 55 days at the sarcoma centre. Conclusion. Centralization per se is not sufficient for optimized and efficient management. Our findings suggest that delays can be minimized by direct referral of patients from primary health care to sarcoma centers...... sarcoma in the southern Sweden health care region 2003-2009 were eligible for the study. Data on referrals and diagnostic investigations were collected from clinical files from primary health care, local hospitals, and from the sarcoma centre. Lead times were divided into patient delays and health care...... delays caused by primary health care, local hospitals, or procedures at the sarcoma centre. Results. Complete data were available from 33 patients and demonstrated a median patient delay of 23 days (0-17 months) and median health care delay of 94 days (1-40 months) with delays of median 15 days...

  16. Delays in the management of retroperitoneal sarcomas

    DEFF Research Database (Denmark)

    Seinen, Jojanneke; Almquist, Martin; Styring, Emelie

    2010-01-01

    at the general practitioner, 36¿days at local hospitals, and 55¿days at the sarcoma centre. Conclusion. Centralization per se is not sufficient for optimized and efficient management. Our findings suggest that delays can be minimized by direct referral of patients from primary health care to sarcoma centers...... sarcoma in the southern Sweden health care region 2003-2009 were eligible for the study. Data on referrals and diagnostic investigations were collected from clinical files from primary health care, local hospitals, and from the sarcoma centre. Lead times were divided into patient delays and health care...... delays caused by primary health care, local hospitals, or procedures at the sarcoma centre. Results. Complete data were available from 33 patients and demonstrated a median patient delay of 23¿days (0-17¿months) and median health care delay of 94¿days (1-40¿months) with delays of median 15¿days...

  17. Interconnected delay and state observer for nonlinear systems with time-varying input delay

    OpenAIRE

    Léchappé, V; Moulay, Emmanuel; Plestan, F; Glumineau, A.

    2016-01-01

    International audience; This work presents a general framework to estimate both state and delay thanks to two interconnected observers. This scheme can be applied to a large class of nonlinear systems with time-varying input delay. In order to illustrate this approach, a new delay observer based on an optimization technique is proposed. Theoretical results are illustrated and compared with existing works in simulation.

  18. Successful radiofrequency catheter ablation of atrioventricular nodal reentrant tachycardia in a patient with dextrocardia due to unilateral pulmonary agenesis: a case report

    Directory of Open Access Journals (Sweden)

    Aksu T

    2015-02-01

    Full Text Available Tolga Aksu, Tumer Erdem Guler, Ebru Golcuk, Ismail Erden, Kazim Serhan Ozcan Department of Cardiology, Kocaeli Derince Education and Research Hospital, Derince, Kocaeli, Turkey Abstract: Radiofrequency catheter ablation of the slow pathway is considered to be the treatment of choice for patients with atrioventricular nodal reentrant tachycardia. We report a 34-year-old female with mirror image dextrocardia due to unilateral pulmonary agenesis who underwent successful slow pathway ablation for typical atrioventricular nodal reentrant tachycardia. Using contrast injection, cardiac anatomy was identified in a short time and successfully ablated. Keywords: dextrocardia, AVNRT, ablation, pulmonary agenesis

  19. Bridge to success: A better method of cryoablation for atrioventricular nodal reentrant tachycardia in children.

    Science.gov (United States)

    Reddy, Charitha D; Ceresnak, Scott R; Motonaga, Kara S; Avasarala, Kishor; Feller, Christine; Trela, Anthony; Hanisch, Debra; Dubin, Anne M

    2017-07-14

    Cryoablation for atrioventricular nodal reentrant tachycardia (AVNRT) is associated with higher recurrence rates than radiofrequency ablation (RFA). Junctional tachycardia marks procedural success with RFA, but no such indicator exists for cryoablation. The purpose of this study as to determine the impact of voltage mapping plus longer ablation lesions on midterm success of cryoablation for children with AVNRT. We performed a single-center retrospective analysis of pediatric patients with AVNRT who underwent cryoablation from 2011 to 2015. Patients ablated using a standard electroanatomic approach (control) were compared with patients ablated using voltage mapping (voltage group). In the voltage group, EnSite NavX navigation and visualization technology (St Jude Medical, St Paul, MN) was used to develop a "bridge" of lower voltage gradients (0.3-0.8 mV) of the posteroseptal right atrium to guide cryoablation. Kaplan-Meier analysis was used to determine freedom from recurrence of supraventricular tachycardia. In all, 122 patients were included (71 voltage, 51 control). There was no difference between groups regarding age, sex, or catheter-tip size. Short-term success was similar in both groups (98.5% voltage vs 92% control; P = .159), but recurrence rates were lower in the voltage group (0% vs 11%, P = .006). Follow-up time was shorter in the voltage group (15 ± 7 months vs 22 ± 17 months, P < .05). The 1-year freedom from recurrence was lower in the voltage group (100% vs 91.5%, P <.05). Ablation times were longer in the voltage group (43.7 ± 20.9 minutes vs 34.3 ± 20.5 minutes, P = .01), but overall procedure times were shorter in the voltage group (157 ± 40 minutes vs 198 ± 133 minutes; P = .018). No significant complication was seen in either group. Voltage gradient mapping and longer lesion time can decrease recurrence rates in pediatric patients with AVNRT. Copyright © 2017 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.

  20. Estudio descriptivo sobre bloqueos atrio-ventriculares en infartos posteroinferiores en el Hospital de Caldas ESE.

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    Wilmar Alberto Díaz

    2009-11-01

    Full Text Available Introducción: El infarto agudo de miocardio (IAM es un problema de salud pública a escala mundial y nacional, que merece una prevención, diagnóstico y tratamiento oportunos. El IAM de cara inferior presenta entre sus complicaciones el bloqueo atrio-ventricular (bloqueo AV en sus diversas manifestaciones. Materiales y métodos: El presente es un estudio de tipo descriptivo, retrospectivo realizado en el Hospital Universitario de Caldas ESE, por medio de la revisión de historias clínicas corresponismo atrio-DACCION diagnóstico, de alta calidad y de gran importancia. dientes a los años 1999 a 2002, de los pacientes que presentaron infarto agudo de miocardio de cara inferior. Se tomaron de las historias variables como edad, sexo, consumo de alcohol, tabaco, sedentarismo y la presencia o ausencia de enfermedades previas tales como hipertensión arterial, diabetes mellitus, dislipidemias e infarto agudo de miocardio previo y el tiempo de aparición del bloqueo (menor o mayor de 24 horas. Resultados: Se encontró una asociación significativa entre la incidencia de bloqueos AV con la edad (p=0.017 y el IAM previo (p=0.001 y entre mortalidad y tipo de bloqueo (p=0.028. No se presentó asociación entre los factores de riesgo asociados para IAM y la presentación de bloqueo, excepto una posible relación con la hipertensión arterial (p=0.176, no del todo clara, por lo cual se recomienda que sea explorada por estudios posteriores; 32.7% de personas con infarto de cara inferior tuvieron algún tipo de bloqueo y 77.1% de los bloqueos fueron en las primeras 24 horas. Conclusiones: Los pacientes que presenten un IAM de cara inferior con una edad >65 años, se deben someter a seguimiento con monitoría continua por electrocardiograma durante las primeras 24 horas; lo mismo todo paciente con IAM de cara inferior, se debe incluir dentro del grupo de seguimiento clínico, electrocardiográfico y de monitoreo estricto.

  1. Characterization and influence of cardiac background sodium current in the atrioventricular node.

    Science.gov (United States)

    Cheng, Hongwei; Li, Jue; James, Andrew F; Inada, Shin; Choisy, Stéphanie C M; Orchard, Clive H; Zhang, Henggui; Boyett, Mark R; Hancox, Jules C

    2016-08-01

    Background inward sodium current (IB,Na) that influences cardiac pacemaking has been comparatively under-investigated. The aim of this study was to determine for the first time the properties and role of IB,Na in cells from the heart's secondary pacemaker, the atrioventricular node (AVN). Myocytes were isolated from the AVN of adult male rabbits and mice using mechanical and enzymatic dispersion. Background current was measured using whole-cell patch clamp and monovalent ion substitution with major voltage- and time-dependent conductances inhibited. In the absence of a selective pharmacological inhibitor of IB,Na, computer modelling was used to assess the physiological contribution of IB,Na. Net background current during voltage ramps was linear, reversing close to 0mV. Switching between Tris- and Na(+)-containing extracellular solution in rabbit and mouse AVN cells revealed an inward IB,Na, with an increase in slope conductance in rabbit cells at -50mV from 0.54±0.03 to 0.91±0.05nS (mean±SEM; n=61 cells). IB,Na magnitude varied in proportion to [Na(+)]o. Other monovalent cations could substitute for Na(+) (Rb(+)>K(+)>Cs(+)>Na(+)>Li(+)). The single-channel conductance with Na(+) as charge carrier estimated from noise-analysis was 3.2±1.2pS (n=6). Ni(2+) (10mM), Gd(3+) (100μM), ruthenium red (100μM), or amiloride (1mM) produced modest reductions in IB,Na. Flufenamic acid was without significant effect, whilst La(3+) (100μM) or extracellular acidosis (pH6.3) inhibited the current by >60%. Under the conditions of our AVN cell simulations, removal of IB,Na arrested spontaneous activity and, in a simulated 1D-strand, reduced conduction velocity by ~20%. IB,Na is carried by distinct low conductance monovalent non-selective cation channels and can influence AVN spontaneous activity and conduction.

  2. Estudio descriptivo sobre bloqueos atrio-ventriculares en infartos posteroinferiores en el Hospital de Caldas ESE

    Directory of Open Access Journals (Sweden)

    Wilmar Alberto Díaz

    2005-09-01

    Full Text Available Introducción: El infarto agudo de miocardio (IAM es un problema de salud pública a escala mundial y nacional, que merece una prevención, diagnóstico y tratamiento oportunos. El IAM de cara inferior presenta entre sus complicaciones el bloqueo atrio-ventricular (bloqueo AV en sus diversas manifestaciones. Materiales y métodos: El presente es un estudio de tipo descriptivo, retrospectivo realizado en el Hospital Universitario de Caldas ESE, por medio de la revisión de historias clínicas corresponismo atrio-DACCION diagnóstico, de alta calidad y de gran importancia. dientes a los años 1999 a 2002, de los pacientes que presentaron infarto agudo de miocardio de cara inferior. Se tomaron de las historias variables como edad, sexo, consumo de alcohol, tabaco, sedentarismo y la presencia o ausencia de enfermedades previas tales como hipertensión arterial, diabetes mellitus, dislipidemias e infarto agudo de miocardio previo y el tiempo de aparición del bloqueo (menor o mayor de 24 horas. Resultados: Se encontró una asociación significativa entre la incidencia de bloqueos AV con la edad (p=0.017 y el IAM previo (p=0.001 y entre mortalidad y tipo de bloqueo (p=0.028. No se presentó asociación entre los factores de riesgo asociados para IAM y la presentación de bloqueo, excepto una posible relación con la hipertensión arterial (p=0.176, no del todo clara, por lo cual se recomienda que sea explorada por estudios posteriores; 32.7% de personas con infarto de cara inferior tuvieron algún tipo de bloqueo y 77.1% de los bloqueos fueron en las primeras 24 horas. Conclusiones: Los pacientes que presenten un IAM de cara inferior con una edad >65 años, se deben someter a seguimiento con monitoría continua por electrocardiograma durante las primeras 24 horas; lo mismo todo paciente con IAM de cara inferior, se debe incluir dentro del grupo de seguimiento clínico, electrocardiográfico y de monitoreo estricto.

  3. Two pedigrees of autosomal dominant atrioventricular canal defect (AVCD): Exclusion from the critical region on 8p

    Energy Technology Data Exchange (ETDEWEB)

    Amati, F.; Mari, A.; Mingarelli, R. [Universita Tor Vergata, Rome (Italy)] [and others

    1995-07-03

    Atrioventricular canal defects (AVCD) constitute the predominant congenital heart defect in Down`s syndrome. For this reason, a candidate gene involved in atrioventricular canal development was previously searched and excluded in dominant pedigrees of AVCD, using linkage analysis of polymorphisms from chromosome 21. Because of the striking association between 8p deletion and AVCD, a search for an AVCD gene was carried out in two pedigrees of individuals with autosomal dominant AVCD using a set of DNA markers of the 8pter{r_arrow}q12 region. These two families include affected individuals and subjects who have transmitted the defect but are not clinically affected. Two-point lod scores were significantly negative for all markers at penetrance levels of 90% and 50%. Multipoint analysis excluded the region covered by the markers LPL-D8S262 and 30 cM to either side of this area. This result corroborates heterogeneity of this heart defect and indicates that the genetic basis of familial AVCD is different from AVCD associated to either trisomy 21 or 8p deletion. 25 refs., 3 figs., 2 tabs.

  4. Outcomes and Prognostic Factors for Adult Patients With Congenital Heart Disease Undergoing Primary or Reoperative Systemic Atrioventricular Valve Surgery.

    Science.gov (United States)

    Stephens, Elizabeth H; Han, Jiho; Ginns, Jonathan; Rosenbaum, Marlon; Chai, Paul; Bacha, Emile; Kalfa, David

    2017-05-01

    Adults with congenital heart disease (ACHD) undergoing systemic atrioventricular valve (SAVV) surgery are a complex, understudied population. We assessed midterm outcomes and prognostic factors in ACHD undergoing SAVV surgery. We performed retrospective evaluation of ACHD undergoing SAVV surgery from January 2005 to February 2016: 14 (33%) patients with congenital mitral valve stenosis/regurgitation, 15 (35%) with atrioventricular septal defect (AVSD), and 14 (33%) with congenitally corrected transposition of the great arteries (ccTGA) with systemic tricuspid valve regurgitation. Adverse events were defined as mortality, reoperation on SAVV, and late more-than-moderate (> moderate) SAVV regurgitation. Statistical analysis was performed using Fisher's exact test and one-way analysis of variance as well as univariate and multivariate risk factor analysis. Fifteen (35%) patients had preoperative systemic ventricular dysfunction, including 13 patients with ccTGA (93%, P moderate SAVV regurgitation, and SAVV reoperation rates were 5% (n = 2), 2% (n = 1), 9% (n = 3), and 7% (n = 3), respectively. On multivariate analysis, predischarge SAVV regurgitation grade was the only significant predictor of adverse events (odds ratio = 8.2, 95% confidence interval: 1.1-63.8, P = .045). Overall outcomes in this challenging population are good. The single factor associated with adverse events was predischarge SAVV regurgitation grade.

  5. Takotsubo Cardiomyopathy With Significant Coronary Stenosis and Atrioventricular Conduction Block: A Rare Case Report With 3 Year Follow-Up

    Directory of Open Access Journals (Sweden)

    Saadatifar

    2015-12-01

    Full Text Available Introduction Takotsubo cardiomyopathy (TCMP is a rare acute cardiomyopathy characterized by acute chest pain syndrome, similar to myocardial infarction, except that no significant stenosis is observed on coronary angiography in patients with this condition; these findings aid the diagnosis of TCMP. Case Presentation We discuss an unusual case of TCMP in a 45-year-old woman with complete heart block and significant coronary artery stenosis. Maximal exercise test and perfusion scan after 1 month from the acute event did not show any ischemia; therefore, revascularization was not recommended. Her follow-up with normal echocardiographic data 3 years after the first event showed no recurrence Conclusions The present case and a few previous cases have showed that severe coronary artery disease may be occur in patients with TCMP and that TCMP may be associated with a high-degree atrioventricular block. The association between atrioventricular conduction block and TCMP as well as significant coronary stenosis is rarely reported; therefore, coronary angiography should be performed in all patients with clinical TCMP and the previous definition should be reconsidered. The occurrence of arrhythmia and later recovery is expected in these patients (due to a catecholamine surge.

  6. Surgical treatment of partial atrioventricular septal defect: functional analysis of the mitral valve in the postoperative period

    Directory of Open Access Journals (Sweden)

    Josué Viana Castro Neto

    2002-11-01

    Full Text Available OBJECTIVE: To study mitral valve function in the postoperative period after correction of the partial form of atrioventricular septal defect. METHODS: Fifty patients underwent surgical correction of the partial form of atrioventricular septal defect. Their mean age was 11.8 years and 62% of the patients were males. Preoperative echocardiography showed moderate and severe mitral insufficiency in 44% of the patients. The mitral valve cleft was sutured in 45 (90% patients (group II - GII. Echocardiographies were performed in the early postoperative period, and 6 and 12 months after hospital discharge. RESULTS: The patients who had some type of arrhythmia in the postoperative period had ostium primum atrial septal defect of a larger size (2.74 x 2.08 cm. All 5 patients in group I (GI, who did not undergo closure of the cleft, had a competent mitral valve or mild mitral insufficiency in the preoperative period. One of these patients began to have moderate mitral insufficiency in the postoperative period. On the other hand, in GII, 88.8% and 82.2% of the patients had competent mitral valve or mild mitral insufficiency in the early and late postoperative periods, respectively. CONCLUSION: The mitral valve cleft was repaired in 90% of cases. Echocardiography revealed competent mitral valve or mild mitral insufficiency in 88.8% and 82.2% of GII patients in the early and late postoperative periods, respectively.

  7. DYNAMIC LABELING BASED FPGA DELAY OPTIMIZATION ALGORITHM

    Institute of Scientific and Technical Information of China (English)

    L; Zong-wei(

    2001-01-01

    [1]Puntambekar N V, Jablokow A G, Sommer H J. Unified review of 3D model generation for reverse engineering[J]. Computer Integrated Manufacturing System,1994,7(4):259~268.[2]Chikofsky E J. Reverse engineering and design recovery: a taxonomy[J]. IEEE Software,1990,6(3):13~17.[3]Chou Hon-yue. Application of reverse engineering in die and mold manufacturing[A]. 3rd Int Conf on Mould & Die Technique in Asia[C]. Taibei, China,1995.753~764.[4]Dipl-Ing Thomas Haller. Rapid mould and die making using reverse engineering and rapid prototyping[A]. 3rd Int Conf on Mould & Die Technique in Asia[C]. Taibei, China,1995.739~752.[5]Abella R J, Daschbach J M. Reverse engineering industrial applications[J]. Computers Ind Engng,1994,26(2):381~385.[6]Chen Y D, Tang X J. Automatic digitization of freeform curves by coordinate measuring machines[J]. ASME PED,1992,62:113~125.[7]Antonie van Rensburg. Implementing IDEF techniques as simulation modeling specifications[J]. Computers Ind Engng,1994,29(1-4):467~571.[8]Eastma C M, Fereshetian N. Informaiton models for use in product design: a comparison[J]. Computer-Aided Design.1994,26(7):551~572.

  8. Online Delay-Evaluation Approach in Networked Control Systems

    Institute of Scientific and Technical Information of China (English)

    魏震; 马向华; 谢剑英

    2003-01-01

    This paper presents an online evaluation approach of time delays for networked control systems (NCS), which characterizes the time delays without any synchronized clock in the network and any assumptions of time delays. With this approach, an optimal control scheme based on the approach is designed to achieve the desired performance despite the uncertain delays in the system. The experimental results based on CANbus illustrate the effectiveness of the proposed control design and satisfactory performance of the closed-loop system.

  9. Stepwise transition of 2:1 atrio-ventricular block to 1:1 conduction induced by ventricular premature beats in a patient with atypical AVNRT.

    NARCIS (Netherlands)

    Sorgente, A.; Chierchia, G.B.; Asmundis, C. de; Yazaki, Y.; Sarkozy, A.; Brugada, P.

    2010-01-01

    A 55-year-old man with a 2-year history of recurrent paroxysmal palpitations and with an electrocardiogram documentation of atypical atrioventricular nodal re-entrant tachycardia (AVNRT) was referred to us for catheter ablation. After an initial ablation attempt, several episodes of atypical AVNRT w

  10. Vagi and dual atrioventricular nodal physiology%迷走神经与房室结双径路研究进展

    Institute of Scientific and Technical Information of China (English)

    马晓华; 徐海

    2012-01-01

    Atrioventricular nodal reentrant tachycardia is a kind of clinically paroxysmal supraventricular tachycardia, anatomically based on dual atrioventricular nodal physiology ( DAVNP ). Studies in the recent years find that there are plenty of vagi in the slow pathway area of DAVNP, affecting the clinical and electrophysiological characteristics of DAVNP. An insight into the relationship of DAVNP with vagi is significant for the diagnosis and treatment of the problem.%房室结折返性心动过速(atrioventricular nodal reentry tachycardia,AVNRT)是临床上常见的阵发性室上性心动过速的类型之一,其解剖基础为房室结双径路(dual atrioventricular nodal physiology,DAVNP).近年来研究发现DAVNP的慢径路区域分布有丰富的迷走神经,影响DAVNP的临床表现及电生理性质.深入了解迷走神经与DAVNP的关系对临床诊断和治疗具有重要的意义.

  11. Electrophysiological measurements that can explain and guide temporary accelerated pacing to avert (re)occurrence of torsade de pointes arrhythmias in the canine chronic atrioventricular block model

    NARCIS (Netherlands)

    Wijers, Sofieke C.; Bossu, Alexandre; Dunnink, Albert; Beekman, Jet D.M.|info:eu-repo/dai/nl/297687883; Varkevisser, Rosanne; Aranda Hernández, Alfonso; Meine, Mathias|info:eu-repo/dai/nl/304821497; Vos, Marc A.|info:eu-repo/dai/nl/07461522X

    2017-01-01

    Background Pacing at higher rates is known to suppress torsade de pointes (TdP) arrhythmias. Nevertheless, exact application and mechanism need further clarification. In the anesthetized canine chronic atrioventricular block model, ventricular remodeling is responsible for a high and reproducible

  12. Análise dos fatores de risco na correção cirúrgica do defeito septal atrioventricular de forma total Risk factors analysis in the surgical repair of complete atrioventricular septal defect

    Directory of Open Access Journals (Sweden)

    Eduardo Keller Saadi

    1993-06-01

    Full Text Available Pacientes com defeito septal atrioventricular de forma total (DSAVT freqüentemente apresentam insuficiência cardíaca intratável e hipertensão arterial pulmonar nos primeiros meses de vida, e apenas uma minoria sobrevive sem tratamento cirúrgico precoce. Por essa razão, indica-se a correção definitiva para alterar favoravelmente a história natural da doença. Entretanto, vários fatores são responsáveis pela alta mortalidade cirúrgica. O presente trabalho estuda a experiência na correção cirúrgica do DSAVT com o objetivo de identificar alguns fatores de risco estatisticamente significativos para a ocorrência de morte operatória. Analisaram-se, retrospectivamente, 52 pacientes submetidos, entre janeiro de 1974 e dezembro de 1990, a cirurgia definitiva para correção de DSAVT no Royal Brompton and National Heart and Lung Institute, sendo estudadas as seguintes variáveis: idade, peso, sexo, ano da operação, presença de síndrome de Down, grau de regurgitação da valva AV, bandagem prévia do tronco pulmonar, presença de anomalias associadas, pressão sistólica pulmonar, duplo orifício mitral, classificação do defeito segundo Rastelli, emprego de parada circulatória e técnica de correção (1 x 2 retalhos. Todos os fatores foram avaliados isoladamente, mediante a análise univariada. Para determinar quais os fatores que, independentemente da ação de outros, contribuíram significativamente para maior mortalidade cirúrgica, foi utilizada a análise multivariada com regressão logística. A análise multivariada demonstrou que o baixo peso na época da operação e a técnica de correção com um retalho aumentam significativamente a mortalidade cirúrgica.Patients with complete atrioventricular septal defects (CAVSD frequently present with severe heart failure which cannot be controllable medically and pulmonary hypertension in infancy. Just a small number survives without early surgical treatment. For this reason

  13. The Right Delay

    NARCIS (Netherlands)

    Datadien, A.H.R.; Haselager, W.F.G.; Sprinkhuizen-Kuyper, I.G.

    2011-01-01

    Axonal conduction delays should not be ignored in simulations of spiking neural networks. Here it is shown that by using axonal conduction delays, neurons can display sensitivity to a specific spatio-temporal spike pattern. By using delays that complement the firing times in a pattern, spikes can ar

  14. O efeito da morfina na inibição vagal do coração: demonstração da dupla via do nodo atrioventricular - DOI: 10.4025/actascihealthsci.v28i2.1102 The effect of morphine on vagal inhibition of the heart: demonstration of dual atrioventricular nodal pathways - DOI: 10.4025/actascihealthsci.v28i2.1102

    Directory of Open Access Journals (Sweden)

    José Geraldo Pereira da Cruz

    2006-03-01

    Full Text Available A estimulação elétrica do nervo vago diminui a freqüência cardíaca e aumenta o intervalo PQ no eletrocardiograma, podendo ativar a via anterógrada do nodo atrioventricular. Neste experimento é investigada a interação da morfina sobre o controle nervoso parassimpático cardíaco em relação à dupla condução do nodo atrioventricular. A estimulação do nervo vago induz uma significativa bradicardia e um bloqueio atrioventricular de terceiro grau, com a onda P aparecendo negativa na derivação II. Devido aos efeitos moduladores da anestesia sobre o coração, administração de injeções de morfina induz o aparecimento de onda P positiva através de uma ação inibitória sobre a reentrância do nodo atrioventricular. Tudo sugere a presença de duas vias atrioventriculares, anatômica e funcionalmente distintasThat electrical stimulation of the vagus decreased heart rate and increased the PQ interval in electrocardiogram, consistent with anterograde dual atriventricular conduction. The present experiments were investigating the interaction of the morphine with cardiac parasympathetic nervous control in dual atrioventricular node. Electrical stimulation of the vagus nerve induced significant bradycardia and of third degree atrioventricular block and the P wave appearance was negative in leads II. Because background anesthesia modulates the heart, administered morphine injection the P waves appearance was positive through one inhibitory action on atrioventricular nodal reentry. All suggest the presence of two functionally and anatomically distinct atrioventricular pathways

  15. Possibility as an anti-cancer drug of astemizole: Evaluation of arrhythmogenicity by the chronic atrioventricular block canine model

    Directory of Open Access Journals (Sweden)

    Hiroko Izumi-Nakaseko

    2016-06-01

    Full Text Available Since astemizole in an oral dose of 50 mg/kg/day was recently reported to exert anti-cancer effect in mice, we evaluated its proarrhythmic potential using the atrioventricular block dogs in order to clarify its cardiac safety profile. An oral dose of 3 mg/kg prolonged the QT interval without affecting the QTc (n = 4, whereas that of 30 mg/kg increased the short-term variability of repolarization and induced premature ventricular contractions in each animal, resulting in the onset of torsade de pointes in 1 animal (n = 4. Thus, proarrhythmic dose of astemizole would be lower than anti-cancer one, limiting its re-profiling as an anti-cancer drug.

  16. [Intra-uterine detection of atrio-ventricular block in two children whose mother had Sjögren's syndrome].

    Science.gov (United States)

    Herreman, G; Betous, F; Batisse, P; Bessis, R; Lesavre, P; Ferme, I

    1982-02-27

    A woman with isolated juvenile Sjögren's syndrome gave birth, at 3 years' interval, to two children with complete atrio-ventricular heart block (AVB). This is the first published case of AVB in children of mothers with Sjögren's syndrome without any clinical and laboratory evidence of connective tissue disease, notably lupus. Ultrasonography showed that the AVB was acquired in utero and occurred during the 23rd week of gestation. In both children the AVB was isolated, without any symptom of congenital malformation of the heart; there were no abnormalities of conduction in the mother. Early corticosteroid treatment of the mother's disease had no beneficial effect on AVB in the foetuses. Attempts to reproduce the condition experimentally met with failure.

  17. Cardiogenic Shock with Complete Atrio-ventricular Block in an Octogenarian Woman: Are we going too far?

    Directory of Open Access Journals (Sweden)

    Ziad Dahdouh

    2014-07-01

    Full Text Available We report a case of an octogenarian woman who suffered from cardiogenic shock following an inferolateral myocardial infarction extending to the right ventricle associated with complete atrioventricular heart block. Her initial status was critical with a poor prognosis. She requested an invasive full management to be able to continue to take care of her ill husband. She was managed with circulatory assistance, temporary pacing and percutaneous coronary intervention. The procedure was successfully performed and the patient showed a remarkable improvement in clinical condition. Cardiogenic shock complicating right heart ventricle in elderly requires careful patient selection for invasive strategies that can sometimes rely on the willingness of the patient, as the procedural outcome appears to be poor in this high-risk population.

  18. An Analytical Delay Model

    Institute of Scientific and Technical Information of China (English)

    MIN Yinghua; LI Zhongcheng

    1999-01-01

    Delay consideration has been a majorissue in design and test of high performance digital circuits. Theassumption of input signal change occurring only when all internal nodesare stable restricts the increase of clock frequency. It is no longertrue for wave pipelining circuits. However, previous logical delaymodels are based on the assumption. In addition, the stable time of arobust delay test generally depends on the longest sensitizable pathdelay. Thus, a new delay model is desirable. This paper explores thenecessity first. Then, Boolean process to analytically describe thelogical and timing behavior of a digital circuit is reviewed. Theconcept of sensitization is redefined precisely in this paper. Based onthe new concept of sensitization, an analytical delay model isintroduced. As a result, many untestable delay faults under thelogical delay model can be tested if the output waveforms can be sampledat more time points. The longest sensitizable path length is computedfor circuit design and delay test.

  19. Long-term outcome in patients receiving permanent pacemaker implantation for atrioventricular block: Comparison of VDD and DDD pacing.

    Science.gov (United States)

    Liao, Jo-Nan; Chao, Tze-Fan; Tuan, Ta-Chuan; Kong, Chi-Woon; Chen, Shih-Ann

    2016-08-01

    A permanent pacemaker (PPM) with dual chamber pacing (DDD) offers atrioventricular synchronization for patients with atrioventricular block (AVB). Single lead atrial synchronous ventricular pacing mode (VDD) is an alternative, but there are concerns about its efficacy and risk of atrial undersensing. Whether VDD can be a good alternative in patients with AVB remains unknown. The aim of the present study was to compare the long-term risk of mortality of VDD with DDD pacing.A total of 207 patients undergoing PPM implantations for AVB with VDD mode were enrolled from 2000 to 2013. Another 828 age- and sex-matched patients undergoing DDD implantations during the same period of time were selected as the control group in a 1 to 4 ratio. The study endpoint was mortality.A total of 1035 patients (64.3% male) were followed up for 46.5 ± 43.2 months. The mean ages were 75.0 years for VDD, and 74.9 years for DDD. The Kaplan-Meier survival analysis showed no significant difference in long-term survival between the VDD and DDD groups (log-rank P = 0.313). After adjustment for baseline characteristics, the VDD and DDD groups had a similar long-term prognosis with an adjusted hazard ratio of 0.875 (P = 0.445). Further analyses for the risk of cardiovascular and noncardiovascular deaths also showed no significant differences between the 2 groups.The long-term prognosis of VDD mode is comparable to that of DDD mode. Single lead VDD can be considered as an alternative choice in patients with AVB without sinus nodal dysfunction.

  20. Radiofrequency Catheter Ablation of Atrioventricular Nodal Reentrant Tachycardia: Success Rates and Complications during 14 Years of Experience

    Directory of Open Access Journals (Sweden)

    Mansour Moghaddam

    2010-05-01

    Full Text Available Background: Radiofrequency catheter ablation (RFCA has been introduced as the treatment of choice for supraventricular tachycardia. The aim of this study was to evaluate the success rate as well as procedural and in-hospital complications of RFCA for the treatment of atrioventricular nodal reentrant tachycardia (AVNRT.Methods: Between March 1995 and February 2009, 544 patients (75.9% female, age: 48.89 ± 13.19 years underwent 548 RFCAs for AVNRT in two large university hospitals. Echocardiography was performed for all the patients before and after the procedure. Electrocardiograms were recorded on digital multichannel systems (EP-Med or Bard EP system. Anticoagulation was initiated during the procedure.Results: From the 548 patients, 36 had associated arrhythmias, atrial flutter (4%, atrial fibrillation (0.7%, concurrent atrial fibrillation and atrial flutter (0.7%, and concealed atrioventricular pathway (0.4%. The overall success rate was 99.6%. There were 21 (3.9% transient III-degree AV blocks (up to a few seconds and 4 (0.7% prolonged II- or III-degree AV blocks, 2 (0.25% of which required permanent pacemaker insertion, 3(0.5% deep vein thrombosis, and one (0.2% arteriovenous fistula following the procedure. No difference was observed in the echocardiography parameters before and after the ablation.Conclusion: RFCA had a high success rate. The complication rate was generally low and in the above-mentioned centers it was similar to those in other large centers worldwide. Echocardiography showed no difference before and after the ablation. The results from this study showed that the risk of permanent II or III-degree AV block in patients undergoing RFCA was low and deep vein thrombosis was the second important complication. There was no risk of life-threatening complications.

  1. Echocardiographic features defining right dominant unbalanced atrioventricular septal defect: a multi-institutional Congenital Heart Surgeons' Society study.

    Science.gov (United States)

    Cohen, Meryl S; Jegatheeswaran, Anusha; Baffa, Jeanne M; Gremmels, David B; Overman, David M; Caldarone, Christopher A; McCrindle, Brian W; Mertens, Luc

    2013-07-01

    Definition and management of right dominant unbalanced atrioventricular septal defect (AVSD) remains challenging because unbalance entails a spectrum of left heart hypoplasia. Previous work has highlighted atrioventricular valve (AVV) index as a reasonable defining echocardiographic measure. We sought to assess which additional echocardiographic features might provide further characterization. From a multi-institutional cohort of complete AVSD, 52 preoperative echocardiograms of patients with presumed right dominant unbalanced AVSD (based on AVV index) and 60 randomly selected preoperative echocardiograms from patients with presumed balanced AVSD were reviewed. Cluster analysis of echocardiographic variables was used to group patients with similar features. Discriminant function analysis was used to explore which variables differentiated these groups. Three groups were identified from the cluster analysis. Echocardiographic variables that differentiated these groups were right ventricle:left ventricle inflow angle, LV width/LV length, left AVV color diameter at smallest inflow, left AVV color diameter at annulus, right AVV overriding left atrium, and LV width. Based on procedures and outcomes, 1 group likely represented balanced patients, whereas 2 groups with similar outcomes likely represented unbalanced patients. The dominant differentiating echocardiographic variable between the 3 cluster groups was the right ventricle:LV inflow angle (partial R²=0.86), defined as the angle between the base of the right ventricle and LV free wall, using the crest of the ventricular septum as apex of the angle. The angle of right ventricle/LV inflow and other surrogates of inflow may be important defining echocardiographic measures of right dominant unbalanced AVSD, although confirmation is needed.

  2. An Excess of Deleterious Variants in VEGF-A Pathway Genes in Down-Syndrome-Associated Atrioventricular Septal Defects

    Science.gov (United States)

    Ackerman, Christine; Locke, Adam E.; Feingold, Eleanor; Reshey, Benjamin; Espana, Karina; Thusberg, Janita; Mooney, Sean; Bean, Lora J.H.; Dooley, Kenneth J.; Cua, Clifford L.; Reeves, Roger H.; Sherman, Stephanie L.; Maslen, Cheryl L.

    2012-01-01

    About half of people with trisomy 21 have a congenital heart defect (CHD), whereas the remainder have a structurally normal heart, demonstrating that trisomy 21 is a significant risk factor but is not causal for abnormal heart development. Atrioventricular septal defects (AVSD) are the most commonly occurring heart defects in Down syndrome (DS), and ∼65% of all AVSD is associated with DS. We used a candidate-gene approach among individuals with DS and complete AVSD (cases = 141) and DS with no CHD (controls = 141) to determine whether rare genetic variants in genes involved in atrioventricular valvuloseptal morphogenesis contribute to AVSD in this sensitized population. We found a significant excess (p < 0.0001) of variants predicted to be deleterious in cases compared to controls. At the most stringent level of filtering, we found potentially damaging variants in nearly 20% of cases but fewer than 3% of controls. The variants with the highest probability of being damaging in cases only were found in six genes: COL6A1, COL6A2, CRELD1, FBLN2, FRZB, and GATA5. Several of the case-specific variants were recurrent in unrelated individuals, occurring in 10% of cases studied. No variants with an equal probability of being damaging were found in controls, demonstrating a highly specific association with AVSD. Of note, all of these genes are in the VEGF-A pathway, even though the candidate genes analyzed in this study represented numerous biochemical and developmental pathways, suggesting that rare variants in the VEGF-A pathway might contribute to the genetic underpinnings of AVSD in humans. PMID:23040494

  3. Space object tracking with delayed measurements

    Science.gov (United States)

    Chen, Huimin; Shen, Dan; Chen, Genshe; Blasch, Erik; Pham, Khanh

    2010-04-01

    This paper is concerned with the nonlinear filtering problem for tracking a space object with possibly delayed measurements. In a distributed dynamic sensing environment, due to limited communication bandwidth and long distances between the earth and the satellites, it is possible for sensor reports to be delayed when the tracking filter receives them. Such delays can be complete (the full observation vector is delayed) or partial (part of the observation vector is delayed), and with deterministic or random time lag. We propose an approximate approach to incorporate delayed measurements without reprocessing the old measurements at the tracking filter. We describe the optimal and suboptimal algorithms for filter update with delayed measurements in an orbital trajectory estimation problem without clutter. Then we extend the work to a single object tracking under clutter where probabilistic data association filter (PDAF) is used to replace the recursive linear minimum means square error (LMMSE) filter and delayed measurements with arbitrary lags are be handled without reprocessing the old measurements. Finally, we demonstrate the proposed algorithms in realistic space object tracking scenarios using the NASA General Mission Analysis Tool (GMAT).

  4. Queueing Delay and Energy Efficiency Analyses of Sleep Based Power Saving Mechanism

    Science.gov (United States)

    Zhu, Fan; Wu, Yiqun; Niu, Zhisheng

    In wireless networks, sleep mode based power saving mechanisms can reduce the energy consumption at the expense of additional packet delay. This letter analyzes its packet queueing delay and wireless terminals' energy efficiency. Based on the analysis, optimal sleep window size can be derived to optimize terminal energy efficiency with delay constraint.

  5. Cardiac output response to changes of the atrioventricular delay in different body positions and during exercise in patients receiving cardiac resynchronization therapy

    DEFF Research Database (Denmark)

    Ståhlberg, Marcus; Damgaard, Morten; Norsk, Peter

    2009-01-01

    , the estimated pulmonary artery diastolic pressure (ePAD) was analysed. RESULTS: The magnitude of CO response to AVD changes was greater in CRT patients than in controls (0.25 vs. 0.20 L/min, P... and prolonged by 40 ms in 27 CRT patients and 9 controls without heart failure. Cardiac output (CO) was measured by inert gas rebreathing (Innocor) as the average over different body positions (left-lateral, supine, sitting, standing, and exercise). In eight CRT patients with an implantable haemodynamic monitor...

  6. Delayed emergence after anesthesia.

    Science.gov (United States)

    Tzabazis, Alexander; Miller, Christopher; Dobrow, Marc F; Zheng, Karl; Brock-Utne, John G

    2015-06-01

    In most instances, delayed emergence from anesthesia is attributed to residual anesthetic or analgesic medications. However, delayed emergence can be secondary to unusual causes and present diagnostic dilemmas. Data from clinical studies is scarce and most available published material is comprised of case reports. In this review, we summarize and discuss less common and difficult to diagnose reasons for delayed emergence and present cases from our own experience or reference published case reports/case series. The goal is to draw attention to less common reasons for delayed emergence, identify patient populations that are potentially at risk and to help anesthesiologists identifying a possible cause why their patient is slow to wake up.

  7. Efeitos da mudança de modo de estimulação ventricular para atrioventricular sobre a qualidade de vida em pacientes com cardiopatia chagásica e bloqueio atrioventricular na troca eletiva do gerador de pulsos Health-related quality of life in patients with Chagas' cardiomiopathy and complete atrioventricular block at elective pulse generator replacement: effects of pacing mode upgraded from VVI to DDD

    Directory of Open Access Journals (Sweden)

    Luiz Antonio Castilho Teno

    2005-03-01

    Full Text Available OBJETIVO: Avaliar os efeitos da mudança de modo de estimulação ventricular para atrioventricular sobre a qualidade de vida em pacientes com cardiopatia chagásica e bloqueio atrioventricular, na troca eletiva do gerador de pulsos. MÉTODO: No período de 8 de setembro de 2001 a 18 de março de 2004, no Instituto do Coração da Faculdade de Medicina da Universidade de São Paulo e no Hospital de Beneficência Portuguesa de Ribeirão Preto, foram estudados comparativamente sob estimulação ventricular e atrioventricular 27 pacientes com cardiopatia chagásica e bloqueio atrioventricular, com indicação de troca eletiva do gerador de pulsos. Os pacientes foram analisados na inclusão do estudo e alternadamente no modo ventricular e atrioventricular em duas fases com duração de 90 dias, considerando-se o comportamento clínico, avaliado pela qualidade de vida. A análise estatística foi realizada na condição basal, modo VVI e modo DDD, utilizando-se o teste de variância para medidas repetidas, considerando-se nível de significância de 0,05. RESULTADOS: Não foram detectadas diferenças de comportamento na qualidade de vida, avaliada pela capacidade funcional pelo estado geral e pela vitalidade, entre os dois modos de estimulação cardíaca estudados. Ocorreram três casos de complicações relacionadas à mudança de modo de estimulação: dois casos de taquiarritmias atriais conduzidas pelo marcapasso e um caso de deslocamento de eletrodo atrial. CONCLUSÕES: A análise comparativa da estimulação ventricular com a atrioventricular, na troca eletiva do gerador, demonstrou que não houve diferença de comportamento clínico sobre a qualidade de vida.OBJECTIVE: Health-related quality of life in patients with Chagas' cardiomyopathy and complete atrioventricular block at elective pulse generator replacement: effects of pacing mode upgraded from VVI to DDD. METHOD: From September 8, 2001 to March 18, 2004, at the Instituto do Cora

  8. Post-CTS Delay Insertion

    Directory of Open Access Journals (Sweden)

    Jianchao Lu

    2010-01-01

    clock skew operation is performed only at the clock sinks in order to preserve the structure and the optimizations implemented in the clock tree synthesis stage. The methodology is implemented as a linear programming model amenable to two design objectives: fixing timing violations or optimizing the clock period. Experimental results show that the clock networks of the largest ISCAS'89 circuits can be corrected post-CTS to resolve the timing conflicts in approximately 90% of the circuits with minimal delay insertion (0.159  ×  clock period per clock path on average. It is also shown that the majority of the clock period improvement achievable through unrestricted clock skew scheduling are obtained through very limited insertion (≈43% average improvement through 10% of max insertion.

  9. American Dream Delayed

    DEFF Research Database (Denmark)

    Khorunzhina, Natalia; Miller, Robert A.

    This paper investigates the delay in homeownership and a subsequent reduction in homeownership rate observed over the past decades. We focus on the delay in giving birth to children and increased labor market participation as contributing factors to homeownership dynamics for prime-age female hou...

  10. Radio resource allocation over fading channels under statistical delay constraints

    CERN Document Server

    Le-Ngoc, Tho

    2017-01-01

    This SpringerBrief presents radio resource allocation schemes for buffer-aided communications systems over fading channels under statistical delay constraints in terms of upper-bounded average delay or delay-outage probability. This Brief starts by considering a source-destination communications link with data arriving at the source transmission buffer. The first scenario, the joint optimal data admission control and power allocation problem for throughput maximization is considered, where the source is assumed to have a maximum power and an average delay constraints. The second scenario, optimal power allocation problems for energy harvesting (EH) communications systems under average delay or delay-outage constraints are explored, where the EH source harvests random amounts of energy from renewable energy sources, and stores the harvested energy in a battery during data transmission. Online resource allocation algorithms are developed when the statistical knowledge of the random channel fading, data arrivals...

  11. Dynamic Electrocardiogram Analysis of Vagal-Related Atrioventricular Block%迷走性房室阻滞动态心电图分析

    Institute of Scientific and Technical Information of China (English)

    潘懿坤; 李永华; 朱志坚

    2012-01-01

    Objective: To investigate the occurrence, development and outcome of vagal-related atrioventricular block (AV block). Methods: Clinical documents from 48 patients with vagal-related AV block were analyzed to explore the relationship and clinical significance between incidence of vagal-related AV block and age. Results: Vagal-related atrioventricular block is more common under 40 years of age, and it often occurs in the night sleep when heart rate is low. Conclusion: Vagal-related atrioventricular block is functional disorder, which is not need to do special treatment, let alone the permanent artificial pacemaker thereapy.%目的:探讨迷走性房室阻滞的发生、发展及转归。方法:通过对48例迷走性房室阻滞患者的年龄及发生时间的观察,研究年龄与房室阻滞的关系及临床意义。结果:迷走性房室阻滞多见于40岁以下,多发生于夜间睡眠(心率减慢)时。结论:迷走性房室阻滞属于功能性,无需特殊治疗,更不必安装永久性人工起搏器。

  12. Fast-slow and slow-slow form of atrioventricular nodal reentrant tachycardia sustained by the same reentrant circuit: a case report.

    Science.gov (United States)

    Cantù, Francesco; De Filippo, Paolo; Rordorf, Roberto; De Ferrari, Gaetano M; Frattini, Folco; Petracci, Barbara; Russo, Giovanni; Cerrone, Marina; Landolina, Maurizio

    2005-01-01

    It has been suggested that a reentrant circuit confined to the posterior extensions of the atrioventricular node underlies both fast-slow and slow-slow types of atrioventricular nodal reentrant tachycardia (AVNRT). According to this hypothesis the fast-slow reentrant circuit would be formed by two slow pathways, located in the rightward and leftward posterior extension of the atrioventricular node. Thus, the fast pathway would act as a bystander with respect to the reentrant circuit. We describe the case of a 40-year-old woman with several episodes of palpitations unresponsive to antiarrhythmic drugs. The ECG during symptoms showed a narrow QRS tachycardia with a long ventriculo-atrial interval and a negative P wave in the inferior leads. Electrophysiological study showed the inducibility of a slow-slow AVNRT which rapidly shifted to a fast-slow AVNRT without any change in the duration of the tachycardia cycle. Our observation is in agreement with the hypothesis that the fast-slow reentrant circuit consists of two slow pathways with the fast pathway acting as a bystander.

  13. Solving Nonlinear Time Delay Control Systems by Fourier series

    Directory of Open Access Journals (Sweden)

    Mohammad Hadi Farahi

    2014-06-01

    Full Text Available In this paper we present a method to find the solution of time-delay optimal control systems using Fourier series. The method is based upon expanding various time functions in the system as their truncated Fourier series. Operational matrices of integration and delay are presented and are utilized to reduce the solution of time-delay control systems to the solution of algebraic equations. Illustrative examples are included to demonstrate the validity and applicability of the technique.

  14. Congestion aware forwarding in delay tolerant and social opportunistic networks

    OpenAIRE

    Radenkovic, Milena; Grundy, Andrew

    2011-01-01

    We propose an approach for opportunistic forwarding that supports optimization of multipoint high volume data flow transfer while maintaining high buffer availability and low delays. This paper explores a number of social, buffer and delay heuristics to offload the traffic from congested parts of the network and spread it over less congested parts of the network in order to keep low delays, high success ratios and high availability of nodes. We conduct an extensive set of experiments for asse...

  15. Time-Delay System Identification Using Genetic Algorithm

    DEFF Research Database (Denmark)

    Yang, Zhenyu; Seested, Glen Thane

    2013-01-01

    Due to the unknown dead-time coefficient, the time-delay system identification turns to be a non-convex optimization problem. This paper investigates the identification of a simple time-delay system, named First-Order-Plus-Dead-Time (FOPDT), by using the Genetic Algorithm (GA) technique...

  16. Delay Analysis and Formulation Inference of Signalized Intersection for Traffic Congestion Conditions

    Institute of Scientific and Technical Information of China (English)

    刘广萍; 丁建梅

    2004-01-01

    Vehicle delay is an important measure to evaluate the signal timings of signalized intersections.When optimization the signal control parameters, delays of vehicles from all approach directions of an intersection should be considered. Based on the analysis of the vehicle delay on an approach of intersection, directed against the typical condition of a congested intersection-over-saturated condition, the paper has analyzed and inferred the intersection delay dynamic formulation, and has established the relation between intersection delay,the signal timings, vehicle arrival rate and the queue lengths, and that provides useful information for understanding vehicle delay of signalized intersection and for establishing performance index function of signal timing optimization.

  17. Delay-time-based model of optimization grouping maintenance type and case study%基于时间延迟的维修类型优化组合模型及案例分析

    Institute of Scientific and Technical Information of China (English)

    吕文元; 郑睿

    2013-01-01

    There are many kinds of defects occurred in production plant,and those defects have different effects on the performance of production plant.So many kinds of inspection activities,or maintenance types such as daily inspection,weekly inspection,monthly inspection,yearly maintenance,and overhaul as well,are simultaneously applied on a production plant.The current research about inspection modeling pays more attention on the calculation of inspection cycle which is only for one maintenance type,not on the modeling of multiple nested inspection cycle.This has caused the serious problems of either over maintenance or insufficient maintenance.In this paper,all kinds of inspection activities are firstly given,and the relationship between different maintenance types is described.Secondly,a model of optimization grouping maintenance type at different inspection cycles for production plant is established.Based on the delay time maintenance theory,the key two terms,namely the expected failures number occurred in inspection cycle T and the expected defects number identified in inspection activities,are calculated.Thirdly,a new heuristic algorithm is proposed for solving the established model.As the proposed algorithm is very simple and easy to use,so it is better than branch-and-bound procedure to solve the nonlinear target function of integer variables.Finally,a case study is given to demonstrate the modeling and solution processes.%设备的缺陷类型有多种,各种类型的缺陷对设备故障停机影响不同,为此对设备采用多种维修类型(日检、周检、月检、年度检修和大修).目前的检查模型局限于计算单个维修类型的检查周期,而不能同时确定出各种维修类型的检查周期,维修类型优化组合的模型尚未建立,存在“维修不足和维修过剩”的两大难题.为此,首先阐述了各种维修类型之间的关系,并提出了相应的假定条件.其次建立了维修类型优化组合模型.利用时

  18. Robust delay-dependent feedforward control of neutral time-delay systems via dynamic IQCs

    Science.gov (United States)

    Ucun, L.; Küçükdemiral, I. B.

    2014-05-01

    This paper studies the design problem of delay-dependent ? based robust and optimal feedforward controller design for a class of time-delay control systems having state, control and neutral type delays which are subject to norm-bounded uncertainties and ? type measurable or observable disturbance signals. Two independent loops which include state-feedback and dynamic feedforward controller form the basis of the proposed control scheme in this study. State-feedback controller is generally used in stabilisation of the nominal delay-free system, whereas the feedforward controller is used for improving disturbance attenuation performance of the overall system. In order to obtain less conservative results, the delay and parametric uncertainty effects are treated in operator view point and represented by frequency-dependent (dynamic) integral quadratic constraints (IQCs). Moreover, sufficient delay-dependent criterion is developed in terms of linear matrix inequalities (LMIs) such that the time-delay system having parametric uncertainties is guaranteed to be asymptotically stable with minimum achievable disturbance attenuation level. Plenty of numerical examples are provided at the end, in order to illustrate the efficiency of the proposed technique. The achieved results on minimum achievable disturbance attenuation level and maximum allowable delay bounds are exhibited to be less conservative in comparison to those of controllers having only feedback loop.

  19. Radiotherapy as a cause of complete atrioventricular block in Hodgkin's disease: an electrophysiological-pathological correlation

    Energy Technology Data Exchange (ETDEWEB)

    Cohen, S.I.; Bharati, S.; Glass, J.; Lev, M.

    1981-04-01

    A 20-year-old man contracted Hodgkin's disease and was treated with mantle radiotherapy. Heart block developed 11 years later. Electrocardiograms revealed predominant atrioventricular (AV) block and occasional AV conduction. Intracardiac electrograms demonstrated that the site of AV block was above the level of the His bundle. A permanent transvenous pacemaker was implanted. Seven months later the patient died of complications from cryptococcal meningitis. Pathological study of the heart revealed marked arteriosclerosis with fibrosis of the epicardium, myocardium, and endocardium. Examination of the conduction system revealed extensive arteriolosclerosis of the sinoatrial node and its approaches. In addition, there was marked fibrosis of the approaches to the AV node, the AV bundle, and both bundle branches. There was no evidence of Hodgkin's disease. This case documents the rare occurrence of AV block due to tissue destruction by radiotherapy. There was a good correlation between block proximal to the His bundle recording site and fibrosis of the approaches to the AV node.

  20. Radiotherapy as a cause of complete atrioventricular block in Hodgkin's disease. An electrophysiological-pathological correlation

    Energy Technology Data Exchange (ETDEWEB)

    Cohen, S.I.; Bharati, S.; Glass, J.; Lev, M.

    1981-04-01

    A 20-year-old man contracted Hodgkin's disease and was treated with mantle radiotherapy. Heart block developed 11 years later. Electrocardiograms revealed predominant atrioventricular (AV) block and occasional AV conduction. Intracardiac electrograms demonstrated that the site of AV block was above the level of the His bundle. A permanent transvenous pacemaker was implanted. Seven months later the patient died of complications from cryptococcal meningitis. Pathological study of the heart revealed marked arteriosclerosis with fibrosis of the epicardium, myocardium, and endocardium. Examination of the conduction system revealed extensive arteriolosclerosis of the sinoatrial node and its approaches. In addition, there was marked fibrosis of the approaches to the AV node, the AV bundle, and both bundle branches. There was no evidence of Hodgkin's disease. This case documents the rare occurrence of AV block due to tissue destruction by radiotherapy. There was a good correlation between block proximal to the His bundle recording site and fibrosis of the approaches to the AV node.

  1. Sudden death and its risk factors after atrioventricular junction ablation and pacemaker implantation in patients with atrial fibrillation.

    Science.gov (United States)

    Wang, Ru-Xing; Lee, Hon-Chi; Li, Jia-Ping; Hodge, David O; Cha, Yong-Mei; Friedman, Paul A; Munger, Thomas M; Srivathsan, Komandoor; Pavri, Behzad B; Shen, Win-Kuang

    2017-01-01

    Although sudden death (SD) is a rare complication after atrioventricular junction (AVJ) ablation and permanent pacemaker implantation, the risk factors leading to this SD remain unknown. The purpose of this study was to investigate SD and its risk factors after ablate-and-pace strategy for rate control in atrial fibrillation (AF) patients during long-term follow-up. METHODS: From January 2005 to December 2009, we enrolled into this study 517 AF patients with AVJ ablation and right ventricular pacemaker implantation. Patients were divided into 2 groups, SD and non-SD. Cox proportional hazards models were used to assess potential risk factors for overall mortality and SD. During a mean follow-up of 25.8 ± 18.6 months (range, 3 days to 63.8 months), 53 patients died (15 with SD). Cox proportional hazards models showed that the presence of congestive heart failure, New York Heart Association functional class, chronic renal failure, and nonsustained ventricular tachycardia were risk factors that predicted overall mortality. For SD, the presence of dilated cardiomyopathy and mitral stenosis were associated risk factors. SD was exclusively seen in patients who had narrow QRS complex or right bundle branch block prior to AVJ ablation and pacemaker implantation; SD was not seen in any patient with preexisting complete left bundle branch block. Dilated cardiomyopathy, mitral stenosis, and baseline QRS morphology should be examined as potential risk factors for SD after AVJ ablation and pacemaker implantation. © 2016 Wiley Periodicals, Inc.

  2. The Distributed Network Monitoring Model with Bounded Delay Constraints

    Institute of Scientific and Technical Information of China (English)

    LIU Xiang-hui; YIN Jian-ping; LU Xi-cheng; CAI Zhi-ping; ZHAO Jian-min

    2004-01-01

    We address the problem of optimizing a distributed monitoring system and the goal of the optimization is to reduce the cost of deployment of the monitoring infrastructure by identifying a minimum aggregating set subject to delay constraint on the aggregating path. We show that this problem is NP-hard and propose approximation algorithm proving the approximation ratio with ln m+1, where is the number of monitoring nodes. At last we extend our modal with more constraint of bounded delay variation.

  3. commensurate point delays

    Directory of Open Access Journals (Sweden)

    M. de la Sen

    2005-01-01

    nominal controller is maintained. In the current approach, the finite spectrum assignment is only considered as a particular case of the designer's choice of a (delay-dependent arbitrary spectrum assignment objective.

  4. Time Delay Cosmography

    OpenAIRE

    Treu, Tommaso; Marshall, Philip J.

    2016-01-01

    Gravitational time delays, observed in strong lens systems where the variable background source is multiply-imaged by a massive galaxy in the foreground, provide direct measurements of cosmological distance that are very complementary to other cosmographic probes. The success of the technique depends on the availability and size of a suitable sample of lensed quasars or supernovae, precise measurements of the time delays, accurate modeling of the gravitational potential of the main deflector,...

  5. Data-assimilation by delay-coordinate nudging

    CERN Document Server

    Pazó, D; López, J M

    2015-01-01

    A new nudging method for data assimilation, delay-coordinate nudging, is presented. Delay-coordinate nudging makes explicit use of present and past observations in the formulation of the forcing driving the model evolution at each time-step. Numerical experiments with a low order chaotic system show that the new method systematically outperforms standard nudging in different model and observational scenarios, also when using an un-optimized formulation of the delay-nudging coefficients. A connection between the optimal delay and the dominant Lyapunov exponent of the dynamics is found based on heuristic arguments and is confirmed by the numerical results, providing a guideline for the practical implementation of the algorithm. Delay-coordinate nudging preserves the easiness of implementation, the intuitive functioning and the reduced computational cost of the standard nudging, making it a potential alternative especially in the field of seasonal-to-decadal predictions with large Earth system models that limit ...

  6. Integrated fleet assignment and aircraft routing based on delay propagation

    Indian Academy of Sciences (India)

    WAN-MING LIU; XING-HUI ZHU; YAN-LONG QI

    2016-07-01

    Airlines’ expensive resources, especially aircraft, are to be optimally scheduled to cover flights of timetables. However, the irregular flight, due to bad weather, mechanical fault and so on, is inevitable.Moreover, flight delays become more severe with the rapid development of the air transport industry in China and have huge irregular flight cost. In order to alleviate flight delays impact on the flight plan, we present a double objective multi-commodity network flow model of flight delay propagation-based aircraft scheduling and minimize the total delay propagation and airline operation cost as the optimization objective. Branch-and-price solution and column generation algorithm are used to solve the problem. Computational results obtained by using data from a major domestic airline show that our approach can reduce delay propagation significantly, thus improving on-time performance and robustness of aircraft scheduling, and decreasing the total cost simultaneously.

  7. Delayed Sequential Coding of Correlated Sources

    CERN Document Server

    Ma, Nan; Ishwar, Prakash

    2007-01-01

    Motivated by video coding applications, we study the problem of sequential coding of correlated sources with (noncausal) encoding and/or decoding frame-delays. The fundamental tradeoffs between individual frame rates, individual frame distortions, and encoding/decoding frame-delays are derived in terms of a single-letter information-theoretic characterization of the rate-distortion region for general inter-frame source correlations and certain types of (potentially frame-specific and coupled) single-letter fidelity criteria. For video sources which are spatially stationary memoryless and temporally Gauss--Markov, MSE frame distortions, and a sum-rate constraint, our results expose the optimality of differential predictive coding among all causal sequential coders. Somewhat surprisingly, causal sequential encoding with one-step delayed noncausal sequential decoding can exactly match the sum-rate-MSE performance of joint coding for all nontrivial MSE-tuples satisfying certain positive semi-definiteness conditio...

  8. Left ventricular atrioventricular plane displacement is preserved with lifelong endurance training and is the main determinant of maximal cardiac output.

    Science.gov (United States)

    Steding-Ehrenborg, Katarina; Boushel, Robert C; Calbet, José A; Åkeson, Per; Mortensen, Stefan P

    2015-12-01

    Age-related decline in cardiac function can be prevented or postponed by lifelong endurance training. However, effects of normal ageing as well as of lifelong endurance exercise on longitudinal and radial contribution to stroke volume are unknown. The aim of this study was to determine resting longitudinal and radial pumping in elderly athletes, sedentary elderly and young sedentary subjects. Furthermore, we aimed to investigate determinants of maximal cardiac output in elderly. Eight elderly athletes (63 ± 4 years), seven elderly sedentary (66 ± 4 years) and ten young sedentary subjects (29 ± 4 years) underwent cardiac magnetic resonance imaging. All subjects underwent maximal exercise testing and for elderly subjects maximal cardiac output during cycling was determined using a dye dilution technique. Longitudinal and radial contribution to stroke volume did not differ between groups (longitudinal left ventricle (LV) 52-65%, P = 0.12, right ventricle (RV) 77-87%, P = 0.16, radial 7.9-8.6%, P = 1.0). Left ventricular atrioventricular plane displacement (LVAVPD) was higher in elderly athletes and young sedentary compared with elderly sedentary subjects (14 ± 3, 15 ± 2 and 11 ± 1 mm, respectively, P cardiac output (R(2) = 0.61, P Longitudinal and radial contributions to stroke volume did not differ between groups. However, how longitudinal pumping was achieved differed; elderly athletes and young sedentary subjects showed similar AVPD whereas this was significantly lower in elderly sedentary subjects. Elderly sedentary subjects achieved longitudinal pumping through increased short-axis area of the ventricle. Large AVPD was a determinant of maximal cardiac output and exercise capacity.

  9. Differential displaying of mRNAs from the atrioventricular region of developing chicken hearts at stages 15 and 21.

    Science.gov (United States)

    Wang, D Z; Hu, X; Lin, J L; Kitten, G T; Solursh, M; Lin, J J

    1996-01-01

    In an effort to isolate novel genes that may be involved in the development of the cardiac cushions and then the formation of cardiac valves and septa, we utilized the differential mRNA display method in conjunction with the whole-mount in situ hybridization. The total RNAs used to differentially display were prepared from atrioventricular (AV) canal regions of stage 15 and stage 21 chicken hearts because critical events known to be important for the AV valve and septum formation occur during this period of the development. We have successfully obtained 14 potential candidate genes. Three examples, 15H16 (phospholamban), E13 (skeletal alpha-tropomyosin) and 21C (a novel gene), are discussed here. Levels of mRNA expression in developing hearts were determined by Northern blot analysis and their expression patterns were revealed and compared using whole-mount in situ hybridization. Both phospholamban and skeletal alpha-tropomyosin messages in the myocardium of the AV canal region showed significant decrease during this period of the development. The 21C differential display product detects a novel 9.5 Kb message whose expression is cardiac-specific at early stages of development. The expression level of the 21C gene appeared to be increased from stage 15 to stages 21 and 25 as determined by both Northern blot analysis and in situ hybridization. From these data, we demonstrate that the differential display method together with the whole-mount in situ hybridization could be an effective means for the isolation of novel and differentially expressed genes.

  10. De Novo and Rare Variants at Multiple Loci Support the Oligogenic Origins of Atrioventricular Septal Heart Defects

    Science.gov (United States)

    Priest, James R.; Osoegawa, Kazutoyo; Mohammed, Nebil; Nanda, Vivek; Kundu, Ramendra; Schultz, Kathleen; Girirajan, Santhosh; Scheetz, Todd; Waggott, Daryl; Haddad, Francois; Reddy, Sushma; Bernstein, Daniel; Burns, Trudy; Steimle, Jeffrey D.; Yang, Xinan H.; Moskowitz, Ivan P.; Hurles, Matthew; Lifton, Richard P.; Nickerson, Debbie; Bamshad, Michael; Eichler, Evan E.; Mital, Seema; Sheffield, Val; Quertermous, Thomas; Gelb, Bruce D.; Portman, Michael; Ashley, Euan A.

    2016-01-01

    Congenital heart disease (CHD) has a complex genetic etiology, and recent studies suggest that high penetrance de novo mutations may account for only a small fraction of disease. In a multi-institutional cohort surveyed by exome sequencing, combining analysis of 987 individuals (discovery cohort of 59 affected trios and 59 control trios, and a replication cohort of 100 affected singletons and 533 unaffected singletons) we observe variation at novel and known loci related to a specific cardiac malformation the atrioventricular septal defect (AVSD). In a primary analysis, by combining developmental coexpression networks with inheritance modeling, we identify a de novo mutation in the DNA binding domain of NR1D2 (p.R175W). We show that p.R175W changes the transcriptional activity of Nr1d2 using an in vitro transactivation model in HUVEC cells. Finally, we demonstrate previously unrecognized cardiovascular malformations in the Nr1d2tm1-Dgen knockout mouse. In secondary analyses we map genetic variation to protein-interaction networks suggesting a role for two collagen genes in AVSD, which we corroborate by burden testing in a second replication cohort of 100 AVSDs and 533 controls (p = 8.37e-08). Finally, we apply a rare-disease inheritance model to identify variation in genes previously associated with CHD (ZFPM2, NSD1, NOTCH1, VCAN, and MYH6), cardiac malformations in mouse models (ADAM17, CHRD, IFT140, PTPRJ, RYR1 and ATE1), and hypomorphic alleles of genes causing syndromic CHD (EHMT1, SRCAP, BBS2, NOTCH2, and KMT2D) in 14 of 59 trios, greatly exceeding variation in control trios without CHD (p = 9.60e-06). In total, 32% of trios carried at least one putatively disease-associated variant across 19 loci,suggesting that inherited and de novo variation across a heterogeneous group of loci may contribute to disease risk. PMID:27058611

  11. De Novo and Rare Variants at Multiple Loci Support the Oligogenic Origins of Atrioventricular Septal Heart Defects.

    Directory of Open Access Journals (Sweden)

    James R Priest

    2016-04-01

    Full Text Available Congenital heart disease (CHD has a complex genetic etiology, and recent studies suggest that high penetrance de novo mutations may account for only a small fraction of disease. In a multi-institutional cohort surveyed by exome sequencing, combining analysis of 987 individuals (discovery cohort of 59 affected trios and 59 control trios, and a replication cohort of 100 affected singletons and 533 unaffected singletons we observe variation at novel and known loci related to a specific cardiac malformation the atrioventricular septal defect (AVSD. In a primary analysis, by combining developmental coexpression networks with inheritance modeling, we identify a de novo mutation in the DNA binding domain of NR1D2 (p.R175W. We show that p.R175W changes the transcriptional activity of Nr1d2 using an in vitro transactivation model in HUVEC cells. Finally, we demonstrate previously unrecognized cardiovascular malformations in the Nr1d2tm1-Dgen knockout mouse. In secondary analyses we map genetic variation to protein-interaction networks suggesting a role for two collagen genes in AVSD, which we corroborate by burden testing in a second replication cohort of 100 AVSDs and 533 controls (p = 8.37e-08. Finally, we apply a rare-disease inheritance model to identify variation in genes previously associated with CHD (ZFPM2, NSD1, NOTCH1, VCAN, and MYH6, cardiac malformations in mouse models (ADAM17, CHRD, IFT140, PTPRJ, RYR1 and ATE1, and hypomorphic alleles of genes causing syndromic CHD (EHMT1, SRCAP, BBS2, NOTCH2, and KMT2D in 14 of 59 trios, greatly exceeding variation in control trios without CHD (p = 9.60e-06. In total, 32% of trios carried at least one putatively disease-associated variant across 19 loci,suggesting that inherited and de novo variation across a heterogeneous group of loci may contribute to disease risk.

  12. Spontaneous rupture of atrioventricular valve tensor apparatus as late manifestation of anti-Ro/SSA antibody-mediated cardiac disease.

    Science.gov (United States)

    Cuneo, Bettina F; Fruitman, Deborah; Benson, D Woodrow; Ngan, Bo-Yee; Liske, Michael R; Wahren-Herlineus, Marie; Ho, S Yen; Jaeggi, Edgar

    2011-03-01

    Atrioventricular (AV) block and endocardial fibroelastosis associated with dilated cardiomyopathy are the most common clinical manifestations of anti-Ro/SSA-mediated fetal cardiac disease. Valvar dysfunction has not been a prominent feature of this disease; however, recent anecdotal cases have suggested an association between rupture of the AV valve tensor apparatus and maternal anti-Ro/SSA antibodies. In the present study, we have described the clinical and laboratory findings and reviewed the published data for infants of anti-Ro/SSA-positive pregnancies with AV valve insufficiency due to chordal rupture from the papillary muscles. The histopathologic features of the papillary muscle and ventricular free wall and septum biopsy specimens were examined and compared to the sections of AV leaflets from 6 autopsied fetuses with anti-Ro/SSA-mediated complete AV block without chordal disruption. Specific epitopes to the p200 region of Ro52, and Ro60 antibodies were evaluated in cases with chordal rupture. Severe AV valve insufficiency was detected prenatally (as early as 34 weeks of gestation) or postnatally (as late as 182 days) after areas of patchy echogenicity were noted in the papillary muscle at 19 to 22 weeks of gestation. Postnatally, urgent valve surgery was performed in 5 of 6 patients; 1 of 6 patients died preoperatively. All patients tested positive for Ro52. Valve leaflet tissue from the autopsy specimens was normal. The ventricular free wall and septum biopsy specimens from a patient with chordal rupture showed normal tissue; however, the papillary muscle biopsy specimens demonstrated severe atrophy with near total replacement of myocytes by fibrosis and dystrophic calcifications, and negative immunochemistry findings. In conclusion, these findings have defined an underappreciated complication of fetal antibody-mediated cardiac inflammation.

  13. Time Delay Cosmography

    CERN Document Server

    Treu, Tommaso

    2016-01-01

    Gravitational time delays, observed in strong lens systems where the variable background source is multiply-imaged by a massive galaxy in the foreground, provide direct measurements of cosmological distance that are very complementary to other cosmographic probes. The success of the technique depends on the availability and size of a suitable sample of lensed quasars or supernovae, precise measurements of the time delays, accurate modeling of the gravitational potential of the main deflector, and our ability to characterize the distribution of mass along the line of sight to the source. We review the progress made during the last 15 years, during which the first competitive cosmological inferences with time delays were made, and look ahead to the potential of significantly larger lens samples in the near future.

  14. Prediction of delayed subsidence

    Science.gov (United States)

    Burns, K.

    A predictive model of delayed subsidence is discussed. A numerical implementation is tested on one of the best-described study areas, Allegheny County in Pennsylvania. In planning insurance of restitution measures, a predictive model is of value in estimating the magnitude of the problem and the size of long-term budgetary commitments. Contrary to active subsidence, which occurs concurrently with mining operations, or is completed within a few days following coal extraction, delayed subsidence may take many years to appear at the surface after coal mines are abandoned. There are two principal morphological types of delayed subsidence: troughs, which are shallow depressions, and sinks, which are steep-sided crown pits. Both types are damaging to surface structures, and a variety of methods were introduced to deal with the problem, ranging from subsidence insurance to site restitution.

  15. Time delay cosmography

    Science.gov (United States)

    Treu, Tommaso; Marshall, Philip J.

    2016-07-01

    Gravitational time delays, observed in strong lens systems where the variable background source is multiply imaged by a massive galaxy in the foreground, provide direct measurements of cosmological distance that are very complementary to other cosmographic probes. The success of the technique depends on the availability and size of a suitable sample of lensed quasars or supernovae, precise measurements of the time delays, accurate modeling of the gravitational potential of the main deflector, and our ability to characterize the distribution of mass along the line of sight to the source. We review the progress made during the last 15 years, during which the first competitive cosmological inferences with time delays were made, and look ahead to the potential of significantly larger lens samples in the near future.

  16. Approximation of distributed delays

    CERN Document Server

    Lu, Hao; Eberard, Damien; Simon, Jean-Pierre

    2010-01-01

    We address in this paper the approximation problem of distributed delays. Such elements are convolution operators with kernel having bounded support, and appear in the control of time-delay systems. From the rich literature on this topic, we propose a general methodology to achieve such an approximation. For this, we enclose the approximation problem in the graph topology, and work with the norm defined over the convolution Banach algebra. The class of rational approximates is described, and a constructive approximation is proposed. Analysis in time and frequency domains is provided. This methodology is illustrated on the stabilization control problem, for which simulations results show the effectiveness of the proposed methodology.

  17. Genetics progress on atrioventricular septal defect%先天性房室间隔缺损的遗传学进展

    Institute of Scientific and Technical Information of China (English)

    李晓维

    2011-01-01

    先天性房室间隔缺损(atrioventricular sepial defect,AVSD)是一种常见的心血管畸形,由于存在房室间隔(房间隔下部、室间隔上部)以及中央心内膜垫组织的缺损,造成左右心腔之间的异常交通.虽然AVSD的胚胎学、病理生理学以及诊断和治疗目前都已基本阐明,但其确切的发病机制仍无突破性进展.随着分子生物学技术的广泛应用以及分子遗传学研究的深入开展,AVSD在遗传学的研究中取得一系列新进展,一些基因被证实与AVSD的发生发展存在一定的相关性.%Atrioventricular septal defect (AVSD) is a common cardiovascular malformation because of atrioventricular septal (lower atrial septum, ventricular septal upper) and the endocardial cushion defect,resulting in abnormal chambers of the heart. At the present, although the embryology, pathophysiology,diagnosis and treatment of the AVSD are clarified, but its precise pathogenesis has still no breakthrough progress.With the wide application of molecular biology and the depth research of molecular genetics, a series of new progress about AVSD has been made in the genetic study, and some genes are confirmed to be related to the occurrence and development of AVSD. The aim of this article is to review and discuss genetic mechanisms and related genes of AVSD, and to further identify the major genes causing AVSD.

  18. Application of dual-source CT in diagnosis of common atrioventricular canal%双源CT在共同房室通道诊断中的应用

    Institute of Scientific and Technical Information of China (English)

    冯越; 刘铁; 翟利浩

    2012-01-01

    目的 探讨双源CT(DSCT)在共同房室通道(CAC)诊断中的应用价值.方法 选取9例CAC患儿,采用DSCT心电门控下对比增强完成心脏检查,并在图像工作站完成多平面(MPR)、最大密度投影(MIP)和三维容积漫游(VR)处理.同期所有患儿均完成超声心动图检查.比较两种检查方法的诊断结果.结果 DSCT均作出CAC诊断,共发现合并畸形29处;超声心动图亦均作出CAC诊断,共发现合并畸形16处.结论 DSCT可以对CAC患儿作出准确诊断,较之超声心动图能发现更多合并畸形,有助于临床手术方案的制定与完善.%Objective To evaluate the clinical values of dual-source CT (DSCT) in diagnosis of common atrioventricular canal. Methods Nine children aged 135 days to 6 y with common atrioventricular canal (CAC) underwent dual-source cardiac CT scan. Two- and three-dimensional images were processed by means of MPR (coronal, sagital and oblique), MIP and VR. E-chocardiography was performed in all cases at same time; and 2 cases received surgical treatment. Results DSCT confirmed diagnosis of CAC in all 9 cases. DSCT revealed 29 concomitant anomalies and echocardiography revealed 16 in all 9 cases. Conclusion DSCT can confirm diagnosis of common atrioventricular canal, which contributes to the planning of operation and better surgical outcomes of patients.

  19. Solving quadratic programming problems by delayed projection neural network.

    Science.gov (United States)

    Yang, Yongqing; Cao, Jinde

    2006-11-01

    In this letter, the delayed projection neural network for solving convex quadratic programming problems is proposed. The neural network is proved to be globally exponentially stable and can converge to an optimal solution of the optimization problem. Three examples show the effectiveness of the proposed network.

  20. Delay Bounds for Multiclass FIFO

    OpenAIRE

    Jiang, Yuming; Misra, Vishal

    2016-01-01

    FIFO is perhaps the simplest scheduling discipline. For single-class FIFO, its delay guarantee performance has been extensively studied: The well-known results include a stochastic delay bound for $GI/GI/1$ by Kingman and a deterministic delay bound for $D/D/1$ by Cruz. However, for multiclass FIFO, few such results are available. To fill the gap, we prove delay bounds for multiclass FIFO in this work, considering both deterministic and stochastic cases. Specifically, delay bounds are present...

  1. Risk markers of late high-degree atrioventricular block in patients with left ventricular dysfunction after an acute myocardial infarction: a CARISMA substudy

    DEFF Research Database (Denmark)

    Gang, Uffe Jakob Ortved; Jøns, Christian; Jørgensen, Rikke Mørch;

    2011-01-01

    was documented in 28 (10%) patients during a median follow-up of 2.0 (0.4-2.0) years. Heart rate variability (HRV) measures and non-sustained ventricular tachycardia occurring at the week 6 Holter monitoring were highly predictive of HAVB. Power law slope .... An ILR was implanted for continuous arrhythmia surveillance. Risk stratification testing was performed at inclusion and 6 weeks after AMI. The tests included echocardiography, electrocardiogram (ECG), 24 h Holter monitoring, and an invasive electrophysiological study. High-degree atrioventricular block...

  2. Identification of a New Lamin A/C Mutation in a Chinese Family Affected with Atrioventricular Block as the Prominent Phenotype

    Institute of Scientific and Technical Information of China (English)

    吴小艳; 王擎; 桂乐; 刘木根; 张贤钦; 金润铭; 李伟; 闫露; 杜戎; 王秋芬; 祝建芳; 杨钧国

    2010-01-01

    Even though mutations in LMNA have been reported in patients with typical dilated cardio-myopathy(DCM)and atrioventricular block(AVB)previously,the purpose of this study was to disclose this novel genetic abnormality in one Chinese family with the atypical phenotype of progressive AVB followed by DCM with normal QRS interval.Genome-wide linkage analysis mapped the AVB gene in this family to a marker at chromosome 1q21.2,where the LMNA gene was located.Direct DNA sequence analysis revealed a heterozygous G t...

  3. Delayed breast implant reconstruction

    DEFF Research Database (Denmark)

    Hvilsom, Gitte B.; Hölmich, Lisbet R.; Steding-Jessen, Marianne;

    2012-01-01

    We evaluated the association between radiation therapy and severe capsular contracture or reoperation after 717 delayed breast implant reconstruction procedures (288 1- and 429 2-stage procedures) identified in the prospective database of the Danish Registry for Plastic Surgery of the Breast during...... reconstruction approaches other than implants should be seriously considered among women who have received radiation therapy....

  4. Delayed traumatic diaphragmatic hernia

    Science.gov (United States)

    Lu, Jing; Wang, Bo; Che, Xiangming; Li, Xuqi; Qiu, Guanglin; He, Shicai; Fan, Lin

    2016-01-01

    Abstract Background: Traumatic diaphragmatic hernias (TDHs) are sometimes difficult to identify at an early stage and can consequently result in diagnostic delays with life-threatening outcomes. It is the aim of this case study to highlight the difficulties encountered with the earlier detection of traumatic diaphragmatic hernias. Methods: Clinical data of patients who received treatment for delayed traumatic diaphragmatic hernias in registers of the First Affiliated Hospital of Xi’an Jiaotong University from 1998 to 2014 were analyzed retrospectively. Results: Six patients were included in this study. Left hemidiaphragm was affected in all of them. Most of the patients had a history of traffic accident and 1 a stab-penetrating injury. The interval from injury to developing symptoms ranged from 2 to 11 years (median 5 years). The hernial contents included the stomach, omentum, small intestine, and colon. Diaphragmatic injury was missed in all of them during the initial managements. All patients received operations once the diagnosis of delayed TDH was confirmed, and no postoperative mortality was detected. Conclusions: Delayed TDHs are not common, but can lead to serious consequences once occurred. Early detection of diaphragmatic injuries is crucial. Surgeons should maintain a high suspicion for injuries of the diaphragm in cases with abdominal or lower chest traumas, especially in the initial surgical explorations. We emphasize the need for radiographical follow-up to detect diaphragmatic injuries at an earlier stage. PMID:27512848

  5. 'No delays achiever'.

    Science.gov (United States)

    2007-05-01

    The latest version of the NHS Institute for Innovation and Improvement's 'no delays achiever', a web based tool created to help NHS organisations achieve the 18-week target for GP referrals to first treatment, is available at www.nodelaysachiever.nhs.uk.

  6. Delayed fluorescence in photosynthesis.

    Science.gov (United States)

    Goltsev, Vasilij; Zaharieva, Ivelina; Chernev, Petko; Strasser, Reto J

    2009-01-01

    Photosynthesis is a very efficient photochemical process. Nevertheless, plants emit some of the absorbed energy as light quanta. This luminescence is emitted, predominantly, by excited chlorophyll a molecules in the light-harvesting antenna, associated with Photosystem II (PS II) reaction centers. The emission that occurs before the utilization of the excitation energy in the primary photochemical reaction is called prompt fluorescence. Light emission can also be observed from repopulated excited chlorophylls as a result of recombination of the charge pairs. In this case, some time-dependent redox reactions occur before the excitation of the chlorophyll. This delays the light emission and provides the name for this phenomenon-delayed fluorescence (DF), or delayed light emission (DLE). The DF intensity is a decreasing polyphasic function of the time after illumination, which reflects the kinetics of electron transport reactions both on the (electron) donor and the (electron) acceptor sides of PS II. Two main experimental approaches are used for DF measurements: (a) recording of the DF decay in the dark after a single turnover flash or after continuous light excitation and (b) recording of the DF intensity during light adaptation of the photosynthesizing samples (induction curves), following a period of darkness. In this paper we review historical data on DF research and recent advances in the understanding of the relation between the delayed fluorescence and specific reactions in PS II. An experimental method for simultaneous recording of the induction transients of prompt and delayed chlorophyll fluorescence and decay curves of DF in the millisecond time domain is discussed.

  7. When good pigeons make bad decisions: Choice with probabilistic delays and outcomes.

    Science.gov (United States)

    Pisklak, Jeffrey M; McDevitt, Margaret A; Dunn, Roger M; Spetch, Marcia L

    2015-11-01

    Pigeons chose between an (optimal) alternative that sometimes provided food after a 10-s delay and other times after a 40-s delay and another (suboptimal) alternative that sometimes provided food after 10 s but other times no food after 40 s. When outcomes were not signaled during the delays, pigeons strongly preferred the optimal alternative. When outcomes were signaled, choices of the suboptimal alternative increased and most pigeons preferred the alternative that provided no food after the long delay despite the cost in terms of obtained food. The pattern of results was similar whether the short delays occurred on 25% or 50% of the trials. Shortening the 40-s delay to food sharply reduced suboptimal choices, but shortening the delay to no food had little effect. The results suggest that a signaled delay to no food does not punish responding in probabilistic choice procedures. The findings are discussed in terms of conditioned reinforcement by signals for good news.

  8. Effects of time delay on stochastic resonance of the stock prices in financial system

    Energy Technology Data Exchange (ETDEWEB)

    Li, Jiang-Cheng [Department of Physics, Yunnan University, Kunming, 650091 (China); Li, Chun [Department of Computer Science, Puer Teachers' College, Puer 665000 (China); Mei, Dong-Cheng, E-mail: meidch@ynu.edu.cn [Department of Physics, Yunnan University, Kunming, 650091 (China)

    2014-06-13

    The effect of time delay on stochastic resonance of the stock prices in finance system was investigated. The time delay is introduced into the Heston model driven by the extrinsic and intrinsic periodic information for stock price. The signal power amplification (SPA) was calculated by numerical simulation. The results indicate that an optimal critical value of delay time maximally enhances the reverse-resonance in the behaviors of SPA as a function of long-run variance of volatility or cross correlation coefficient between noises for both cases of intrinsic and extrinsic periodic information. Moreover, in both cases, being a critical value in the delay time, when the delay time takes value below the critical value, reverse-resonance increases with the delay time increasing, however, when the delay time takes value above the critical value, the reverse-resonance decrease with the delay time increasing. - Highlights: • The effects of delay time on stochastic resonance of the stock prices was investigated. • There is an optimal critical value of delay time maximally enhances the reverse-resonance • The reverse-resonance increases with the delay time increasing as the delay time takes value below the critical value • The reverse-resonance decrease with the delay time increasing as the delay time takes value above the critical value.

  9. Delay or anticipatory synchronization in one-way coupled systems using variable delay with reset

    Indian Academy of Sciences (India)

    G Ambika; R E Amritkar

    2011-11-01

    We present a mechanism for the synchronization of one-way coupled nonlinear systems in which the coupling uses a variable delay, that is reset at finite intervals. Here the delay varies in the same way as the system in time and so the coupling function remains constant for the reset interval at the end of which it is reset to the value at that time. This leads to a novel and discrete error dynamics and the resulting general stability analysis is applicable to chaotic or hyperchaotic systems. We apply this method to standard chaotic systems and hyperchaotic time delay systems. The results of the detailed numerical analysis agree with the results from stability analysis in both cases. This method has the advantage that it is cost-effective since information from the driving system is needed only at intervals of reset. Further, in the context of time delay systems, optimization among the different time-scales depending upon the application is possible due to the flexibility among the four different time-scales in our method, viz. delay in the driving system, anticipation in the response system, system delay time and reset time. We suggest a bi-channel scheme for implementing this method in communication field with enhanced security

  10. A novel stability criterion for interval time-delay chaotic systems via the evolutionary programming approach

    Energy Technology Data Exchange (ETDEWEB)

    Yan, J.-J. [Department of Computer and Communication, Shu-Te University, Kaohsiung 824, Taiwan (China)]. E-mail: jjyan@mail.stu.edu.tw; Hung, M.-L. [Department of Electrical Engineering, Far-East College, No. 49, Jung-Haw Road, Hsin-Shih Town, Tainan 744, Taiwan (China)

    2006-09-15

    This paper investigates a novel stability criterion for interval time-delay chaotic systems via the evolutionary programming (EP) approach. First a delay-dependent criterion is derived for ensuring the stability of degenerate time-delay systems, and then by solving eigenvalue location optimization problems, which will be defined later, the robust stability of interval time-delay systems can be guaranteed. An example is given to verify our method that yields less conservative results than those appeared in the literature.

  11. Antiarrhythmic properties of a rapid delayed-rectifier current activator in rabbit models of acquired long QT syndrome

    DEFF Research Database (Denmark)

    Diness, Thomas G; Yeh, Yung-Hsin; Qi, Xiao Yan;

    2008-01-01

    effect of a novel compound (NS1643) that activates the rapid delayed-rectifier K+ current, I(Kr), in two rabbit models of acquired LQTS. METHODS AND RESULTS: We used two clinically relevant in vivo rabbit models of TdP in which we infused NS1643 or vehicle: (i) three-week atrioventricular block...... with ventricular bradypacing; (ii) dofetilide-induced I(Kr) inhibition in methoxamine-sensitized rabbits. In addition, we studied effects on ionic currents in cardiomyocytes with I(Kr) suppressed by bradycardia remodelling or dofetilide exposure. Bradypaced rabbits developed QT interval prolongation, spontaneous...... ventricular ectopy, and TdP. Infusion of NS1643 completely suppressed arrhythmic activity and shortened the QT interval; vehicle had no effect. NS1643 also suppressed ventricular tachyarrhythmias caused by infusion of dofetilide to methoxamine-sensitized rabbits, and reversed dofetilide-induced QT...

  12. Radiofrequency catheter ablation of atrioventricular nodal reentrant tachycardia guided by magnetic navigation system: a prospective randomized comparison with conventional procedure

    Institute of Scientific and Technical Information of China (English)

    ZHANG Yu-xiao; LU Cai-yi; XUE Qiao; LI Ke; YAN Wei; ZHOU Sheng-hua

    2012-01-01

    Background Atrioventricular nodal reentrant tachycardia (AVNRT) is one of the most common paroxysmal supraventricular tachyarrhythmias.The aim of the study was to prospectively compare the characteristics of radiofrequency catheter ablation of AVNRT guided by a magnetic navigation system with the conventional procedure.Methods Patients with AVNRT diagnosed by electrophysiological tests were randomized into two groups.In the conventional technique group (CMT),a common 4-mm-tip quadrapolar temperature-controlled ablation catheter was used. In the magnetic navigation system guidance group (MNS), a magnetic 4-mm-tip quadrapolar temperature-controlled ablation catheter was used.The following parameters were collected and compared between the two groups: ablation procedure time,patient fluoroscopy time,operator fluoroscopy time,energy delivery numbers,maximal energy per deployment,success rate,complication rate and operative cost.Results Forty patients were enrolled and randomized into CMT and MNS groups.The age,gender,tachycardia history and basic cardiovascular diseases of the two groups were comparable (P >0.05).All procedures were conducted successfully without complications.No tachycardia recurred during the follow-up period of (9.3±2.6) months.In the MNS group,the patient and operator fluoroscopy times ((11.5±4.3) min,(4.2±1.5) min),energy delivery numbers (3.2±0.9),and maximal energy per deployment ((16.9±3.4) W) were shorter or lower than those of the CMT group ((14.3±6.2) min,(13.6±3.5) min,6.3±2.1,(23.7±1.3) W,respectively) (P <0.05).But the operative cost for the MNS group was higher than that of the CMT group (P <0.01 ).Conclusion Magnetic navigation system guided radiofrequency catheter ablation of AVNRT has the advantages of shorter fluoroscopy time and lower energy delivery numbers and maximal energy per deployment compared to the present conventional ablation technique.

  13. Agenesia de cava superior associada a bloqueio atrioventricular de 3º grau Agenesis of the right superior vena cava associated with total heart block

    Directory of Open Access Journals (Sweden)

    Gustavo J. Ventura Couto

    2008-03-01

    Full Text Available A persistência de veia cava superior esquerda com ausência da veia cava superior é uma anomalia rara, principalmente quando associada a bloqueio atrioventricular de 3º grau. Relatamos o caso de uma paciente, na qual durante implante de marca-passo definitivo, para a correção de bloqueio atrioventricular total, foi detectada presença de veia cava superior esquerda com suspeição de ausência de veia cava superior, o que levou ao emprego de técnica diferenciada para fixação do eletrodo ventricular. Para confirmação da provável agenesia, foram realizados diversos exames complementares de imagem, demonstrando-se a dificuldade no diagnóstico da síndrome aqui descrita.The superior left vena cava with the absent superior vena cava is a rare abnormality, especially when associated with total heart block. We report a case of a patient in which the presence of superior left vena cava and the absence of the superior vena cava was detected during the implantation of a pacemaker for the correction of a total heart block, which led us to use a different technique for the fixation of the ventricular electrode. To confirm the supposed absence, several image exams were made showing the difficulty on the diagnosis of the described syndrome.

  14. Complex phenotype linked to a mutation in exon 11 of the lamin A/C gene: Hypertrophic cardiomyopathy, atrioventricular block, severe dyslipidemia and diabetes.

    Science.gov (United States)

    Francisco, Ana Rita G; Santos Gonçalves, Inês; Veiga, Fátima; Mendes Pedro, Mónica; Pinto, Fausto J; Brito, Dulce

    2017-09-01

    The lamin A/C (LMNA) gene encodes lamins A and C, which have an important role in nuclear cohesion and chromatin organization. Mutations in this gene usually lead to the so-called laminopathies, the primary cardiac manifestations of which are dilated cardiomyopathy and intracardiac conduction defects. Some mutations, associated with lipodystrophy but not cardiomyopathy, have been linked to metabolic abnormalities such as diabetes and severe dyslipidemia. Herein we describe a new phenotype associated with a mutation in exon 11 of the LMNA gene: hypertrophic cardiomyopathy, atrioventricular block, severe dyslipidemia and diabetes. A 64-year-old woman with hypertrophic cardiomyopathy and a point mutation in exon 11 of the LMNA gene (c.1718C>T, Ser573Leu) presented with severe symptomatic ventricular hypertrophy and left ventricular outflow tract obstruction. She underwent septal alcohol ablation, followed by Morrow myectomy. The patient was also diagnosed with severe dyslipidemia, diabetes and obesity, and fulfilled diagnostic criteria for metabolic syndrome. No other characteristics of LMNA mutation-related phenotypes were identified. The development of type III atrioventricular block with no apparent cause, and mildly depressed systolic function, prompted referral for cardiac resynchronization therapy. In conclusion, the association between LMNA mutations and different phenotypes is complex and not fully understood, and can present with a broad spectrum of severity. Copyright © 2017 Sociedade Portuguesa de Cardiologia. Publicado por Elsevier España, S.L.U. All rights reserved.

  15. Delay-independent stabilization for teleoperation with time varying delay

    OpenAIRE

    Fujita, Hiroyuki; Namerikawa, Toru

    2009-01-01

    This paper deals with the stability for nonlinear teleoperation with time varying communication delays. The proposed method is passivity-based controllers with time varying gains which depend on the rate of change of time varying delay. In our proposed method, stability condition is independent of the magnitude of the communication delay and the damping of the system. The delay-independent stability is shown via Lyapunov stability methods. Several experimental results show the effectiveness o...

  16. [Striated and delayed nephrography].

    Science.gov (United States)

    Marlois, O; Padovani, J; Faure, F; Devred, P; Grangier, M L; Panuel, M

    1985-10-01

    About a case of striated and delayed nephrogram seen on a diabetic child, authors come back to the different etiologies. Among them, the tubular precipitation of Tamm-Horsfall protein seems to be given like on the right possibilities. Whatever is its etiology, the mechanism of striated appearance is always the same, being founded on the radiated disposal of the collecting ducts and on a tubular stasis beeing with iodine concentration.

  17. Theoretical Delay Time Distributions

    CERN Document Server

    Nelemans, Gijs; Bours, Madelon

    2012-01-01

    We briefly discuss the method of population synthesis to calculate theoretical delay time distributions of type Ia supernova progenitors. We also compare the results of the different research groups and conclude that although one of the main differences in the results for single degenerate progenitors is the retention efficiency with which accreted hydrogen is added to the white dwarf core, this cannot explain all the differences.

  18. Theoretical Delay Time Distributions

    Science.gov (United States)

    Nelemans, Gijs; Toonen, Silvia; Bours, Madelon

    2013-01-01

    We briefly discuss the method of population synthesis to calculate theoretical delay time distributions of Type Ia supernova progenitors. We also compare the results of different research groups and conclude that, although one of the main differences in the results for single degenerate progenitors is the retention efficiency with which accreted hydrogen is added to the white dwarf core, this alone cannot explain all the differences.

  19. Time-Delay Interferometry

    OpenAIRE

    Dhurandhar Sanjeev V.; Tinto Massimo

    2005-01-01

    Equal-arm interferometric detectors of gravitational radiation allow phase measurements many orders of magnitude below the intrinsic phase stability of the laser injecting light into their arms. This is because the noise in the laser light is common to both arms, experiencing exactly the same delay, and thus cancels when it is differenced at the photo detector. In this situation, much lower level secondary noises then set overall performance. If, however, the two arms have different lengths (...

  20. Delay in atomic photoionization

    CERN Document Server

    Kheifets, A S

    2010-01-01

    We analyze the time delay between emission of photoelectrons from the outer valence $ns$ and $np$ sub-shells in noble gas atoms following absorption of an attosecond XUV pulse. By solving the time dependent Schr\\"odinger equation and carefully examining the time evolution of the photoelectron wave packet, we establish the apparent "time zero" when the photoelectron leaves the atom. Various processes such as elastic scattering of the photoelectron on the parent ion and many-electron correlation affect the quantum phase of the dipole transition matrix element, the energy dependence of which defines the emission timing. This qualitatively explains the time delay between photoemission from the $2s$ and $2p$ sub-shells of Ne as determined experimentally by attosecond streaking [{\\em Science} {\\bf 328}, 1658 (2010)]. However, with our extensive numerical modeling, we were only able to account for less than a half of the measured time delay of $21\\pm5$~as. We argue that the XUV pulse alone cannot produce such a larg...

  1. Time-Delay Interferometry

    Directory of Open Access Journals (Sweden)

    Massimo Tinto

    2014-08-01

    Full Text Available Equal-arm detectors of gravitational radiation allow phase measurements many orders of magnitude below the intrinsic phase stability of the laser injecting light into their arms. This is because the noise in the laser light is common to both arms, experiencing exactly the same delay, and thus cancels when it is differenced at the photo detector. In this situation, much lower level secondary noises then set the overall performance. If, however, the two arms have different lengths (as will necessarily be the case with space-borne interferometers, the laser noise experiences different delays in the two arms and will hence not directly cancel at the detector. In order to solve this problem, a technique involving heterodyne interferometry with unequal arm lengths and independent phase-difference readouts has been proposed. It relies on properly time-shifting and linearly combining independent Doppler measurements, and for this reason it has been called time-delay interferometry (TDI. This article provides an overview of the theory, mathematical foundations, and experimental aspects associated with the implementation of TDI. Although emphasis on the application of TDI to the Laser Interferometer Space Antenna (LISA mission appears throughout this article, TDI can be incorporated into the design of any future space-based mission aiming to search for gravitational waves via interferometric measurements. We have purposely left out all theoretical aspects that data analysts will need to account for when analyzing the TDI data combinations.

  2. Delayed Speech or Language Development

    Science.gov (United States)

    ... to 2-Year-Old Delayed Speech or Language Development KidsHealth > For Parents > Delayed Speech or Language Development ... child is right on schedule. Normal Speech & Language Development It's important to discuss early speech and language ...

  3. Robotic reactions: delay-induced patterns in autonomous vehicle systems.

    Science.gov (United States)

    Orosz, Gábor; Moehlis, Jeff; Bullo, Francesco

    2010-02-01

    Fundamental design principles are presented for vehicle systems governed by autonomous cruise control devices. By analyzing the corresponding delay differential equations, it is shown that for any car-following model short-wavelength oscillations can appear due to robotic reaction times, and that there are tradeoffs between the time delay and the control gains. The analytical findings are demonstrated on an optimal velocity model using numerical continuation and numerical simulation.

  4. Delayed sequence intubation: is it ready for prime time?

    Science.gov (United States)

    Taylor, John A; Hohl, Corinne Michele

    2017-01-01

    Clinical question Does delayed sequence intubation (DSI) improve preoxygenation and safety when intubating otherwise uncooperative patients? Article chosen Weingart SD, Trueger S, Wong N, et al. Delayed sequence intubation: a prospective observational study. Ann Emerg Med 2015;65(4):349-55. doi:10.1016/j.annemergmed.2014.09.025 OBJECTIVE: To investigate whether the administration of ketamine 3 minutes prior to the administration of a muscle relaxant allows for optimal preoxygenation in uncooperative patients undergoing intubation.

  5. Robotic reactions: Delay-induced patterns in autonomous vehicle systems

    Science.gov (United States)

    Orosz, Gábor; Moehlis, Jeff; Bullo, Francesco

    2010-02-01

    Fundamental design principles are presented for vehicle systems governed by autonomous cruise control devices. By analyzing the corresponding delay differential equations, it is shown that for any car-following model short-wavelength oscillations can appear due to robotic reaction times, and that there are tradeoffs between the time delay and the control gains. The analytical findings are demonstrated on an optimal velocity model using numerical continuation and numerical simulation.

  6. Characteristics of delayed admission to stroke unit.

    Science.gov (United States)

    Silvestrelli, Giorgio; Parnetti, Lucilla; Tambasco, Nicola; Corea, Francesco; Capocchi, Giuseppe

    2006-01-01

    Early admission to stroke unit (SU) and factors that may cause admission delay represent relevant issues to obtain an optimal management of acute stroke. This study was aimed at recording timing from clinical onset to admission to our SU and to identify the reasons for delay. We prospectively examined acute stroke patients consecutively admitted to the Perugia SU. Baseline characteristics of stroke patients, stroke type and etiology, time from symptom onset to arrival in the SU were obtained from the Hospital-Based Perugia Stroke Registry. 60.8% of 2,213 consecutive stroke patients admitted to the SU arrived within 6 hrs and 39.2% after 6 hrs. Underestimation of symptoms was the cause of delay in 48.7% of cases. Younger age, especially for females, ischemic stroke, mild and/or unspecific symptoms and the underestimation of symptoms seem to be the main reasons for delayed arrival in the SU. To increase the proportion of stroke patients arriving in the SU within 3 hr of symptom onset, it is necessary to improve public and general practitioner awareness of stroke through educational programs.

  7. Delay Choice vs. Delay Maintenance: Different Measures of Delayed Gratification in Capuchin Monkeys (Cebus apella)

    Science.gov (United States)

    Addessi, Elsa; Paglieri, Fabio; Beran, Michael J.; Evans, Theodore A.; Macchitella, Luigi; De Petrillo, Francesca; Focaroli, Valentina

    2013-01-01

    Delaying gratification involves two components: (i) delay choice (selecting a delayed reward over an immediate one), and (ii) delay maintenance (sustaining the decision to delay gratification even if the immediate reward is available during the delay). In primates, two tasks most commonly have explored these components, the Intertemporal choice task and the Accumulation task. It is unclear whether these tasks provide equivalent measures of delay of gratification. Here, we compared the performance of the same capuchin monkeys, belonging to two study populations, between these tasks. We found only limited evidence of a significant correlation in performance. Consequently, in contrast to what is often assumed, our data provide only partial support to the hypothesis that these tasks provide equivalent measures of delay of gratification. PMID:23544770

  8. Delaying information search

    Directory of Open Access Journals (Sweden)

    Yaniv Shani

    2012-11-01

    Full Text Available In three studies, we examined factors that may temporarily attenuate information search. People are generally curious and dislike uncertainty, which typically encourages them to look for relevant information. Despite these strong forces that promote information search, people sometimes deliberately delay obtaining valuable information. We find they may do so when they are concerned that the information might interfere with future pleasurable activities. Interestingly, the decision to search or to postpone searching for information is influenced not only by the value and importance of the information itself but also by well-being maintenance goals related to possible detrimental effects that negative knowledge may have on unrelated future plans.

  9. Networked Control System Time-Delay Compensation Based on Time-Delay Prediction and Improved Implicit GPC

    Directory of Open Access Journals (Sweden)

    Zhong-Da Tian

    2015-01-01

    Full Text Available The random time delay in a networked control system can usually deteriorate the control performance and stability of the networked control system. In order to solve this problem, this paper puts forward a networked control system random time-delay compensation method based on time-delay prediction and improved implicit generalized predictive control (GPC. The least squares support vector machine is used to predict the future time delay of network. The parameters of the least squares support vector machine time-delay prediction model are difficult to determine, and the genetic algorithm is used for least squares support vector machine optimal prediction parameter optimization. Then, an improved implicit generalized predictive control method is adopted to compensate for the time delay. The simulation results show that the method in this paper has high prediction accuracy and a good compensation effect for the random time delay of the networked control system, has a small amount of on-line calculation and that the output response and control stability of the system are improved.

  10. Analysis of Onset Mechanisms of a Sphingosine 1-Phosphate Receptor Modulator Fingolimod-Induced Atrioventricular Conduction Block and QT-Interval Prolongation

    Energy Technology Data Exchange (ETDEWEB)

    Yagi, Yukihiro [Department of Pharmacology, Faculty of Medicine, Toho University, 5-21-16 Omori-nishi, Ota-ku, Tokyo 143–8540 (Japan); Pharmaceutical Research Center, Meiji Seika Pharma Co., Ltd., 760 Morooka-cho, Kohoku-ku, Yokohama, Kanagawa 222–8567 (Japan); Nakamura, Yuji [Department of Pharmacology, Faculty of Medicine, Toho University, 5-21-16 Omori-nishi, Ota-ku, Tokyo 143–8540 (Japan); Kitahara, Ken [Department of Pharmacology, Faculty of Medicine, Toho University, 5-21-16 Omori-nishi, Ota-ku, Tokyo 143–8540 (Japan); Division of Cardiovascular Medicine, Department of Internal Medicine, Faculty of Medicine, Toho University, 6-11-1 Omori-nishi, Ota-ku, Tokyo 143–8541 (Japan); Harada, Takuma [Department of Pharmacology, Faculty of Medicine, Toho University, 5-21-16 Omori-nishi, Ota-ku, Tokyo 143–8540 (Japan); Kato, Kazuhiko; Ninomiya, Tomohisa [Pharmaceutical Research Center, Meiji Seika Pharma Co., Ltd., 760 Morooka-cho, Kohoku-ku, Yokohama, Kanagawa 222–8567 (Japan); Cao, Xin [Department of Pharmacology, Faculty of Medicine, Toho University, 5-21-16 Omori-nishi, Ota-ku, Tokyo 143–8540 (Japan); Ohara, Hiroshi [Department of Pharmacology, Faculty of Medicine, Toho University, 5-21-16 Omori-nishi, Ota-ku, Tokyo 143–8540 (Japan); Division of Cardiovascular Medicine, Department of Internal Medicine, Faculty of Medicine, Toho University, 6-11-1 Omori-nishi, Ota-ku, Tokyo 143–8541 (Japan); Izumi-Nakaseko, Hiroko [Department of Pharmacology, Faculty of Medicine, Toho University, 5-21-16 Omori-nishi, Ota-ku, Tokyo 143–8540 (Japan); Suzuki, Kokichi [Pharmaceutical Research Center, Meiji Seika Pharma Co., Ltd., 760 Morooka-cho, Kohoku-ku, Yokohama, Kanagawa 222–8567 (Japan); Ando, Kentaro [Department of Pharmacology, Faculty of Medicine, Toho University, 5-21-16 Omori-nishi, Ota-ku, Tokyo 143–8540 (Japan); and others

    2014-11-15

    Fingolimod, a sphingosine 1-phosphate (S1P) receptor subtype 1, 3, 4 and 5 modulator, has been used for the treatment of patients with relapsing forms of multiple sclerosis, but atrioventricular conduction block and/or QT-interval prolongation have been reported in some patients after the first dose. In this study, we directly compared the electropharmacological profiles of fingolimod with those of siponimod, a modulator of sphingosine 1-phosphate receptor subtype 1 and 5, using in vivo guinea-pig model and in vitro human ether-a-go-go-related gene (hERG) assay to better understand the onset mechanisms of the clinically observed adverse events. Fingolimod (0.01 and 0.1 mg/kg) or siponimod (0.001 and 0.01 mg/kg) was intravenously infused over 10 min to the halothane-anaesthetized guinea pigs (n = 4), whereas the effects of fingolimod (1 μmol/L) and siponimod (1 μmol/L) on hERG current were examined (n = 3). The high doses of fingolimod and siponimod induced atrioventricular conduction block, whereas the low dose of siponimod prolonged PR interval, which was not observed by that of fingolimod. The high dose of fingolimod prolonged QT interval, which was not observed by either dose of siponimod. Meanwhile, fingolimod significantly inhibited hERG current, which was not observed by siponimod. These results suggest that S1P receptor subtype 1 in the heart could be one of the candidates for fingolimod- and siponimod-induced atrioventricular conduction block since S1P receptor subtype 5 is localized at the brain, and that direct I{sub Kr} inhibition may play a key role in fingolimod-induced QT-interval prolongation. - Highlights: • Fingolimod and siponimod are S1P{sub 1,3,4,5} and S1P{sub 1,5} receptor modulators, respectively. • Fingolimod and siponimod induced AV block in the halothane-anesthetized guinea pigs. • S1P{sub 1} in the hearts may be the target of fingolimod- and siponimod-induced AV block. • Fingolimod directly inhibited hERG current, which was not

  11. Fundamentals of Delayed Coking Joint Industry Project

    Energy Technology Data Exchange (ETDEWEB)

    Michael Volk; Keith Wisecarver

    2004-09-26

    is 2,937,439 barrels/calendar day. These cokers produce 154,607 tons of coke per day and delayed coking accounts for 88% of the world capacity. The delayed coking charge capacity in the United States is 1,787,860 b/cd. Despite its wide commercial use, only relatively few contractors and refiners are truly knowledgeable in delayed-coking design, so that this process carries with it a ''black art'' connotation. Until recently, the expected yield from cokers was determined by a simple laboratory test on the feedstock. As a result of Tulsa University's prior related research, a process model was developed that with additional work could be used to optimize existing delayed cokers over a wide range of potential feedstocks and operating conditions. The objectives of this research program are to: utilize the current micro, batch and pilot unit facilities at The University of Tulsa to enhance the understanding of the coking process; conduct additional micro and pilot unit tests with new and in-house resids and recycles to make current optimization models more robust; conduct focused kinetic experiments to enhance the furnace tube model and to enhance liquid production while minimizing sulfur in the products; conduct detailed foaming studies to optimize the process and minimize process upsets; quantify the parameters that affect coke morphology; and to utilize the knowledge gained from the experimental and modeling studies to enhance the computer programs developed in the previous JIP for optimization of the coking process. These refined computer models will then be tested against refinery data provided by the member companies. Novel concepts will also be explored for hydrogen sulfide removal of furnace gases as well as gas injection studies to reduce over-cracking.

  12. Fundamentals of Delayed Coking Joint Industry Project

    Energy Technology Data Exchange (ETDEWEB)

    Michael Volk; Keith Wisecarver

    2003-09-26

    is 2,937,439 barrels/calendar day. These cokers produce 154,607 tons of coke per day and delayed coking accounts for 88% of the world capacity. The delayed coking charge capacity in the United States is 1,787,860 b/cd. Despite its wide commercial use, only relatively few contractors and refiners are truly knowledgeable in delayed-coking design, so that this process carries with it a ''black art'' connotation. Until recently, the expected yield from cokers was determined by a simple laboratory test on the feedstock. As a result of Tulsa University's prior related research, a process model was developed that with additional work could be used to optimize existing delayed cokers over a wide range of potential feedstocks and operating conditions. The objectives of this research program are to: utilize the current micro, batch and pilot unit facilities at The University of Tulsa to enhance the understanding of the coking process; conduct additional micro and pilot unit tests with new and in-house resids and recycles to make current optimization models more robust; conduct focused kinetic experiments to enhance the furnace tube model and to enhance liquid production while minimizing sulfur in the products; conduct detailed foaming studies to optimize the process and minimize process upsets; quantify the parameters that affect coke morphology; and to utilize the knowledge gained from the experimental and modeling studies to enhance the computer programs developed in the previous JIP for optimization of the coking process. These refined computer models will then be tested against refinery data provided by the member companies. Novel concepts will also be explored for hydrogen sulfide removal of furnace gases as well as gas injection studies to reduce over-cracking.

  13. Pseudotumoral delayed cerebral radionecrosis

    Energy Technology Data Exchange (ETDEWEB)

    Ciaudo-Lacroix, C.; Lapresle, J. (Centre Hospitalier de Bicetre, 94 - Le Kremlin-Bicetre (France))

    1985-01-01

    A 60 year-old woman with a scalp epithelioma underwent radiotherapy, the dose being 57 Gray. A first epileptic seizure occurred twenty months later. Neurological examination revealed signs of left hemisphere involvement. ..gamma..EG, angiography, CT scans, demonstrated a pseudotumoral avascular process. On account of the localisation, the patient being right-handed, no surgical procedure was performed. In spite of corticotherapy and anticonvulsive treatment, seizures recurred and neurological signs slowly progressed. The patient died, 22 months after the first seizure, of an associated disseminated carcinoma with cachexia. Neuropathological examination showed a massive lesion presenting all the features of delayed radionecrosis in the left hemisphere: situated mainly in the white matter; numerous vascular abnormalities; wide-spread demyelination; disappearance of oligoglial cells. The Authors recall the clinical and anatomical aspects of this condition for which the only successful treatment is surgical removal when location and size of the lesion permit. Finally, the mechanisms which have been proposed to explain this delayed cerebral radionecrosis are discussed.

  14. Epidemiology of delayed ejaculation.

    Science.gov (United States)

    Di Sante, Stefania; Mollaioli, Daniele; Gravina, Giovanni Luca; Ciocca, Giacomo; Limoncin, Erika; Carosa, Eleonora; Lenzi, Andrea; Jannini, Emmanuele A

    2016-08-01

    A large body of literature on diminished ejaculatory disorders has been generated without the use of a clear diagnostic definition. Many studies have not distinguished between the orgasm and ejaculation disorders leading to doubtful results. Delayed ejaculation (DE) is one of the diminished ejaculatory disorders, which range from varying delays in ejaculatory latency to a complete inability to ejaculate. The present review is aimed at providing a comprehensive overview of the current knowledge on the definition and epidemiology of diminished ejaculatory disorders. We focus on the acquired diseases, such as benign prostatic hyperplasia (BPH) and specific drug regimens that may cause an iatrogenic form of ejaculatory disorder. In addition, the impact of aging is discussed since the prevalence of DE appears to be moderately but positively related to age. Finally, we also focus on the importance of the hormonal milieu on male ejaculation. To date, evidence on the endocrine control of ejaculation is derived from small clinical trials, but the evidence suggests that hormones modulate the ejaculatory process by altering its overall latency.

  15. Finite-Dimensional Representations for Controlled Diffusions with Delay

    Energy Technology Data Exchange (ETDEWEB)

    Federico, Salvatore, E-mail: salvatore.federico@unimi.it [Università di Milano, Dipartimento di Economia, Management e Metodi Quantitativi (Italy); Tankov, Peter, E-mail: tankov@math.univ-paris-diderot.fr [Université Paris Diderot, Laboratoire de Probabilités et Modèles Aléatoires (France)

    2015-02-15

    We study stochastic delay differential equations (SDDE) where the coefficients depend on the moving averages of the state process. As a first contribution, we provide sufficient conditions under which the solution of the SDDE and a linear path functional of it admit a finite-dimensional Markovian representation. As a second contribution, we show how approximate finite-dimensional Markovian representations may be constructed when these conditions are not satisfied, and provide an estimate of the error corresponding to these approximations. These results are applied to optimal control and optimal stopping problems for stochastic systems with delay.

  16. Stability and delay sensitivity of neutral fractional-delay systems

    Science.gov (United States)

    Xu, Qi; Shi, Min; Wang, Zaihua

    2016-08-01

    This paper generalizes the stability test method via integral estimation for integer-order neutral time-delay systems to neutral fractional-delay systems. The key step in stability test is the calculation of the number of unstable characteristic roots that is described by a definite integral over an interval from zero to a sufficient large upper limit. Algorithms for correctly estimating the upper limits of the integral are given in two concise ways, parameter dependent or independent. A special feature of the proposed method is that it judges the stability of fractional-delay systems simply by using rough integral estimation. Meanwhile, the paper shows that for some neutral fractional-delay systems, the stability is extremely sensitive to the change of time delays. Examples are given for demonstrating the proposed method as well as the delay sensitivity.

  17. Origem das artérias dos nós sinoatrial e atrioventricular em população do sul da Índia: um estudo angiográfico Origen de las arterias de los nódulos sinusal y atrioventricular en población del Sur de la India: un estudio angiográfico Origin of the sinoatrial and atrioventricular nodal arteries in South Indians: an angiographic study

    Directory of Open Access Journals (Sweden)

    Lakshmi Ramanathan

    2009-05-01

    Full Text Available FUNDAMENTO: Estudar o suprimento arterial do sistema condutor e sua correlação com a dominância das artérias coronárias em população do sul da Índia. OBJETIVO: Determinar angiograficamente as origens da artéria do nó sinoatrial (AnSA e artéria do nó atrioventricular (AnAV em indianos. MÉTODOS: O ESTudo incluiu 300 pacientes consecutivos (114 do sexo feminino e 186 do sexo masculino; idade média, 55 anos, habitantes da região costeira ao sul da Índia, submetidos a cineangiocoronariografia devido a sintomas como dor no peito, angina pectoris ou teste ergométrico positivo. As angiografias incluíram ambas as artérias coronárias (direita e esquerda em posição oblíqua anterior direita e esquerda. A origem da AnSA e AnAV a partir das artérias coronárias foi observada e correlacionada à dominância arterial. RESULTADOS: O nó SA (sinoatrial recebeu suprimento pela artéria coronária direita (ACD em 53% dos casos, pelo ramo circunflexo (Cx da artéria coronária esquerda (ACE em 42,66% dos casos, e em 4,33% dos casos esse nó foi irrigado por ambas as artérias coronárias. O nó AV (atrioventricular também recebeu suprimento sanguíneo com mais frequência da ACD (72,33% dos casos do que do ramo Cx da ACE (27,66%. Surpreendentemente, em nenhum caso este nó recebeu suprimento de ambas as artérias coronárias. CONCLUSÃO: Os Resultados do presente estudo podem auxiliar os cirurgiões cardíacos, sobretudo em cirurgias relacionadas a valvopatias, devido à franca proximidade entre os ramos nodais e o complexo valvar.FUNDAMENTO: Estudiar el suministro arterial del sistema conductor y su correlación con la dominancia de las arterias coronarias en población del Sur de la India. OBJETIVO: Determinar angiográficamente los orígenes de la arteria del nódulo sinusal (AnSA y la arteria del nódulo atrioventricular (AnAV en indios. MÉTODOS: El estudio incluyó 300 pacientes consecutivos (114 del sexo femenino y 186 del sexo

  18. Delayed onset of tricuspid valve flow in repaired tetralogy of Fallot: an additional mechanism of diastolic dysfunction and interventricular dyssynchrony

    Directory of Open Access Journals (Sweden)

    Benson Lee N

    2011-08-01

    Full Text Available Abstract Background Diastolic dysfunction of the right ventricle (RV is common after repair of tetralogy of Fallot. While restrictive physiology in late diastole has been well known, dysfunction in early diastole has not been described. The present study sought to assess the prevalence and mechanism of early diastolic dysfunction of the RV defined as delayed onset of the tricuspid valve (TV flow after TOF repair. Methods The study population consisted of 31 children with repaired TOF (mean age ± SD, 12.3 ± 4.1 years who underwent postoperative cardiovascular magnetic resonance (CMR. The CMR protocol included simultaneous phase-contrast velocity mapping of the atrioventricular valves, which enabled direct comparison of the timing and patterns of tricuspid (TV and mitral (MV valve flow. The TV flow was defined to have delayed onset when its onset was > 20 ms later than the onset of the MV flow. The TV and MV flow from 14 normal children was used for comparison. The CMR results were correlated with the findings on echocardiography and electrocardiography. Result Delayed onset of the TV flow was observed in 16/31 patients and in none of the controls. The mean delay time was 64.81 ± 27.07 ms (8.7 ± 3.2% of R-R interval. The delay time correlated with the differences in duration of the TV and MV flow (55.94 ± 32.88 ms (r = 0.90, p Conclusions Early diastolic dysfunction with delayed onset of TV flow is common after TOF repair, and is associated with reduced RV ejection fraction. It is a further manifestation of interventricular dyssynchrony and represent an additional mechanism of ventricular diastolic dysfunction.

  19. Beneficial and Adverse Effects of Electro-acupuncture Assessed in the Canine Chronic Atrio-ventricular Block Model Having Severe Hypertension and Chronic Heart Failure.

    Science.gov (United States)

    Cao, Xin; Lu, Shengfeng; Ohara, Hiroshi; Nakamura, Yuji; Izumi-Nakaseko, Hiroko; Ando, Kentaro; Zhu, Bingmei; Xu, Bin; Sugiyama, Atsushi

    2015-01-01

    Regarding the effects of electro-acupuncture for severe hypertension, we assessed its acute cardiovascular consequences with 4 subjects of the chronic atrioventricular block dogs having severe hypertension and chronic heart failure. The electro-acupuncture consisting of 2 mA at 2 Hz frequency was carried out for 30 min at Renying (ST-9) and Taichong (LR-3) every other day. Seven sessions were performed within 2 weeks. In the 1st and 7th sessions, the animals were anesthetized with pentobarbital to analyze the effects of the electro-acupuncture on cardiovascular variables. No significant change was detected in any of the basal control values of the cardiohemodynamic or electrophysiological variables between the 1st and 7th sessions. During the 1st session, electo-acupuncture produced a peak increase in mean blood pressure by 8.7% at 35 min (p hypertensive crisis at the beginning, clinicians have to pay attention on its use for patients with hypertension.

  20. Synchronizing time delay systems using variable delay in coupling

    Energy Technology Data Exchange (ETDEWEB)

    Ambika, G., E-mail: g.ambika@iiserpune.ac.in [Indian Institute of Science Education and Research, Pune 411 021 (India); Amritkar, R.E., E-mail: amritkar@prl.res.in [Physical Research Laboratory, Ahmedabad 380 009 (India)

    2011-11-15

    Highlights: > Delay and anticipation in coupling function varies with system dynamics. > Delay or anticipation of the synchronized state is independent of system delay. > Stability analysis developed is quite general. > We demonstrate enhanced security in communication. > Generalized synchronization possible over a wide range of parameter mismatch. - Abstract: We present a mechanism for synchronizing time delay systems using one way coupling with a variable delay in coupling that is reset at finite intervals. We present the analysis of the error dynamics that helps to isolate regions of stability of the synchronized state in the parameter space of interest for single and multiple delays. We supplement this by numerical simulations in a standard time delay system like Mackey Glass system. This method has the advantage that it can be adjusted to be delay or anticipatory in synchronization with a time which is independent of the system delay. We demonstrate the use of this method in communication using the bi channel scheme. We show that since the synchronizing channel carries information from transmitter only at intervals of reset time, it is not susceptible to an easy reconstruction.

  1. Small delay approximation of stochastic delay differential equations

    Science.gov (United States)

    Guillouzic, Steve; L'heureux, Ivan; Longtin, André

    1999-04-01

    Delay differential equations evolve in an infinite-dimensional phase space. In this paper, we consider the effect of external fluctuations (noise) on delay differential equations involving one variable, thus leading to univariate stochastic delay differential equations (SDDE's). For small delays, a univariate nondelayed stochastic differential equation approximating such a SDDE is presented. Another approximation, complementary to the first, is also obtained using an average of the SDDE's drift term over the delayed dynamical variable, which defines a conditional average drift. This second approximation is characterized by the fact that the diffusion term is identical to that of the original SDDE. For small delays, our approach yields a steady-state probability density and a conditional average drift which are in close agreement with numerical simulations of the original SDDE. We illustrate this scheme with the delayed linear Langevin equation and a stochastic version of the delayed logistic equation. The technique can be used with any type of noise, and is easily generalized to multiple delays.

  2. Delay tolerant networks

    CERN Document Server

    Gao, Longxiang; Luan, Tom H

    2015-01-01

    This brief presents emerging and promising communication methods for network reliability via delay tolerant networks (DTNs). Different from traditional networks, DTNs possess unique features, such as long latency and unstable network topology. As a result, DTNs can be widely applied to critical applications, such as space communications, disaster rescue, and battlefield communications. The brief provides a complete investigation of DTNs and their current applications, from an overview to the latest development in the area. The core issue of data forward in DTNs is tackled, including the importance of social characteristics, which is an essential feature if the mobile devices are used for human communication. Security and privacy issues in DTNs are discussed, and future work is also discussed.

  3. An all-optical time-delay relay based n a bacteriorhodopsin film

    Institute of Scientific and Technical Information of China (English)

    Chen Gui-Ying; Xu Xu-Xu; Zhang Chun-Ping; Qi Shen-Wen; Song Qi-Wang

    2008-01-01

    Using a special property of dynamic complementary-suppression-modulated transmission (DCSMT) in the bacteriorhodopsin (bR) film,we have demonstrated an all-optical time-delay relay.To extend our work,the relationship between the delay time of the all-optical time-delay relay and parameters of a bR film is numerically studied.We show how the delay time changes with the product of concentration and thickness (PCT) of a bR film.Furthermore,the shortest and longest delay times are given for the relay of 'switch off'.The saturable delay time and maximum delaytime of 'switch on' are also given.How the wavelengths (632.8,568,533 and 412 nm) and intensities of the illuminating light influence the delay time is also discussed.The simulation results are useful for optimizing the design of all-optical time-delay relays.

  4. A combination therapy protocol of plasmapheresis, intravenous immunoglobulins and betamethasone to treat anti-Ro/La-related congenital atrioventricular block. A case series and review of the literature.

    Science.gov (United States)

    Ruffatti, Amelia; Marson, Piero; Svaluto-Moreolo, Giorgio; Marozio, Luca; Tibaldi, Maria; Favaro, Maria; Calligaro, Antonia; Grava, Chiara; Hoxha, Ariela; Pengo, Vittorio; Punzi, Leonardo

    2013-05-01

    The aim of this report was to evaluate the efficacy and safety of a combined treatment protocol used to treat 2nd and 3rd degree anti-Ro/La-related congenital atrioventricular block (CAVB). Six consecutive women diagnosed with 2nd degree (three cases) or 3rd degree block (three cases) between 2009 and 2011 referred to our outpatient clinic underwent a combination therapy protocol composed of weekly plasmapheresis, fortnightly 1g/kg intravenous immunoglobulins (IVIG) and daily betamethasone (4mg/day) throughout pregnancy. IVIG (1g/kg) treatment in the neonates was begun at birth and administered every fifteen days until passive maternal antibodies became undetectable. The fetuses affected with 2nd degree block (cases 1, 2 and 3) reverted to a normal atrioventricular conduction after combined therapy, while those with a 3rd degree block remained stable (case 4), showed an increase in the ventricular rate (case 5) or an improvement in cardiac function (case 6). None of the fetuses with 3rd degree CAVB had other cardiac complications such as cardiomyopathy or fetal hydrops. The follow-up of the children affected with 2nd degree CAVB revealed a complete regression of the block in cases 1 and 3, and no signs of relevant worsening in case 2. The infants affected with 3rd degree block (cases 4, 5, and 6) remained stable and until now only one has required a pacemaker at the age of 10months. If these results are confirmed by large-scale studies, this protocol could lead to improved outcomes in the treatment of this devastating disease. Copyright © 2013 Elsevier B.V. All rights reserved.

  5. Treatment of delayed jejunal perforation after irreducible femoral hernia repair with open abdomen management and delayed abdominal closure with skin flap approximation

    Directory of Open Access Journals (Sweden)

    Fahri Yetişir

    2015-01-01

    Conclusion: Delayed bowel perforation may develop after irreducible femoral hernia surgery. OA management with NPT and DAC with skin flap approximation are optimal treatment modalities for the hemodynamically instable patient.

  6. ACTIVE CONTROL OF A FLEXIBLE CANTILEVER PLATE WITH MULTIPLE TIME DELAYS

    Institute of Scientific and Technical Information of China (English)

    Longxiang Chen; Ji Pan; Guoping Cai

    2008-01-01

    Active control of a flexible cantilever plate with multiple time delays is investigated using the discrete optimal control method.A controller with multiple time delays is presented.In this controller,time delay effect is incorporated in the mathematical model of the dynamic system throughout the control design and no approximations and assumptions are made in the controller derivation,so the system stability is easily guaranteed.Furthermore,this controller is available for both small time delays and large time delays.The feasibility and efficiency of the proposed controller are verified through numerical simulations in the end of this paper.

  7. On the Gravitomagnetic Time Delay

    OpenAIRE

    Ciufolini, I.; Kopeikin, S.; Mashhoon, B.; Ricci, F

    2002-01-01

    We study the gravitational time delay in ray propagation due to rotating masses in the linear approximation of general relativity. Simple expressions are given for the gravitomagnetic time delay that occurs when rays of radiation cross a slowly rotating shell and propagate in the field of a distant rotating source. Moreover, we calculate the local gravitational time delay in the Goedel universe. The observational consequences of these results in the case of weak gravitational lensing are disc...

  8. Demographic determinants of delayed divorce.

    Science.gov (United States)

    Chan, L Y; Heaton, T B

    1989-01-01

    This study identifies factors that predict delayed divorce in the US. The findings show that factors which influence marital stability in general also correlate with delayed divorce in the same direction. Wife's age at marriage, age of the youngest child, wife's religion, region of residence, and metropolitan residence have substantial effects of delayed divorce, but the effects of race, parental divorce, premarital pregnancy, and socioeconomic status are small.

  9. Location Estimation using Delayed Measurements

    DEFF Research Database (Denmark)

    Bak, Martin; Larsen, Thomas Dall; Nørgård, Peter Magnus

    1998-01-01

    When combining data from various sensors it is vital to acknowledge possible measurement delays. Furthermore, the sensor fusion algorithm, often a Kalman filter, should be modified in order to handle the delay. The paper examines different possibilities for handling delays and applies a new techn...... technique to a sensor fusion system for estimating the location of an autonomous guided vehicle. The system fuses encoder and vision measurements in an extended Kalman filter. Results from experiments in a real environment are reported...

  10. Concurrent Delay in Construction Disputes

    DEFF Research Database (Denmark)

    Cavaleri, Sylvie Cécile

    period of delay can potentially be attributed to several events falling within both parties' spheres of responsibility, commonly termed concurrent delay, is rarely regulated in construction contracts in spite of its common occurrence. This book analyses both the theoretical foundations and the practical......Delay is one of the issues most frequently encountered in today’s construction industry; it causes significant economic damage to all parties involved. Construction contracts, standard and bespoke, almost invariably consider delay from a perspective of single liability. If the event causing...

  11. Concurrent Delay in Construction Disputes

    DEFF Research Database (Denmark)

    Cavaleri, Sylvie Cécile

    Delay is one of the issues most frequently encountered in today’s construction industry; it causes significant economic damage to all parties involved. Construction contracts, standard and bespoke, almost invariably consider delay from a perspective of single liability. If the event causing...... period of delay can potentially be attributed to several events falling within both parties' spheres of responsibility, commonly termed concurrent delay, is rarely regulated in construction contracts in spite of its common occurrence. This book analyses both the theoretical foundations and the practical...

  12. Time-Delay Estimation in Dispersed Spectrum Cognitive Radio Systems

    Directory of Open Access Journals (Sweden)

    Celebi Hasari

    2010-01-01

    Full Text Available Time-delay estimation is studied for cognitive radio systems, which facilitate opportunistic use of spectral resources. A two-step approach is proposed to obtain accurate time-delay estimates of signals that occupy multiple dispersed bands simultaneously, with significantly lower computational complexity than the optimal maximum likelihood (ML estimator. In the first step of the proposed approach, an ML estimator is used for each band of the signal in order to estimate the unknown parameters of the signal occupying that band. Then, in the second step, the estimates from the first step are combined in various ways in order to obtain the final time-delay estimate. The combining techniques that are used in the second step are called optimal combining, signal-to-noise ratio (SNR combining, selection combining, and equal combining. It is shown that the performance of the optimal combining technique gets very close to the Cramer-Rao lower bound at high SNRs. These combining techniques provide various mechanisms for diversity combining for time-delay estimation and extend the concept of diversity in communications systems to the time-delay estimation problem in cognitive radio systems. Simulation results are presented to evaluate the performance of the proposed estimators and to verify the theoretical analysis.

  13. Receding horizon H∞ control for constrained time-delay systems

    Institute of Scientific and Technical Information of China (English)

    Lu Mei; Jin Chengbo; Shao Huihe

    2009-01-01

    A receding horizon H∞ control algorithm is presented for linear discrete time-delay system in the presence of constrained input and disturbances. Disturbance attenuation level is optimized at each time instant, and the receding optimization problem includes several linear matrix inequality constraints. When the convex hull is applied to denote the saturating input, the algorithm has better performance. The numerical example can verify this result.

  14. Resource Allocation for Delay Differentiated Traffic in Multiuser OFDM Systems

    CERN Document Server

    Tao, Meixia; Zhang, Fan

    2007-01-01

    Most existing work on adaptive allocation of subcarriers and power in multiuser orthogonal frequency division multiplexing (OFDM) systems has focused on homogeneous traffic consisting solely of either delay-constrained data (guaranteed service) or non-delay-constrained data (best-effort service). In this paper, we investigate the resource allocation problem in a heterogeneous multiuser OFDM system with both delay-constrained (DC) and non-delay-constrained (NDC) traffic. The objective is to maximize the sum-rate of all the users with NDC traffic while maintaining guaranteed rates for the users with DC traffic under a total transmit power constraint. Through our analysis we show that the optimal power allocation over subcarriers follows a multi-level water-filling principle; moreover, the valid candidates competing for each subcarrier include only one NDC user but all DC users. By converting this combinatorial problem with exponential complexity into a convex problem or showing that it can be solved in the dual...

  15. Optimally Stopped Optimization

    Science.gov (United States)

    Vinci, Walter; Lidar, Daniel A.

    2016-11-01

    We combine the fields of heuristic optimization and optimal stopping. We propose a strategy for benchmarking randomized optimization algorithms that minimizes the expected total cost for obtaining a good solution with an optimal number of calls to the solver. To do so, rather than letting the objective function alone define a cost to be minimized, we introduce a further cost-per-call of the algorithm. We show that this problem can be formulated using optimal stopping theory. The expected cost is a flexible figure of merit for benchmarking probabilistic solvers that can be computed when the optimal solution is not known and that avoids the biases and arbitrariness that affect other measures. The optimal stopping formulation of benchmarking directly leads to a real-time optimal-utilization strategy for probabilistic optimizers with practical impact. We apply our formulation to benchmark simulated annealing on a class of maximum-2-satisfiability (MAX2SAT) problems. We also compare the performance of a D-Wave 2X quantum annealer to the Hamze-Freitas-Selby (HFS) solver, a specialized classical heuristic algorithm designed for low-tree-width graphs. On a set of frustrated-loop instances with planted solutions defined on up to N =1098 variables, the D-Wave device is 2 orders of magnitude faster than the HFS solver, and, modulo known caveats related to suboptimal annealing times, exhibits identical scaling with problem size.

  16. Optimization and Optimal Control

    CERN Document Server

    Chinchuluun, Altannar; Enkhbat, Rentsen; Tseveendorj, Ider

    2010-01-01

    During the last four decades there has been a remarkable development in optimization and optimal control. Due to its wide variety of applications, many scientists and researchers have paid attention to fields of optimization and optimal control. A huge number of new theoretical, algorithmic, and computational results have been observed in the last few years. This book gives the latest advances, and due to the rapid development of these fields, there are no other recent publications on the same topics. Key features: Provides a collection of selected contributions giving a state-of-the-art accou

  17. Online Delay-Evaluation Control for Networked Control Systems

    Institute of Scientific and Technical Information of China (English)

    马向华; 魏震; 谢剑英

    2003-01-01

    This paper presented an evaluation approach of time delays for networked control systems (NCS). Animproved scheme based on optimal LQG control was designed to achieve desired performance despite the uncertaindelays in the system. The experimental results illustrate the effectiveness of the proposed control design and satis-factory performance of the closed-loop system.

  18. Control of delay dominant systems with costs related to switching

    DEFF Research Database (Denmark)

    Deng, Honglian; Larsen, Lars Finn Sloth; Stoustrup, Jakob

    2010-01-01

    The objective of this paper is to extend a novel low complexity method for optimizing switch control developed by the authors earlier to work with delay dominant systems and demonstrate that the method works in practice with a refrigeration test system. The extended method solves switching problems...

  19. Registration Delay and Student Performance

    Science.gov (United States)

    Siefken, Jason

    2017-01-01

    Tracking the difference between the time a first-year student is allowed to register for a course and the time he or she does register for a course (a student's registration delay), we notice a negative correlation between registration delay and final grade in a course. The difference between a student who registers within the first two minutes…

  20. 78 FR 59422 - Delayed Applications

    Science.gov (United States)

    2013-09-26

    ... Pipeline and Hazardous Materials Safety Administration Delayed Applications AGENCY: Office of Hazardous... applications delayed more than 180 days. SUMMARY: In accordance with the requirements of 49 U.S.C. 5117(c), PHMSA is publishing the following list of special permit applications that have been in process for 180...

  1. High resolution digital delay timer

    Science.gov (United States)

    Martin, Albert D.

    1988-01-01

    Method and apparatus are provided for generating an output pulse following a trigger pulse at a time delay interval preset with a resolution which is high relative to a low resolution available from supplied clock pulses. A first lumped constant delay (20) provides a first output signal (24) at predetermined interpolation intervals corresponding to the desired high resolution time interval. Latching circuits (26, 28) latch the high resolution data (24) to form a first synchronizing data set (60). A selected time interval has been preset to internal counters (142, 146, 154) and corrected for circuit propagation delay times having the same order of magnitude as the desired high resolution. Internal system clock pulses (32, 34) count down the counters to generate an internal pulse delayed by an interval which is functionally related to the preset time interval. A second LCD (184) corrects the internal signal with the high resolution time delay. A second internal pulse is then applied to a third LCD (74) to generate a second set of synchronizing data (76) which is complementary with the first set of synchronizing data (60) for presentation to logic circuits (64). The logic circuits (64) further delay the internal output signal (72) to obtain a proper phase relationship of an output signal (80) with the internal pulses (32, 34). The final delayed output signal (80) thereafter enables the output pulse generator (82) to produce the desired output pulse (84) at the preset time delay interval following input of the trigger pulse (10, 12).

  2. Calibrating for Ionospheric Phase Delays

    Science.gov (United States)

    Macdoran, P. F.

    1985-01-01

    Technique determines ionospheric phase delay on real-time universally applicable basis in terms of electrons per meter squared by coherently modulating two L-band carrier frequencies received from two Global Positioning System satelites. Two pseudorandom number sequences cross-correlated to derive delay time.

  3. #FakeNobelDelayReasons

    CERN Multimedia

    2013-01-01

    Tuesday’s hour-long delay of the Nobel Prize in Physics announcement was (and still is) quite the cause for speculation. But on the Twittersphere, it was simply the catalyst for some fantastic puns, so-bad-they're-good physics jokes and other shenanigans. Here are some of our favourite #FakeNobelDelayReasons.    

  4. Imitation dynamics with time delay.

    Science.gov (United States)

    Wang, Shi-Chang; Yu, Jie-Ru; Kurokawa, Shun; Tao, Yi

    2017-05-07

    Based on the classic imitation dynamics (Hofbauer and Sigmund, 1998, Evolutionary Games and Population Dynamics, Cambridge University Press), the imitation dynamics with time delay is investigated, where the probability that an individual will imitate its opponent's own strategy is assumed to depend on the comparison between the past expected payoff of this individual's own strategy and the past expected payoff of its opponent's own strategy, i.e. there is a time delay effect. For the two-phenotype model, we show that if the system has an interior equilibrium and this interior equilibrium is stable when there is no time delay, then there must be a critical value of time delay such that the system tends to a stable periodic solution when the time delay is larger than the critical value. On the other hand, for three-phenotype (rock-scissors-paper) model, the numerical analysis shows that for the stable periodic solution induced by the time delay, the amplitude and the period will increase with the increase of the time delay. These results should help to understand the evolution of behavior based on the imitation dynamics with time delay. Copyright © 2017 Elsevier Ltd. All rights reserved.

  5. Magnetic bearing optical delay line

    NARCIS (Netherlands)

    Dool, T.C. van den; Kamphues, F.G.; Fouss, B.; Henrioulle, K.; Hogenhuis, H.

    2004-01-01

    TNO TPD, in close cooperation with Micromega-Dynamics and Dutch Space, has developed an advanced Optical Delay Line (ODL) for use in PRIMA, GENIE and other ground based interferometers. The delay line design is modular and flexible, which makes scaling for other applications a relatively easy task.

  6. Autaptic self-feedback-induced synchronization transitions in Newman-Watts neuronal network with time delays

    Science.gov (United States)

    Wang, Qi; Gong, Yubing; Wu, Yanan

    2015-04-01

    Autapse is a special synapse that connects a neuron to itself. In this work, we numerically study the effect of chemical autapse on the synchronization of Newman-Watts Hodgkin-Huxley neuron network with time delays. It is found that the neurons exhibit synchronization transitions as autaptic self-feedback delay is varied, and the phenomenon enhances when autaptic self-feedback strength increases. Moreover, this phenomenon becomes strongest when network time delay or coupling strength is optimal. It is also found that the synchronization transitions by network time delay can be enhanced by autaptic activity and become strongest when autaptic delay is optimal. These results show that autaptic delayed self-feedback activity can intermittently enhance and reduce the synchronization of the neuronal network and hence plays an important role in regulating the synchronization of the neurons. These findings could find potential implications for the information processing and transmission in neural systems.

  7. Delay-enhanced coherence of spiral waves in noisy Hodgkin-Huxley neuronal networks

    Energy Technology Data Exchange (ETDEWEB)

    Wang Qingyun [State Key Laboratory for Turbulence and Complex Systems, Department of Mechanics and Aerospace Engineering, College of Engineering, Peking University, Beijing 100871 (China) and School of Statistics and Mathematics, Inner Mongolia Finance and Economics College, Huhhot 010051 (China)], E-mail: nmqingyun@163.com; Perc, Matjaz [Department of Physics, Faculty of Natural Sciences and Mathematics, University of Maribor, Koroska cesta 160, SI-2000 Maribor (Slovenia); Duan Zhisheng [State Key Laboratory for Turbulence and Complex Systems, Department of Mechanics and Aerospace Engineering, College of Engineering, Peking University, Beijing 100871 (China); Chen Guanrong [State Key Laboratory for Turbulence and Complex Systems, Department of Mechanics and Aerospace Engineering, College of Engineering, Peking University, Beijing 100871 (China); Department of Electronic Engineering, City University of Hong Kong, Hong Kong (China)

    2008-08-25

    We study the spatial dynamics of spiral waves in noisy Hodgkin-Huxley neuronal ensembles evoked by different information transmission delays and network topologies. In classical settings of coherence resonance the intensity of noise is fine-tuned so as to optimize the system's response. Here, we keep the noise intensity constant, and instead, vary the length of information transmission delay amongst coupled neurons. We show that there exists an intermediate transmission delay by which the spiral waves are optimally ordered, hence indicating the existence of delay-enhanced coherence of spatial dynamics in the examined system. Additionally, we examine the robustness of this phenomenon as the diffusive interaction topology changes towards the small-world type, and discover that shortcut links amongst distant neurons hinder the emergence of coherent spiral waves irrespective of transmission delay length. Presented results thus provide insights that could facilitate the understanding of information transmission delay on realistic neuronal networks.

  8. Time-delay damping theory

    Institute of Scientific and Technical Information of China (English)

    洪峰

    2002-01-01

    In this paper, existing damping theories are briefly reviewed. On the basis of the existing damping theories, a new kind of damping theory, i.e., the time-delay damping theory, is developed. In the time-delay damping theory, the damping force is considered to be directly proportional to the increment of displacement. The response analysis of an SDOF time-delay damping system is carried out, and the methods for obtaining the solution for a time-delay damping system in the time domain as well as the frequency domain are given. The comparison between results from different damping theories shows that the time-delay damping theory is both reasonable and convenient.

  9. Asynchronous Bounded Expected Delay Networks

    CERN Document Server

    Bakhshi, Rena; Fokkink, Wan; Pang, Jun

    2010-01-01

    The commonly used asynchronous bounded delay (ABD) network models assume a fixed bound on message delay. We propose a probabilistic network model, called asynchronous bounded expected delay (ABE) model. Instead of a strict bound, the ABE model requires only a bound on the expected message delay. While the conditions of ABD networks restrict the set of possible executions, in ABE networks all asynchronous executions are possible, but executions with extremely long delays are less probable. In contrast to ABD networks, ABE networks cannot be synchronised efficiently. At the example of an election algorithm, we show that the minimal assumptions of ABE networks are sufficient for the development of efficient algorithms. For anonymous, unidirectional ABE rings of known size N we devise a probabilistic leader election algorithm having average message and time complexity O(N).

  10. Fundamentals of Delayed Coking Joint Industry Project

    Energy Technology Data Exchange (ETDEWEB)

    Michael Volk Jr; Keith Wisecarver

    2005-10-01

    is 2,937,439 barrels/calendar day. These cokers produce 154,607 tons of coke per day and delayed coking accounts for 88% of the world capacity. The delayed coking charge capacity in the United States is 1,787,860 b/cd. Despite its wide commercial use, only relatively few contractors and refiners are truly knowledgeable in delayed-coking design, so that this process carries with it a ''black art'' connotation. Until recently, the expected yield from cokers was determined by a simple laboratory test on the feedstock. As a result of Tulsa University's prior related research, a process model was developed that with additional work could be used to optimize existing delayed cokers over a wide range of potential feedstocks and operating conditions. The objectives of this research program are to: utilize the current micro, batch and pilot unit facilities at The University of Tulsa to enhance the understanding of the coking process; conduct additional micro and pilot unit tests with new and in-house resids and recycles to make current optimization models more robust; conduct focused kinetic experiments to enhance the furnace tube model and to enhance liquid production while minimizing sulfur in the products; conduct detailed foaming studies to optimize the process and minimize process upsets; quantify the parameters that affect coke morphology; and to utilize the knowledge gained from the experimental and modeling studies to enhance the computer programs developed in the previous JIP for optimization of the coking process. These refined computer models will then be tested against refinery data provided by the member companies. Novel concepts will also be explored for hydrogen sulfide removal of furnace gases as well as gas injection studies to reduce over-cracking. The following deliverables are scheduled from the two projects of the three-year JIP: (1) A novel method for enhancing liquid yields from delayed cokers and data that provide insight as to

  11. Experimental study of delayed positive feedback control for a flexible beam

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    Recently, some researches indicate that positive feedback can benefit the control if appropriate time delay is intentionally introduced into control system. However, most work is theoretical one but few are experimental. This paper presents theoretical and experimental studies of delayed positive feedback control technique using a flexible beam as research object. The positive feedback weighting coefficient is designed by using the optimal control method. The available time delay is determined by analyzing ...

  12. New asymptotic stability criteria for neural networks with time-varying delay

    Energy Technology Data Exchange (ETDEWEB)

    Tian Junkang, E-mail: tianjunkang1980@163.co [School of Sciences, Southwest Petroleum University, Chengdu, Sichuan 610500 (China); Xie Xiangjun [School of Sciences, Southwest Petroleum University, Chengdu, Sichuan 610500 (China)

    2010-02-01

    The problem of delay-dependent asymptotic stability criteria for neural networks with time-varying delay is investigated. A new class of Lyapunov functional is constructed to derive some new delay-dependent stability criteria.The obtained criterion are less conservative because free-weighting matrices method and a convex optimization approach are considered. Finally, numerical examples are given to demonstrate the effectiveness of the proposed method.

  13. Delayed radiation neuropathy

    Energy Technology Data Exchange (ETDEWEB)

    Nagashima, T.; Miyamoto, K.; Beppu, H.; Hirose, K.; Yamada, K. (Tokyo Metropolitan Neurological Hospital (Japan))

    1981-07-01

    A case of cervical plexus neuropathy was reported in association with chronic radio-dermatitis, myxedema with thyroid adenoma and epiglottic tumor. A 38-year-old man has noticed muscle weakness and wasting of the right shoulder girdle since age 33. A detailed history taking revealed a previous irradiation to the neck because of the cervical lymphadenopathy at age 10 (X-ray 3,000 rads), keroid skin change at age 19, obesity and edema since 26, and hoarseness at 34. Laryngoscopic examination revealed a tumor on the right vocal cord, diagnosed as benign papilloma by histological study. In addition, there were chronic radio-dermatitis around the neck, primary hypothyroidism with a benign functioning adenoma on the right lobe of the thyroid, the right phrenic nerve palsy and the right recurrent nerve palsy. All these lesions were considered to be the late sequellae of radiation to the neck in childhood. Other neurological signs were weakness and amyotrophy of the right shoulder girdle with patchy sensory loss, and areflexia of the right arm. Gross power was fairly well preserved in the right hand. EMG showed neurogenic changes in the tested muscles, suggesting a peripheral nerve lesion. Nerve conduction velocities were normal. No abnormal findings were revealed by myelography and spinal CT. The neurological findings of the patient were compatible with the diagnosis of middle cervical plexus palsy apparently due to late radiation effect. In the literature eight cases of post-radiation neuropathy with a long latency have been reported. The present case with the longest latency after the radiation should be included in the series of the reported cases of ''delayed radiation neuropathy.'' (author).

  14. Effect of spike-timing-dependent plasticity on coherence resonance and synchronization transitions by time delay in adaptive neuronal networks

    Science.gov (United States)

    Xie, Huijuan; Gong, Yubing; Wang, Qi

    2016-06-01

    In this paper, we numerically study how time delay induces multiple coherence resonance (MCR) and synchronization transitions (ST) in adaptive Hodgkin-Huxley neuronal networks with spike-timing dependent plasticity (STDP). It is found that MCR induced by time delay STDP can be either enhanced or suppressed as the adjusting rate Ap of STDP changes, and ST by time delay varies with the increase of Ap, and there is optimal Ap by which the ST becomes strongest. It is also found that there are optimal network randomness and network size by which ST by time delay becomes strongest, and when Ap increases, the optimal network randomness and optimal network size increase and related ST is enhanced. These results show that STDP can either enhance or suppress MCR and optimal STDP can enhance ST induced by time delay in the adaptive neuronal networks. These findings provide a new insight into STDP's role for the information processing and transmission in neural systems.

  15. Clinical significance of late high-degree atrioventricular block in patients with left ventricular dysfunction after an acute myocardial infarction--a Cardiac Arrhythmias and Risk Stratification After Acute Myocardial Infarction (CARISMA) substudy

    DEFF Research Database (Denmark)

    Gang, Uffe Jakob Ortved; Jøns, Christian; Jørgensen, Rikke Mørch;

    2011-01-01

    High-degree atrioventricular block (HAVB) is a frequent complication in the acute stages of a myocardial infarction associated with an increased rate of mortality. However, the incidence and clinical significance of HAVB in late convalescent phases of an AMI is largely unknown. The aim of this st......High-degree atrioventricular block (HAVB) is a frequent complication in the acute stages of a myocardial infarction associated with an increased rate of mortality. However, the incidence and clinical significance of HAVB in late convalescent phases of an AMI is largely unknown. The aim...... of this study was to assess the incidence and prognostic value of late HAVB documented by continuous electrocardiogram (ECG) monitoring in post-AMI patients with reduced left ventricular function....

  16. Simultaneous conduction over the fast and slow pathways during induction of atrioventricular nodal reentrant arrhythmia with a rate of less than 100 bpm and infra-His block after radiofrequency ablation of the slow pathway.

    Science.gov (United States)

    Amasyalı, Basri; Köktürk, Bülent; Otomo, Kiyoshi; Köse, Sedat

    2011-04-01

    Atrioventricular nodal reentrant tachycardia (AVNRT) is the most common form of paroxysmal regular supraventricular tachycardia in adults. It is typically induced with an anterograde block over the fast pathway (FP) and conduction over the slow pathway (SP), with subsequent retrograde conduction over the FP. Rarely, a simultaneous conduction of a premature atrial complex occurs over the FP and SP to induce AVNRT and is called "one for two phenomenon". We present a 46-year-old woman with atrioventricular nodal rhythm with a rate of 95 beats per minute with distinct electrophysiological characteristics showing simultaneous conduction over the FP and SP during induction of tachycardia and an infra-His block after radiofrequency ablation of the SP.

  17. Bloqueo aurículo-ventricular familiar progresivo tipo I: descripción clínica de una familia Progressive familial atrio-ventricular block type I: clinical description of a family

    Directory of Open Access Journals (Sweden)

    Guillermo Mora

    2011-10-01

    Full Text Available Se presenta el caso de una familia con bloqueo aurículo-ventricular, que compromete varias generaciones, con herencia mendeliana autosómica dominante, que afecta de manera progresiva el sistema de conducción cardiaco llevando a síncope y muerte súbita en edades tempranas. Esta entidad corresponde al bloqueo familiar cardiaco progresivo tipo I, descrito principalmente en Suráfrica. El tratamiento con marcapaso definitivo fue exitoso.We present the case of a family with atrio-ventricular block that involves several generations, with dominant autosomal mendelian inheritance that progressively affects the cardiac conduction system leading to syncope and sudden death in early life. This entity corresponds to progressive familial atrio-ventricular block type I, described mainly in South Africa . Treatment with permanent pacemaker therapy was successful.

  18. Multi-net optimization of VLSI interconnect

    CERN Document Server

    Moiseev, Konstantin; Wimer, Shmuel

    2015-01-01

    This book covers layout design and layout migration methodologies for optimizing multi-net wire structures in advanced VLSI interconnects. Scaling-dependent models for interconnect power, interconnect delay and crosstalk noise are covered in depth, and several design optimization problems are addressed, such as minimization of interconnect power under delay constraints, or design for minimal delay in wire bundles within a given routing area. A handy reference or a guide for design methodologies and layout automation techniques, this book provides a foundation for physical design challenges of interconnect in advanced integrated circuits.  • Describes the evolution of interconnect scaling and provides new techniques for layout migration and optimization, focusing on multi-net optimization; • Presents research results that provide a level of design optimization which does not exist in commercially-available design automation software tools; • Includes mathematical properties and conditions for optimal...

  19. An improved heuristic for one-machine scheduling with delays constraints

    Institute of Scientific and Technical Information of China (English)

    杜东雷; 韩继业; 陈礴

    1997-01-01

    An improved heuristic is proposed for one-machine scheduling problem with delay constraints,thus an open problem raised by Wikum et al.is solved.The heuristic solves the corresponding unit-execution-time problem optimally.

  20. Delayed High-dose Methotrexate Excretion and Influencing Factors in Osteosarcoma Patients

    Directory of Open Access Journals (Sweden)

    Wei Zhang

    2016-01-01

    Conclusions: Precaution of delayed excretion of MTX is needed during osteosarcoma treatment using HD-MTX. An optimal individualized rescue strategy can be created with consideration of gender, age, and C24 h.

  1. Clinical significance of late high-degree atrioventricular block in patients with left ventricular dysfunction after an acute myocardial infarction--a Cardiac Arrhythmias and Risk Stratification After Acute Myocardial Infarction (CARISMA) substudy

    DEFF Research Database (Denmark)

    Gang, Uffe Jakob Ortved; Jøns, Christian; Jørgensen, Rikke Mørch;

    2011-01-01

    High-degree atrioventricular block (HAVB) is a frequent complication in the acute stages of a myocardial infarction associated with an increased rate of mortality. However, the incidence and clinical significance of HAVB in late convalescent phases of an AMI is largely unknown. The aim of this st...... of this study was to assess the incidence and prognostic value of late HAVB documented by continuous electrocardiogram (ECG) monitoring in post-AMI patients with reduced left ventricular function....

  2. FPGA adders: performance evaluation and optimal design

    OpenAIRE

    Xing, S.; Yu, WWH

    1998-01-01

    Delay models and cost analyses developed for ASIC technology are not useful in designing and implementing FPGA devices. The authors discuss costs and operational delays of fixed-point adders on Xilinx 4000 series devices and propose timing models and optimization schemes for carry-skip and carry-select adders.

  3. Time Delay in Molecular Photoionization

    CERN Document Server

    Hockett, P; Villeneuve, D M; Corkum, P B

    2015-01-01

    Time-delays in the photoionization of molecules are investigated. As compared to atomic ionization, the time-delays expected from molecular ionization present a much richer phenomenon, with a strong spatial dependence due to the anisotropic nature of the molecular scattering potential. We investigate this from a scattering theory perspective, and make use of molecular photoionization calculations to examine this effect in representative homonuclear and hetronuclear diatomic molecules, nitrogen and carbon monoxide. We present energy and angle-resolved maps of the Wigner delay time for single-photon valence ionization, and discuss the possibilities for experimental measurements.

  4. A new efficient method for solving delay differential equations and a comparison with other methods

    Science.gov (United States)

    Bildik, Necdet; Deniz, Sinan

    2017-01-01

    In this paper, a new analytical technique, namely the optimal perturbation iteration method, is presented and applied to delay differential equations to find an efficient algorithm for their approximate solutions. Effectiveness of this method is tested by various examples of linear and nonlinear problems of delay differential equations. Obtained results reveal that optimal perturbation iteration algorithm is very effective, easy to use and simple to perform.

  5. Advances in fetal immune mediated atrioventricular block%胎儿免疫性房室传导阻滞研究进展

    Institute of Scientific and Technical Information of China (English)

    严华林; 李一飞(综述); 周开宇; 华益民(审校)

    2015-01-01

    Fetal atrioventricular block (AVB) is a type of fetal bradyarrhythmias. The reported incidence of fetal complete atrioventricular block (CAVB) and mortality of perinatal fetuses and neonates are signiifcantly higher in pregnancies of anti-SSA/Ro-positive mothers than that of anti-SSA/Ro-negative mothers. The auto-antibodies in maternal serum that can be transported into fetal circulation through placenta may damage fetal cardiac conductive system and eventually result in fetal AVB. There are evidences that early diagnosis and proper treatment can improve the prognosis and survival rate of affected fetuses. In this article, the pathogenesis, risk factors, prenatal diagnosis, treatment and prognosis of fetal immune mediated AVB is reviewed.%胎儿房室传导阻滞属于胎儿缓慢性心律失常。当母体血清抗-SSA/Ro、抗-SSB/La抗体阳性时,胎儿完全性房室传导阻滞发病率和相关围生期胎儿/新生儿死亡率显著升高。母体血清自身抗体可经胎盘转运进入胎儿体内,可能导致胎儿心脏传导系统免疫损伤,从而引起房室传导阻滞发生。如果能进行胎儿免疫性房室传导阻滞的早期诊断和及时干预,可能阻止病情进展,改善免疫性房室传导阻滞胎儿的预后并提高其生存率。文章综述胎儿免疫性房室传导阻滞的发病机制、危险因素、产前诊断、胎儿期干预及预后等。

  6. Leibniz Dynamics with Time Delay

    OpenAIRE

    Albu, I. D.; Opris, D.

    2005-01-01

    In this paper we show that several dynamical systems with time delay can be described as vector fields associated to smooth functions via a bracket of Leibniz structure. Some examples illustrate the theoretical considerations.

  7. Delays and networked control systems

    CERN Document Server

    Hetel, Laurentiu; Daafouz, Jamal; Johansson, Karl

    2016-01-01

    This edited monograph includes state-of-the-art contributions on continuous time dynamical networks with delays. The book is divided into four parts. The first part presents tools and methods for the analysis of time-delay systems with a particular attention on control problems of large scale or infinite-dimensional systems with delays. The second part of the book is dedicated to the use of time-delay models for the analysis and design of Networked Control Systems. The third part of the book focuses on the analysis and design of systems with asynchronous sampling intervals which occur in Networked Control Systems. The last part of the book exposes several contributions dealing with the design of cooperative control and observation laws for networked control systems. The target audience primarily comprises researchers and experts in the field of control theory, but the book may also be beneficial for graduate students. .

  8. A Kac CROW Delay Line

    CERN Document Server

    Sumetsky, M

    2013-01-01

    A low-loss CROW delay line with a weak inter-resonator coupling determined by the Kac matrix is dispersionless and can be easily impedance-matched by adjusting the coupling to the input/output waveguide.

  9. Systematics in delayed neutron yields

    Energy Technology Data Exchange (ETDEWEB)

    Ohsawa, Takaaki [Kinki Univ., Higashi-Osaka, Osaka (Japan). Atomic Energy Research Inst.

    1998-03-01

    An attempt was made to reproduce the systematic trend observed in the delayed neutron yields for actinides on the basis of the five-Gaussian representation of the fission yield together with available data sets for delayed neutron emission probability. It was found that systematic decrease in DNY for heavier actinides is mainly due to decrease of fission yields of precursors in the lighter side of the light fragment region. (author)

  10. Time Delay in Molecular Photoionization

    OpenAIRE

    Hockett, P.; Frumker, E.; Villeneuve, D M; Corkum, P. B.

    2015-01-01

    Time-delays in the photoionization of molecules are investigated. As compared to atomic ionization, the time-delays expected from molecular ionization present a much richer phenomenon, with a strong spatial dependence due to the anisotropic nature of the molecular scattering potential. We investigate this from a scattering theory perspective, and make use of molecular photoionization calculations to examine this effect in representative homonuclear and hetronuclear diatomic molecules, nitroge...

  11. Measuring information-transfer delays.

    Directory of Open Access Journals (Sweden)

    Michael Wibral

    Full Text Available In complex networks such as gene networks, traffic systems or brain circuits it is important to understand how long it takes for the different parts of the network to effectively influence one another. In the brain, for example, axonal delays between brain areas can amount to several tens of milliseconds, adding an intrinsic component to any timing-based processing of information. Inferring neural interaction delays is thus needed to interpret the information transfer revealed by any analysis of directed interactions across brain structures. However, a robust estimation of interaction delays from neural activity faces several challenges if modeling assumptions on interaction mechanisms are wrong or cannot be made. Here, we propose a robust estimator for neuronal interaction delays rooted in an information-theoretic framework, which allows a model-free exploration of interactions. In particular, we extend transfer entropy to account for delayed source-target interactions, while crucially retaining the conditioning on the embedded target state at the immediately previous time step. We prove that this particular extension is indeed guaranteed to identify interaction delays between two coupled systems and is the only relevant option in keeping with Wiener's principle of causality. We demonstrate the performance of our approach in detecting interaction delays on finite data by numerical simulations of stochastic and deterministic processes, as well as on local field potential recordings. We also show the ability of the extended transfer entropy to detect the presence of multiple delays, as well as feedback loops. While evaluated on neuroscience data, we expect the estimator to be useful in other fields dealing with network dynamics.

  12. Cerebral computed tomographic angiography scan delay in subarachnoid hemorrhage

    Directory of Open Access Journals (Sweden)

    Lukosevicius Saulius

    2005-01-01

    Full Text Available CONTEXT: Computed tomographic angiography (CTA is widely applied in the evaluation of cerebral vessels. Contrast enhancement in cerebral CTA without care or test bolus is not always sufficient for high-quality images. AIMS: Evaluation of the possibilities of calculation of scan delay for cerebral CTA in case of subarachnoid hemorrhage (SAH, based on clinical data of a patient and to find out prognostic error of the model. SETTINGS AND DESIGN: Prospective study in Neurosurgery and Radiology departments. MATERIALS AND METHODS: Scan delay in 53 patients suffering an acute SAH was measured employing test bolus technique. Cerebral CTA was performed afterwards. STATISTICAL ANALYSIS USED: SPSS for Windows v.10.1 software package was applied for dispersion analysis, including one-sample Kolmogorov-Smirnov′s test and Levene′s Test of Equality of Error Variances. RESULTS: A statistical model for the prediction of scan delay in SAH was developed. Cerebral CTA scan delay was dependent upon age, neurological status and impact of the latter factors together (P<0.05. The determined mean square error of prognosis of scan delay of the developed model equals 3.3 sec. CONCLUSION: Using our proposed model it is possible to estimate an optimal delay time for CTA in most patients with SAH with a determined error.

  13. Gompertzian stochastic model with delay effect to cervical cancer growth

    Energy Technology Data Exchange (ETDEWEB)

    Mazlan, Mazma Syahidatul Ayuni binti; Rosli, Norhayati binti [Faculty of Industrial Sciences and Technology, Universiti Malaysia Pahang, Lebuhraya Tun Razak, 26300 Gambang, Pahang (Malaysia); Bahar, Arifah [Department of Mathematical Sciences, Faculty of Science, Universiti Teknologi Malaysia, 81310 Johor Bahru, Johor and UTM Centre for Industrial and Applied Mathematics (UTM-CIAM), Universiti Teknologi Malaysia, 81310 Johor Bahru, Johor (Malaysia)

    2015-02-03

    In this paper, a Gompertzian stochastic model with time delay is introduced to describe the cervical cancer growth. The parameters values of the mathematical model are estimated via Levenberg-Marquardt optimization method of non-linear least squares. We apply Milstein scheme for solving the stochastic model numerically. The efficiency of mathematical model is measured by comparing the simulated result and the clinical data of cervical cancer growth. Low values of Mean-Square Error (MSE) of Gompertzian stochastic model with delay effect indicate good fits.

  14. Gompertzian stochastic model with delay effect to cervical cancer growth

    Science.gov (United States)

    Mazlan, Mazma Syahidatul Ayuni binti; Rosli, Norhayati binti; Bahar, Arifah

    2015-02-01

    In this paper, a Gompertzian stochastic model with time delay is introduced to describe the cervical cancer growth. The parameters values of the mathematical model are estimated via Levenberg-Marquardt optimization method of non-linear least squares. We apply Milstein scheme for solving the stochastic model numerically. The efficiency of mathematical model is measured by comparing the simulated result and the clinical data of cervical cancer growth. Low values of Mean-Square Error (MSE) of Gompertzian stochastic model with delay effect indicate good fits.

  15. Chaos and Synchronization in Delayed System : Applications to Laser Networks

    Directory of Open Access Journals (Sweden)

    Schöll Eckehard

    2013-05-01

    Full Text Available We discuss recent results on chaos synchronization of delayed systems. We investigate the limit of large coupling delays and discuss how in this limit the stability problem for the synchronized solution is drastically simplified. We use these results to derive rigorous conditions for chaos synchronization of all-optically coupled laser networks. In laser systems the optical coupling phases have to be taken into account and give rise to interference conditions. We show that the relative phases between lasers can be used to optimize the effective coupling matrix.

  16. Scheduling Production Orders, Taking into Account Delays and Waste

    Directory of Open Access Journals (Sweden)

    Dylewski Robert

    2014-09-01

    Full Text Available The article addresses the problem of determining the sequence of entering orders for production in a flexible manufacturing system implementing technological operations of cutting sheet metal. Adopting a specific ranking of production orders gives rise to the vector of delays and waste in the form of incompletely used sheets. A new method was postulated for determining the optimal sequence of orders in terms of two criteria: the total cost of delays and the amount of production waste. The examples illustrate the advantages of the proposed method compared with the popular heuristic principles.

  17. Cooperative relay-based multicasting for energy and delay minimization

    KAUST Repository

    Atat, Rachad

    2012-08-01

    Relay-based multicasting for the purpose of cooperative content distribution is studied. Optimized relay selection is performed with the objective of minimizing the energy consumption or the content distribution delay within a cluster of cooperating mobiles. Two schemes are investigated. The first consists of the BS sending the data only to the relay, and the second scheme considers the scenario of threshold-based multicasting by the BS, where a relay is selected to transmit the data to the mobiles that were not able to receive the multicast data. Both schemes show significant superiority compared to the non-cooperative scenarios, in terms of energy consumption and delay reduction. © 2012 IEEE.

  18. Basin stability in delayed dynamics

    Science.gov (United States)

    Leng, Siyang; Lin, Wei; Kurths, Jürgen

    2016-02-01

    Basin stability (BS) is a universal concept for complex systems studies, which focuses on the volume of the basin of attraction instead of the traditional linearization-based approach. It has a lot of applications in real-world systems especially in dynamical systems with a phenomenon of multi-stability, which is even more ubiquitous in delayed dynamics such as the firing neurons, the climatological processes, and the power grids. Due to the infinite dimensional property of the space for the initial values, how to properly define the basin’s volume for delayed dynamics remains a fundamental problem. We propose here a technique which projects the infinite dimensional initial state space to a finite-dimensional Euclidean space by expanding the initial function along with different orthogonal or nonorthogonal basis. A generalized concept of basin’s volume in delayed dynamics and a highly practicable calculating algorithm with a cross-validation procedure are provided to numerically estimate the basin of attraction in delayed dynamics. We show potential applicabilities of this approach by applying it to study several representative systems of biological or/and physical significance, including the delayed Hopfield neuronal model with multistability and delayed complex networks with synchronization dynamics.

  19. Optimal Service Policies to Remote Customers with Delay-Limits

    NARCIS (Netherlands)

    Berg, M.; van der Duyn Schouten, F.A.; Jansen, J.B.

    1996-01-01

    This work deals with service provision to remote customers.Two examples are: (i) a manufacturer that has to deliver items to customers in a remote destination, and (ii) a company that provides repair and replacement service to distant clients.In both cases the remoteness of customers suggests order

  20. Optimal Service Policies to Remote Customers with Delay-Limits

    NARCIS (Netherlands)

    Berg, M.; van der Duyn Schouten, F.A.; Jansen, J.B.

    1996-01-01

    This work deals with service provision to remote customers.Two examples are: (i) a manufacturer that has to deliver items to customers in a remote destination, and (ii) a company that provides repair and replacement service to distant clients.In both cases the remoteness of customers suggests order

  1. Delay and Delay Variation Constrained Algorithm based on VNS Algorithm for RP Management in Mobile IPv6

    Directory of Open Access Journals (Sweden)

    Youssef Baddi

    2012-11-01

    Full Text Available On account the progress of network multimedia technologymore and more real-time multimedia applications arrive with the need to transmit information using multicast communicationThese applications are more important with arrival of mobile IPv6 protocol with mobile receivers and sources. These applications require a multicast routing protocol which has packets arriving at the multicast receptors within a specified QoS guaranteed and a quick recovery mechanism. In multicasting with mobile IPv6, the mobility of a receivers and senders may lead to serious problems. When the receiver or sender moves, the quality of full multicast tree may degrade so that multicasdatagrams cannot be forwarded efficiently. D2V-RPM (delay and delay variation RP Manager problem consist of choosing an optimal multicast router in the network as the root of the shared multicast tree (ST within a specified delay and delay variation bound for all multicast session, and recovering this RP if it's ofoptimal or failed. This NP hard problem needs to be solved through a heuristic algorithm. In this paper, we propose a new RP Management algorithm based on Variable Neighborhood Search algorithm, based on a systematic neighborhood changing. D2V-VNS-RPM algorithm selects and recovers the RP router by considering tree cost, delay and delay variation. Simulation results show that good performance is achieved.

  2. Defeito total do septo atrioventricular. Correlação anatomofuncional entre pacientes com e sem síndrome de Down

    Directory of Open Access Journals (Sweden)

    Ferrín Liliana María

    1997-01-01

    Full Text Available OBJETIVO: Comparar o grau de repercussão, fatores responsáveis e época de aparecimento dos sintomas do defeito do septo atrioventricular (DSAV, em pacientes com e sem síndrome de Down. MÉTODOS: Foram estudados 80 pacientes com idade 50mmHg ocorreu em 56% dos casos do GI em relação a 28% do GII p<0,019. A evolução até a cirurgia foi instável (agravamentos da insuficiência cardíaca em 33 (60% do GI e em 21 (84% do GII p<0,03. O tipo A de Rastelli foi o mais encontrado nos dois grupos, 35 (67% pacientes no GI e nos 25 (100% do GII. A alteração anatômica da VAV foi importante em 8% no GI e em 38% no GII. CONCLUSÃO: Há sugestão de predominância de hiper-reatividade vascular pulmonar nas crianças com síndrome de Down e de manifestações de insuficiência cardíaca nas geneticamente normais.

  3. [Partial closure of the atrial septal primum defect and biventricular repair for a case of hypoplastic right ventricle with partial atrioventricular canal defect].

    Science.gov (United States)

    Oshima, Y; Yamaguchi, M; Imai, M; Ohashi, H; Tsukube, T; Hosokawa, Y

    1990-11-01

    An eight-year-old girl with partial atrioventricular canal defect and hypoplastic right ventricle was treated successfully by a palliative open-heart surgery. The preoperative right ventricular pressure was 58/7 mmHg (RVP/LVP = 0.67) and morphology of the right ventricle showed severe tricuspid stenosis and small outflow portion. The preoperative RVEDVI was 31 (41% of normal and tricuspid annulus was 17 mm (47% of normal). The right ventricular outflow was reconstructed with insertion of MVOP and the ASD was partially left open (the amplitude of the interatrial communication was 7 mm). Angiocardiogram two and half years after the operation demonstrated significant right ventricular growth with no right to left shunt through interatrial communication. The RVEDVI was 46 (56% of normal) and tricuspid annulus was 36 mm (90% of normal). This technique can be a procedure of choice in patient with right ventricular hypoplasia, who is not candidate for simple right ventricular reconstruction nor Fontan procedure, as the growth of the right ventricule is expected in the future.

  4. Bloqueo aurículo-ventricular de primer grado en tirotoxicosis aguda First degree atrio-ventricular block in acute thyrotoxicosis

    Directory of Open Access Journals (Sweden)

    Antonio R. Vilches

    2004-02-01

    Full Text Available El cuadro clínico de la tirotoxicosis incluye síntomas cardiovasculares variados. La taquicardia sinusal es el trastorno electrocardiográfico más frecuente y los trastornos de conducción son extremadamente raros como modo de presentación. Comunicamos un caso de bloqueo aurículo-ventricular de primer grado en una paciente con hipertiroidismo recién diagnosticado y que comenzó días antes de la consulta con un cuadro general inespecífico. Su evaluación ulterior demostró que se trataba de una tirotoxicosis aguda autoinmune, y su tratamiento con metimazol corrigió el trastorno totalmente. Se discuten los mecanismos fisiopatológicos involucrados y las implicancias clínicas desde el punto de vista del internista.Thyrotoxicosis may present with a variety of cardiovascular symptoms. Sinus tachycardia is the most frequently encountered electrocardiographic abnormality and conduction disturbances are extremely uncommon. We present a case of first degree atrio-ventricular block in a patient with newly diagnosed hyperthyroidism and discuss the underlying pathophysiological mechanisms and the clinical implications from the internist’s standpoint.

  5. Atrioventricular Left Ventricular Apical Pacing Improves Haemodynamic, Rotational, and Deformation Variables in Comparison to Pacing at the Lateral Wall in Intact Myocardium: Experimental Study

    Directory of Open Access Journals (Sweden)

    Savvas Toumanidis

    2014-01-01

    Full Text Available Aim. To assess the effect on left ventricular (LV function of atrioventricular (AV and ventricular pacing at the LV apical or lateral wall and to compare the normal torsional and deformation pattern of the intact LV myocardium with those created by the aforementioned LV pacing modes and sites. Methods. Experiments were conducted in pigs (n=21 with normal LV function to investigate the acute hemodynamic effects of epicardial AV and ventricular LV pacing at the LV apical or lateral wall. Torsional and deformation indices of LV function were assessed using speckle tracking echocardiography. Results. AV pacing at the apex revealed a significant reduction in the radial strain of the base (P<0.03, without affecting significantly the ejection fraction and the LV torsion or twist. In contrast, AV pacing at the lateral wall produced, in addition to the reduction of the radial strain of the base (P<0.01, significant reduction of the circumferential and the radial strain of the apex (both P<0.01 as well as of the ejection fraction (P<0.002 and twist (P<0.05. Conclusions. In pig hearts with intact myocardium, LV function is maintained at sinus rhythm level when AV pacing is performed at the LV apex.

  6. In vivo analysis of torsadogenic potential of an antipsychotic drug paliperidone using the acute atrioventricular block rabbit as a proarrhythmia model

    Directory of Open Access Journals (Sweden)

    Mihoko Hagiwara

    2016-09-01

    Full Text Available We assessed electrophysiological effects of an atypical antipsychotic drug paliperidone in acute atrioventricular block rabbits. Intravenous administration of paliperidone at a clinically relevant dose (0.06 mg/kg hardly affected the QT interval or monophasic action potential (MAP duration, and the higher doses (0.6 and 6 mg/kg prolonged the QT interval and MAP duration. Meanwhile, premature ventricular contractions with R on T phenomenon were observed in 3 out of 6 animals at the middle dose, and torsades de pointes (TdP episodes were detected in 2 out of 6 animals at the high dose. Intravenous administration of its chemically related compound risperidone at a clinically relevant dose (0.03 mg/kg hardly affected the electrophysiological parameters, and the higher doses (0.3 and 3 mg/kg prolonged the QT interval and MAP duration. Meanwhile, the premature ventricular contractions with R on T were observed in 2 out of 6 animals at the middle dose, and TdP episodes were detected in 4 out of 6 animals at the high dose. These results suggest that paliperidone showed torsadogenic potential at supra-therapeutic doses, whose potency can be estimated to be equal or slightly subordinate in comparison with that of risperidone.

  7. Cardiac resynchronization therapy: Dire need for targeted left ventricular lead placement and optimal device programming

    Institute of Scientific and Technical Information of China (English)

    Sokratis; Pastromas; Antonis; S; Manolis

    2014-01-01

    Cardiac resynchronization therapy(CRT) effected via biventricular pacing has been established as prime therapy for heart failure patients of New York Heart Association functional class Ⅱ, Ⅲ and ambulatory Ⅳ, reduced left ventricular(LV) function, and a widened QRS complex. CRT has been shown to improve symptoms, LV function, hospitalization rates, and survival. In order to maximize the benefit from CRT and reduce the number of non-responders, consideration should be given to target the optimal site for LV lead implantation away from myocardial scar and close to the latest LV site activation; and also to appropriately program the device paying particular attention to optimal atrioventricular and interventricular intervals. We herein review current data related to both optimal LV lead placement and device programming and their effects on CRT clinical outcomes.

  8. Bloqueio atrioventricular no pós-operatório de cirurgia cardíaca valvar: incidência, fatores de risco e evolução hospitalar Atrioventricular block in the postoperative period of heart valve surgery: incidence, risk factors and hospital evolution

    Directory of Open Access Journals (Sweden)

    Andres Di Leoni Ferrari

    2011-09-01

    Full Text Available INTRODUÇÃO: Distúrbios do sistema de condução cardíaco são complicações potenciais e conhecidas dos procedimentos de cirurgia cardíaca valvar. OBJETIVOS: Investigar a associação entre fatores peri-operatórios com bloqueio atrioventricular (BAV e a necessidade de estimulação cardíaca artificial temporária (ECAT e, se necessário, implante de marcapasso definitivo no pós-operatório de cirurgia cardíaca (POCC valvar. MÉTODOS: Coorte histórica de pacientes submetidos a cirurgia cardíaca valvar, sendo realizada análise de banco de dados por regressão logística. RESULTADOS: No período de janeiro de 1996 a dezembro de 2008, foram realizadas 1102 cirurgias cardíacas valvares: 718 (65,2% na valva aórtica e 407 (36,9% na valva mitral; destas, 190 (17,2% cirurgias de revascularização miocárdica associadas à cirurgia valvar e 23 (2,1% cirurgias valvares combinadas (aórtica+mitral. Cento e oitenta e sete (17% pacientes apresentaram quadro clínico e eletrocardiográfico de BAV durante o POCC valvar, necessitando de ECAT. Quatorze (7,5% pacientes evoluíram para implante de marcapasso definitivo (1,27% do total da amostra. A análise multivariada evidenciou associação significativa de BAV com cirurgia de valva mitral (OR=1,76; IC 95% 1,08-2,37; P=0,002, implante de prótese biológica (OR=1,59; IC 95% 1,02-3,91; P= 0,039, idade maior que 60 anos (OR = 1,99; IC 95% 1,35-2,85; PINTRODUCTION: Disturbances of the cardiac conduction system are potential complications after cardiac valve surgery. OBJECTIVES: This study was designed to investigate the association between perioperative factors and atrio-ventricular block, the need for temporary cardiac artificial pacing and, if necessary, permanent pacemaker implantation after cardiac valve surgery. METHODS: Retrospective analysis of the Cardiac Surgery Database - Hospital São Lucas/PUCRS. The data are collected prospectively and analyzed retrospectively. RESULTS: Between January

  9. Exact solution of a delay difference equation modeling traffic flow and their ultra-discrete limit

    OpenAIRE

    Matsuya, Keisuke; Kanai, Masahiro

    2015-01-01

    We consider a car-following model described by a delay difference equation and give its exact solutions that present propagation of a traffic jam. This model is a discrete-time version of the delayed optimal-velocity model; in the continuum limit, we recover the delay differential equation for this model and the exact solutions as well. We then work in the ultra-discrete limit, obtaining a delay cellular-automaton model, which successfully inherits the solutions. Also the dispersion relation ...

  10. A new model for deteriorating items with inflation under permissible delay in payments

    Directory of Open Access Journals (Sweden)

    R.P. Tripathi

    2014-05-01

    Full Text Available Inflation is an important factor influencing traditional economic order quality models. Marketing strategy depends on inflation due to public demand and availability of the materials. This paper presents an optimal inventory policy for deteriorating items using exponential demand rate under permissible delay in payments. Mathematical model has been derived under two cases: case I: cycle time is greater than or equal to permissible delay period, case II: cycle time is less than permissible delay period by considering holding cost as a function of time. Numerical examples and sensitivity analysis are given to reflect the numerical results. Mathematica software is used for finding optimal solutions.

  11. Economic Order Quantity Model with Two Levels of Delayed Payment and Bad Debt

    Directory of Open Access Journals (Sweden)

    Qin Juanjuan

    2012-08-01

    Full Text Available The purpose of this study is to determine the optimal retailer’s replenishment policies considering the customers’ bad debt and delayed payment in the three-stage supply chain with the dominant retailer. The effect of bad debt is analyzed on the interest earned and interest charged to build the models of the retailer’s decision in two cases. By analyzing the model, the retailer’s optimal replenishment time and the optimal order quantity are obtained. Furthermore, analyze the effect of parameters on the retailer’s optimal order policies. Finally, the numerical analysis is presented to demonstrate the conclusions. The results show that the delayed payment offered by the manufacturer becomes large, the retailer's optimal order cycle and the optimal order quantity increases or remains the same; When the delayed payment time offered by the retailer decreases, the retailer's optimal order cycle and the optimal order quantity increases or remains the same. When the fixed ordering cost is reduced, the retailer's optimal order cycle and the optimal order quantity decreases or remains the same. When the charged interest is greater than the earned interest, with the bad debt rate increasing, the retailer's optimal order cycle and optimal order quantity is converged to a certain value.

  12. Delay Independent Criterion for Multiple Time-delay Systems

    Science.gov (United States)

    Chang, C. J.; Liu, K. F. R.; Yeh, K.; Chen, C. W.; Chung, P. Y.

    Based on the fuzzy Lyapunov method, this work addresses the stability conditions for nonlinear systems with multiple time delays to ensure the stability of building structure control systems. The delay independent conditions are derived via the traditional Lyapunov and fuzzy Lyapunov methods for multiple time-delay systems as approximated by the Tagagi-Sugeno (T-S) fuzzy model. The fuzzy Lyapunov function is defined as a fuzzy blending of quadratic Lyapunov functions. A parallel distributed compensation (PDC) scheme is utilized to construct a global fuzzy logic control (FLC) by blending all linear local state feedback controllers in the controller design procedure. Furthermore, the H infinity performance and robustness of the design for modeling errors also need to be considered in the stability conditions.

  13. A new method for choosing parameters in delay reconstruction-based forecast strategies

    CERN Document Server

    Garland, Joshua; Bradley, Elizabeth

    2015-01-01

    Delay-coordinate reconstruction is a proven modeling strategy for building effective forecasts of nonlinear time series. The first step in this process is the estimation of good values for two parameters, the time delay and the reconstruction dimension. Many heuristics and strategies have been proposed in the literature for estimating these values. Few, if any, of these methods were developed with forecasting in mind, however, and their results are not optimal for that purpose. Even so, these heuristics -- intended for other applications -- are routinely used when building delay coordinate reconstruction-based forecast models. In this paper, we propose a general framework for choosing optimal parameter values for forecast methods that are based on delay-coordinate reconstructions. The basic calculation involves maximizing the shared information between each delay vector and the future state of the system. We illustrate the effectiveness of this method on several synthetic and experimental systems, showing tha...

  14. Power and delay optimisation in multi-hop wireless networks

    KAUST Repository

    Xia, Li

    2014-02-05

    In this paper, we study the optimisation problem of transmission power and delay in a multi-hop wireless network consisting of multiple nodes. The goal is to determine the optimal policy of transmission rates at various buffer and channel states in order to minimise the power consumption and the queueing delay of the whole network. With the assumptions of interference-free links and independently and identically distributed (i.i.d.) channel states, we formulate this problem using a semi-open Jackson network model for data transmission and a Markov model for channel states transition. We derive a difference equation of the system performance under any two different policies. The necessary and sufficient condition of optimal policy is obtained. We also prove that the system performance is monotonic with respect to (w.r.t.) the transmission rate and the optimal transmission rate can be either maximal or minimal. That is, the ‘bang-bang’ control is an optimal control. This optimality structure greatly reduces the problem complexity. Furthermore, we develop an iterative algorithm to find the optimal solution. Finally, we conduct the simulation experiments to demonstrate the effectiveness of our approach. We hope our work can shed some insights on solving this complicated optimisation problem.

  15. An approach to constitutional delay of growth and puberty

    Directory of Open Access Journals (Sweden)

    Ashraf T Soliman

    2012-01-01

    Full Text Available Constitutional delay of growth and puberty is a transient state of hypogonadotropic hypogonadism associated with prolongation of childhood phase of growth, delayed skeletal maturation, delayed and attenuated pubertal growth spurt, and relatively low insulin-like growth factor-1 secretion. In a considerable number of cases, the final adult height (Ht does not reach the mid-parental or the predicted adult Ht for the individual, with some degree of disproportionately short trunk. In the pre-pubertal male, testosterone (T replacement therapy can be used to induce pubertal development, accelerate growth and relieve the psychosocial complaints of the adolescents. However, some issues in the management are still unresolved. These include type, optimal timing, dose and duration of sex steroid treatment and the possible use of adjunctive or alternate therapy including: oxandrolone, aromatase inhibitors and human growth hormone.

  16. Swing Damping for Helicopter Slung Load Systems using Delayed Feedback

    DEFF Research Database (Denmark)

    Bisgaard, Morten; la Cour-Harbo, Anders; Bendtsen, Jan Dimon

    2009-01-01

    of swing. The design of the delayed feedback controller is presented as an optimization problem which gives the possibility of an automated design process. Simulations and flight test verifications of the control system on two different autonomous helicopters are presented and it is shown how a significant......This paper presents the design and verification of a swing reducing controller for helicopter slung load systems using intentional delayed feedback. It is intended for augmenting a trajectory tracking helicopter controller and thereby improving the slung load handing capabilities for autonomous...... helicopters. The delayed feedback controller is added to actively reduce oscillations of the slung load by improving the damping of the slung load pendulum modes. Furthermore, it is intended for integration with a feedforward control scheme based on input shaping for concurrent avoidance and dampening...

  17. Dynamic Server Allocation over Time Varying Channels with Switchover Delay

    CERN Document Server

    Celik, Güner D; Modiano, Eytan

    2012-01-01

    We consider a dynamic server allocation problem over parallel queues with randomly varying connectivity and server switchover delay between the queues. At each time slot the server decides either to stay with the current queue or switch to another queue based on the current connectivity and the queue length information. Switchover delay occurs in many telecommunications applications and is a new modeling component of this problem that has not been previously addressed. We show that the simultaneous presence of randomly varying connectivity and switchover delay changes the system stability region and the structure of optimal policies. In the first part of the paper, we consider a system of two parallel queues, and develop a novel approach to explicitly characterize the stability region of the system using state-action frequencies which are stationary solutions to a Markov Decision Process (MDP) formulation. We then develop a frame-based dynamic control (FBDC) policy, based on the state-action frequencies, and ...

  18. Self-Restoration Properties of VWP Networks by Spare Wavelength Optimization

    Institute of Scientific and Technical Information of China (English)

    Yu; Sasaki; Kiyoshi; Nakagawa; Katsumi; Takano; Kazuhiro; Kondo

    2003-01-01

    The self-restoration properties in VWP networks are investigated with optimization about spare wavelength by simulations. Rapid restoration can be achieved by selection of rerouting path with long delay and no delay-limitation for new routes.

  19. Robust stability of discrete-time nonlinear system with time-delay

    Institute of Scientific and Technical Information of China (English)

    LIU Xin-ge; WU Min

    2005-01-01

    The robustly asymptotical stability problem for discrete-time nonlinear systems with time-delay was investigated. Positive definite matrix are constructed through Lyapunov functional. With the identity transform, property of matrix inverse and S-procedure, a new sufficient condition independent of the size of time-delay for robust stability of discrete-time nonlinear systems with time-delay is established. With Schur complement, another equivalent sufficient condition for robust stability of discrete-time nonlinear systems with time-delay is given. Finally, a sufficient condition dependent on the size of time-delay for robust stability of discrete-time nonlinear systems with time-delay is obtained. A unified approach is used to cast the robust stability problem into a convex optimization involving linear matrix inequalities.

  20. 49 CFR 236.563 - Delay time.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Delay time. 236.563 Section 236.563 Transportation... Cab Signal Systems Rules and Instructions; Locomotives § 236.563 Delay time. Delay time of automatic... requirements of § 236.24 shall take into consideration the delay time....