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Sample records for epicardial reentrant circuits

  1. A SHORT-TERM CIRCUIT RESISTANCE PROGRAMME REDUCED EPICARDIAL FAT IN OBESE AGED WOMEN.

    Science.gov (United States)

    Rosety, Miguel Angel; Pery, Maria Teresa; Rodriguez-Pareja, Maria Antonia; Diaz, Antonio; Rosety, Jesus; Garcia, Natalia; Brenes-Martin, Francisco; Rosety-Rodríguez, Manuel; Toro, Rocío; Ordoñez, Francisco Javier; Rosety, Ignacio

    2015-11-01

    this study was conducted to ascertain the effects of resistance circuit training on epicardial adipose tissue (EAT) in obese aged women. A secondary objective was to assess muscle damage induced by supervised resistance training to confirm the intervention program was effective and safe. in the present interventional study, a total of 48 obese aged women were recruited from the community. Twenty-four of them were randomly assigned to perform a 12-week resistance circuit training programme, 3-days per week. This training was circularly performed in 6 stations: arm curl, leg extension, seated row, leg curl, triceps extension and leg press. The Jamar handgrip electronic dynamometer was used to assess maximal handgrip strength of the dominant hand. Two experienced observers assessed EAT by transthoracic two-dimensional echocardiography. Lastly, serum samples were analysed using one-step sandwich assays for creatine kinase activity (CK) and myoglobin (MB) concentration. as was hypothesized, resistance training significantly reduced EAT thickness (8.4 ± 1.0 vs. 7.3 ± 1.3 mm; p = 0.014; d = 0.76) in the experimental group. Resistance training induced no significant changes in markers of muscle damage such as CK (181.6 ± 36.9 vs. 194.2 ± 37.8 U/l; p = 0.31) and MB (62.4 ± 7.1 vs. 67.3 ± 7.7 ng/ml; p = 0.26). No significant changes in any of the tested outcomes were found in the control group. resistance training reduced EAT in aged obese women. A secondary finding was that the training program was effective and safe. While current results are promising, future studies are still required to consolidate this approach in clinical application. Copyright AULA MEDICA EDICIONES 2014. Published by AULA MEDICA. All rights reserved.

  2. Radiation Dose from Reentrant Electrons

    Science.gov (United States)

    Badhwar, G.D.; Cleghorn, T. E.; Watts, J.

    2003-01-01

    In estimating the crew exposures during an EVA, the contribution of reentrant electrons has always been neglected. Although the flux of these electrons is small compared to the flux of trapped electrons, their energy spectrum extends to several GeV compared to about 7 MeV for trapped electrons. This is also true of splash electrons. Using the measured reentrant electron energy spectra, it is shown that the dose contribution of these electrons to the blood forming organs (BFO) is more than 10 times greater than that from the trapped electrons. The calculations also show that the dose-depth response is a very slowly changing function of depth, and thus adding reasonable amounts of additional shielding would not significantly lower the dose to BFO.

  3. Reentrant processing in intuitive perception.

    Directory of Open Access Journals (Sweden)

    Phan Luu

    Full Text Available The process of perception requires not only the brain's receipt of sensory data but also the meaningful organization of that data in relation to the perceptual experience held in memory. Although it typically results in a conscious percept, the process of perception is not fully conscious. Research on the neural substrates of human visual perception has suggested that regions of limbic cortex, including the medial orbital frontal cortex (mOFC, may contribute to intuitive judgments about perceptual events, such as guessing whether an object might be present in a briefly presented fragmented drawing. Examining dense array measures of cortical electrical activity during a modified Waterloo Gestalt Closure Task, results show, as expected, that activity in medial orbital frontal electrical responses (about 250 ms was associated with intuitive judgments. Activity in the right temporal-parietal-occipital (TPO region was found to predict mOFC (approximately 150 ms activity and, in turn, was subsequently influenced by the mOFC at a later time (approximately 300 ms. The initial perception of gist or meaning of a visual stimulus in limbic networks may thus yield reentrant input to the visual areas to influence continued development of the percept. Before perception is completed, the initial representation of gist may support intuitive judgments about the ongoing perceptual process.

  4. Catheter ablation of epicardial ventricular tachycardia

    Directory of Open Access Journals (Sweden)

    Takumi Yamada, MD, PhD

    2014-08-01

    Full Text Available Ventricular tachycardias (VTs can usually be treated by endocardial catheter ablation. However, some VTs can arise from the epicardial surface, and their substrate can be altered only by epicardial catheter ablation. There are two approaches to epicardial catheter ablation: transvenous and transthoracic. The transvenous approach through the coronary venous system (CVS has been commonly used because it is easily accessible. However, this approach may be limited by the distribution of the CVS and insufficient radiofrequency energy delivery. Transthoracic epicardial catheter ablation has been developed to overcome these limitations of the transvenous approach. It is a useful supplemental or even preferred strategy to eliminate epicardial VTs in the electrophysiology laboratory. This technique has been applied for scar-related VTs secondary to often non-ischemic cardiomyopathy and sometimes ischemic cardiomyopathy, and idiopathic VTs as the epicardial substrates of these VTs have become increasingly recognized. When endocardial ablation and epicardial ablation through the CVS are unsuccessful, transthoracic epicardial ablation should be the next option. Intrapericardial access is usually obtained through a subxiphoidal pericardial puncture. This approach might not be possible in patients with pericardial adhesions caused by prior cardiac surgery or pericarditis. In such cases, a hybrid procedure involving surgical access with a subxiphoid pericardial window and a limited anterior or lateral thoracotomy might be a feasible and safe method of performing an epicardial catheter ablation in the electrophysiology laboratory. Potential complications associated with this technique include bleeding and collateral damage to the coronary arteries and phrenic nerve. Although the risk of these complications is low, electrophysiologists who attempt epicardial catheter ablation should know the complications associated with this technique, how to minimize their

  5. Design of half-reentrant SRF cavities

    International Nuclear Information System (INIS)

    Meidlinger, M.; Grimm, T.L.; Hartung, W.

    2006-01-01

    The shape of a TeSLA inner cell can be improved to lower the peak surface magnetic field at the expense of a higher peak surface electric field by making the cell reentrant. Such a single-cell cavity was designed and tested at Cornell, setting a world record accelerating gradient [V. Shemelin et al., An optimized shape cavity for TESLA: concept and fabrication, 11th Workshop on RF Superconductivity, Travemuende, Germany, September 8-12, 2003; R. Geng, H. Padamsee, Reentrant cavity and first test result, Pushing the Limits of RF Superconductivity Workshop, Argonne National Laboratory, September 22-24, 2004]. However, the disadvantage to a cavity is that liquids become trapped in the reentrant portion when it is vertically hung during high pressure rinsing. While this was overcome for Cornell's single-cell cavity by flipping it several times between high pressure rinse cycles, this may not be feasible for a multi-cell cavity. One solution to this problem is to make the cavity reentrant on only one side, leaving the opposite wall angle at six degrees for fluid drainage. This idea was first presented in 2004 [T.L. Grimm et al., IEEE Transactions on Applied Superconductivity 15(6) (2005) 2393]. Preliminary designs of two new half-reentrant (HR) inner cells have since been completed, one at a high cell-to-cell coupling of 2.1% (high-k cc HR) and the other at 1.5% (low-k cc HR). The parameters of a HR cavity are comparable to a fully reentrant cavity, with the added benefit that a HR cavity can be easily cleaned with current technology

  6. Epicardial mapping of ventricular fibrillation over the posterior descending artery and left posterior papillary muscle of the swine heart.

    Science.gov (United States)

    Nielsen, Thomas D; Huang, Jian; Rogers, Jack M; Killingsworth, Cheryl R; Ideker, Raymond E

    2009-01-01

    Recent studies suggest that during ventricular fibrillation (VF) epicardial vessels may be a site of conduction block and the posterior papillary muscle (PPM) in the left ventricle (LV) may be the location of a "mother rotor." The goal of this study was to obtain evidence to support or refute these possibilities. Epicardial activation over the posterior LV and right ventricle (RV) was mapped during the first 20 s of electrically induced VF in six open-chest pigs with a 504 electrode plaque covering a 20 cm(2) area centered over the posterior descending artery (PDA). The locations of epicardial breakthrough as well as reentry clustered in time and space during VF. Spatially, reentry occurred significantly more frequently over the LV than the RV in all 48 episodes, and breakthrough clustered near the PPM (p < 0.001). Significant temporal clustering occurred in 79% of breakthrough episodes and 100% of reentry episodes. These temporal clusters occurred at different times so that there was significantly less breakthrough when reentry was present (p < 0.0001). Conduction block occurred significantly more frequently near the PDA than elsewhere. The PDA is a site of epicardial block which may contribute to VF maintenance. Epicardial breakthrough clusters near the PPM. Reentry also clusters in space but at a separate site. The fact that breakthrough and reentry cluster at different locations and at different times supports the possibility of a drifting filament at the PPM so that at times reentry is present on the surface but at other times the reentrant wavefront breaks through to the epicardium.

  7. The quantitative assessment of epicardial fat distribution on human hearts: Implications for epicardial electrophysiology.

    Science.gov (United States)

    Mattson, Alexander R; Soto, Mario J; Iaizzo, Paul A

    2018-07-01

    Epicardial electrophysiological procedures rely on dependable interfacing with the myocardial tissue. For example, epicardial pacing systems must generate sustainable chronic pacing capture, while epicardial ablations must effectively deliver energy to the target hyper-excitable myocytes. The human heart has a significant adipose layer which may impede epicardial procedures. The objective of this study was to quantitatively assess the relative location of epicardial adipose on the human heart, to define locations where epicardial therapies might be performed successfully. We studied perfusion-fixed human hearts (n = 105) in multiple isolated planes including: left ventricular margin, diaphragmatic surface, and anterior right ventricle. Relative adipose distribution was quantitatively assessed via planar images, using a custom-generated image analysis algorithm. In these specimens, 76.7 ± 13.8% of the left ventricular margin, 72.7 ± 11.3% of the diaphragmatic surface, and 92.1 ± 8.7% of the anterior right margin were covered with superficial epicardial adipose layers. Percent adipose coverage significantly increased with age (P history of coronary artery disease (P history of hypertension, and/or history of congestive heart failure. Additionally, we describe two-dimensional probability distributions of epicardial adipose coverage for each of the three analysis planes. In this study, we detail the quantitative assessment and probabilistic mapping of the distribution of superficial epicardial adipose on the adult human heart. These findings have implications relative to performing epicardial procedures and/or designing procedures or tools to successfully perform such treatments. Clin. Anat. 31:661-666, 2018. © 2018 Wiley Periodicals, Inc. © 2018 Wiley Periodicals, Inc.

  8. Dielectric studies of fluids with reentrant resonators

    International Nuclear Information System (INIS)

    Goodwin, A.R.H.; Moldover, M.R.

    1993-01-01

    The authors have used a reentrant radio-frequency (rf) cavity as a resonator operating near 375 MHz to measure changes in the dielectric constant of fluids within it. The utility of these measurements was demonstrated by determining the dipole moment of 1,1,1,2,3,3-hexafluoropropane, a candidate replacement refrigerant (denoted R236ea) and by detecting the phase boundaries in the mixture [(1-x)C 2 H 6 + xCO 2 ], for the mole fraction x = 0.492. The densities of the coexisting phases of the mixture were determined using the Clausius-Mossotti relation which has errors on the order of 0.5% in this application. To test the accuracy of the present techniques, the rf resonator was calibrated with helium and then used to redetermine the molar polarizability A e of argon. The results were in excellent agreement with published values. The design of the reentrant resonator makes it suitable for use with corrosive fluids at temperature up to 400 degrees C

  9. Epicardial adipose tissue in endocrine and metabolic diseases.

    Science.gov (United States)

    Iacobellis, Gianluca

    2014-05-01

    Epicardial adipose tissue has recently emerged as new risk factor and active player in metabolic and cardiovascular diseases. Albeit its physiological and pathological roles are not completely understood, a body of evidence indicates that epicardial adipose tissue is a fat depot with peculiar and unique features. Epicardial fat is able to synthesize, produce, and secrete bioactive molecules which are then transported into the adjacent myocardium through vasocrine and/or paracrine pathways. Based on these evidences, epicardial adipose tissue can be considered an endocrine organ. Epicardial fat is also thought to provide direct heating to the myocardium and protect the heart during unfavorable hemodynamic conditions, such as ischemia or hypoxia. Epicardial fat has been suggested to play an independent role in the development and progression of obesity- and diabetes-related cardiac abnormalities. Clinically, the thickness of epicardial fat can be easily and accurately measured. Epicardial fat thickness can serve as marker of visceral adiposity and visceral fat changes during weight loss interventions and treatments with drugs targeting the fat. The potential of modulating the epicardial fat with targeted pharmacological agents can open new avenues in the pharmacotherapy of endocrine and metabolic diseases. This review article will provide Endocrine's reader with a focus on epicardial adipose tissue in endocrinology. Novel, established, but also speculative findings on epicardial fat will be discussed from the unexplored perspective of both clinical and basic Endocrinologist.

  10. Microscopic origin of black hole reentrant phase transitions

    Science.gov (United States)

    Zangeneh, M. Kord; Dehyadegari, A.; Sheykhi, A.; Mann, R. B.

    2018-04-01

    Understanding the microscopic behavior of the black hole ingredients has been one of the important challenges in black hole physics during the past decades. In order to shed some light on the microscopic structure of black holes, in this paper, we explore a recently observed phenomenon for black holes namely reentrant phase transition, by employing the Ruppeiner geometry. Interestingly enough, we observe two properties for the phase behavior of small black holes that leads to reentrant phase transition. They are correlated and they are of the interaction type. For the range of pressure in which the system underlies reentrant phase transition, it transits from the large black holes phase to the small one which possesses higher correlation than the other ranges of pressures. On the other hand, the type of interaction between small black holes near the large/small transition line differs for usual and reentrant phase transitions. Indeed, for the usual case, the dominant interaction is repulsive whereas for the reentrant case we encounter an attractive interaction. We show that in the reentrant phase transition case, the small black holes behave like a bosonic gas whereas in the usual phase transition case, they behave like a quantum anyon gas.

  11. Doubly Reentrant Cavities Prevent Catastrophic Wetting Transitions on Intrinsically Wetting Surfaces

    KAUST Repository

    Domingues, Eddy; Arunachalam, Sankara; Mishra, Himanshu

    2017-01-01

    immersed in mineral oil or water, doubly reentrant microtextures in silica (θo ≈ 40° for water) were not penetrated even after several days of investigation. Thus, microtextures comprising of doubly reentrant cavities might enable applications

  12. Performance Spread of Re-entrant System Structures

    DEFF Research Database (Denmark)

    Nielsen, Erland Hejn

    2001-01-01

    -to-day operations. It might well be the case that those badly behaving systems merely constitute a set with a measure of almost zero. The key parameters that determine whether a re-entrant system is one of the badly behaving ones are essentially flow-structure, processing times and rules of priority between...... satisfactory. They are all vulnerable to certain job flow patterns and process time settings to a significant degree. The LBFS priority policy therefore presents itself not only as a stable, but also the safe and robust choice par excellence in relation to the control of re-entrant systems....... different job-classes on specific machines. Let us therefore face a re-entrant flow-shop production set-up in an order-driven production system, by which I mean that the flow structure relative to each production-batch shows great variability and where the size of the individual batches is quite large. One...

  13. Modeling and Analysis of Reentrant Manufacturing Systems: Micro- and Macroperspectives

    Directory of Open Access Journals (Sweden)

    Fenglan He

    2011-01-01

    Full Text Available In order to obtain the better analysis of the multiple reentrant manufacturing systems (MRMSs, their modeling and analysis from both micro- and macroperspectives are considered. First, this paper presents the discrete event simulation models for MRMS and the corresponding algorithms are developed. In order to describe MRMS more accurately, then a modified continuum model is proposed. This continuum model takes into account the re-entrant degree of products, and its effectiveness is verified through numerical experiments. Finally, based on the discrete event simulation and the modified continuum models, a numerical example is used to analyze the MRMS. The changes in the WIP levels and outflux are also analyzed in details for multiple re-entrant supply chain networks. Meanwhile, some interesting observations are discussed.

  14. Reentrant Metal-Insulator Transitions in Silicon -

    Science.gov (United States)

    Campbell, John William M.

    This thesis describes a study of reentrant metal -insulator transitions observed in the inversion layer of extremely high mobility Si-MOSFETs. Magneto-transport measurements were carried out in the temperature range 20mK-4.2 K in a ^3He/^4 He dilution refrigerator which was surrounded by a 15 Tesla superconducting magnet. Below a melting temperature (T_{M}~500 mK) and a critical electron density (n_{s }~9times10^{10} cm^{-2}), the Shubnikov -de Haas oscillations in the diagonal resistivity enormous maximum values at the half filled Landau levels while maintaining deep minima corresponding to the quantum Hall effect at filled Landau levels. At even lower electron densities the insulating regions began to spread and eventually a metal-insulator transition could be induced at zero magnetic field. The measurement of extremely large resistances in the milliKelvin temperature range required the use of very low currents (typically in the 10^ {-12} A range) and in certain measurements minimizing the noise was also a consideration. The improvements achieved in these areas through the use of shielding, optical decouplers and battery operated instruments are described. The transport signatures of the insulating state are considered in terms of two basic mechanisms: single particle localization with transport by variable range hopping and the formation of a collective state such as a pinned Wigner crystal or electron solid with transport through the motion of bound dislocation pairs. The experimental data is best described by the latter model. Thus the two dimensional electron system in these high mobility Si-MOSFETs provides the first and only experimental demonstration to date of the formation of an electron solid at zero and low magnetic fields in the quantum limit where the Coulomb interaction energy dominates over the zero point oscillation energy. The role of disorder in favouring either single particle localization or the formation of a Wigner crystal is explored by

  15. Online scheduling of 2-re-entrant flexible manufacturing systems

    NARCIS (Netherlands)

    Pinxten, J. van; Waqas, U.; Geilen, M.; Basten, T.; Somers, L.

    2017-01-01

    Online scheduling of operations is essential to optimize productivity of flexible manufacturing systems (FMSs) where manufacturing requests arrive on the fly. An FMS processes products according to a particular flow through processing stations. This work focusses on online scheduling of re-entrant

  16. Simple explanation for the reentrant magnetic phase transition in Pr ...

    Indian Academy of Sciences (India)

    The reentrant magnetic phase transition in Pr0.5Sr0.41Ca0.09MnO3 perovskite is explained using the Ising spin model on the square lattice with mixed ferromagnetic and antiferromagnetic exchange interactions. It is shown using numerical calculations that this effect is strongly affected by the external magnetic field and ...

  17. Equilibrium polymerization models of re-entrant self-assembly

    Science.gov (United States)

    Dudowicz, Jacek; Douglas, Jack F.; Freed, Karl F.

    2009-04-01

    As is well known, liquid-liquid phase separation can occur either upon heating or cooling, corresponding to lower and upper critical solution phase boundaries, respectively. Likewise, self-assembly transitions from a monomeric state to an organized polymeric state can proceed either upon increasing or decreasing temperature, and the concentration dependent ordering temperature is correspondingly called the "floor" or "ceiling" temperature. Motivated by the fact that some phase separating systems exhibit closed loop phase boundaries with two critical points, the present paper analyzes self-assembly analogs of re-entrant phase separation, i.e., re-entrant self-assembly. In particular, re-entrant self-assembly transitions are demonstrated to arise in thermally activated equilibrium self-assembling systems, when thermal activation is more favorable than chain propagation, and in equilibrium self-assembly near an adsorbing boundary where strong competition exists between adsorption and self-assembly. Apparently, the competition between interactions or equilibria generally underlies re-entrant behavior in both liquid-liquid phase separation and self-assembly transitions.

  18. Revealing new mouse epicardial cell markers through transcriptomics.

    Directory of Open Access Journals (Sweden)

    Lars Bochmann

    2010-06-01

    Full Text Available The epicardium has key functions during myocardial development, by contributing to the formation of coronary endothelial and smooth muscle cells, cardiac fibroblasts, and potentially cardiomyocytes. The epicardium plays a morphogenetic role by emitting signals to promote and maintain cardiomyocyte proliferation. In a regenerative context, the adult epicardium might comprise a progenitor cell population that can be induced to contribute to cardiac repair. Although some genes involved in epicardial function have been identified, a detailed molecular profile of epicardial gene expression has not been available.Using laser capture microscopy, we isolated the epicardial layer from the adult murine heart before or after cardiac infarction in wildtype mice and mice expressing a transgenic IGF-1 propeptide (mIGF-1 that enhances cardiac repair, and analyzed the transcription profile using DNA microarrays.Expression of epithelial genes such as basonuclin, dermokine, and glycoprotein M6A are highly enriched in the epicardial layer, which maintains expression of selected embryonic genes involved in epicardial development in mIGF-1 transgenic hearts. After myocardial infarct, a subset of differentially expressed genes are down-regulated in the epicardium representing an epicardium-specific signature that responds to injury.This study presents the description of the murine epicardial transcriptome obtained from snap frozen tissues, providing essential information for further analysis of this important cardiac cell layer.

  19. Source-Sink Mismatch Causing Functional Conduction Block in Re-Entrant Ventricular Tachycardia.

    Science.gov (United States)

    Ciaccio, Edward J; Coromilas, James; Wit, Andrew L; Peters, Nicholas S; Garan, Hasan

    2018-01-01

    Ventricular tachycardia (VT) caused by a re-entrant circuit is a life-threatening arrhythmia that at present cannot always be treated adequately. A realistic model of re-entry would be helpful to accurately guide catheter ablation for interruption of the circuit. In this review, models of electrical activation wavefront propagation during onset and maintenance of re-entrant VT are discussed. In particular, the relationship between activation mapping and maps of transition in infarct border zone thickness, which results in source-sink mismatch, is considered in detail and supplemented with additional data. Based on source-sink mismatch, the re-entry isthmus can be modeled from its boundary properties. Isthmus boundary segments with large transitions in infarct border zone thickness have large source-sink mismatch, and functional block forms there during VT. These alternate with segments having lesser thickness change and therefore lesser source-sink mismatch, which act as gaps, or entrance and exit points, to the isthmus during VT. Besides post-infarction substrates, the source-sink model is likely applicable to other types of volumetric changes in the myocardial conducting medium, such as when there is presence of fibrosis or dissociation of muscle fibers. Copyright © 2018 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.

  20. Reentrant behaviour in polyvinyl alcohol-borax hydrogels

    Science.gov (United States)

    Lawrence, Mathias B.; Desa, J. A. E.; Aswal, V. K.

    2018-01-01

    Polyvinyl alcohol (PVA) hydrogels, cross-linked with varying concentrations of borax, were studied with small angle neutron scattering (SANS), x-ray diffraction (XRD) and differential thermal analysis (DTA). The SANS data satisfy the Ornstein-Zernike approximation. The hydrogels are modelled as PVA chains bound by borate cross-links. Water occupies the spaces within the three-dimensional hydrogel network. The mesh size ξ indicates reentrant behaviour i.e. at first, ξ increases and later decreases as a function of borax concentration. The behaviour is explained on the basis of the balance between the charged di-diol cross-links and the shielding by free ions in the solvent. XRD and DTA show the molecular size of water in the solvent and the glass transition temperature commensurate with reentrant behaviour.

  1. Minimal invasive epicardial lead implantation: optimizing cardiac resynchronization with a new mapping device for epicardial lead placement.

    Science.gov (United States)

    Maessen, J G; Phelps, B; Dekker, A L A J; Dijkman, B

    2004-05-01

    To optimize resynchronization in biventricular pacing with epicardial leads, mapping to determine the best pacing site, is a prerequisite. A port access surgical mapping technique was developed that allowed multiple pace site selection and reproducible lead evaluation and implantation. Pressure-volume loops analysis was used for real time guidance in targeting epicardial lead placement. Even the smallest changes in lead position revealed significantly different functional results. Optimizing the pacing site with this technique allowed functional improvement up to 40% versus random pace site selection.

  2. Highly Sensitive Reentrant Cavity-Microstrip Patch Antenna Integrated Wireless Passive Pressure Sensor for High Temperature Applications

    Directory of Open Access Journals (Sweden)

    Fei Lu

    2017-01-01

    Full Text Available A novel reentrant cavity-microstrip patch antenna integrated wireless passive pressure sensor was proposed in this paper for high temperature applications. The reentrant cavity was analyzed from aspects of distributed model and equivalent lumped circuit model, on the basis of which an optimal sensor structure integrated with a rectangular microstrip patch antenna was proposed to better transmit/receive wireless signals. In this paper, the proposed sensor was fabricated with high temperature resistant alumina ceramic and silver metalization with weld sealing, and it was measured in a hermetic metal tank with nitrogen pressure loading. It was verified that the sensor was highly sensitive, keeping stable performance up to 300 kPa with an average sensitivity of 981.8 kHz/kPa at temperature 25°C, while, for high temperature measurement, the sensor can operate properly under pressure of 60–120 kPa in the temperature range of 25–300°C with maximum pressure sensitivity of 179.2 kHz/kPa. In practical application, the proposed sensor is used in a method called table lookup with a maximum error of 5.78%.

  3. Human Pluripotent Stem Cell Differentiation into Functional Epicardial Progenitor Cells

    NARCIS (Netherlands)

    Guadix, Juan Antonio; Orlova, Valeria V.; Giacomelli, Elisa; Bellin, Milena; Ribeiro, Marcelo C.; Mummery, Christine L.; Pérez-Pomares, José M.; Passier, Robert

    2017-01-01

    Human pluripotent stem cells (hPSCs) are widely used to study cardiovascular cell differentiation and function. Here, we induced differentiation of hPSCs (both embryonic and induced) to proepicardial/epicardial progenitor cells that cover the heart during development. Addition of retinoic acid (RA)

  4. Feasibility of remote magnetic navigation for epicardial ablation

    NARCIS (Netherlands)

    P. Abraham; L.D. Abkenari; E.C.H. Peters; T. Szili-Torok (Tamas)

    2013-01-01

    textabstractPercutaneous epicardial mapping and ablation is an emerging method to treat ventricular tachycardias (VT), premature ventricular complexes (PVC), and accessory pathways. The use of a remote magnetic navigation system (MNS) could enhance precision and maintain safety. This multiple case

  5. Performance of a reentrant cavity beam position monitor

    Directory of Open Access Journals (Sweden)

    Claire Simon

    2008-08-01

    Full Text Available The beam-based alignment and feedback systems, essential operations for the future colliders, require high resolution beam position monitors (BPMs. In the framework of the European CARE/SRF program, a reentrant cavity BPM with its associated electronics was developed by the CEA/DSM/Irfu in collaboration with DESY. The design, the fabrication, and the beam test of this monitor are detailed within this paper. This BPM is designed to be inserted in a cryomodule, work at cryogenic temperature in a clean environment. It has achieved a resolution better than 10  μm and has the possibility to perform bunch to bunch measurements for the x-ray free electron laser (X-FEL and the International Linear Collider (ILC. Its other features are a small size of the rf cavity, a large aperture (78 mm, and an excellent linearity. A first prototype of a reentrant cavity BPM was installed in the free electron laser in Hamburg (FLASH, at Deutsches Elektronen-Synchrotron (DESY and demonstrated its operation at cryogenic temperature inside a cryomodule. The second, installed, also, in the FLASH linac to be tested with beam, measured a resolution of approximately 4  μm over a dynamic range ±5  mm in single bunch.

  6. Manganite/Cuprate Superlattice as Artificial Reentrant Spin Glass

    KAUST Repository

    Ding, Junfeng

    2016-05-04

    Emerging physical phenomena at the unit-cell-controlled interfaces of transition-metal oxides have attracted lots of interest because of the rich physics and application opportunities. This work reports a reentrant spin glass behavior with strong magnetic memory effect discovered in oxide heterostructures composed of ultrathin manganite La0.7Sr0.3MnO3 (LSMO) and cuprate La2CuO4 (LCO) layers. These heterostructures are featured with enhanced ferromagnetism before entering the spin glass state: a Curie temperature of 246 K is observed in the superlattice with six-unit-cell LSMO layers, while the reference LSMO film with the same thickness shows much weaker magnetism. Furthermore, an insulator-metal transition emerges at the Curie temperature, and below the freezing temperature the superlattices can be considered as a glassy ferromagnetic insulator. These experimental results are closely related to the interfacial spin reconstruction revealed by the first-principles calculations, and the dependence of the reentrant spin glass behavior on the LSMO layer thickness is in line with the general phase diagram of a spin system derived from the infinite-range SK model. The results of this work underscore the manganite/cuprate superlattices as a versatile platform of creating artificial materials with tailored interfacial spin coupling and physical properties. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  7. Performance of a reentrant cavity beam position monitor

    International Nuclear Information System (INIS)

    Simon, C.; Luong, M.; Chel, S.; Napoly, O.; Novo, J.; Roudier, D.; Rouviere, N.; Baboi, N.; Mildner, N.; Nolle, D.

    2008-01-01

    The beam-based alignment and feedback systems, essential operations for the future colliders, require high resolution beam position monitors (BPMs). In the framework of the European CARE/SRF program, a reentrant cavity BPM with its associated electronics was developed by the CEA/DSM/Irfu in collaboration with DESY. The design, the fabrication, and the beam test of this monitor are detailed within this paper. This BPM is designed to be inserted in a cryo-module, work at cryogenic temperature in a clean environment. It has achieved a resolution better than 10 μm and has the possibility to perform bunch to bunch measurements for the X-ray free electron laser (X-FEL) and the International Linear Collider (ILC). Its other features are a small size of the rf cavity, a large aperture (78 mm), and an excellent linearity. A first prototype of a reentrant cavity BPM was installed in the free electron laser in Hamburg (FLASH), at Deutsches Elektronen-Synchrotron (DESY) and demonstrated its operation at cryogenic temperature inside a cryo-module. The second, installed, also, in the FLASH linac to be tested with beam, measured a resolution of approximately 4 μm over a dynamic range ± 5 mm in single bunch. (authors)

  8. Performance of a reentrant cavity beam position monitor

    Science.gov (United States)

    Simon, Claire; Luong, Michel; Chel, Stéphane; Napoly, Olivier; Novo, Jorge; Roudier, Dominique; Rouvière, Nelly; Baboi, Nicoleta; Mildner, Nils; Nölle, Dirk

    2008-08-01

    The beam-based alignment and feedback systems, essential operations for the future colliders, require high resolution beam position monitors (BPMs). In the framework of the European CARE/SRF program, a reentrant cavity BPM with its associated electronics was developed by the CEA/DSM/Irfu in collaboration with DESY. The design, the fabrication, and the beam test of this monitor are detailed within this paper. This BPM is designed to be inserted in a cryomodule, work at cryogenic temperature in a clean environment. It has achieved a resolution better than 10μm and has the possibility to perform bunch to bunch measurements for the x-ray free electron laser (X-FEL) and the International Linear Collider (ILC). Its other features are a small size of the rf cavity, a large aperture (78 mm), and an excellent linearity. A first prototype of a reentrant cavity BPM was installed in the free electron laser in Hamburg (FLASH), at Deutsches Elektronen-Synchrotron (DESY) and demonstrated its operation at cryogenic temperature inside a cryomodule. The second, installed, also, in the FLASH linac to be tested with beam, measured a resolution of approximately 4μm over a dynamic range ±5mm in single bunch.

  9. The radio frequency catheter ablation of inter-fascicular reentrant tachycardia: new insights into the electrophysiological and anatomical characteristics

    NARCIS (Netherlands)

    Okishige, Kaoru; Sakurada, Harumizu; Mizusawa, Yuka; Yamauchi, Yasuteru; Fukamizu, Seiji; Aoyagi, Hideshi; Okano, Yoshifumi; Azegami, Koji; Sasano, Tetsuo; Hirao, Kenzo

    2014-01-01

    Macro-reentrant ventricular tachycardias (VT) utilizing the bundle branches and Purkinje fibers have been reported as verapamil sensitive VT (idiopathic left VT), bundle branch reentrant VT (BBRT) and inter-fascicular reentrant tachycardia (inter-fascicular VT). However, diagnostic confusion exists

  10. Unipolar atrial electrogram morphology from an epicardial and endocardial perspective.

    Science.gov (United States)

    van der Does, Lisette J M E; Knops, Paul; Teuwen, Christophe P; Serban, Corina; Starreveld, Roeliene; Lanters, Eva A H; Mouws, Elisabeth M J P; Kik, Charles; Bogers, Ad J J C; de Groot, Natasja M S

    2018-02-22

    Endo-epicardial asynchrony (EEA) and the interplay between the endocardial and epicardial layers could be important in the pathophysiology of atrial arrhythmias. The morphologic differences between epicardial and endocardial atrial electrograms have not yet been described, and electrogram morphology may hold information about the presence of EEA. The purpose of this study was to directly compare epicardial to endocardial unipolar electrogram morphology during sinus rhythm (SR) and to evaluate whether EEA contributes to electrogram fractionation by correlating fractionation to spatial activation patterns. In 26 patients undergoing cardiac surgery, unipolar electrograms were simultaneously recorded from the epicardium and endocardium at the inferior, middle, and superior right atrial (RA) free wall during SR. Potentials were analyzed for epi-endocardial differences in local activation time, voltage, RS ratio, and fractionation. The surrounding and opposite electrograms of fractionated deflections were evaluated for corresponding local activation times in order to determine whether fractionation originated from EEA. The superior RA was predisposed to delayed activation, EEA, and fractionation. Both epicardial and endocardial electrograms demonstrated an S-predominance. Fractionation was mostly similar between the 2 sides; however, incidentally deflections up to 4 mV on 1 side could be absent on the other side. Remote activation was responsible for most fractionated deflections (95%) in SR, of which 4% could be attributed to EEA. Local epi-endocardial differences in electrogram fractionation occur occasionally during SR but will likely increase during arrhythmias due to increasing EEA and (functional) conduction disorders. Electrogram fractionation can originate from EEA, and this study demonstrated that unipolar electrogram fractionation can potentially identify EEA. Copyright © 2018 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.

  11. Slot Antenna Integrated Re-Entrant Resonator Based Wireless Pressure Sensor for High-Temperature Applications.

    Science.gov (United States)

    Su, Shujing; Lu, Fei; Wu, Guozhu; Wu, Dezhi; Tan, Qiulin; Dong, Helei; Xiong, Jijun

    2017-08-25

    The highly sensitive pressure sensor presented in this paper aims at wireless passive sensing in a high temperature environment by using microwave backscattering technology. The structure of the re-entrant resonator was analyzed and optimized using theoretical calculation, software simulation, and its equivalent lump circuit model was first modified by us. Micro-machining and high-temperature co-fired ceramic (HTCC) process technologies were applied to fabricate the sensor, solving the common problem of cavity sealing during the air pressure loading test. In addition, to prevent the response signal from being immersed in the strong background clutter of the hermetic metal chamber, which makes its detection difficult, we proposed two key techniques to improve the signal to noise ratio: the suppression of strong background clutter and the detection of the weak backscattered signal of the sensor. The pressure sensor demonstrated in this paper works well for gas pressure loading between 40 and 120 kPa in a temperature range of 24 °C to 800 °C. The experimental results show that the sensor resonant frequency lies at 2.1065 GHz, with a maximum pressure sensitivity of 73.125 kHz/kPa.

  12. Modeling of Reduced-Beta Half-Reentrant Cavities: Final Report

    International Nuclear Information System (INIS)

    Popielarksi, J.T.; Hartung, W.; Johnson, M.J.

    2011-01-01

    The linear accelerator for the Spallation Neutron Source uses multi-cell elliptical superconducting cavities to provide much of the accelerating voltage. Similar technology is being considered for other projects, including a proposed superconducting proton linac at Fermilab and the European Spallation Source. A new type of accelerating structure, a 'half-reentrant' elliptical cavity has been studied at Michigan State University. A half-reentrant cavity can potentially improve upon existing elliptical cavity designs by reducing the cryogenic load by as much as 40% for the same accelerating gradient. Alternatively, with the same peak surface magnetic field as traditional elliptical cavities, it is anticipated that half-reentrant designs could operate at up to 25% higher accelerating gradient. With a half-reentrant shape, liquids can drain easily during chemical etching and high pressure rinsing, which allows standard multi-cell processing techniques to be used. Electromagnetic designs have been developed for three half-reentrant cell shapes suitable for an ion or proton linac (β = 0.47, 0.61 and 0.81). The mechanical designs have been done for prototypes at 805 MHz. The design and optimization of the reduced-β half-reentrant cavities are summarized in this report.

  13. Optimum thermal design of microchannel heat sink with triangular reentrant cavities

    International Nuclear Information System (INIS)

    Xia Guodong; Chai Lei; Wang Haiyan; Zhou Mingzheng; Cui Zhenzhen

    2011-01-01

    The effect of geometric parameters on water flow and heat transfer characteristics in microchannel heat sink with triangular reentrant cavities is numerically investigated. A three-dimensional laminar flow model, consisting of Navier-Stokes equations and energy conservation equation, with the conjugate heat transfer between the silicon base and water taken into consideration is solved numerically. In order to find the optimum geometric parameters, four variables, representing the distance and geometry of the triangular reentrant cavity, are designed. It is found that the vortices in the triangular reentrant cavities lead to chaotic advection and can greatly enhance the convective fluid mixing. The thermal and hydraulic boundary layers are interrupted and the repeated developing flow enhances heat transfer in the constant cross-section segment. Furthermore, the effects of the four design variables on heat transfer augmentation and pressure drop penalty are investigated depending on different Reynolds numbers by using the simulated annealing method. Based on the thermal enhancement factor performance maps, the optimal geometric parameters are obtained in principle. - Research highlights: → The microchannels with different triangular reentrant cavities are numerically investigated. → The heat transfer enhancement attributes to fluid mixing and redeveloped thermal boundary layers. → The optimal distance and geometry of the triangular reentrant cavity are obtained in principle.

  14. Human Pluripotent Stem Cell Differentiation into Functional Epicardial Progenitor Cells

    Directory of Open Access Journals (Sweden)

    Juan Antonio Guadix

    2017-12-01

    Full Text Available Summary: Human pluripotent stem cells (hPSCs are widely used to study cardiovascular cell differentiation and function. Here, we induced differentiation of hPSCs (both embryonic and induced to proepicardial/epicardial progenitor cells that cover the heart during development. Addition of retinoic acid (RA and bone morphogenetic protein 4 (BMP4 promoted expression of the mesodermal marker PDGFRα, upregulated characteristic (proepicardial progenitor cell genes, and downregulated transcription of myocardial genes. We confirmed the (proepicardial-like properties of these cells using in vitro co-culture assays and in ovo grafting of hPSC-epicardial cells into chick embryos. Our data show that RA + BMP4-treated hPSCs differentiate into (proepicardial-like cells displaying functional properties (adhesion and spreading over the myocardium of their in vivo counterpart. The results extend evidence that hPSCs are an excellent model to study (proepicardial differentiation into cardiovascular cells in human development and evaluate their potential for cardiac regeneration. : The authors have shown that hPSCs can be instructed in vitro to differentiate into a specific cardiac embryonic progenitor cell population called the proepicardium. Proepicardial cells are required for normal formation of the heart during development and might contribute to the development of cell-based therapies for heart repair. Keywords: human pluripotent stem cells, proepicardium, progenitor cells, cardiovascular, differentiation

  15. Single-slice epicardial fat area measurement. Do we need to measure the total epicardial fat volume?

    International Nuclear Information System (INIS)

    Oyama, Noriko; Goto, Daisuke; Ito, Yoichi M.

    2011-01-01

    The aim of this study was to assess a method for measuring epicardial fat volume (EFV) by means of a single-slice area measurement. We investigated the relation between a single-slice fat area measurement and total EFV. A series of 72 consecutive patients (ages 65±11 years; 36 men) who had undergone cardiac computed tomography (CT) on a 64-slice multidetector scanner with prospective electrocardiographic triggering were retrospectively reviewed. Pixels in the pericardium with a density range from -230 to -30 Hounsfield units were considered fat, giving the per-slice epicardial fat area (EFA). The EFV was estimated by the summation of EFAs multiplied by the slice thickness. We investigated the relation between total EFV and each EFA. EFAs measured at several anatomical landmarks - right pulmonary artery, origins of the left main coronary artery, right coronary artery, coronary sinus - all correlated with the EFV (r=0.77-0.92). The EFA at the LMCA level was highly reproducible and showed an excellent correlation with the EFV (r=0.92). The EFA is significantly correlated with the EFV. The EFA is a simple, quick method for representing the time-consuming EFV, which has been used as a predictive indicator of cardiovascular diseases. (author)

  16. Direct Proof of Endo-Epicardial Asynchrony of the Atrial Wall During Atrial Fibrillation in Humans.

    Science.gov (United States)

    de Groot, Natasja; van der Does, Lisette; Yaksh, Ameeta; Lanters, Eva; Teuwen, Christophe; Knops, Paul; van de Woestijne, Pieter; Bekkers, Jos; Kik, Charles; Bogers, Ad; Allessie, Maurits

    2016-05-01

    The presence of focal fibrillation waves during atrial fibrillation (AF) can, besides ectopic activity, also be explained by asynchronous activation of the atrial endo- and epicardial layer and transmurally propagating fibrillation waves. To provide direct proof of endo-epicardial asynchrony, we performed simultaneous high-resolution mapping of the right atrial endo- and epicardial wall during AF in humans. Intraoperative mapping of the endo- and epicardial right atrial wall was performed during (induced) AF in 10 patients with AF (paroxysmal: n=3; persistent: n=4; and longstanding persistent: n=3) and 4 patients without a history of AF. A clamp made of 2 rectangular 8×16 electrode arrays (interelectrode distance 2 mm) was inserted into the incision in the right atrial appendage. Recordings of 10 seconds of AF were analyzed to determine the incidence of asynchronous endo-epicardial activation times (≥15 ms) of opposite electrodes. Asynchronous endo-epicardial activation ranged between 0.9 and 55.9% without preference for either side. Focal waves appeared equally frequent at endocardium and epicardium (11% versus 13%; ITALIC! P=0.18). Using strict criteria for breakthrough (presence of an opposite wave within 4 mm and ≤14 ms before the origin of the focal wave), the majority (65%) of all focal fibrillation waves could be attributed to endo-epicardial excitation. We provided the first evidence for asynchronous activation of the endo-epicardial wall during AF in humans. Endo-epicardial asynchrony may play a major role in the pathophysiology of AF and may offer an explanation why in some patients therapy fails. © 2016 American Heart Association, Inc.

  17. Inverse electrocardiographic transformations: dependence on the number of epicardial regions and body surface data points.

    Science.gov (United States)

    Johnston, P R; Walker, S J; Hyttinen, J A; Kilpatrick, D

    1994-04-01

    The inverse problem of electrocardiography, the computation of epicardial potentials from body surface potentials, is influenced by the desired resolution on the epicardium, the number of recording points on the body surface, and the method of limiting the inversion process. To examine the role of these variables in the computation of the inverse transform, Tikhonov's zero-order regularization and singular value decomposition (SVD) have been used to invert the forward transfer matrix. The inverses have been compared in a data-independent manner using the resolution and the noise amplification as endpoints. Sets of 32, 50, 192, and 384 leads were chosen as sets of body surface data, and 26, 50, 74, and 98 regions were chosen to represent the epicardium. The resolution and noise were both improved by using a greater number of electrodes on the body surface. When 60% of the singular values are retained, the results show a trade-off between noise and resolution, with typical maximal epicardial noise levels of less than 0.5% of maximum epicardial potentials for 26 epicardial regions, 2.5% for 50 epicardial regions, 7.5% for 74 epicardial regions, and 50% for 98 epicardial regions. As the number of epicardial regions is increased, the regularization technique effectively fixes the noise amplification but markedly decreases the resolution, whereas SVD results in an increase in noise and a moderate decrease in resolution. Overall the regularization technique performs slightly better than SVD in the noise-resolution relationship. There is a region at the posterior of the heart that was poorly resolved regardless of the number of regions chosen. The variance of the resolution was such as to suggest the use of variable-size epicardial regions based on the resolution.

  18. Epicardial adipose tissue is associated with visceral fat, metabolic syndrome, and insulin resistance in menopausal women.

    Science.gov (United States)

    Fernández Muñoz, María J; Basurto Acevedo, Lourdes; Córdova Pérez, Nydia; Vázquez Martínez, Ana Laura; Tepach Gutiérrez, Nayive; Vega García, Sara; Rocha Cruz, Alberto; Díaz Martínez, Alma; Saucedo García, Renata; Zárate Treviño, Arturo; González Escudero, Eduardo Alberto; Degollado Córdova, José Antonio

    2014-06-01

    Epicardial adipose tissue has been associated with several obesity-related parameters and with insulin resistance. Echocardiographic assessment of this tissue is an easy and reliable marker of cardiometabolic risk. However, there are insufficient studies on the relationship between epicardial fat and insulin resistance during the postmenopausal period, when cardiovascular risk increases in women. The objective of this study was to examine the association between epicardial adipose tissue and visceral adipose tissue, waist circumference, body mass index, and insulin resistance in postmenopausal women. A cross sectional study was conducted in 34 postmenopausal women with and without metabolic syndrome. All participants underwent a transthoracic echocardiogram and body composition analysis. A positive correlation was observed between epicardial fat and visceral adipose tissue, body mass index, and waist circumference. The values of these correlations of epicardial fat thickness overlying the aorta-right ventricle were r = 0.505 (P < .003), r = 0.545 (P < .001), and r = 0.515 (P < .003), respectively. Epicardial adipose tissue was higher in postmenopausal women with metabolic syndrome than in those without this syndrome (mean [standard deviation], 544.2 [122.9] vs 363.6 [162.3] mm(2); P = .03). Epicardial fat thickness measured by echocardiography was associated with visceral adipose tissue and other obesity parameters. Epicardial adipose tissue was higher in postmenopausal women with metabolic syndrome. Therefore, echocardiographic assessment of epicardial fat may be a simple and reliable marker of cardiovascular risk in postmenopausal women. Copyright © 2013 Sociedad Española de Cardiología. Published by Elsevier Espana. All rights reserved.

  19. Infected Congenital Epicardial Cyst Presenting as Acute Abdomen.

    Science.gov (United States)

    Dribin, Timothy; Files, Matthew D; Rudzinski, Erin R; Kaplan, Ron; Stone, Kimberly P

    2016-12-01

    A previously healthy 3-year-old boy presented to the emergency department with abdominal pain, fever, and emesis. Laboratory and radiologic evaluation for causes of acute abdomen were negative; however, review of the abdominal x-ray demonstrated cardiomegaly with the subsequent diagnosis of pericardial cyst by echocardiogram and computed tomography. The patient underwent surgical decompression and attempted removal of the cystic structure revealing that the cyst originated from the epicardium. His abdominal pain and fever resolved postoperatively and he completed a 3-week course of ceftriaxone for treatment of Propionibacterium acnes infected congenital epicardial cyst. Emergency department physicians must maintain a broad differential in patients with symptoms of acute abdomen to prevent complications from serious cardiac or pulmonary diseases that present with symptoms of referred abdominal pain.

  20. Systolic Compression of Epicardial Coronary and Intramural Arteries

    Science.gov (United States)

    Mohiddin, Saidi A.; Fananapazir, Lameh

    2002-01-01

    It has been suggested that systolic compression of epicardial coronary arteries is an important cause of myocardial ischemia and sudden death in children with hypertrophic cardiomyopathy. We examined the associations between sudden death, systolic coronary compression of intra- and epicardial arteries, myocardial perfusion abnormalities, and severity of hypertrophy in children with hypertrophic cardiomyopathy. We reviewed the angiograms from 57 children with hypertrophic cardiomyopathy for the presence of coronary and septal artery compression; coronary compression was present in 23 (40%). The left anterior descending artery was most often affected, and multiple sites were found in 4 children. Myocardial perfusion abnormalities were more frequently present in children with coronary compression than in those without (94% vs 47%, P = 0.002). Coronary compression was also associated with more severe septal hypertrophy and greater left ventricular outflow gradient. Septal branch compression was present in 65% of the children and was significantly associated with coronary compression, severity of septal hypertrophy, and outflow obstruction. Multivariate analysis showed that septal thickness and septal branch compression, but not coronary compression, were independent predictors of perfusion abnormalities. Coronary compression was not associated with symptom severity, ventricular tachycardia, or a worse prognosis. We conclude that compression of coronary arteries and their septal branches is common in children with hypertrophic cardiomyopathy and is related to the magnitude of left ventricular hypertrophy. Our findings suggest that coronary compression does not make an important contribution to myocardial ischemia in hypertrophic cardiomyopathy; however, left ventricular hypertrophy and compression of intramural arteries may contribute significantly. (Tex Heart Inst J 2002;29:290–8) PMID:12484613

  1. Epicardial oesophageal duplication with hiatal hernia in a case of Turner's syndrome

    International Nuclear Information System (INIS)

    Tamburrini, O.; Cigliano, S.; Esposito, G.; Cucchiara, S.

    1983-01-01

    The authors of this paper report the first case of epicardial oesophageal duplication causing hiatal hernia in a patient afflicted with Turner's syndrome, and they discuss its possible etiology. (orig.)

  2. Conservative Management of an Epicardial Collateral Perforation During Retrograde Chronic Total Occlusion Percutaneous Coronary Intervention.

    Science.gov (United States)

    Ngo, Christian; Christopoulos, George; Brilakis, Emmanouil S

    2016-01-01

    Coronary artery perforation is a highly feared complication of chronic total occlusion (CTO) percutaneous coronary intervention (PCI) and can lead to pericardial effusion, tamponade, and, rarely, emergent cardiac surgery. Perforation of epicardial collaterals during retrograde CTO-PCI may be particularly challenging to treat, as embolization from both sides of the perforation may be required to control the bleeding. However, conservative measures can occasionally be effective. We present a case of epicardial collateral vessel perforation that was managed conservatively with anticoagulation reversal.

  3. Usefulness of Epicardial Area in the Short Axis to Identify Elevated Left Ventricular Mass in Men.

    Science.gov (United States)

    Fitzpatrick, Jesse K; Cohen, Beth E; Rosenblatt, Andrew; Shaw, Richard E; Schiller, Nelson B

    2018-06-15

    Left ventricular (LV) hypertrophy is strongly associated with increased cardiovascular morbidity and mortality. The 2-dimensional LV mass algorithms suffer from measurement variability that can lead to misclassification of patients with LV hypertrophy as normal, or vice versa. Among the 4 echocardiographic measurements required by the 2-dimensional LV mass algorithms, epicardial and endocardial area have the lowest interobserver variation and could be used to corroborate LV mass calculations. We sought cut-off values that are able to discriminate between elevated and normal LV mass based on endocardial or epicardial area alone. Using data from 664 men enrolled in the Mind Your Heart Study, we calculated the correlation of LV mass index with epicardial area and endocardial area. We then used receiver operator characteristic curves to identify epicardial and endocardial area cut-points that could discriminate subjects with normal LV mass and LV hypertrophy. LV mass index was more strongly correlated with epicardial area compared with endocardial area, r = 0.70 versus r = 0.27, respectively. Epicardial area had a significantly higher area under the receiver operator characteristic curve (p versus 0.63 (95% confidence interval 0.57 to 0.71). An epicardial area cut-point of ≥38.0 cm 2 corresponded to a sensitivity of 95.0% and specificity of 54.4% for detecting LV hypertrophy. In conclusion, epicardial area showed promise as a method of rapid screening for LV hypertrophy and could be used to validate formal LV mass calculations. Copyright © 2018 Elsevier Inc. All rights reserved.

  4. Field-induced reentrant magnetoelectric phase in LiNiPO4

    DEFF Research Database (Denmark)

    Toft-Petersen, Rasmus; Fogh, Ellen; Kihara, Takumi

    2017-01-01

    Using pulsed magnetic fields up to 30 T we have measured the bulk magnetization and electrical polarization of LiNiPO4 and have studied its magnetic structure by time-of-flight neutron Laue diffraction. Our data establish the existence of a reentrant magnetoelectric phase between 19 T and 21 T. W...

  5. Contrasting the magnetic response between magnetic-glass and reentrant spin-glass

    OpenAIRE

    Roy, S. B.; Chattopadhyay, M. K.

    2008-01-01

    Magnetic-glass is a recently identified phenomenon in various classes of magnetic systems undergoing a first order magnetic phase transition. We shall highlight here a few experimentally determined characteristics of magnetic-glass and the relevant set of experiments, which will enable to distinguish a magnetic-glass unequivocally from the well known phenomena of spin-glass and reentrant spin-glass.

  6. Atrioventricular node reentrant tachycardia (AVNRT) after mitral valvuloplasty during cardiac rehabilitation.

    Science.gov (United States)

    Fallavollita, Luca; Santillo, Elpidio; Marini, Luciano; Balestrini, Fabrizio

    2012-12-01

    We descrive a patient who presents palpitations during cardiac rehabilitation after mitral valvuloplasty. ECG showed regular narrow QRS tachycardia compatible with Atrioventricular Node Reentrant Tachycardia. After slow pathway radiofrequency catheter ablation, the patient completed the rehabilitation program remained tachycardia and palpitations-free.

  7. Atrial activation during atrioventricular nodal reentrant tachycardia: studies on retrograde fast pathway conduction

    NARCIS (Netherlands)

    Katritsis, Demosthenes G.; Ellenbogen, Kenneth A.; Becker, Anton E.

    2006-01-01

    Detailed right and left septal mapping of retrograde atrial activation during typical atrioventricular nodal reentrant tachycardia (AVNRT) has not been undertaken and may provide insight into the complex physiology of AVNRT, especially the anatomic localization of the fast and slow pathways. The

  8. Relationship Between Neck Circumference and Epicardial Fat Thickness in a Healthy Male Population

    Directory of Open Access Journals (Sweden)

    Uğur Küçük

    2016-01-01

    Full Text Available Abstract Background: Epicardial fat is an upper body visceral fat depot that may play a significant role in the development of adverse metabolic and cardiovascular risk profiles. There is a significant direct relationship between the amount of epicardial fat and general body adiposity (body mass index, BMI, but data regarding subcutaneous adiposity is limited. Objective: We conducted a study to determine the association between neck circumference and epicardial fat thickness in healthy young male individuals, and assess their individual correlations with general body adiposity and cardiometabolic risk factors. Methods: One hundred consecutive male patients aged 18 years or older with no known major medical conditions were included in the study. All participants underwent detailed physical examination including measurement of blood pressure, weight, height, waist/hip ratio, and neck circumference. Blood was collected to determine fasting glucose and lipid parameters. A standard echocardiographic examination was performed with additional epicardial fat thickness determination. Results: Among 100 study participants, neck circumference correlated significantly with weight, waist circumference, BMI, blood glucose, serum total cholesterol, low-density (LDL-cholesterol, and triglycerides levels. No significant correlation was found between neck circumference and high-density lipoprotein (HDL-cholesterol levels. Neck circumference correlated moderately and positively with echocardiographic epicardial fat thickness. Conclusion: Among patients with low cardiometabolic risk, increased neck circumference was associated with increased epicardial fat thickness.

  9. Association between epicardial fat volume and coronary plaques diagnosed by multislice computed tomography

    Directory of Open Access Journals (Sweden)

    José A. Morán Quijada

    2016-01-01

    Full Text Available Introduction: Coronary atherosclerotic disease is a major cause of death in Cuba and elsewhere. The volume of epicardial fat is considered a new cardiovascular risk factor because of its association with coronary atherogenesis.Objective: To determine, by multislice computed tomography, the association between epicardial fat volume and the presence of coronary atherosclerotic plaques.Method: A descriptive study was conducted with a universe of 130 patients with chest pain suggestive of ischemic heart disease, of which 117 were selected by opinion sampling. These patients underwent a calcium score study, a coronary angiography and a measurement of the epicardial fat volume.Results: Male patients predominated (54.7% and those aged 60-69 years (32.5%. A high volume of epicardial fat was found in 51.3% of patients, affecting 52.8% of women; 78.9% of patients with a calcium score between 100 and 399 UH had a high volume of epicardial fat, just as 71.2% of those with plaques and 100% of those with 4 or 5 plaques; 41% of patients had various types of plaque, which were mainly located in the anterior descending artery (88.1%.Conclusions: The measurement of the volume of epicardial fat is a useful tool to estimate the presence of coronary disease. When it was high, it was associated with older age, female gender and the presence of a higher calcium score, more plaques, more injuries and a greater involvement of the anterior descending artery.

  10. An increase in epicardial fat in women is associated with thrombotic risk.

    Science.gov (United States)

    Basurto Acevedo, Lourdes; Barrera Hernández, Susana; Fernández Muñoz, María de Jesús; Saucedo García, Renata Patricia; Rodríguez Luna, Ana Karen; Martínez Murillo, Carlos

    2018-01-29

    A decrease in fibrinolytic activity and an increase in the thickness of the epicardial adipose tissue have been observed in patients with coronary artery disease. The aim of this study was to determine the association between epicardial adipose tissue and fibrinolytic activity by measuring the concentration of plasminogen activator inhibitor-1 (PAI-1). A cross-sectional study was conducted on 56 apparently healthy women aged 45 to 60 years. Anthropometric measurements and biochemical determinations were performed on all participants. The fibrinolytic activity was determined by measuring PAI-1 by ELISA. Epicardial thickness was assessed by transthoracic echocardiography. The concentration of PAI-1 was directly associated with the thickness of the epicardial adipose tissue (r=0.475, P=.001), body mass index (BMI), visceral adipose tissue, insulin resistance, glucose, and HDL-cholesterol. The multivariate regression analysis indicated that epicardial fat independently predicts the concentrations of PAI-1. Women with thicker epicardial adipose tissue have reduced fibrinolytic activity, and consequently greater thrombotic risk. Copyright © 2017 Sociedad Española de Arteriosclerosis. Publicado por Elsevier España, S.L.U. All rights reserved.

  11. Oscillator circuits

    CERN Document Server

    Graf, Rudolf F

    1996-01-01

    This series of circuits provides designers with a quick source for oscillator circuits. Why waste time paging through huge encyclopedias when you can choose the topic you need and select any of the specialized circuits sorted by application?This book in the series has 250-300 practical, ready-to-use circuit designs, with schematics and brief explanations of circuit operation. The original source for each circuit is listed in an appendix, making it easy to obtain additional information.Ready-to-use circuits.Grouped by application for easy look-up.Circuit source listing

  12. Measuring circuits

    CERN Document Server

    Graf, Rudolf F

    1996-01-01

    This series of circuits provides designers with a quick source for measuring circuits. Why waste time paging through huge encyclopedias when you can choose the topic you need and select any of the specialized circuits sorted by application?This book in the series has 250-300 practical, ready-to-use circuit designs, with schematics and brief explanations of circuit operation. The original source for each circuit is listed in an appendix, making it easy to obtain additional information.Ready-to-use circuits.Grouped by application for easy look-up.Circuit source listings

  13. Doubly Reentrant Cavities Prevent Catastrophic Wetting Transitions on Intrinsically Wetting Surfaces

    KAUST Repository

    Domingues, Eddy

    2017-06-05

    Omniphobic surfaces, i.e. which repel all known liquids, have proven of value in applications ranging from membrane distillation to underwater drag reduction. A limitation of currently employed omniphobic surfaces is that they rely on perfluorinated coatings, increasing cost and environmental impact, and preventing applications in harsh environments. There is, thus, a keen interest in rendering conventional materials, such as plastics, omniphobic by micro/nano-texturing rather than via chemical make-up, with notable success having been achieved for silica surfaces with doubly reentrant micropillars. However, we found a critical limitation of microtextures comprising of pillars that they undergo catastrophic wetting transitions (apparent contact angles, θr → 0° from θr > 90°) in the presence of localized physical damages/defects or on immersion in wetting liquids. In response, a doubly reentrant cavity microtexture is introduced, which can prevent catastrophic wetting transitions in the presence of localized structural damage/defects or on immersion in wetting liquids. Remarkably, our silica surfaces with doubly reentrant cavities could exhibited apparent contact angles, θr ≈ 135° for mineral oil, where the intrinsic contact angle, θo ≈ 20°. Further, when immersed in mineral oil or water, doubly reentrant microtextures in silica (θo ≈ 40° for water) were not penetrated even after several days of investigation. Thus, microtextures comprising of doubly reentrant cavities might enable applications of conventional materials without chemical modifications, especially in scenarios that are prone to localized damages or immersion in wetting liquids, e.g. hydrodynamic drag reduction and membrane distillation.

  14. Atrial fibrillation driven by micro-anatomic intramural re-entry revealed by simultaneous sub-epicardial and sub-endocardial optical mapping in explanted human hearts.

    Science.gov (United States)

    Hansen, Brian J; Zhao, Jichao; Csepe, Thomas A; Moore, Brandon T; Li, Ning; Jayne, Laura A; Kalyanasundaram, Anuradha; Lim, Praise; Bratasz, Anna; Powell, Kimerly A; Simonetti, Orlando P; Higgins, Robert S D; Kilic, Ahmet; Mohler, Peter J; Janssen, Paul M L; Weiss, Raul; Hummel, John D; Fedorov, Vadim V

    2015-09-14

    The complex architecture of the human atria may create physical substrates for sustained re-entry to drive atrial fibrillation (AF). The existence of sustained, anatomically defined AF drivers in humans has been challenged partly due to the lack of simultaneous endocardial-epicardial (Endo-Epi) mapping coupled with high-resolution 3D structural imaging. Coronary-perfused human right atria from explanted diseased hearts (n = 8, 43-72 years old) were optically mapped simultaneously by three high-resolution CMOS cameras (two aligned Endo-Epi views (330 µm2 resolution) and one panoramic view). 3D gadolinium-enhanced magnetic resonance imaging (GE-MRI, 80 µm3 resolution) revealed the atrial wall structure varied in thickness (1.0 ± 0.7-6.8 ± 2.4 mm), transmural fiber angle differences, and interstitial fibrosis causing transmural activation delay from 23 ± 11 to 43 ± 22 ms at increased pacing rates. Sustained AF (>90 min) was induced by burst pacing during pinacidil (30-100 µM) perfusion. Dual-sided sub-Endo-sub-Epi optical mapping revealed that AF was driven by spatially and temporally stable intramural re-entry with 107 ± 50 ms cycle length and transmural activation delay of 67 ± 31 ms. Intramural re-entrant drivers were captured primarily by sub-Endo mapping, while sub-Epi mapping visualized re-entry or 'breakthrough' patterns. Re-entrant drivers were anchored on 3D micro-anatomic tracks (15.4 ± 2.2 × 6.0 ± 2.3 mm2, 2.9 ± 0.9 mm depth) formed by atrial musculature characterized by increased transmural fiber angle differences and interstitial fibrosis. Targeted radiofrequency ablation of the tracks verified these re-entries as drivers of AF. Integrated 3D structural-functional mapping of diseased human right atria ex vivo revealed that the complex atrial microstructure caused significant differences between Endo vs. Epi activation during pacing and sustained AF driven by intramural re-entry anchored to fibrosis-insulated atrial bundles. Published on

  15. Computerized analysis of the 12-lead electrocardiogram to identify epicardial ventricular tachycardia exit sites.

    Science.gov (United States)

    Yokokawa, Miki; Jung, Dae Yon; Joseph, Kim K; Hero, Alfred O; Morady, Fred; Bogun, Frank

    2014-11-01

    Twelve-lead electrocardiogram (ECG) criteria for epicardial ventricular tachycardia (VT) origins have been described. In patients with structural heart disease, the ability to predict an epicardial origin based on QRS morphology is limited and has been investigated only for limited regions in the heart. The purpose of this study was to determine whether a computerized algorithm is able to accurately differentiate epicardial vs endocardial origins of ventricular arrhythmias. Endocardial and epicardial pace-mapping were performed in 43 patients at 3277 sites. The 12-lead ECGs were digitized and analyzed using a mixture of gaussian model (MoG) to assess whether the algorithm was able to identify an epicardial vs endocardial origin of the paced rhythm. The MoG computerized algorithm was compared to algorithms published in prior reports. The computerized algorithm correctly differentiated epicardial vs endocardial pacing sites for 80% of the sites compared to an accuracy of 42% to 66% of other described criteria. The accuracy was higher in patients without structural heart disease than in those with structural heart disease (94% vs 80%, P = .0004) and for right bundle branch block (82%) compared to left bundle branch block morphologies (79%, P = .001). Validation studies showed the accuracy for VT exit sites to be 84%. A computerized algorithm was able to accurately differentiate the majority of epicardial vs endocardial pace-mapping sites. The algorithm is not region specific and performed best in patients without structural heart disease and with VTs having a right bundle branch block morphology. Copyright © 2014 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.

  16. Epicardial Fat: Definition, Measurements and Systematic Review of Main Outcomes

    International Nuclear Information System (INIS)

    Bertaso, Angela Gallina; Bertol, Daniela; Duncan, Bruce Bartholow; Foppa, Murilo

    2013-01-01

    Epicardial fat (EF) is a visceral fat deposit, located between the heart and the pericardium, which shares many of the pathophysiological properties of other visceral fat deposits, It also potentially causes local inflammation and likely has direct effects on coronary atherosclerosis. Echocardiography, computed tomography and magnetic resonance imaging have been used to evaluate EF, but variations between methodologies limit the comparability between these modalities. We performed a systematic review of the literature finding associations of EF with metabolic syndrome and coronary artery disease. The summarization of these associations is limited by the heterogeneity of the methods used and the populations studied, where most of the subjects were at high cardiovascular disease risk. EF is also associated with other known factors, such as obesity, diabetes mellitus, age and hypertension, which makes the interpretation of its role as an independent risk marker intricate. Based on these data, we conclude that EF is a visceral fat deposit with potential implications in coronary artery disease. We describe the reference values of EF for the different imaging modalities, even though these have not yet been validated for clinical use. It is still necessary to better define normal reference values and the risk associated with EF to further evaluate its role in cardiovascular and metabolic risk assessment in relation to other criteria currently used

  17. Automatic detection and classification of human epicardial atrial unipolar electrograms

    International Nuclear Information System (INIS)

    Dubé, B; Vinet, A; Xiong, F; Yin, Y; LeBlanc, A-R; Pagé, P

    2009-01-01

    This paper describes an unsupervised signal processing method applied to three-channel unipolar electrograms recorded from human atria. These were obtained by epicardial wires sutured on the right and left atria after coronary artery bypass surgery. Atrial (A) and ventricular (V) activations had to be detected and identified on each channel, and gathered across the channels when belonging to the same global event. The algorithm was developed and optimized on a training set of 19 recordings of 5 min. It was assessed on twenty-seven 2 h recordings taken just before the onset of a prolonged atrial fibrillation for a total of 1593697 activations that were validated and classified as normal atrial or ventricular activations (A, V) and premature atrial or ventricular activations (PAA, PVA). 99.93% of the activations were detected, and amongst these, 99.89% of the A and 99.75% of the V activations were correctly labelled. In the subset of the 39705 PAA, 99.83% were detected and 99.3% were correctly classified as A. The false positive rate was 0.37%. In conclusion, a reliable fully automatic detection and classification algorithm was developed that can detect and discriminate A and V activations from atrial recordings. It can provide the time series needed to develop a monitoring system aiming to identify dynamic predictors of forthcoming cardiac events such as postoperative atrial fibrillation

  18. Epicardial Fat: Definition, Measurements and Systematic Review of Main Outcomes

    Energy Technology Data Exchange (ETDEWEB)

    Bertaso, Angela Gallina [Programa de Pós-Graduação em Ciências da Saúde: Cardiologia e Ciências Cardiovasculares - Universidade Federal do Rio Grande do Sul, Porto Alegre (Brazil); Bertol, Daniela [Programa de Pós-Graduação em Epidemiologia - Universidade Federal do Rio Grande do Sul, Porto Alegre (Brazil); Duncan, Bruce Bartholow; Foppa, Murilo, E-mail: mfoppa@cardiol.br [Programa de Pós-Graduação em Ciências da Saúde: Cardiologia e Ciências Cardiovasculares - Universidade Federal do Rio Grande do Sul, Porto Alegre (Brazil); Programa de Pós-Graduação em Epidemiologia - Universidade Federal do Rio Grande do Sul, Porto Alegre (Brazil)

    2013-07-15

    Epicardial fat (EF) is a visceral fat deposit, located between the heart and the pericardium, which shares many of the pathophysiological properties of other visceral fat deposits, It also potentially causes local inflammation and likely has direct effects on coronary atherosclerosis. Echocardiography, computed tomography and magnetic resonance imaging have been used to evaluate EF, but variations between methodologies limit the comparability between these modalities. We performed a systematic review of the literature finding associations of EF with metabolic syndrome and coronary artery disease. The summarization of these associations is limited by the heterogeneity of the methods used and the populations studied, where most of the subjects were at high cardiovascular disease risk. EF is also associated with other known factors, such as obesity, diabetes mellitus, age and hypertension, which makes the interpretation of its role as an independent risk marker intricate. Based on these data, we conclude that EF is a visceral fat deposit with potential implications in coronary artery disease. We describe the reference values of EF for the different imaging modalities, even though these have not yet been validated for clinical use. It is still necessary to better define normal reference values and the risk associated with EF to further evaluate its role in cardiovascular and metabolic risk assessment in relation to other criteria currently used.

  19. New method for imaging epicardial motion with scattered radiation

    International Nuclear Information System (INIS)

    Tilley, D.G.

    1976-01-01

    A new method for monitoring cardiac motion is described which employs the secondary radiation emerging from the thorax during fluoroscopic x-ray examination of the heart. The motion of selected points on the heart's epicardial surface can be investigated by detecting the intensity variations of radiation scattered in the local vicinity of the heart-lung border. Also discussed are the radiation detectors and signal processing electronics used to produce a voltage analog depicting the periodic displacements of the heart surface. Digital data processing methods are described which are used to accomplish a transformation from a time scale for representing surface motion, to a frequency scale that is better suited for the quantitative analysis of the heart's myocardial dynamics. The dynamic radiographic technique is compared to other methods such as electrocardiography, phonocardiography, radarkymography, and echocardiography; which are also used to sense the dynamic state of the heart. A three-dimensional Monte Carlo computer code is used to investigate the transport of x-radiation in the canine thorax. The Monte Carlo computer studies are used to explore the capabilities and limitations of the dynamic radiograph as it is used to sense motions of the canine heart. Animal studies were conducted with the dynamic radiograph to determine the reproducibility of the examination procedure. Canine case studies are reported showing the effects of increased myocardial contractility resulting from intervention with these inotropic agents

  20. Simultaneous Epicardial and Noncontact Endocardial Mapping of the Canine Right Atrium: Simulation and Experiment

    Science.gov (United States)

    Sabouri, Sepideh; Matene, Elhacene; Vinet, Alain; Richer, Louis-Philippe; Cardinal, René; Armour, J. Andrew; Pagé, Pierre; Kus, Teresa; Jacquemet, Vincent

    2014-01-01

    Epicardial high-density electrical mapping is a well-established experimental instrument to monitor in vivo the activity of the atria in response to modulations of the autonomic nervous system in sinus rhythm. In regions that are not accessible by epicardial mapping, noncontact endocardial mapping performed through a balloon catheter may provide a more comprehensive description of atrial activity. We developed a computer model of the canine right atrium to compare epicardial and noncontact endocardial mapping. The model was derived from an experiment in which electroanatomical reconstruction, epicardial mapping (103 electrodes), noncontact endocardial mapping (2048 virtual electrodes computed from a 64-channel balloon catheter), and direct-contact endocardial catheter recordings were simultaneously performed in a dog. The recording system was simulated in the computer model. For simulations and experiments (after atrio-ventricular node suppression), activation maps were computed during sinus rhythm. Repolarization was assessed by measuring the area under the atrial T wave (ATa), a marker of repolarization gradients. Results showed an epicardial-endocardial correlation coefficients of 0.80 and 0.63 (two dog experiments) and 0.96 (simulation) between activation times, and a correlation coefficients of 0.57 and 0.46 (two dog experiments) and 0.92 (simulation) between ATa values. Despite distance (balloon-atrial wall) and dimension reduction (64 electrodes), some information about atrial repolarization remained present in noncontact signals. PMID:24598778

  1. Is epicardial adipose tissue, assessed by echocardiography, a reliable method for visceral adipose tissue prediction?

    Science.gov (United States)

    Silaghi, Alina Cristina; Poantă, Laura; Valea, Ana; Pais, Raluca; Silaghi, Horatiu

    2011-03-01

    Epicardial adipose tissue is an ectopic fat storage at the heart surface in direct contact with the coronary arteries. It is considered a metabolically active tissue, being a local source of pro-inflammatory factors that contribute to the pathogenesis of coronary artery disease. The AIM of our study was to establish correlations between echocardiographic assessment of epicardial adipose tissue and anthropometric and ultrasound measurements of the central and peripheral fat depots. The study was conducted on 22 patients with or without coronaropathy. Epicardial adipose tissue was measured using Aloka Prosound α 10 machine with a 3.5-7.5 MHz variable-frequency transducer and subcutaneous and visceral fat with Esaote Megas GPX machine and 3.5-7.5 MHz variable frequency transducer. Epicardial adipose tissue measured by echocardiography is correlated with waist circumference (p < 0.05), visceral adipose tissue thickness measured by ultrasonography (US) and is not correlated with body mass index (p = 0.315), hip and thigh circumference or subcutaneous fat thickness measured by US. Our study confirms that US assessment of epicardial fat correlates with anthropometric and US measurements of the central fat, representing an indirect but reliable marker of the visceral fat.

  2. Simultaneous epicardial and noncontact endocardial mapping of the canine right atrium: simulation and experiment.

    Science.gov (United States)

    Sabouri, Sepideh; Matene, Elhacene; Vinet, Alain; Richer, Louis-Philippe; Cardinal, René; Armour, J Andrew; Pagé, Pierre; Kus, Teresa; Jacquemet, Vincent

    2014-01-01

    Epicardial high-density electrical mapping is a well-established experimental instrument to monitor in vivo the activity of the atria in response to modulations of the autonomic nervous system in sinus rhythm. In regions that are not accessible by epicardial mapping, noncontact endocardial mapping performed through a balloon catheter may provide a more comprehensive description of atrial activity. We developed a computer model of the canine right atrium to compare epicardial and noncontact endocardial mapping. The model was derived from an experiment in which electroanatomical reconstruction, epicardial mapping (103 electrodes), noncontact endocardial mapping (2048 virtual electrodes computed from a 64-channel balloon catheter), and direct-contact endocardial catheter recordings were simultaneously performed in a dog. The recording system was simulated in the computer model. For simulations and experiments (after atrio-ventricular node suppression), activation maps were computed during sinus rhythm. Repolarization was assessed by measuring the area under the atrial T wave (ATa), a marker of repolarization gradients. Results showed an epicardial-endocardial correlation coefficients of 0.80 and 0.63 (two dog experiments) and 0.96 (simulation) between activation times, and a correlation coefficients of 0.57 and 0.46 (two dog experiments) and 0.92 (simulation) between ATa values. Despite distance (balloon-atrial wall) and dimension reduction (64 electrodes), some information about atrial repolarization remained present in noncontact signals.

  3. Simultaneous epicardial and noncontact endocardial mapping of the canine right atrium: simulation and experiment.

    Directory of Open Access Journals (Sweden)

    Sepideh Sabouri

    Full Text Available Epicardial high-density electrical mapping is a well-established experimental instrument to monitor in vivo the activity of the atria in response to modulations of the autonomic nervous system in sinus rhythm. In regions that are not accessible by epicardial mapping, noncontact endocardial mapping performed through a balloon catheter may provide a more comprehensive description of atrial activity. We developed a computer model of the canine right atrium to compare epicardial and noncontact endocardial mapping. The model was derived from an experiment in which electroanatomical reconstruction, epicardial mapping (103 electrodes, noncontact endocardial mapping (2048 virtual electrodes computed from a 64-channel balloon catheter, and direct-contact endocardial catheter recordings were simultaneously performed in a dog. The recording system was simulated in the computer model. For simulations and experiments (after atrio-ventricular node suppression, activation maps were computed during sinus rhythm. Repolarization was assessed by measuring the area under the atrial T wave (ATa, a marker of repolarization gradients. Results showed an epicardial-endocardial correlation coefficients of 0.80 and 0.63 (two dog experiments and 0.96 (simulation between activation times, and a correlation coefficients of 0.57 and 0.46 (two dog experiments and 0.92 (simulation between ATa values. Despite distance (balloon-atrial wall and dimension reduction (64 electrodes, some information about atrial repolarization remained present in noncontact signals.

  4. Evaluating the role of reentrant output-to-input feedback in simultaneous pattern processing

    Energy Technology Data Exchange (ETDEWEB)

    Achler, Tsvi [Los Alamos National Laboratory

    2010-01-01

    Simultaneous Pattern Processing (SPP) is defined as the ability to identify simultaneous-intermixed patterns without isolating them individually (e.g. without separating each pattern in space and processing it individually). Enhanced SPP ability is beneficial for many real-life applications such as scene understanding, separating simultaneous voices, and identifying odorant or taste mixes. The first part of this work identifies how SPP scenarios are problematic to models which train synaptic connections or implement lateral inhibition and quantifies how subtle difficulties lead to complex combinatorial issues. The second part of this work proposes and tests an algorithm motivated by Ubiquitous re-entrant 'output to input' connections found throughout sensory processing regions of the brain. Through these connections the model proposes a dynamic gain mechanism that can provide functionality normally achieved through variable synaptic connections. The re-entrant structure combined with enhanced perfonnance suggests the brain may utilize this configuration for SPP flexibility.

  5. [AV-reentrant tachycardia and Wolff-Parkinson-White syndrome : Diagnosis and treatment].

    Science.gov (United States)

    Voss, Frederik; Eckardt, Lars; Busch, Sonia; Estner, Heidi L; Steven, Daniel; Sommer, Philipp; von Bary, Christian; Neuberger, Hans-Ruprecht

    2016-12-01

    The AV-reentrant tachycardia (AVRT) is a supraventricular tachycardia with an incidence of 1-3/1000. The pathophysiological basis is an accessory atrioventricular pathway (AP). Patients with AVRT typically present with palpitations, an on-off characteristic, anxiety, dyspnea, and polyuria. This type of tachycardia may often be terminated by vagal maneuvers. Although the clinical presentation of AVRT is quite similar to AV-nodal reentrant tachycardias, the correct diagnosis is often facilitated by analyzing a standard 12-lead ECG at normal heart rate showing ventricular preexcitation. Curative catheter ablation of the AP represents the therapy of choice in symptomatic patients. This article is the fourth part of a series written to improve the professional education of young electrophysiologists. It explains pathophysiology, symptoms, and electrophysiological findings of an invasive EP study. It focusses on mapping and ablation of accessory pathways.

  6. Modeling Perceptual Grouping and Figure-Ground Segregation by Means of Active Reentrant Connections

    Science.gov (United States)

    Sporns, Olaf; Tononi, Giulio; Edelman, Gerald M.

    1991-01-01

    The segmentation of visual scenes is a fundamental process of early vision, but the underlying neural mechanisms are still largely unknown. Theoretical considerations as well as neurophysiological findings point to the importance in such processes of temporal correlations in neuronal activity. In a previous model, we showed that reentrant signaling among rhythmically active neuronal groups can correlate responses along spatially extended contours. We now have modified and extended this model to address the problems of perceptual grouping and figure-ground segregation in vision. A novel feature is that the efficacy of the connections is allowed to change on a fast time scale. This results in active reentrant connections that amplify the correlations among neuronal groups. The responses of the model are able to link the elements corresponding to a coherent figure and to segregate them from the background or from another figure in a way that is consistent with the so-called Gestalt laws.

  7. Reentrant spin glass ordering in an Fe-based bulk metallic glass

    Energy Technology Data Exchange (ETDEWEB)

    Luo, Qiang; Shen, Jun, E-mail: junshen@tongji.edu.cn [School of Materials Science and Engineering, Tongji University, Shanghai 201804 (China)

    2015-02-07

    We report the results of the complex susceptibility, temperature, and field dependence of DC magnetization and the nonequilibrium dynamics of a bulk metallic glass Fe{sub 40}Co{sub 8}Cr{sub 15}Mo{sub 14}C{sub 15}B{sub 6}Er{sub 2}. Solid indication of the coexistence of reentrant spin glass (SG) and ferromagnetic orderings is determined from both DC magnetization and AC susceptibility under different DC fields. Dynamics scaling of AC susceptibility indicates critical slowing down to a reentrant SG state with a static transition temperature T{sub s} = ∼17.8 K and a dynamic exponent zv = ∼7.3. The SG nature is further corroborated from chaos and memory effects, magnetic hysteresis, and aging behavior. We discuss the results in terms of the competition among random magnetic anisotropy and exchange interactions and compare them with simulation predictions.

  8. Modeling perceptual grouping and figure-ground segregation by means of active reentrant connections.

    Science.gov (United States)

    Sporns, O; Tononi, G; Edelman, G M

    1991-01-01

    The segmentation of visual scenes is a fundamental process of early vision, but the underlying neural mechanisms are still largely unknown. Theoretical considerations as well as neurophysiological findings point to the importance in such processes of temporal correlations in neuronal activity. In a previous model, we showed that reentrant signaling among rhythmically active neuronal groups can correlate responses along spatially extended contours. We now have modified and extended this model to address the problems of perceptual grouping and figure-ground segregation in vision. A novel feature is that the efficacy of the connections is allowed to change on a fast time scale. This results in active reentrant connections that amplify the correlations among neuronal groups. The responses of the model are able to link the elements corresponding to a coherent figure and to segregate them from the background or from another figure in a way that is consistent with the so-called Gestalt laws.

  9. 2D reentrant auxetic structures of graphene/CNT networks for omnidirectionally stretchable supercapacitors.

    Science.gov (United States)

    Kim, Byoung Soo; Lee, Kangsuk; Kang, Seulki; Lee, Soyeon; Pyo, Jun Beom; Choi, In Suk; Char, Kookheon; Park, Jong Hyuk; Lee, Sang-Soo; Lee, Jonghwi; Son, Jeong Gon

    2017-09-14

    Stretchable energy storage systems are essential for the realization of implantable and epidermal electronics. However, high-performance stretchable supercapacitors have received less attention because currently available processing techniques and material structures are too limited to overcome the trade-off relationship among electrical conductivity, ion-accessible surface area, and stretchability of electrodes. Herein, we introduce novel 2D reentrant cellular structures of porous graphene/CNT networks for omnidirectionally stretchable supercapacitor electrodes. Reentrant structures, with inwardly protruded frameworks in porous networks, were fabricated by the radial compression of vertically aligned honeycomb-like rGO/CNT networks, which were prepared by a directional crystallization method. Unlike typical porous graphene structures, the reentrant structure provided structure-assisted stretchability, such as accordion and origami structures, to otherwise unstretchable materials. The 2D reentrant structures of graphene/CNT networks maintained excellent electrical conductivities under biaxial stretching conditions and showed a slightly negative or near-zero Poisson's ratio over a wide strain range because of their structural uniqueness. For practical applications, we fabricated all-solid-state supercapacitors based on 2D auxetic structures. A radial compression process up to 1/10 th densified the electrode, significantly increasing the areal and volumetric capacitances of the electrodes. Additionally, vertically aligned graphene/CNT networks provided a plentiful surface area and induced sufficient ion transport pathways for the electrodes. Therefore, they exhibited high gravimetric and areal capacitance values of 152.4 F g -1 and 2.9 F cm -2 , respectively, and had an excellent retention ratio of 88% under a biaxial strain of 100%. Auxetic cellular and vertically aligned structures provide a new strategy for the preparation of robust platforms for stretchable

  10. Modeling perceptual grouping and figure-ground segregation by means of active reentrant connections.

    OpenAIRE

    Sporns, O; Tononi, G; Edelman, G M

    1991-01-01

    The segmentation of visual scenes is a fundamental process of early vision, but the underlying neural mechanisms are still largely unknown. Theoretical considerations as well as neurophysiological findings point to the importance in such processes of temporal correlations in neuronal activity. In a previous model, we showed that reentrant signaling among rhythmically active neuronal groups can correlate responses along spatially extended contours. We now have modified and extended this model ...

  11. The impact of surface geometry, cavitation, and condensation on wetting transitions: posts and reentrant structures

    Science.gov (United States)

    Panter, J. R.; Kusumaatmaja, H.

    2017-03-01

    The fundamental impacts of surface geometry on the stability of wetting states, and the transitions between them are elucidated for square posts and reentrant structures in three dimensions. We identify three principal outcomes of particular importance for future surface design of liquid-repellent surfaces. Firstly, we demonstrate and quantify how capillary condensation and vapour cavitation affect wetting state stabilities. At high contact angles, cavitation is enhanced about wide, closely-spaced square posts, leading to the existence of suspended states without an associated collapsed state. At low contact angles, narrow reentrant pillars suppress condensation and enable the suspension of even highly wetting liquids. Secondly, two distinct collapse mechanisms are observed for 3D reentrant geometries, base contact and pillar contact, which are operative at different pillar heights. As well as morphological differences in the interface of the penetrating liquid, each mechanism is affected differently by changes in the contact angle with the solid. Finally, for highly-wetting liquids, condensates are shown to critically modify the transition pathways in both the base contact and pillar contact modes.

  12. Epicardial Ablation: Prevention of Phrenic Nerve Damage by Pericardial Injection of Saline and the Use of a Steerable Sheath

    Directory of Open Access Journals (Sweden)

    Kars Neven, MD

    2014-03-01

    Full Text Available Because of the close proximity of the phrenic nerve to the pericardium, phrenic nerve damage caused by epicardial ablation can easily occur. We report two cases of epicardial VT ablation where pericardial injection of saline, combined with the use of a steerable sheath, successfully prevents the phrenic nerve from being damaged.

  13. Changes in myocardial fluid filtration are reflected in epicardial lymph pressure

    NARCIS (Netherlands)

    VanTeeffelen, J. W.; Merkus, D.; Vergroesen, I.; Spaan, J. A.

    1997-01-01

    The effect of increased fluid filtration on stopped-flow epicardial lymph pressure (P(lymph)), used as an indicator of myocardial interstitial volume, was investigated in the anesthetized open-chest dog. Histamine infusion resulted in an increased systolic peak in the P(lymph) signal together with

  14. Epicardial adipose tissue volume estimation by postmortem computed tomography of eviscerated hearts

    DEFF Research Database (Denmark)

    Hindsø, Louise; Jakobsen, Lykke S; Jacobsen, Christina

    2017-01-01

    Epicardial adipose tissue (EAT) may play a role in the development of coronary artery disease. The purpose of this study was to evaluate a method based on postmortem computed tomography (PMCT) for the estimation of EAT volume. We PMCT-scanned the eviscerated hearts of 144 deceased individuals, wh...

  15. Epicardial excitation pattern as observed in the isolated revived and perfused fetal human heart

    NARCIS (Netherlands)

    Durrer, D.; Büller, J.; Graaff, P.; Lo, G.I.; Meijler, F.L.

    1961-01-01

    The resuscitated fetal human heart can be used as an experimental tooI for the investigation of the excitatory process in the human heart. During perfusion the configuration of the epicardial electrocardiograms does not change appreciably. For accurate recording permitting a detailed analysis, the

  16. Primary PCI: time to change focus from epicardial reperfusion towards protection of the microvasculature

    NARCIS (Netherlands)

    van Lavieren, Martijn A.; van de Hoef, Tim P.; Piek, Jan J.

    2014-01-01

    Myocardial tissue perfusion remains compromised in 30-40% of patients with ST-segment elevation myocardial infarction (STEMI) despite restored epicardial patency after primary percutaneous coronary intervention (pPCI). This phenomenon is attributed to microvascular dysfunction secondary to numerous

  17. Association between endothelial dysfunction, epicardial fat and subclinical atherosclerosis during menopause.

    Science.gov (United States)

    Cabrera-Rego, Julio Oscar; Navarro-Despaigne, Daisy; Staroushik-Morel, Liudmila; Díaz-Reyes, Karel; Lima-Martínez, Marcos M; Iacobellis, Gianluca

    Menopausal transition is critical for the development of early, subclinical vascular damage. Multiple factors, such as atherosclerosis, increased epicardial fat, and endothelial dysfunction can play a role. Hence, the objective of this study was the comparison of epicardial adipose tissue and carotid intima media thickness in order to establish the best predictor of carotid stiffness in middle-aged women with endothelial dysfunction. A total of 43 healthy women aged 40-59 years old with endothelial dysfunction previously demonstrated by flow mediated dilation were recruited to have anthropometric, biochemical, hormonal and ultrasound determinations of carotid intima media thickness and epicardial fat thickness. Carotid arterial stiffness parameters (local pulse wave velocity [4.7±0.7 vs 4.8±0.5 vs 5.6±0.5m/s, respectively, p<0.001], pressure strain elastic modulus [55.2±13.4 vs 59.2±11.8 vs 81.9±15.6kPa, respectively, p<0.001], arterial stiffness index β [4.4±1.4 vs 5.0±1.1 vs 6.4±1.3, respectively, p<0.001]) and epicardial fat thickness (2.98±1.4 vs 3.28±1.9 vs 4.70±1.0mm, respectively, p=0.007) showed a significant and proportional increase in the group of late post-menopausal women when compared to early post-menopausal and pre-menopausal groups, respectively. Among body fat markers, epicardial fat was the strongest predictor of local pulse wave velocity, independent of age. In menopausal women with endothelial dysfunction, menopausal transition is associated with increased carotid arterial stiffness and epicardial fat thickness, independent of age. Ultrasound measured epicardial fat was a better independent predictor of arterial stiffness than carotid intima media thickness in these women. Copyright © 2017 Sociedad Española de Arteriosclerosis. Publicado por Elsevier España, S.L.U. All rights reserved.

  18. Focal and Reentrant Mechanisms of Torsades de Pointes: EAD, Reentry, or Chimera?

    Directory of Open Access Journals (Sweden)

    Yuji Murakawa, MD

    2011-01-01

    Full Text Available Torsades de pointes (TdP. is characterized not only by its electrocardiographic morphology but also by a tendency to spontaneously terminate. Although clinical and experimental studies suggested that TdP is triggered exclusively by early afterdepolarization, the reentrant mechanism seems to play a certain role in its maintenance. In this article, I review the studies that investigated the origin and activation sequences of the twisting QRS complexes of TdP, and discuss whether it is fortunate or unfortunate for us if TdP has something to do with reentry.

  19. Familial atrioventricular nodal re-entrant tachycardia: A case seriers and a systematic review

    Directory of Open Access Journals (Sweden)

    Muthiah Subramanian

    2017-11-01

    Full Text Available Multiple reports of familial clustering suggest that genetic factors may contribute in the pathogenesis of atrioventricular nodal re-entrant tachycardia (AVNRT. We report three cases of AVNRT in a father and his two sons along with a review of literature of other similar cases. Electrophysiological studies induced typical AVNRT, which was successfully eliminated by radiofrequency ablation in all of them. Of the 22 reported cases, 96% had typical (slow-fast variant of AVNRT. The predominant pattern of inheritance appears to be autosomal dominant, though other patterns may exist. Further research is needed to understand the genetic influence of AVNRT and its pathophysiology. Keywords: Familial, AVNRT, Tachycardia

  20. Electropolishing on single-cell: (TESLA, Reentrant and Low Loss shapes) Comsol modelling

    International Nuclear Information System (INIS)

    Bruchon, M.

    2007-01-01

    In the framework of improvement of cavity electropolishing, modelling permits to evaluate some parameters not easily accessible by experiments and can also help us to guide them. Different laboratories (DESY, Fermilab) work on electro or chemical polishing modelling with different approaches and softwares. At CEA Saclay, COMSOL software is used to model horizontal electropolishing of cavity in two dimensions. The goal of this study has been motivated by improvement of our electropolishing setup by modifying the arrival of the acid. The influence of a protuberant cathode has been evaluated and compared for different shapes of single cell cavities: TESLA, ILC Low Loss (LL ILC ), and ILC Reentrant (RE ILC ). (author)

  1. Minimally Invasive Epicardial Pacemaker Implantation in Neonates with Congenital Heart Block.

    Science.gov (United States)

    Costa, Roberto; Silva, Katia Regina da; Martinelli Filho, Martino; Carrillo, Roger

    2017-10-01

    Few studies have characterized the surgical outcomes following epicardial pacemaker implantation in neonates with congenital complete atrioventricular block (CCAVB). This study sought to assess the long-term outcomes of a minimally invasive epicardial approach using a subxiphoid access for pacemaker implantation in neonates. Between July 2002 and February 2015, 16 consecutive neonates underwent epicardial pacemaker implantation due to CCAVB. Among these, 12 (75.0%) had congenital heart defects associated with CCAVB. The patients had a mean age of 4.7 ± 5.3 days and nine (56.3%) were female. Bipolar steroid-eluting epicardial leads were implanted in all patients through a minimally invasive subxiphoid approach and fixed on the diaphragmatic ventricular surface. The pulse generator was placed in an epigastric submuscular position. All procedures were successful, with no perioperative complications or early deaths. Mean operating time was 90.2 ± 16.8 minutes. None of the patients displayed pacing or sensing dysfunction, and all parameters remained stable throughout the follow-up period of 4.1 ± 3.9 years. Three children underwent pulse generator replacement due to normal battery depletion at 4.0, 7.2, and 9.0 years of age without the need of ventricular lead replacement. There were two deaths at 12 and 325 days after pacemaker implantation due to bleeding from thrombolytic use and progressive refractory heart failure, respectively. Epicardial pacemaker implantation through a subxiphoid approach in neonates with CCAVB is technically feasible and associated with excellent surgical outcomes and pacing lead longevity.

  2. Resonance circuits for adiabatic circuits

    Directory of Open Access Journals (Sweden)

    C. Schlachta

    2003-01-01

    Full Text Available One of the possible techniques to reduces the power consumption in digital CMOS circuits is to slow down the charge transport. This slowdown can be achieved by introducing an inductor in the charging path. Additionally, the inductor can act as an energy storage element, conserving the energy that is normally dissipated during discharging. Together with the parasitic capacitances from the circuit a LCresonant circuit is formed.

  3. A case of typical atrioventricular nodal (AVN) reentrant tachycardia confined to the compact AV node, showing a variety of rare electrophysiological findings, including eccentric AVN echoes

    OpenAIRE

    Tanaka, Kazushi; Shiotani, Shinji; Fukuda, Keisuke; Fujihara, Masahiko; Higashimori, Akihiro; Morioka, Nobuyuki; Yokoi, Yoshiaki; Fujimura, Osamu

    2014-01-01

    Herein, we report the case of a 49-year-old woman with typical atrioventricular nodal (AVN) reentrant tachycardia, confined to the compact atrioventricular node, showing numerous rare electrophysiological findings such as unique AVN reentrant echoes, double ventricular responses, latent retrograde dual AVN pathways, antegrade triple AVN pathways, and longitudinal dissociation within the lower final common pathway.

  4. A case of typical atrioventricular nodal (AVN reentrant tachycardia confined to the compact AV node, showing a variety of rare electrophysiological findings, including eccentric AVN echoes

    Directory of Open Access Journals (Sweden)

    Kazushi Tanaka, M.D., Ph.D.

    2014-12-01

    Full Text Available Herein, we report the case of a 49-year-old woman with typical atrioventricular nodal (AVN reentrant tachycardia, confined to the compact atrioventricular node, showing numerous rare electrophysiological findings such as unique AVN reentrant echoes, double ventricular responses, latent retrograde dual AVN pathways, antegrade triple AVN pathways, and longitudinal dissociation within the lower final common pathway.

  5. Electronic circuit encyclopedia 2

    International Nuclear Information System (INIS)

    Park, Sun Ho

    1992-10-01

    This book is composed of 15 chapters, which are amplification of weak signal and measurement circuit audio control and power amplification circuit, data transmission and wireless system, forwarding and isolation, signal converting circuit, counter and comparator, discriminator circuit, oscillation circuit and synthesizer, digital and circuit on computer image processing circuit, sensor drive circuit temperature sensor circuit, magnetic control and application circuit, motor driver circuit, measuring instrument and check tool and power control and stability circuit.

  6. Electronic circuit encyclopedia 2

    Energy Technology Data Exchange (ETDEWEB)

    Park, Sun Ho

    1992-10-15

    This book is composed of 15 chapters, which are amplification of weak signal and measurement circuit audio control and power amplification circuit, data transmission and wireless system, forwarding and isolation, signal converting circuit, counter and comparator, discriminator circuit, oscillation circuit and synthesizer, digital and circuit on computer image processing circuit, sensor drive circuit temperature sensor circuit, magnetic control and application circuit, motor driver circuit, measuring instrument and check tool and power control and stability circuit.

  7. Charge ordering transition in GdBaCo2O5: Evidence of reentrant behavior

    Science.gov (United States)

    Allieta, M.; Scavini, M.; Lo Presti, L.; Coduri, M.; Loconte, L.; Cappelli, S.; Oliva, C.; Ghigna, P.; Pattison, P.; Scagnoli, V.

    2013-12-01

    We present a detailed study on the charge ordering transition in a GdBaCo2O5.0 system by combining high-resolution synchrotron powder/single-crystal diffraction with electron paramagnetic resonance experiments as a function of temperature. We found a second-order structural phase transition at TCO = 247 K (Pmmm to Pmma) associated with the onset of long-range charge ordering. At Tmin ≈ 1.2TCO, the electron paramagnetic resonance linewidth rapidly broadens, providing evidence of antiferromagnetic spin fluctuations. This likely indicates that, analogously to manganites, the long-range antiferromagnetic order in GdBaCo2O5.0 sets in at ≈TCO. Pair distribution function analysis of diffraction data revealed signatures of structural inhomogeneities at low temperature. By comparing the average and local bond valences, we found that above TCO the local structure is consistent with a fully random occupation of Co2+ and Co3+ in a 1:1 ratio and with a complete charge ordering below TCO. Below T ≈ 100 K the charge localization is partially melted at the local scale, suggesting a reentrant behavior of charge ordering. This result is supported by the weakening of superstructure reflections and the temperature evolution of electron paramagnetic resonance linewidth that is consistent with paramagnetic reentrant behavior reported in the GdBaCo2O5.5 parent compound.

  8. A Compact Microwave Microfluidic Sensor Using a Re-Entrant Cavity.

    Science.gov (United States)

    Hamzah, Hayder; Abduljabar, Ali; Lees, Jonathan; Porch, Adrian

    2018-03-19

    A miniaturized 2.4 GHz re-entrant cavity has been designed, manufactured and tested as a sensor for microfluidic compositional analysis. It has been fully evaluated experimentally with water and common solvents, namely methanol, ethanol, and chloroform, with excellent agreement with the expected behaviour predicted by the Debye model. The sensor's performance has also been assessed for analysis of segmented flow using water and oil. The samples' interaction with the electric field in the gap region has been maximized by aligning the sample tube parallel to the electric field in this region, and the small width of the gap (typically 1 mm) result in a highly localised complex permittivity measurement. The re-entrant cavity has simple mechanical geometry, small size, high quality factor, and due to the high concentration of electric field in the gap region, a very small mode volume. These factors combine to result in a highly sensitive, compact sensor for both pure liquids and liquid mixtures in capillary or microfluidic environments.

  9. The Theory of the Reentrant Effect in Susceptibility of Cylindrical Mesoscopic Samples

    International Nuclear Information System (INIS)

    Gogadze, G.A.

    2006-01-01

    A theory has been developed to explain the anomalous behavior of the magnetic susceptibility of a normal metal-superconductor (NS) structure in weak magnetic fields at milli kelvin temperatures. The effect was discovered experimentally [A. C. Mota et al., Phys. Rev. Lett. 65, 1514 (1990)]. In cylindrical superconducting samples covered with a thin normal pure metal layer, the susceptibility exhibited a reentrant effect: it started to increase unexpectedly when the temperature was lowered below 100 mK. The effect was observed in mesoscopic NS structures when the N and S metals were in good electric contact. The theory proposed is essentially based on the properties of the Andreev levels in the normal metal. When the magnetic field (or temperature) changes, each of the Andreev levels coincides from time to time with the chemical potential of the metal. As a result, the state of the NS structure experiences strong degeneracy, and the quasiparticle density of states exhibits resonance spikes. This generates a large paramagnetic contribution to the susceptibility, which adds to the diamagnetic contribution, thus leading to the reentrant effect. The explanation proposed was obtained within the model of free electrons. The theory provides a good description of the experimental results

  10. A Compact Microwave Microfluidic Sensor Using a Re-Entrant Cavity

    Directory of Open Access Journals (Sweden)

    Hayder Hamzah

    2018-03-01

    Full Text Available A miniaturized 2.4 GHz re-entrant cavity has been designed, manufactured and tested as a sensor for microfluidic compositional analysis. It has been fully evaluated experimentally with water and common solvents, namely methanol, ethanol, and chloroform, with excellent agreement with the expected behaviour predicted by the Debye model. The sensor’s performance has also been assessed for analysis of segmented flow using water and oil. The samples’ interaction with the electric field in the gap region has been maximized by aligning the sample tube parallel to the electric field in this region, and the small width of the gap (typically 1 mm result in a highly localised complex permittivity measurement. The re-entrant cavity has simple mechanical geometry, small size, high quality factor, and due to the high concentration of electric field in the gap region, a very small mode volume. These factors combine to result in a highly sensitive, compact sensor for both pure liquids and liquid mixtures in capillary or microfluidic environments.

  11. Reentrant behavior in the nearest-neighbor Ising antiferromagnet in a magnetic field

    Science.gov (United States)

    Neto, Minos A.; de Sousa, J. Ricardo

    2004-12-01

    Motived by the H-T phase diagram in the bcc Ising antiferromagnetic with nearest-neighbor interactions obtained by Monte Carlo simulation [Landau, Phys. Rev. B 16, 4164 (1977)] that shows a reentrant behavior at low temperature, with two critical temperatures in magnetic field about 2% greater than the critical value Hc=8J , we apply the effective field renormalization group (EFRG) approach in this model on three-dimensional lattices (simple cubic-sc and body centered cubic-bcc). We find that the critical curve TN(H) exhibits a maximum point around of H≃Hc only in the bcc lattice case. We also discuss the critical behavior by the effective field theory in clusters with one (EFT-1) and two (EFT-2) spins, and a reentrant behavior is observed for the sc and bcc lattices. We have compared our results of EFRG in the bcc lattice with Monte Carlo and series expansion, and we observe a good accordance between the methods.

  12. 3D Printed Auxetic Mechanical Metamaterial with Chiral Cells and Re-entrant Cores.

    Science.gov (United States)

    Jiang, Yunyao; Li, Yaning

    2018-02-05

    By combining the two basic deformation mechanisms for auxetic open-cell metamaterials, re-entrant angle and chirality, new hybrid chiral mechanical metamaterials are designed and fabricated via a multi-material 3D printer. Results from mechanical experiments on the 3D printed prototypes and systematic Finite Element (FE) simulations show that the new designs can achieve subsequential cell-opening mechanism under a very large range of overall strains (2.91%-52.6%). Also, the effective stiffness, the Poisson's ratio and the cell-opening rate of the new designs can be tuned in a wide range by tailoring the two independent geometric parameters: the cell size ratio [Formula: see text], and re-entrant angle θ. As an example application, a sequential particle release mechanism of the new designs was also systematically explored. This mechanism has potential application in drug delivery. The present new design concepts can be used to develop new multi-functional smart composites, sensors and/or actuators which are responsive to external load and/or environmental conditions.

  13. Reentrant high-magnetic field superconductivity in a clean two-dimensional superconductor with shallow band

    Science.gov (United States)

    Koshelev, Alexei E.; Song, Kok Wee

    We investigate the superconducting instability in the magnetic field for a clean two-dimensional multiple-band superconductor in the vicinity of the Lifshitz transition when one of the bands is very shallow. Due to a small number of carriers in this band, the quasiclassical Werthamer-Helfand approximation breaks down and Landau quantization has to be taken into account. We found that the transition temperature Tc 2 (H) has giant oscillations and is resonantly enhanced at the magnetic fields corresponding to full occupancy of the Landau levels in the shallow band. This enhancement is especially pronounced for the lowest Landau level. As a consequence, the reentrant superconducting regions in the temperature-field phase diagram emerge at low temperatures near the magnetic fields at which the chemical potential matches the Landau levels. These regions may be disconnected from the main low-field superconducting region. The specific behavior depends on the relative strength of the intraband and interband coupling constants and the effect is most pronounced when the interband coupling dominates. The Zeeman spin splitting reduces sizes of the reentrant regions and changes their location in the parameter space. The predicted behavior may realize in the gate-tuned FeSe monolayer. This work was supported by the Center for Emergent Superconductivity, an Energy Frontier Research Center funded by the US DOE, Office of Science, under Award No. DEAC0298CH1088.

  14. Catheter-based high-intensity ultrasound for epicardial ablation of the left ventricle: device design and in vivo feasiblity

    Science.gov (United States)

    Salgaonkar, Vasant A.; Nazer, Babak; Jones, Peter D.; Tanaka, Yasuaki; Martin, Alastair; Ng, Bennett; Duggirala, Srikant; Diederich, Chris J.; Gerstenfeld, Edward P.

    2015-03-01

    The development and in vivo testing of a high-intensity ultrasound thermal ablation catheter for epicardial ablation of the left ventricle (LV) is presented. Scar tissue can occur in the mid-myocardial and epicardial space in patients with nonischemic cardiomyopathy and lead to ventricular tachycardia. Current ablation technology uses radiofrequency energy, which is limited epicardially by the presence of coronary vessels, phrenic nerves, and fat. Ultrasound energy can be precisely directed to deliver targeted deep epicardial ablation while sparing intervening epicardial nerve and vessels. The proof-of-concept ultrasound applicators were designed for sub-xyphoid access to the pericardial space through a steerable 14-Fr sheath. The catheter consists of two rectangular planar transducers, for therapy (6.4 MHz) and imaging (5 MHz), mounted at the tip of a 3.5-mm flexible nylon catheter coupled and encapsulated within a custom-shaped balloon for cooling. Thermal lesions were created in the LV in a swine (n = 10) model in vivo. The ultrasound applicator was positioned fluoroscopically. Its orientation and contact with the LV were verified using A-mode imaging and a radio-opaque marker. Ablations employed 60-s exposures at 15 - 30 W (electrical power). Histology indicated thermal coagulation and ablative lesions penetrating 8 - 12 mm into the left ventricle on lateral and anterior walls and along the left anterior descending artery. The transducer design enabled successful sparing from the epicardial surface to 2 - 4 mm of intervening ventricle tissue and epicardial fat. The feasibility of targeted epicardial ablation with catheter-based ultrasound was demonstrated.

  15. A re-entrant flowshop heuristic for online scheduling of the paper path in a large scale printer

    NARCIS (Netherlands)

    Waqas, U.; Geilen, M.C.W.; Kandelaars, J.; Somers, L.J.A.M.; Basten, T.; Stuijk, S.; Vestjens, P.G.H.; Corporaal, H.

    2015-01-01

    A Large Scale Printer (LSP) is a Cyber Physical System (CPS) printing thousands of sheets per day with high quality. The print requests arrive at run-time requiring online scheduling. We capture the LSP scheduling problem as online scheduling of re-entrant flowshops with sequence dependent setup

  16. Reentrant resistance and giant Andreev back scattering in a two-dimensional electron gas coupled to superconductors

    NARCIS (Netherlands)

    den Hartog, Sander; Wees, B.J. van; Nazarov, Yu.V.; Klapwijk, T.M.; Borghs, G.

    1998-01-01

    We first present the bias-voltage dependence of the superconducting phase-dependent reduction in the differential resistance of a disordered T-shaped two-dimensional electron gas (2DEG) coupled to two superconductors. This reduction exhibits a reentrant behavior, since it first increases upon

  17. Quantification of the Arrhythmogenic Effects of Spontaneous Atrial Extrasystole Using High-Resolution Epicardial Mapping.

    Science.gov (United States)

    Teuwen, Christophe P; Kik, Charles; van der Does, Lisette J M E; Lanters, Eva A H; Knops, Paul; Mouws, Elisabeth M J P; Bogers, Ad J J C; de Groot, Natasja M S

    2018-01-01

    Atrial extrasystoles (AES) can initiate atrial fibrillation. However, the impact of spontaneous AES on intra-atrial conduction is unknown. The aims of this study were to examine conduction disorders provoked by AES and to correlate these conduction differences with patient characteristics, mapping locations, and type of AES. High-resolution epicardial mapping (electrodes N=128 or N=192; interelectrode distance, 2 mm) of the entire atrial surface was performed in patients (N=164; 69.5% male; age 67.2±10.5 years) undergoing open-chest cardiac surgery. AES were classified as premature, aberrant, or prematurely aberrant. Conduction delay and conduction block were quantified during sinus rhythm and AES and subsequently compared. Median incidence of conduction delay and conduction block during sinus rhythm was 1.2% (interquartile, 0%-2.3%) and 0.4% (interquartile, 0%-2.1%). In comparison, the median incidence of conduction delay and conduction block during 339 AES was respectively 2.8% (interquartile, 1.3%-4.6%) and 2.2% (interquartile, 0.3%-5.1%) and differed between the types of AES (prematurely aberrant>aberrant>premature). The degree of prematurity was not associated with a higher incidence of conduction disorders ( P >0.05). In contrast, a higher degree of aberrancy was associated with a higher incidence of conduction disorders; AES emerging as epicardial breakthrough provoked most conduction disorders ( P ≥0.002). AES caused most conduction disorders in patients with diabetes mellitus and left atrial dilatation ( P <0.05). Intraoperative high-resolution epicardial mapping showed that conduction disorders are mainly provoked by prematurely aberrant AES, particularly in patients with left atrial dilation and diabetes mellitus or emerging as epicardial breakthrough. © 2017 American Heart Association, Inc.

  18. Epicardial fat volume is correlated with coronary lesion and its severity

    OpenAIRE

    Bo, Xiaohong; Ma, Likun; Fan, Jili; Jiang, Zhe; Zhou, Yuansong; Zhang, Lei; Li, Wanjun

    2015-01-01

    Objective: To evaluate the correlation of epicardial adipose tissue volume (EATV) with the coronary artery lesion and its severity. Methods: Inpatients with suspicious stable angina of coronary heart lesion were recruited. For patients with coronary artery lesions in CTA, further coronary angiography (CAG) was performed to evaluate the coronary artery lesion. Gensini scoring system was employed to assess the severity of coronary artery lesions. Results: Patients were classified as coronary he...

  19. Association between increased epicardial adipose tissue volume and coronary plaque composition

    OpenAIRE

    Yamashita, Kennosuke; Yamamoto, Myong Hwa; Ebara, Seitarou; Okabe, Toshitaka; Saito, Shigeo; Hoshimoto, Koichi; Yakushiji, Tadayuki; Isomura, Naoei; Araki, Hiroshi; Obara, Chiaki; Ochiai, Masahiko

    2013-01-01

    To assess the relationship between epicardial adipose tissue volume (EATV) and plaque vulnerability in significant coronary stenosis using a 40-MHz intravascular ultrasound (IVUS) imaging system (iMap-IVUS), we analyzed 130 consecutive patients with coronary stenosis who underwent dual-source computed tomography (CT) and cardiac catheterization. Culprit lesions were imaged by iMap-IVUS before stenting. The iMAP-IVUS system classified coronary plaque components as fibrous, lipid, necrotic, or ...

  20. Epicardial phrenic nerve displacement during catheter ablation of atrial and ventricular arrhythmias: procedural experience and outcomes.

    Science.gov (United States)

    Kumar, Saurabh; Barbhaiya, Chirag R; Baldinger, Samuel H; Koplan, Bruce A; Maytin, Melanie; Epstein, Laurence M; John, Roy M; Michaud, Gregory F; Tedrow, Usha B; Stevenson, William G

    2015-08-01

    Arrhythmia origin in close proximity to the phrenic nerve (PN) can hinder successful catheter ablation. We describe our approach with epicardial PN displacement in such instances. PN displacement via percutaneous pericardial access was attempted in 13 patients (age 49±16 years, 9 females) with either atrial tachycardia (6 patients) or atrial fibrillation triggered from a superior vena cava focus (1 patient) adjacent to the right PN or epicardial ventricular tachycardia origin adjacent to the left PN (6 patients). An epicardially placed steerable sheath/4 mm-catheter combination (5 patients) or a vascular or an esophageal balloon (8 patients) was ultimately successful. Balloon placement was often difficult requiring manipulation via a steerable sheath. In 2 ventricular tachycardia cases, absence of PN capture was achieved only once the balloon was directly over the ablation catheter. In 3 atrial tachycardia patients, PN displacement was not possible with a balloon; however, a steerable sheath/catheter combination was ultimately successful. PN displacement allowed acute abolishment of all targeted arrhythmias. No PN injury occurred acutely or in follow up. Two patients developed acute complications (pleuro-pericardial fistula 1 and pericardial bleeding 1). Survival free of target arrhythmia was achieved in all atrial tachycardia patients; however, a nontargeted ventricular tachycardia recurred in 1 patient at a median of 13 months' follow up. Arrhythmias originating in close proximity to the PN can be targeted successfully with PN displacement with an epicardially placed steerable sheath/catheter combination, or balloon, but this strategy can be difficult to implement. Better tools for phrenic nerve protection are desirable. © 2015 American Heart Association, Inc.

  1. Epicardial shock-wave therapy improves ventricular function in a porcine model of ischaemic heart disease.

    Science.gov (United States)

    Holfeld, Johannes; Zimpfer, Daniel; Albrecht-Schgoer, Karin; Stojadinovic, Alexander; Paulus, Patrick; Dumfarth, Julia; Thomas, Anita; Lobenwein, Daniela; Tepeköylü, Can; Rosenhek, Raphael; Schaden, Wolfgang; Kirchmair, Rudolf; Aharinejad, Seyedhossein; Grimm, Michael

    2016-12-01

    Previously we have shown that epicardial shock-wave therapy improves left ventricular ejection fraction (LVEF) in a rat model of myocardial infarction. In the present experiments we aimed to address the safety and efficacy of epicardial shock-wave therapy in a preclinical large animal model and to further evaluate mechanisms of action of this novel therapy. Four weeks after left anterior descending (LAD) artery ligation in pigs, the animals underwent re-thoracotomy with (shock-wave group, n = 6) or without (control group, n = 5) epicardial shock waves (300 impulses at 0.38 mJ/mm 2 ) applied to the infarcted anterior wall. Efficacy endpoints were improvement of LVEF and induction of angiogenesis 6 weeks after shock-wave therapy. Safety endpoints were haemodynamic stability during treatment and myocardial damage. Four weeks after LAD ligation, LVEF decreased in both the shock-wave (43 ± 3%, p wave animals 6 weeks after treatment (62 ± 9%, p = 0.006); no improvement was observed in controls (41 ± 4%, p = 0.36), yielding a significant difference. Quantitative histology revealed significant angiogenesis 6 weeks after treatment (controls 2 ± 0.4 arterioles/high-power field vs treatment group 9 ± 3; p = 0.004). No acute or chronic adverse effects were observed. As a potential mechanism of action in vitro experiments showed stimulation of VEGF receptors after shock-wave treatment in human coronary artery endothelial cells. Epicardial shock-wave treatment in a large animal model of ischaemic heart failure exerted a positive effect on LVEF improvement and did not show any adverse effects. Angiogenesis was induced by stimulation of VEGF receptors. Copyright © 2014 John Wiley & Sons, Ltd. Copyright © 2014 John Wiley & Sons, Ltd.

  2. Epicardial fat and atrial fibrillation: current evidence, potential mechanisms, clinical implications, and future directions.

    Science.gov (United States)

    Wong, Christopher X; Ganesan, Anand N; Selvanayagam, Joseph B

    2017-05-01

    Obesity is increasingly recognized as a major modifiable determinant of atrial fibrillation (AF). Although body mass index and other clinical measures are useful indications of general adiposity, much recent interest has focused on epicardial fat, a distinct adipose tissue depot that can be readily assessed using non-invasive imaging techniques. A growing body of data from epidemiological and clinical studies has demonstrated that epicardial fat is consistently associated with the presence, severity, and recurrence of AF across a range of clinical settings. Evidence from basic science and translational studies has also suggested that arrhythmogenic mechanisms may involve adipocyte infiltration, pro-fibrotic, and pro-inflammatory paracrine effects, oxidative stress, and other pathways. Despite these advances, however, significant uncertainty exists and many questions remain unanswered. In this article, we review our present understanding of epicardial fat, including its classification and quantification, existing evidence implicating its role in AF, potential mechanisms, implications for clinicians, and future directions for research. Published on behalf of the European Society of Cardiology. All rights reserved. © The Author 2016. For permissions please email: journals.permissions@oup.com.

  3. Spectral analysis of epicardial 60-lead electrograms in dogs with 4-week-old myocardial infarction.

    Science.gov (United States)

    Hosoya, Y; Ikeda, K; Komatsu, T; Yamaki, M; Kubota, I

    2001-01-01

    There were few studies on the spectral analysis of multiple-lead epicardial electrograms in chronic myocardial infarction. Spectral analysis of multi-lead epicardial electrograms was performed in 6 sham-operated dogs (N group) and 8 dogs with 4-week-old myocardial infarction (MI group). Four weeks after the ligation of left anterior descending coronary artery, fast Fourier transform was performed on 60-lead epicardial electrograms, and then inverse transform was performed on 5 frequency ranges from 0 to 250 Hz. From the QRS onset to QRS offset, the time integration of unsigned value of reconstructed waveform was calculated and displayed as AQRS maps. On 0-25 Hz AQRS map, there was no significant difference between the 2 groups. In the frequency ranges of 25-250 Hz, MI group had significantly smaller AQRS values than N group solely in the infarct zone. It was shown that high frequency potentials (25-250 Hz) within QRS complex were reduced in the infarct zone.

  4. Surgical treatment of Wolff-Parkinson-White syndrome: epicardial approach without the use of cardiopulmonary bypass.

    Science.gov (United States)

    Graffigna, A; Pagani, F; Vigano, M

    1993-03-01

    Epicardial dissection without the use of cardiopulmonary bypass (CPB) was performed in 88 patients (56 males and 32 females, mean age 31.9 years). With intraoperative epicardial mapping, 101 accessory pathways were detected, with multiple pathways in 11 patients. CPB was avoided in all but one patient due to frequent onset of atrial fibrillation with rapid ventricular rate. Surgical ablation was successful in 86 patients (97.6%). Three patients required multiple surgical procedures because of persistence of conduction along a component of the original pathway. All but two patients were discharged without antiarrhythmic medication; these two patients were given quinidine therapy because of atrial fibrillation, but had normal early and late electrophysiological studies. Surgical ablation of Kent bundles by the epicardial approach for the treatment of Wolff-Parkinson-White syndrome can be achieved without the use of CPB. Optimal and steady exposure of the area are mandatory for the procedure, and dissection is eased by avoidance of heparin required for CPB.

  5. Radiofrequency Catheter Ablation of Coexistent Idiopathic Left Ventricular Tachycardia and Atrioventricular Nodal Reentrant Tachycardia

    Directory of Open Access Journals (Sweden)

    Ken-Pen Weng

    2005-10-01

    Full Text Available A healthy 15-year-old male patient presented with a 6-month history of recurrent attacks of palpitations. On multiple emergency room visits, a sustained wide QRS complex tachycardia with a right bundle branch block and northwest axis deviation was documented. The tachycardia was not terminated by intravenous adenosine, but was suppressed with intravenous verapamil. There was no evidence of structural heart disease, myocarditis, long QT syndrome, or electrolyte imbalance after a series of standard examinations. Idiopathic left ventricular tachycardia (ILVT was suspected. Electrophysiologic studies revealed 2 inducible tachycardias, which were shown to represent atrioventricular nodal reentrant tachycardia (AVNRT and ILVT. Transformation from AVNRT to ILVT occurred spontaneously following atrial pacing. Successful ablation of ILVT and the slow atrioventricular nodal pathway resulted in cure of the double tachycardia.

  6. Phase diagram and re-entrant fermionic entanglement in a hybrid Ising-Hubbard ladder

    Science.gov (United States)

    Sousa, H. S.; Pereira, M. S. S.; de Oliveira, I. N.; Strečka, J.; Lyra, M. L.

    2018-05-01

    The degree of fermionic entanglement is examined in an exactly solvable Ising-Hubbard ladder, which involves interacting electrons on the ladder's rungs described by Hubbard dimers at half-filling on each rung, accounting for intrarung hopping and Coulomb terms. The coupling between neighboring Hubbard dimers is assumed to have an Ising-like nature. The ground-state phase diagram consists of four distinct regions corresponding to the saturated paramagnetic, the classical antiferromagnetic, the quantum antiferromagnetic, and the mixed classical-quantum phase. We have exactly computed the fermionic concurrence, which measures the degree of quantum entanglement between the pair of electrons on the ladder rungs. The effects of the hopping amplitude, the Coulomb term, temperature, and magnetic fields on the fermionic entanglement are explored in detail. It is shown that the fermionic concurrence displays a re-entrant behavior when quantum entanglement is being generated at moderate temperatures above the classical saturated paramagnetic ground state.

  7. Female preponderance in atrioventricular node reentrant tachycardia, but no sex related electrophysiological differences

    Directory of Open Access Journals (Sweden)

    Claes Williamsson

    2014-01-01

    Full Text Available The mechanism behind the female preponderance for atrio-ventricular node reentrant tachycardia (AVNRT is not clear. We compared baseline electrophysiological measurements and clinical data in 141 consecutive patients (96 women who underwent successful AVNRT ablation at their fi rst therapeutic procedure. Women had on average 9% higher resting heart rate than men (p<0.05, but were similar in all measures of AV node function. Isoproterenol infusion was required for AVNRT induction in 69 cases (49%, and the need for isoproterenol was associated with lower resting heart rate and longer anterograde and retrograde AV node refractory periods (p<0.05 for comparisons, but not with sex. We conclude that the spectrum of baseline AV node physiology in AVNRT patients is wide, and is similar in men and women. The female preponderance for AVNRT cannot be explained from comparisons of baseline AV node electrophysiological properties.

  8. Reentrant phase transitions and defensive alliances in social dilemmas with informed strategies

    Science.gov (United States)

    Szolnoki, Attila; Perc, Matjaž

    2015-05-01

    Knowing the strategy of an opponent in a competitive environment conveys obvious evolutionary advantages. But this information is costly, and the benefit of being informed may not necessarily offset the additional cost. Here we introduce social dilemmas with informed strategies, and we show that this gives rise to two cyclically dominant triplets that form defensive alliances. The stability of these two alliances is determined by the rotation velocity of the strategies within each triplet. A weaker strategy in a faster rotating triplet can thus overcome an individually stronger competitor. Fascinating spatial patterns favor the dominance of a single defensive alliance, but enable also the stable coexistence of both defensive alliances in very narrow regions of the parameter space. A continuous reentrant phase transition reveals before unseen complexity behind the stability of strategic alliances in evolutionary social dilemmas.

  9. The evaluation of cutoff rigidities and reentrant albedo calculations for Palestine, Dallas, and Midland, Texas

    International Nuclear Information System (INIS)

    Shea, M.A.; Smart, D.F.

    1975-01-01

    By using the trajectory-tracing technique, cutoff rigidities for Palestine, Dallas, and Midland, Texas, have been calculated as a function of various zenith and azimuth angles. Extensive analysis of the trajectory calculations shows that there is a systematic uncertainty involved in computing the lowest allowed rigidity, and this uncertainty may be a significant fraction of the penumbral width. Continuation of the trajectory-tracing process below the Stormer cutoff allows an evaluation of the reentrant albedo, showing that the average invariant latitude of the guiding center of the trajectory at the albedo origin is the same as the average invariant latitude of the guiding center of the particle trajectory at the detection point. No significant difference in the cutoff rigidities for these locations is found when the external magnetic fields present in the magnetosphere are added to the geomagnetic field of internal origin

  10. Role of high-resolution image integration to visualize left phrenic nerve and coronary arteries during epicardial ventricular tachycardia ablation.

    Science.gov (United States)

    Yamashita, Seigo; Sacher, Frédéric; Mahida, Saagar; Berte, Benjamin; Lim, Han S; Komatsu, Yuki; Amraoui, Sana; Denis, Arnaud; Derval, Nicolas; Laurent, François; Montaudon, Michel; Hocini, Mélèze; Haïssaguerre, Michel; Jaïs, Pierre; Cochet, Hubert

    2015-04-01

    Epicardial ventricular tachycardia (VT) ablation is associated with risks of coronary artery (CA) and phrenic nerve (PN) injury. We investigated the role of multidetector computed tomography in visualizing CA and PN during VT ablation. Ninety-five consecutive patients (86 men; age, 57 ± 15) with VT underwent cardiac multidetector computed tomography. The PN detection rate and anatomic variability were analyzed. In 49 patients undergoing epicardial mapping, real-time multidetector computed tomographic integration was used to display CAs/PN locations in 3-dimensional mapping systems. Elimination of local abnormal ventricular activities (LAVAs) was used as ablation end point. The distribution of CAs/PN with respect to LAVA was analyzed and compared between VT etiologies. Multidetector computed tomography detected PN in 81 patients (85%). Epicardial LAVAs were observed in 44 of 49 patients (15 ischemic cardiomyopathy, 15 nonischemic cardiomyopathy, and 14 arrhythmogenic right ventricular cardiomyopathy) with a mean of 35 ± 37 LAVA points/patient. LAVAs were located within 1 cm from CAs and PN in 35 (80%) and 18 (37%) patients, respectively. The prevalence of LAVA adjacent to CAs was higher in nonischemic cardiomyopathy and arrhythmogenic right ventricular cardiomyopathy than in ischemic cardiomyopathy (100% versus 86% versus 53%; P < 0.01). The prevalence of LAVAs adjacent to PN was higher in nonischemic cardiomyopathy than in ischemic cardiomyopathy (93% versus 27%; P < 0.001). Epicardial ablation was performed in 37 patients (76%). Epicardial LAVAs could not be eliminated because of the proximity to CAs or PN in 8 patients (18%). The epicardial electrophysiological VT substrate is often close to CAs and PN in patients with nonischemic cardiomyopathy. High-resolution image integration is potentially useful to minimize risks of PN and CA injury during epicardial VT ablation. © 2015 American Heart Association, Inc.

  11. Controllable circuit

    DEFF Research Database (Denmark)

    2010-01-01

    A switch-mode power circuit comprises a controllable element and a control unit. The controllable element is configured to control a current in response to a control signal supplied to the controllable element. The control unit is connected to the controllable element and provides the control...

  12. Circuit Training.

    Science.gov (United States)

    Nelson, Jane B.

    1998-01-01

    Describes a research-based activity for high school physics students in which they build an LC circuit and find its resonant frequency of oscillation using an oscilloscope. Includes a diagram of the apparatus and an explanation of the procedures. (DDR)

  13. Epicardial left ventricular lead placement for cardiac resynchronization therapy: optimal pace site selection with pressure-volume loops.

    Science.gov (United States)

    Dekker, A L A J; Phelps, B; Dijkman, B; van der Nagel, T; van der Veen, F H; Geskes, G G; Maessen, J G

    2004-06-01

    Patients in heart failure with left bundle branch block benefit from cardiac resynchronization therapy. Usually the left ventricular pacing lead is placed by coronary sinus catheterization; however, this procedure is not always successful, and patients may be referred for surgical epicardial lead placement. The objective of this study was to develop a method to guide epicardial lead placement in cardiac resynchronization therapy. Eleven patients in heart failure who were eligible for cardiac resynchronization therapy were referred for surgery because of failed coronary sinus left ventricular lead implantation. Minithoracotomy or thoracoscopy was performed, and a temporary epicardial electrode was used for biventricular pacing at various sites on the left ventricle. Pressure-volume loops with the conductance catheter were used to select the best site for each individual patient. Relative to the baseline situation, biventricular pacing with an optimal left ventricular lead position significantly increased stroke volume (+39%, P =.01), maximal left ventricular pressure derivative (+20%, P =.02), ejection fraction (+30%, P =.007), and stroke work (+66%, P =.006) and reduced end-systolic volume (-6%, P =.04). In contrast, biventricular pacing at a suboptimal site did not significantly change left ventricular function and even worsened it in some cases. To optimize cardiac resynchronization therapy with epicardial leads, mapping to determine the best pace site is a prerequisite. Pressure-volume loops offer real-time guidance for targeting epicardial lead placement during minimal invasive surgery.

  14. Contribution of different Erbium sublattices in magnetic ordering of the reentrant superconductor [Snsub(1-x)Ersub(x)]Er4Rh6Sn18

    International Nuclear Information System (INIS)

    Hodeau, J.L.; Marezio, M.; Pannetier, J.; Benoit, A.

    1984-01-01

    The compound [Sn(1)sub(1-x)Er(1)sub(x)]Er(2) 4 Rh 6 Sn 18 with x = 1/3 is a reentrant superconductor; it belongs to a series of compounds whose formula is MRhsub(x)Snsub(y), M = rare earth. We have determined by X-ray diffraction the structure of these compounds and we have also studied the magnetic ordering by neutron diffraction of the reentrant superconductor [fr

  15. Ventricular tachycardia in ischemic cardiomyopathy; a combined endo-epicardial ablation as the first procedure versus a stepwise approach (EPILOGUE) - study protocol for a randomized controlled trial

    NARCIS (Netherlands)

    A.A. Hendriks (Astrid A.); M. Khan (M.); L. Geller (Laszlo); A. Kardos (Attila); L.J. de Vries (Lennart); S-C. Yap (Sing-Chien); S.A. Wijchers (Sip A.); D.A.M.J. Theuns (Dominic); T. Szili-Torok (Tamas)

    2015-01-01

    textabstractBackground: The role of epicardial substrate ablation of ventricular tachycardia (VT) as a first-line approach in patients with ischemic heart disease is not clearly defined. Epicardial ablation as a first-line option is standard for patients with nonischemic dilated cardiomyopathy and

  16. Synchronized Re-Entrant Flux Reversal of Multiple FeSiB Amorphous Wires Having the Larger Output

    Science.gov (United States)

    Takajo, Minoru; Yamasaki, Jiro

    Technique to synchronize the re-entrant flux reversal of the multiple magnetostrictive Fe77.5Si7.5B15 amorphous wires was developed using a flux keeper of amorphous ribbons contacted to the wire ends. It is comprehended that the characteristics of the re-entrant flux takes place respectively at almost the same time in the three Fe-Si-B amorphous wires with a diameter of 65, 95μm. This phenomenon can be explained by considering the strong magnetic coupling of wires and amorphous ribbon by stray field from the each wire ends. As a result, the magnitude of the induced voltage in the sense coil is increased in proportion to the multiplication of the number of the wires.

  17. The time-course of visual masking effects on saccadic responses indicates that masking interferes with reentrant processing

    DEFF Research Database (Denmark)

    Crouzet, S.; Pin, Simon Hviid Del; Overgaard, Morten

    2013-01-01

    Object substitution masking (OSM) occurs when a briefly presented target in a search array is surrounded by small dots that remain visible after the target disappears. Here, we tested the widespread assumption that OSM selectively impairs reentrant processing. If OSM interferes selectively...... with reentrant processing, then the first feedforward sweep should be left relatively intact. Using a standard OSM paradigm in combination with a saccadic choice task, giving access to an early phase of visual processing (the fastest saccades occurring only 100 ms after target onset), we compared the masking....... Interestingly, the same result was observed using backward masking. In a follow-up experiment, where we assessed observer’s visual awareness using single-trial visibility ratings, we demonstrated that these ultra-fast responses were actually linked to subsequent reported visibility. Taken together...

  18. ZP123 increases gap junctional conductance and prevents reentrant ventricular tachycardia during myocardial ischemia in open chest dogs

    DEFF Research Database (Denmark)

    Xing, Dezhi; Kjølbye, Anne Louise; Nielsen, Morten S

    2003-01-01

    INTRODUCTION: The aim of this study was to determine if the stable antiarrhythmic peptide (AAP) analogue ZP123 increases gap junctional intercellular conductance and prevents reentrant ventricular tachycardia (VT) during coronary artery occlusion. METHODS AND RESULTS: Voltage clamp experiments...... demonstrated that 10 nM ZP123 improved gap junctional intercellular conductance by 69% +/- 20% in pairs of guinea pig ventricular myocytes. VT was induced by programmed stimulation in alpha-chloralose anaesthetized open chest dogs 1 to 4 hours after coronary artery occlusion. Three-dimensional activation...... AAP analogue ZP123 increased gap junctional intercellular conductance and specifically prevented the induction of reentrant VT during ischemia in a broad dose range without proarrhythmic or hemodynamic side effects. ZP123 is a promising candidate for use in preventing ischemia-induced VT....

  19. Relationship Between Neck Circumference and Epicardial Fat Thickness in a Healthy Male Population.

    Science.gov (United States)

    Küçük, Uğur; Küçük, Hilal Olgun; Cüce, Ferhat; Balta, Sevket

    2016-09-01

    Epicardial fat is an upper body visceral fat depot that may play a significant role in the development of adverse metabolic and cardiovascular risk profiles. There is a significant direct relationship between the amount of epicardial fat and general body adiposity (body mass index, BMI), but data regarding subcutaneous adiposity is limited. We conducted a study to determine the association between neck circumference and epicardial fat thickness in healthy young male individuals, and assess their individual correlations with general body adiposity and cardiometabolic risk factors. One hundred consecutive male patients aged 18 years or older with no known major medical conditions were included in the study. All participants underwent detailed physical examination including measurement of blood pressure, weight, height, waist/hip ratio, and neck circumference. Blood was collected to determine fasting glucose and lipid parameters. A standard echocardiographic examination was performed with additional epicardial fat thickness determination. Among 100 study participants, neck circumference correlated significantly with weight, waist circumference, BMI, blood glucose, serum total cholesterol, low-density (LDL)-cholesterol, and triglycerides levels. No significant correlation was found between neck circumference and high-density lipoprotein (HDL)-cholesterol levels. Neck circumference correlated moderately and positively with echocardiographic epicardial fat thickness. Among patients with low cardiometabolic risk, increased neck circumference was associated with increased epicardial fat thickness. A gordura epicárdica é um depósito de gordura visceral na parte superior do organismo que pode desempenhar um papel importante no desenvolvimento de perfis cardiovasculares e metabólicos adversos. Há uma relação direta significativa entre a quantidade de gordura epicárdica e a adiposidade corporal geral (índice de massa corporal, IMC), mas dados sobre a adiposidade

  20. Novel approach to epicardial pacemaker implantation in patients with limited venous access.

    Science.gov (United States)

    Costa, Roberto; Scanavacca, Mauricio; da Silva, Kátia Regina; Martinelli Filho, Martino; Carrillo, Roger

    2013-11-01

    Limited venous access in certain patients increases the procedural risk and complexity of conventional transvenous pacemaker implantation. The purpose of this study was to determine a minimally invasive epicardial approach using pericardial reflections for dual-chamber pacemaker implantation in patients with limited venous access. Between June 2006 and November 2011, 15 patients underwent epicardial pacemaker implantation. Procedures were performed through a minimally invasive subxiphoid approach and pericardial window with subsequent fluoroscopy-assisted lead placement. Mean patient age was 46.4 ± 15.3 years (9 male [(60.0%], 6 female [40.0%]). The new surgical approach was used in patients determined to have limited venous access due to multiple abandoned leads in 5 (33.3%), venous occlusion in 3 (20.0%), intravascular retention of lead fragments from prior extraction in 3 (20.0%), tricuspid valve vegetation currently under treatment in 2 (13.3%), and unrepaired intracardiac defects in 2 (13.3%). All procedures were successful with no perioperative complications or early deaths. Mean operating time for isolated pacemaker implantation was 231.7 ± 33.5 minutes. Lead placement on the superior aspect of right atrium, through the transverse sinus, was possible in 12 patients. In the remaining 3 patients, the atrial lead was implanted on the left atrium through the oblique sinus, the postcaval recess, or the left pulmonary vein recess. None of the patients displayed pacing or sensing dysfunction, and all parameters remained stable throughout the follow-up period of 36.8 ± 25.1 months. Epicardial pacemaker implantation through pericardial reflections is an effective alternative therapy for those patients requiring physiologic pacing in whom venous access is limited. © 2013 Heart Rhythm Society. All rights reserved.

  1. Posterior Coronary Vein as the Substrate for an Epicardial Accessory Pathway

    Directory of Open Access Journals (Sweden)

    Laura Cipoletta, MD

    2013-07-01

    Full Text Available Catheter ablation of Wolff-Parkinson-White syndrome is associated with up to 5% of failure. Coronary sinus (CS abnormalities or connections between CS myocardial coat and left ventricular epicardium are associated with posteroseptal and left posterior accessory pathways (AP. A 41-year-old patient with WPW syndrome was referred to our hospital after three unsuccessful ablations. The 12-lead ECG suggested a left posteroseptal AP. CT imaging and electro-anatomic mapping showed a relationship between AP electrical course and CS posterior branch. This finding supports the hypothesis CSAPs lie in the myocardial coat around CS and represent an extensive connection between atrial and ventricular epicardial surface.

  2. Epicardial Breakthrough Waves During Sinus Rhythm: Depiction of the Arrhythmogenic Substrate?

    Science.gov (United States)

    Mouws, Elisabeth M J P; Lanters, Eva A H; Teuwen, Christophe P; van der Does, Lisette J M E; Kik, Charles; Knops, Paul; Bekkers, Jos A; Bogers, Ad J J C; de Groot, Natasja M S

    2017-09-01

    Epicardial breakthrough waves (EBW) during atrial fibrillation are important elements of the arrhythmogenic substrate and result from endo-epicardial asynchrony, which also occurs to some degree during sinus rhythm (SR). We examined the incidence and characteristics of EBW during SR and its possible value in the detection of the arrhythmogenic substrate associated with atrial fibrillation. Intraoperative epicardial mapping (interelectrode distances 2 mm) of the right atrium, Bachmann's bundle, the left atrioventricular groove, and the pulmonary vein area was performed during SR in 381 patients (289 male, 67±10 years) with ischemic or valvular heart disease. EBW were referred to as sinus node breakthrough waves if they were the earliest right atrial activated site. A total of 218 EBW and 57 sinus node breakthrough waves were observed in 168 patients (44%). EBW mostly occurred at right atrium (N=105, 48%) and left atrioventricular groove (N=67, 31%), followed by Bachmann's bundle (N=27, 12%) and pulmonary vein area (N=19, 9%; P <0.001). EBW occurred most often in ischemic heart disease patients (N=114, 49%) compared with (ischemic and) valvular heart disease patients (N=26, 17%; P <0.001). EBW electrograms most often consisted of double and fractionated potentials (N=137, 63%). In case of single potentials, an R wave was observed in 88% (N=71) of EBW, as opposed to 21% of sinus node breakthrough waves (N=5; P <0.001). Fractionated EBW potentials were more often observed at the right atrium and Bachmann's bundle ( P <0.001). During SR, EBW are present in over a third of patients, particularly in thicker parts of the atrial wall. Features of SR EBW indicate that muscular connections between endo- and epicardium underlie EBW and that a slight degree of endo-epicardial asynchrony required for EBW to occur is already present in some areas during SR. Hence, an anatomic substrate is present, which may enhance the occurrence of EBW during atrial fibrillation, thereby

  3. Relation of epicardial adipose tissue with arterial compliance and stiffness in patients with hypertension.

    Science.gov (United States)

    Korkmaz, Levent; Cirakoglu, Omer Faruk; Ağaç, Mustafa Tarik; Erkan, Hakan; Korkmaz, Ayca Ata; Acar, Zeydin; Kul, Selim; Hatem, Engin; Çelik, Şükrü

    2014-09-01

    The main aim of the present study was to investigate the association between epicardial adipose tissue (EAT) and arterial function in patients with asymptomatic hypertension. Patients with hypertension (n = 155) were enrolled consecutively. Patients with decreased arterial compliance (AC) and increased cardioankle vascular index (CAVI) had higher EAT values compared with those with normal AC and CAVI (6.23 ± 1.67 vs 4.91 ± 1.40, P arterial function in patients with asymptomatic hypertension. The link between EAT and arterial stiffness deserves further investigation. © The Author(s) 2013.

  4. Impact of irrigation flow rate and intrapericardial fluid on cooled-tip epicardial radiofrequency ablation.

    Science.gov (United States)

    Aryana, Arash; O'Neill, Padraig Gearoid; Pujara, Deep K; Singh, Steve K; Bowers, Mark R; Allen, Shelley L; d'Avila, André

    2016-08-01

    The optimal irrigation flow rate (IFR) during epicardial radiofrequency (RF) ablation has not been established. This study specifically examined the impact of IFR and intrapericardial fluid (IPF) accumulation during epicardial RF ablation. Altogether, 452 ex vivo RF applications (10 g for 60 seconds) delivered to the epicardial surface of bovine myocardium using 3 open-irrigated ablation catheters (ThermoCool SmartTouch, ThermoCool SmartTouch-SF, and FlexAbility) and 50 in vivo RF applications delivered (ThermoCool SmartTouch-SF) in 4 healthy adult swine in the presence or absence of IPF were examined. Ex vivo, RF was delivered at low (≤3 mL/min), reduced (5-7 mL/min), and high (≥10 mL/min) IFRs using intermediate (25-35 W) and high (35-45 W) power. In vivo, applications were delivered (at 9.3 ± 2.2 g for 60 seconds at 39 W) using reduced (5 mL/min) and high (15 mL/min) IFRs. Ex vivo, surface lesion diameter inversely correlated with IFR, whereas maximum lesion diameter and depth did not differ. While steam pops occurred more frequently at low IFR using high power (ThermoCool SmartTouch and ThermoCool SmartTouch-SF), tissue disruption was rare and did not vary with IFR. In vivo, charring/steam pop was not detected. Although there were no discernible differences in lesion size with IFR, surface lesion diameter, maximum diameter, depth, and volume were all smaller in the presence of IPF at both IFRs. Cooled-tip epicardial RF ablation created using reduced IFRs (5-7 mL/min) yields lesion sizes similar to those created using high IFRs (≥10 mL/min) without an increase in steam pop/tissue disruption, whereas the presence of IPF significantly reduces the lesion size. Copyright © 2016 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.

  5. Creating tuneable microwave media from a two-dimensional lattice of re-entrant posts

    Energy Technology Data Exchange (ETDEWEB)

    Goryachev, Maxim; Tobar, Michael E. [ARC Centre of Excellence for Engineered Quantum Systems, University of Western Australia, 35 Stirling Highway, Crawley, Western Australia 6009 (Australia)

    2015-11-28

    The potential capabilities of resonators based on two dimensional arrays of re-entrant posts is demonstrated. Such posts may be regarded as magnetically coupled lumped element microwave harmonic oscillators, arranged in a 2D lattices structure, which is enclosed in a 3D cavity. By arranging these elements in certain 2D patterns, we demonstrate how to achieve certain requirements with respect to field localisation and device spectra. Special attention is paid to symmetries of the lattices, mechanical tuning, design of areas of high localisation of magnetic energy; this in turn creates unique discrete mode spectra. We demonstrate analogies between systems designed on the proposed platform and well known physical phenomena such as polarisation, frustration, and Whispering Gallery Modes. The mechanical tunability of the cavity with multiple posts is analysed, and its consequences to optomechanical applications is calculated. One particular application to quantum memory is demonstrated with a cavity design consisting of separate resonators analogous to discrete Fabry–Pérot resonators. Finally, we propose a generalised approach to a microwave system design based on the concept of Programmable Cavity Arrays.

  6. Reentrant stability of Bose-Einstein-condensate standing-wave patterns

    International Nuclear Information System (INIS)

    Kalas, Ryan M.; Solenov, Dmitry; Timmermans, Eddy

    2010-01-01

    We describe standing-wave patterns induced by an attractive finite-ranged external potential inside a large Bose-Einstein Condensate (BEC). As the potential depth increases, the time-independent Gross-Pitaevskii equation develops pairs of solutions that have nodes in their wave function. We elucidate the nature of these states and study their dynamical stability. Although we study the problem in a two-dimensional BEC subject to a cylindrically symmetric square well potential of a radius that is comparable to the coherence length of the BEC, our analysis reveals general trends that are valid in two and three dimensions, independent of the symmetry of the localized potential well, and suggestive of the behavior in general short-range and large-range potentials. One set of nodal BEC wave functions resembles the single particle n-node bound-state wave function of the potential well, the other wave functions resemble the n-1-node bound-state wave function with a kink state pinned by the potential. The second state, though corresponding to the lower free energy value of the pair of n-node BEC states, is always unstable, whereas the first can be dynamically stable in intervals of the potential well depth, implying that the standing-wave BEC can evolve from being dynamically unstable to stable and back to unstable as the potential well is adiabatically deepened - a phenomenon that we refer to as 'reentrant dynamical stability'.

  7. Mechanical characterization of auxetic stainless steel thin sheets with reentrant structure

    Science.gov (United States)

    Lekesiz, H.; Bhullar, S. K.; Karaca, A. A.; Jun, M. B. G.

    2017-08-01

    Smart materials in auxetic form present a great potential for various medical applications due to their unique deformation mechanisms along with durable infrastructure. Both analytical and finite element (FE) models are extensively used in literature to characterize mechanical response of auxetic structures but these structures are mostly thick enough to be considered as bulk material and 3D inherently. Auxetic plates in very thin form, a.e. foil, may bring numerous advantages such as very light design and better biodegradability when needed. However, there is a gap in literature on mechanical characterization of auxetic thin plates. In this study, structural analysis of very thin auxetic plates under uniaxial loading is investigated using both FE method and experimental method. 25 μm thick stainless steel (316L) plates are fabricated with reentrant texture for three different unit cell dimensions and tested under uniaxial loading using universal testing machine. 25 and 50 μm thick sheets with same cell dimensions were analyzed using implicit transient FE model including strain hardening and failure behaviors. FE results cover all the deformation schemes seen in actual tests and total deformation level matches with test results. Effect of plate thickness and cell geometry on auxetic behavior is discussed in detail using FE results. Finally, based on FE analysis results, an optimum geometry for prolonged auxetic behavior, high flexibility and high durability is suggested for future potential applications.

  8. A Tunable Reentrant Resonator with Transverse Orientation of Electric Field for in Vivo EPR Spectroscopy

    Science.gov (United States)

    Chzhan, Michael; Kuppusamy, Periannan; Samouilov, Alexandre; He, Guanglong; Zweier, Jay L.

    1999-04-01

    There has been a need for development of microwave resonator designs optimized to provide high sensitivity and high stability for EPR spectroscopy and imaging measurements ofin vivosystems. The design and construction of a novel reentrant resonator with transversely oriented electric field (TERR) and rectangular sample opening cross section for EPR spectroscopy and imaging ofin vivobiological samples, such as the whole body of mice and rats, is described. This design with its transversely oriented capacitive element enables wide and simple setting of the center frequency by trimming the dimensions of the capacitive plate over the range 100-900 MHz with unloadedQvalues of approximately 1100 at 750 MHz, while the mechanical adjustment mechanism allows smooth continuous frequency tuning in the range ±50 MHz. This orientation of the capacitive element limits the electric field based loss of resonatorQobserved with large lossy samples, and it facilitates the use of capacitive coupling. Both microwave performance data and EPR measurements of aqueous samples demonstrate high sensitivity and stability of the design, which make it well suited forin vivoapplications.

  9. Hybrid particle swarm optimization with Cauchy distribution for solving reentrant flexible flow shop with blocking constraint

    Directory of Open Access Journals (Sweden)

    Chatnugrob Sangsawang

    2016-06-01

    Full Text Available This paper addresses a problem of the two-stage flexible flow shop with reentrant and blocking constraints in Hard Disk Drive Manufacturing. This problem can be formulated as a deterministic FFS|stage=2,rcrc, block|Cmax problem. In this study, adaptive Hybrid Particle Swarm Optimization with Cauchy distribution (HPSO was developed to solve the problem. The objective of this research is to find the sequences in order to minimize the makespan. To show their performances, computational experiments were performed on a number of test problems and the results are reported. Experimental results show that the proposed algorithms give better solutions than the classical Particle Swarm Optimization (PSO for all test problems. Additionally, the relative improvement (RI of the makespan solutions obtained by the proposed algorithms with respect to those of the current practice is performed in order to measure the quality of the makespan solutions generated by the proposed algorithms. The RI results show that the HPSO algorithm can improve the makespan solution by averages of 14.78%.

  10. Epicardial adipose tissue as a predictor of coronary artery disease in asymptomatic subjects.

    Science.gov (United States)

    Bachar, Gil N; Dicker, Dror; Kornowski, Ran; Atar, Eli

    2012-08-15

    This study sought to elucidate the relation between epicardial adipose tissue (EAT) thickness measured by multidetector computed tomography and presence of coronary artery atherosclerosis. Recent studies have suggested that fat disposition in visceral organs and epicardial tissue could serve as a predictor of coronary artery disease (CAD). The sample included 190 asymptomatic subjects with ≥ 1 cardiovascular risk factor who were referred for cardiac computed tomographic angiography. Body mass index, blood pressure, fasting glucose level, and lipid profile were measured. Multidetector computed tomographic results were analyzed for atherosclerosis burden, calcium Agatston score, and EAT thickness: mean EAT values were 3.54 ± 1.59 mm in patients with atherosclerosis and 1.85 ± 1.28 mm in patients without atherosclerosis (p 50% diameter) coronary artery stenosis. There was a significant difference in EAT values between patients with and without metabolic syndrome (2.58 ± 1.63 vs 2.04 ± 1.46 mm, p 400 and <400 (3.38 ± 1.58 vs 2.02 ± 1.42 mm, p <0.0001). In conclusion, asymptomatic patients with CAD have significantly more EAT than patients without CAD. An EAT thickness of 2.4 mm is the optimal cutoff for prediction of presence of significant CAD. Copyright © 2012 Elsevier Inc. All rights reserved.

  11. Increased bioactive lipids content in human subcutaneous and epicardial fat tissue correlates with insulin resistance.

    Science.gov (United States)

    Błachnio-Zabielska, Agnieszka U; Baranowski, Marcin; Hirnle, Tomasz; Zabielski, Piotr; Lewczuk, Anna; Dmitruk, Iwona; Górski, Jan

    2012-12-01

    Obesity is a risk factor for metabolic diseases. Intramuscular lipid accumulation of ceramides, diacylglycerols, and long chain acyl-CoA is responsible for the induction of insulin resistance. These lipids are probably implicated in obesity-associated insulin resistance not only in skeletal muscle but also in fat tissue. Only few data are available about ceramide content in human subcutaneous adipose tissue. However, there are no data on DAG and LCACoA content in adipose tissue. The aim of our study was to measure the lipids content in human SAT and epicardial adipose tissue we sought to determine the bioactive lipids content by LC/MS/MS in fat tissue from lean non-diabetic, obese non-diabetic, and obese diabetic subjects and test whether the lipids correlate with HOMA-IR. We found, that total content of measured lipids was markedly higher in OND and OD subjects in both types of fat tissue (for all p lipids content is greater in subcutaneous and epicardial fat tissue and the particular lipids content positively correlates with HOMA-IR.

  12. Blood plasma lipidomic signature of epicardial fat in healthy obese women.

    Science.gov (United States)

    Scherer, Max; Montoliu, Ivan; Qanadli, Salah D; Collino, Sebastiano; Rezzi, Serge; Kussmann, Martin; Giusti, Vittorio; Martin, François-Pierre J

    2015-01-01

    A lipidomic approach was employed in a clinically well-defined cohort of healthy obese women to explore blood lipidome phenotype ascribed to body fat deposition, with emphasis on epicardial adipose tissue (EAT). The present investigation delivered a lipidomics signature of epicardial adiposity under healthy clinical conditions using a cohort of 40 obese females (age: 25-45 years, BMI: 28-40 kg/m(2) ) not showing any metabolic disease traits. Lipidomics analysis of blood plasma was employed in combination with in vivo quantitation of mediastinal fat depots by computerized tomography. All cardiac fat depots correlated to indicators of hepatic dysfunctions (ALAT and ASAT), which describe physiological connections between hepatic and cardiac steatosis. Plasma lipidomics encompassed overall levels of lipid classes, fatty acid profiles, and individual lipid species. EAT and visceral fat associated with diacylglycerols (DAG), triglycerides, and distinct phospholipid and sphingolipid species. A pattern of DAG and phosphoglycerols was specific to EAT. Human blood plasma lipidomics appears to be a promising clinical and potentially diagnostic readout for patient stratification and monitoring. Association of blood lipidomics signature to regio-specific mediastinal and visceral adiposity under healthy clinical conditions may help provide more biological insights into obese patient stratification for cardiovascular disease risks. © 2014 The Obesity Society.

  13. Prognostic value of epicardial fat volume measurements by computed tomography: a systematic review of the literature

    Energy Technology Data Exchange (ETDEWEB)

    Spearman, James V.; Krazinski, Aleksander W. [Medical University of South Carolina, Department of Radiology and Radiological Science, Charleston, SC (United States); Renker, Matthias [Medical University of South Carolina, Department of Radiology and Radiological Science, Charleston, SC (United States); Giessen University, Department of Internal Medicine I, Cardiology/Angiology, Giessen (Germany); Schoepf, U.J. [Medical University of South Carolina, Department of Radiology and Radiological Science, Charleston, SC (United States); Medical University of South Carolina, Division of Cardiology, Department of Medicine, Charleston, SC (United States); Herbert, Teri L. [Medical University of South Carolina, Department of Library Science and Informatics, Charleston, SC (United States); De Cecco, Carlo N. [Medical University of South Carolina, Department of Radiology and Radiological Science, Charleston, SC (United States); University of Rome ' Sapienza' - Polo Pontino, Department of Radiological Sciences, Oncology and Pathology, Latina (Italy); Nietert, Paul J. [Medical University of South Carolina, Department of Public Health Sciences, Charleston, SC (United States); Meinel, Felix G. [Medical University of South Carolina, Department of Radiology and Radiological Science, Charleston, SC (United States); Ludwig-Maximilians-University Hospital, Institute for Clinical Radiology, Munich (Germany)

    2015-11-15

    To perform a systematic review of the growing body of literature evaluating the prognostic value of epicardial fat volume (EFV) quantified by cross-sectional imaging. Two independent reviewers performed systematic searches on both PubMed and Scopus using search terms developed with a medical librarian. Peer-reviewed articles were selected based on the inclusion of outcome data, utilization of epicardial fat volume and sufficient reporting for analysis. A total of 411 studies were evaluated with nine studies meeting the inclusion criteria. In all, the studies evaluated 10,252 patients. All nine studies were based on CT measurements. Seven studies evaluated the prognostic value of EFV unadjusted for calcium score, and six of these studies found a significant association between EFV and clinical outcomes. Seven studies evaluated the incremental value of EFV beyond calcium scoring, and six of these studies found a significant association. The majority of studies suggest that EFV quantification is significantly associated with clinical outcomes and provides incremental prognostic value over coronary artery calcium scoring. Future research should use a binary cutoff of 125 mL for evaluation of EFV to provide consistency with other research. (orig.)

  14. Is epicardial adipose tissue, another measure of central obesity, correlated with erectile dysfunction?

    Directory of Open Access Journals (Sweden)

    Chih-Wei Tsao

    2016-01-01

    Full Text Available Background: This study investigated the correlation between epicardial adipose tissue (EAT, a measure of central obesity, and sexual function in males with vasculogenic erectile dysfunction (ED. Materials and Methods: The study was a cross-sectional study of selected males with ED aged <75 years who attended the Urology Outpatient Department of Tri-Service General Hospital. Sixty subjects were included in the study, which employed biochemical data, anthropometric indexes, echocardiography, and questionnaires. Biochemical lipid profiles and associated inflammation markers were recorded. The anthropometric indexes included general and central obesity and bioelectrical impedance analysis. Echocardiography results were assessed by a single experienced cardiologist and included epicardial and pericardial fat thickness measurements. Sexual function was evaluated using the International Index of Erectile Function-5 (IIEF-5 score. Results: According to the analysis of variance and multivariate logistic regression, only the erectile hardness score (EHS was statistically positively correlated with the IIEF-5 score. All other anthropometric indexes and echocardiography parameters, including EAT thickness, pericardial adipose tissue thickness, and ejection fraction (EF, were not significantly associated with sexual function. Conclusions: Only EHS was statistically associated with sexual function in the male subjects with ED. The anthropometric indexes and EAT thickness, a measure of central obesity, were not significantly correlated with sexual function in the male patients with ED.

  15. Communication between integrin receptors facilitates epicardial cell adhesion and matrix organization.

    Science.gov (United States)

    Pae, So Hyun; Dokic, Danijela; Dettman, Robert W

    2008-04-01

    Formation of the epicardium requires interactions between alpha(4)beta(1) integrin, and the extracellular matrix. We investigated the role of other integrins expressed by epicardial cells. We detected transcripts for alpha(5), alpha(8), alpha(v), beta(1), beta(3), and beta(5) integrins in the chick proepicardial organ (PE). We demonstrate that alpha(5)beta(1), alpha(8)beta(1), and alpha(v)beta(3) integrins are expressed by chick epicardial mesothelial cells (EMCs). Migration of EMCs in vitro was reduced by RGD-containing peptides. Using adenoviruses expressing an antisense to chick alpha(4) (AdGFPalpha4AS), full-length (Adhalpha4V5), and C-terminal deleted alpha(4) (Adhalpha4DeltaCV5), we found that EMCs were less able to adhere to vitronectin and fibronectin(120) indicating that alpha(4)beta(1) plays a role in regulating EMC adhesion to ligands of alpha(5)beta(1), alpha(8)beta(1), and alpha(v)beta(3). In Adhalpha4DeltaCV5-infected EMCs, alpha(5)beta(1) was diminished in fibrillar adhesions and new FN matrix assembly was abnormal. We propose that cooperation between alpha(4)beta(1) and RGD integrins is important for EMC adhesion and subepicardial matrix formation. (c) 2008 Wiley-Liss, Inc.

  16. Association between increased epicardial adipose tissue volume and coronary plaque composition.

    Science.gov (United States)

    Yamashita, Kennosuke; Yamamoto, Myong Hwa; Ebara, Seitarou; Okabe, Toshitaka; Saito, Shigeo; Hoshimoto, Koichi; Yakushiji, Tadayuki; Isomura, Naoei; Araki, Hiroshi; Obara, Chiaki; Ochiai, Masahiko

    2014-09-01

    To assess the relationship between epicardial adipose tissue volume (EATV) and plaque vulnerability in significant coronary stenosis using a 40-MHz intravascular ultrasound (IVUS) imaging system (iMap-IVUS), we analyzed 130 consecutive patients with coronary stenosis who underwent dual-source computed tomography (CT) and cardiac catheterization. Culprit lesions were imaged by iMap-IVUS before stenting. The iMAP-IVUS system classified coronary plaque components as fibrous, lipid, necrotic, or calcified tissue, based on the radiofrequency spectrum. Epicardial adipose tissue was measured as the tissue ranging from -190 to -30 Hounsfield units. EATV, calculated as the sum of the fat areas on short-axis images, was 85.0 ± 34.0 cm(3). There was a positive correlation between EATV and the percentage of necrotic plaque tissue (R (2) = 0.34, P EATV and the percentage of fibrous tissue (R (2) = 0.24, P EATV (β = 0.14, P = 0.02) were independently associated with the percentage of necrotic plaque tissue. An increase in EATV was associated with the development of coronary atherosclerosis and, potentially, with the most dangerous type of plaque.

  17. LOGIC CIRCUIT

    Science.gov (United States)

    Strong, G.H.; Faught, M.L.

    1963-12-24

    A device for safety rod counting in a nuclear reactor is described. A Wheatstone bridge circuit is adapted to prevent de-energizing the hopper coils of a ball backup system if safety rods, sufficient in total control effect, properly enter the reactor core to effect shut down. A plurality of resistances form one arm of the bridge, each resistance being associated with a particular safety rod and weighted in value according to the control effect of the particular safety rod. Switching means are used to switch each of the resistances in and out of the bridge circuit responsive to the presence of a particular safety rod in its effective position in the reactor core and responsive to the attainment of a predetermined velocity by a particular safety rod enroute to its effective position. The bridge is unbalanced in one direction during normal reactor operation prior to the generation of a scram signal and the switching means and resistances are adapted to unbalance the bridge in the opposite direction if the safety rods produce a predetermined amount of control effect in response to the scram signal. The bridge unbalance reversal is then utilized to prevent the actuation of the ball backup system, or, conversely, a failure of the safety rods to produce the predetermined effect produces no unbalance reversal and the ball backup system is actuated. (AEC)

  18. Short- circuit tests of circuit breakers

    OpenAIRE

    Chorovský, P.

    2015-01-01

    This paper deals with short-circuit tests of low voltage electrical devices. In the first part of this paper, there are described basic types of short- circuit tests and their principles. Direct and indirect (synthetic) tests with more details are described in the second part. Each test and principles are explained separately. Oscilogram is obtained from short-circuit tests of circuit breakers at laboratory. The aim of this research work is to propose a test circuit for performing indirect test.

  19. Collective of mechatronics circuit

    International Nuclear Information System (INIS)

    1987-02-01

    This book is composed of three parts, which deals with mechatronics system about sensor, circuit and motor. The contents of the first part are photo sensor of collector for output, locating detection circuit with photo interrupts, photo sensor circuit with CdS cell and lamp, interface circuit with logic and LED and temperature sensor circuit. The second part deals with oscillation circuit with crystal, C-R oscillation circuit, F-V converter, timer circuit, stability power circuit, DC amp and DC-DC converter. The last part is comprised of bridge server circuit, deformation bridge server, controlling circuit of DC motor, controlling circuit with IC for PLL and driver circuit of stepping motor and driver circuit of Brushless.

  20. Collective of mechatronics circuit

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1987-02-15

    This book is composed of three parts, which deals with mechatronics system about sensor, circuit and motor. The contents of the first part are photo sensor of collector for output, locating detection circuit with photo interrupts, photo sensor circuit with CdS cell and lamp, interface circuit with logic and LED and temperature sensor circuit. The second part deals with oscillation circuit with crystal, C-R oscillation circuit, F-V converter, timer circuit, stability power circuit, DC amp and DC-DC converter. The last part is comprised of bridge server circuit, deformation bridge server, controlling circuit of DC motor, controlling circuit with IC for PLL and driver circuit of stepping motor and driver circuit of Brushless.

  1. Impact of ischemic and valvular heart disease on atrial excitation : A high-resolution epicardial mapping study

    NARCIS (Netherlands)

    E.M.J.P. Mouws (Elisabeth); E. Lanters (Eva); C. Teuwen (Christophe); L. van der Does (Lisette); C. Kik (Charles); S.P. Knops (Simon); A. Yaksh (Ameeta); J.A. Bekkers (Jos); A.J.J.C. Bogers (Ad); N.M.S. de Groot (Natasja)

    2018-01-01

    markdownabstractBackground--The influence of underlying heart disease or presence of atrial fibrillation (AF) on atrial excitation during sinus rhythm (SR) is unknown. We investigated atrial activation patterns and total activation times of the entire atrial epicardial surface during SR in patients

  2. Circuit parties.

    Science.gov (United States)

    Guzman, R

    2000-03-01

    Circuit parties are extended celebrations, lasting from a day to a week, primarily attended by gay and bisexual men in their thirties and forties. These large-scale dance parties move from city to city and draw thousands of participants. The risks for contracting HIV during these parties include recreational drug use and unsafe sex. Limited data exists on the level of risk at these parties, and participants are skeptical of outside help because of past criticism of these events. Health care and HIV advocates can promote risk-reduction strategies with the cooperation of party planners and can counsel individuals to personally reduce their own risk. To convey the message, HIV prevention workers should emphasize positive and community-centered aspects of the parties, such as taking care of friends and avoiding overdose.

  3. Unipolar Endocardial Voltage Mapping in the Right Ventricle: Optimal Cutoff Values Correcting for Computed Tomography-Derived Epicardial Fat Thickness and Their Clinical Value for Substrate Delineation.

    Science.gov (United States)

    Venlet, Jeroen; Piers, Sebastiaan R D; Kapel, Gijsbert F L; de Riva, Marta; Pauli, Philippe F G; van der Geest, Rob J; Zeppenfeld, Katja

    2017-08-01

    Low endocardial unipolar voltage (UV) at sites with normal bipolar voltage (BV) may indicate epicardial scar. Currently applied UV cutoff values are based on studies that lacked epicardial fat information. This study aimed to define endocardial UV cutoff values using computed tomography-derived fat information and to analyze their clinical value for right ventricular substrate delineation. Thirty-three patients (50±14 years; 79% men) underwent combined endocardial-epicardial right ventricular electroanatomical mapping and ablation of right ventricular scar-related ventricular tachycardia with computed tomographic image integration, including computed tomography-derived fat thickness. Of 6889 endocardial-epicardial mapping point pairs, 547 (8%) pairs with distance 1.50 mV, the optimal endocardial UV cutoff for identification of epicardial BV the curve, 0.75; sensitivity, 60%; specificity, 79%) and cutoff for identification of abnormal epicardial electrogram was 3.7 mV (area under the curve, 0.88; sensitivity, 100%; specificity, 67%). The majority of abnormal electrograms (130 of 151) were associated with transmural scar. Eighty-six percent of abnormal epicardial electrograms had corresponding endocardial sites with BV the remaining could be identified by corresponding low endocardial UV right ventricular scar, an endocardial UV cutoff value of 3.9 mV is more accurate than previously reported cutoff values. Although the majority of epicardial abnormal electrograms are associated with transmural scar with low endocardial BV, the additional use of endocardial UV at normal BV sites improves the diagnostic accuracy resulting in identification of all epicardial abnormal electrograms at sites with <1.0 mm fat. © 2017 American Heart Association, Inc.

  4. Commutation circuit for an HVDC circuit breaker

    Science.gov (United States)

    Premerlani, William J.

    1981-01-01

    A commutation circuit for a high voltage DC circuit breaker incorporates a resistor capacitor combination and a charging circuit connected to the main breaker, such that a commutating capacitor is discharged in opposition to the load current to force the current in an arc after breaker opening to zero to facilitate arc interruption. In a particular embodiment, a normally open commutating circuit is connected across the contacts of a main DC circuit breaker to absorb the inductive system energy trapped by breaker opening and to limit recovery voltages to a level tolerable by the commutating circuit components.

  5. Influence of technical parameters on epicardial fat volume quantification at cardiac CT

    Energy Technology Data Exchange (ETDEWEB)

    Bucher, Andreas M. [Department of Radiology and Radiological Science, Medical University of South Carolina, Charleston, SC (United States); Department of Diagnostic and Interventional Radiology, Clinic of the Goethe University, Frankfurt (Germany); Joseph Schoepf, U., E-mail: schoepf@musc.edu [Department of Radiology and Radiological Science, Medical University of South Carolina, Charleston, SC (United States); Division of Cardiology, Department of Medicine, Medical University of South Carolina, Charleston, SC (United States); Krazinski, Aleksander W.; Silverman, Justin; Spearman, James V. [Department of Radiology and Radiological Science, Medical University of South Carolina, Charleston, SC (United States); De Cecco, Carlo N. [Department of Radiology and Radiological Science, Medical University of South Carolina, Charleston, SC (United States); Department of Radiological Sciences, Oncology and Pathology, University of Rome “Sapienza” – Polo Pontino, Latina (Italy); Meinel, Felix G. [Department of Radiology and Radiological Science, Medical University of South Carolina, Charleston, SC (United States); Institute for Clinical Radiology, Ludwig-Maximilians-University Hospital, Munich (Germany); Vogl, Thomas J. [Department of Diagnostic and Interventional Radiology, Clinic of the Goethe University, Frankfurt (Germany); Geyer, Lucas L. [Department of Radiology and Radiological Science, Medical University of South Carolina, Charleston, SC (United States); Institute for Clinical Radiology, Ludwig-Maximilians-University Hospital, Munich (Germany)

    2015-06-15

    Highlights: • Upper threshold levels and contrast enhancement influence epicardial fat volumetry. • Cardiac cycle does not significantly influence epicardial fat volumetry. • Adjustments of upper threshold can lead to comparable volumetry results. - Abstract: Objectives: To systematically analyze the influence of technical parameters on quantification of epicardial fat volume (EATV) at cardiac CT. Methods: 153 routine cardiac CT data sets were analyzed using three-dimensional pericardial border delineation. Three image series were reconstructed per patient: (a) CTA{sub D}: coronary CT angiography (CTA), diastolic phase; (b) CTA{sub S}: coronary CTA, systolic phase; (c) CaSc{sub D}: non-contrast CT, diastolic phase. EATV was calculated using three different upper thresholds (−15HU, −30HU, −45HU). Repeated measures ANOVA, Spearman's rho, and Bland Altman plots were used. Results: Mean EATV differed between all three image series at a −30HU threshold (CTA{sub D} 87.2 ± 38.5 ml, CTA{sub S} 90.9 ± 37.7 ml, CaSc{sub D} 130.7 ± 49.5 ml, P < 0.001). EATV of diastolic and systolic CTA reconstructions did not differ significantly (P = 0.225). Mean EATV for contrast enhanced CTA at a −15HU threshold (CTA{sub D15} 102.4 ± 43.6 ml, CTA{sub S15} 105.3 ± 42.3 ml) could be approximated most closely by non-contrast CT at −45HU threshold (CaSc{sub D45} 105.3 ± 40.8 ml). The correlation was excellent: CTA{sub S15}–CTA{sub D15}, rho = 0.943; CTA{sub D15}–CaSc{sub D45}, rho = 0.905; CTA{sub S15}–CaSc{sub D45}, rho = 0.924; each P < 0.001). Bias values from Bland Altman Analysis were: CTA{sub S15}–CTA{sub D15}, 4.9%; CTA{sub D15}–CaSc{sub D45}, −4.3%; CTA{sub S15}–CaSc{sub D45}, 0.6%. Conclusions: Measured EATV can differ substantially between contrast enhanced and non-contrast CT studies, which can be reconciled by threshold modification. Heart cycle phase does not significantly influence EATV measurements.

  6. Influence of technical parameters on epicardial fat volume quantification at cardiac CT

    International Nuclear Information System (INIS)

    Bucher, Andreas M.; Joseph Schoepf, U.; Krazinski, Aleksander W.; Silverman, Justin; Spearman, James V.; De Cecco, Carlo N.; Meinel, Felix G.; Vogl, Thomas J.; Geyer, Lucas L.

    2015-01-01

    Highlights: • Upper threshold levels and contrast enhancement influence epicardial fat volumetry. • Cardiac cycle does not significantly influence epicardial fat volumetry. • Adjustments of upper threshold can lead to comparable volumetry results. - Abstract: Objectives: To systematically analyze the influence of technical parameters on quantification of epicardial fat volume (EATV) at cardiac CT. Methods: 153 routine cardiac CT data sets were analyzed using three-dimensional pericardial border delineation. Three image series were reconstructed per patient: (a) CTA D : coronary CT angiography (CTA), diastolic phase; (b) CTA S : coronary CTA, systolic phase; (c) CaSc D : non-contrast CT, diastolic phase. EATV was calculated using three different upper thresholds (−15HU, −30HU, −45HU). Repeated measures ANOVA, Spearman's rho, and Bland Altman plots were used. Results: Mean EATV differed between all three image series at a −30HU threshold (CTA D 87.2 ± 38.5 ml, CTA S 90.9 ± 37.7 ml, CaSc D 130.7 ± 49.5 ml, P < 0.001). EATV of diastolic and systolic CTA reconstructions did not differ significantly (P = 0.225). Mean EATV for contrast enhanced CTA at a −15HU threshold (CTA D15 102.4 ± 43.6 ml, CTA S15 105.3 ± 42.3 ml) could be approximated most closely by non-contrast CT at −45HU threshold (CaSc D45 105.3 ± 40.8 ml). The correlation was excellent: CTA S15 –CTA D15 , rho = 0.943; CTA D15 –CaSc D45 , rho = 0.905; CTA S15 –CaSc D45 , rho = 0.924; each P < 0.001). Bias values from Bland Altman Analysis were: CTA S15 –CTA D15 , 4.9%; CTA D15 –CaSc D45 , −4.3%; CTA S15 –CaSc D45 , 0.6%. Conclusions: Measured EATV can differ substantially between contrast enhanced and non-contrast CT studies, which can be reconciled by threshold modification. Heart cycle phase does not significantly influence EATV measurements

  7. Reentrant phase transitions of higher-dimensional AdS black holes in dRGT massive gravity

    International Nuclear Information System (INIS)

    Zou, De-Cheng; Yue, Ruihong; Zhang, Ming

    2017-01-01

    We study the P-V criticality and phase transition in the extended phase space of anti-de Sitter (AdS) black holes in higher-dimensional de Rham, Gabadadze and Tolley (dRGT) massive gravity, treating the cosmological constant as pressure and the corresponding conjugate quantity is interpreted as thermodynamic volume. Besides the usual small/large black hole phase transitions, the interesting thermodynamic phenomena of reentrant phase transitions (RPTs) are observed for black holes in all d ≥ 6-dimensional spacetime when the coupling coefficients c_im"2 of massive potential satisfy some certain conditions. (orig.)

  8. Reentrant phase transitions of higher-dimensional AdS black holes in dRGT massive gravity

    Energy Technology Data Exchange (ETDEWEB)

    Zou, De-Cheng; Yue, Ruihong [Yangzhou University, College of Physical Science and Technology, Yangzhou (China); Zhang, Ming [Xi' an Aeronautical University, Faculty of Science, Xi' an (China)

    2017-04-15

    We study the P-V criticality and phase transition in the extended phase space of anti-de Sitter (AdS) black holes in higher-dimensional de Rham, Gabadadze and Tolley (dRGT) massive gravity, treating the cosmological constant as pressure and the corresponding conjugate quantity is interpreted as thermodynamic volume. Besides the usual small/large black hole phase transitions, the interesting thermodynamic phenomena of reentrant phase transitions (RPTs) are observed for black holes in all d ≥ 6-dimensional spacetime when the coupling coefficients c{sub i}m{sup 2} of massive potential satisfy some certain conditions. (orig.)

  9. Analog circuit design designing dynamic circuit response

    CERN Document Server

    Feucht, Dennis

    2010-01-01

    This second volume, Designing Dynamic Circuit Response builds upon the first volume Designing Amplifier Circuits by extending coverage to include reactances and their time- and frequency-related behavioral consequences.

  10. Trigger circuit

    International Nuclear Information System (INIS)

    Verity, P.R.; Chaplain, M.D.; Turner, G.D.J.

    1984-01-01

    A monostable trigger circuit comprises transistors TR2 and TR3 arranged with their collectors and bases interconnected. The collector of the transistor TR2 is connected to the base of transistor TR3 via a capacitor C2 the main current path of a grounded base transistor TR1 and resistive means R2,R3. The collector of transistor TR3 is connected to the base of transistor TR2 via resistive means R6, R7. In the stable state all the transistors are OFF, the capacitor C2 is charged, and the output is LOW. A positive pulse input to the base of TR2 switches it ON, which in turn lowers the voltage at points A and B and so switches TR1 ON so that C2 can discharge via R2, R3, which in turn switches TR3 ON making the output high. Thus all three transistors are latched ON. When C2 has discharged sufficiently TR1 switches OFF, followed by TR3 (making the output low again) and TR2. The components C1, C3 and R4 serve to reduce noise, and the diode D1 is optional. (author)

  11. Troponin elevation in patients with various tachycardias and normal epicardial coronaries

    Directory of Open Access Journals (Sweden)

    Yousuf Kanjwal

    2008-08-01

    Full Text Available Troponin elevation is usually synonymous with acute coronary syndrome (ACS. Although sensitive for ACS, the elevation of serum troponin, in the absence of clinical evidence of ischemia, should prompt a search for other etiologies of myocardial necrosis. In fact, elevated values of troponin are correlated with myocardial necrosis even though it does not discriminate the mechanism involved. We report a series of seven patients (age range 18-67 years, who presented with complaints of chest discomfort and were found to have regular supraventricular tachycardia (5 patients and one patient each with atrial fibrillation and ventricular tachycardia. All these patients had elevated troponin I and underwent coronary angiography that revealed normal epicardial coronary arteries. This is first case series in which all patients underwent coronary angiography and none of the patients was hemodynamically unstable at the time of presentation. Patients with elevated troponin due to conditions other than ACS can receive inappropriate and delayed definitive diagnosis and treatment.

  12. Atrioesophageal Fistula after Minimally Invasive Video-Assisted Epicardial Ablation for Lone Atrial Fibrillation.

    Science.gov (United States)

    Kik, Charles; van Valen, Richard; Mokhles, Mostafa M; Bekkers, Jos A; Bogers, Ad J J C

    2017-09-01

    Minimally invasive video-assisted epicardial beating heart ablation for lone atrial fibrillation claims to be safe and effective. We, however, report on three patients with an atrioesophageal fistula after this procedure. The exact pathogenesis of this complication is unknown. All patients presented around 6 weeks after surgery with either fever or neurological deficits. Diagnosis can be made by computed tomography scan. We advocate an aggressive surgical approach with closure of the atrial defect on cardiopulmonary bypass and closure and reinforcement of the esophagus with an intercostal muscle flap in a single-stage surgery. Some caution as to the low-risk character of this procedure seems to be realistic. Georg Thieme Verlag KG Stuttgart · New York.

  13. Epicardial adipose tissue and cardiometabolic risk factors in overweight and obese children and adolescents.

    Science.gov (United States)

    Schusterova, I; Leenen, F H H; Jurko, A; Sabol, F; Takacova, J

    2014-02-01

    What is already known about this subject The prevalence of childhood obesity has increased markedly in the past 2 decades. Abdominal fat is a better predictor of risk than body mass index. Waist circumference (WC) as a measure of abdominal fat has limited sensitivity and specificity. What this study adds Epicardial adipose tissue (EAT) as measured by echocardiography represents a simple and reliable marker of visceral adiposity. In children, both body mass index and EAT show a similar or better correlation with markers of cardiometabolic risk than does waist circumference. Epicardial adipose tissue (EAT) is the visceral fat deposit around the heart and is commonly increased in obese subjects. EAT is related to cardiometabolic risk factors and non-alcoholic fatty liver disease (NAFLD) in adults, but this relationship is not well known in children. Echocardiographic assessment of EAT and its association with cardiometabolic risk factors in overweight and obese children. In 25 (mean age 13.0 ± 2.3) overweight and obese subjects and 24 lean controls, blood pressure (BP), WC, fasting plasma glucose and insulin, lipids, uric acid and hepatic enzymes were measured. EAT thickness was measured by transthoracic echocardiography. In overweight and obese subjects, EAT was significantly higher compared to normal weight children. Overweight and obese children had significantly higher body mass index (BMI), WC, BP, triglycerides (TAG), low-density lipoprotein and total cholesterol, hepatic enzymes alanine aminotransferase (ALT) and γ-glutamyl transferase, and lower high-density lipoprotein cholesterol (HDL-C). EAT correlated significantly with BP, TAG, uric acid, HDL-C, apoprotein B and ALT. Correlation coefficients were similar or better than for WC, but similar or lower than for BMI. EAT thickness in children is associated with an unfavourable cardiometabolic risk profile including biochemical signs of NAFLD and hyperuricaemia, but is not a stronger indicator than BMI.

  14. Triiodothyronine promotes the proliferation of epicardial progenitor cells through the MAPK/ERK pathway

    International Nuclear Information System (INIS)

    Deng, Song-Bai; Jing, Xiao-Dong; Wei, Xiao-ming; Du, Jian-Lin; Liu, Ya-Jie; Qin, Qin; She, Qiang

    2017-01-01

    Thyroid hormone has important functions in the development and physiological function of the heart. The aim of this study was to determine whether 3,5,3′-Triiodothyronine (T3) can promote the proliferation of epicardial progenitor cells (EPCs) and to investigate the potential underlying mechanism. Our results showed that T3 significantly promoted the proliferation of EPCs in a concentration- and time-dependent manner. The thyroid hormone nuclear receptor inhibitor bisphenol A (100 μmol/L) did not affect T3's ability to induce proliferation. Further studies showed that the mRNA expression levels of mitogen-activated protein kinase 1 (MAPK1), MAPK3, and Ki67 in EPCs in the T3 group (10 nmol/L) increased 2.9-, 3-, and 4.1-fold, respectively, compared with those in the control group (P < 0.05). In addition, the mRNA expression of the cell cycle protein cyclin D1 in the T3 group increased approximately 2-fold compared with the control group (P < 0.05), and there were more EPCs in the S phase of the cell cycle (20.6% vs. 12.0%, P < 0.05). The mitogen-activated protein kinase/extracellular signal-regulated kinase (MAPK/ERK) signaling pathway inhibitor U0126 (10 μmol/L) significantly inhibited the ability of T3 to promote the proliferation of EPCs and to alter cell cycle progression. This study suggested that T3 significantly promotes the proliferation of EPCs, and this effect may be achieved through activation of the MAPK/ERK signaling pathway. - Highlights: • Epicardial progenitor cells were successfully cultured from E12.5 mice. • Thyroid hormone T3 significantly promoted the proliferation of EPCs. • This biological effect may be mediated via activation of the MAPK/ERK pathway.

  15. Association of chemerin mRNA expression in human epicardial adipose tissue with coronary atherosclerosis

    Directory of Open Access Journals (Sweden)

    Wang Linjie

    2011-10-01

    Full Text Available Abstract Background Growing evidence suggests that epicardial adipose tissue (EAT may play a key role in the pathogenesis and development of coronary artery disease (CAD by producing several inflammatory adipokines. Chemerin, a novel adipokine, has been reported to be involved in regulating immune responses and glucolipid metabolism. Given these properties, chemerin may provide an interesting link between obesity, inflammation and atherosclerosis. In this study, we sought to determine the relationship of chemerin expression in EAT and the severity of coronary atherosclerosis in Han Chinese patients. Methods Serums and adipose tissue biopsies (epicardial and thoracic subcutaneous were obtained from CAD (n = 37 and NCAD (n = 16 patients undergoing elective cardiac surgery. Gensini score was used to assess the severity of CAD. Serum levels of chemerin, adiponectin and insulin were measured by ELISA. Chemerin protein expression in adipose tissue was detected by immunohistochemistry. The mRNA levels of chemerin, chemR23, adiponectin and TNF-alpha in adipose tissue were detected by RT-PCR. Results We found that EAT of CAD group showed significantly higher levels of chemerin and TNF-alpha mRNA, and significantly lower level of adiponectin mRNA than that of NCAD patients. In CAD group, significantly higher levels of chemerin mRNA and protein were observed in EAT than in paired subcutaneous adipose tissue (SAT, whereas such significant difference was not found in NCAD group. Chemerin mRNA expression in EAT was positively correlated with Gensini score (r = 0.365, P P P P P P P > 0.05. Conclusions The expressions of chemerin mRNA and protein are significantly higher in EAT from patients with CAD in Han Chinese patients. Furthermore, the severity of coronary atherosclerosis is positive correlated with the level of chemerin mRNA in EAT rather than its circulating level.

  16. Epicardial adipose tissue radiodensity is independently related to coronary atherosclerosis. A multidetector computed tomography study

    International Nuclear Information System (INIS)

    Pracon, R.; Kruk, M.; Kepka, C.

    2011-01-01

    Preliminary research indicates that epicardial adipose tissue (EAT) may display both anti- and proatherosclerotic properties. Because the varying radiodensities of selected human tissues assessed by multidetector computed tomography (MDCT) has been shown to reflect differences in biological characteristics, the present study investigated the hypothesis that the proatherosclerotic properties of EAT may be linked to its radiodensity. The study included 164 consecutive patients (82 females, mean age 58.8±11.1 years) with suspected coronary artery disease (CAD) undergoing MDCT coronary angiography. Coronary atherosclerosis was defined as: CAD (id est (ie), presence of at least 1 coronary stenosis ≥50%) and coronary artery calcium (CAC) determined by Agatston score. EAT radiodensity was assessed by MDCT and averaged -81.00±4.64 HU (Hounsfield unit (HU) scale). Mean CAC score was 96.0±220.0. Patients with CAD (n=36) showed higher EAT radiodensity than patients without CAD (-78.99±4.12 vs. -81.57±4.64 HU, P<0.01). In the multivariable model, only EAT radiodensity and age were independently associated with CAD (odds ratio (OR) 1.15, 95%confidence interval (CI) 1.04-1.28; OR 1.08, 95%CI 1.04-1.12; respectively). EAT radiodensity also correlated with CAC score (r=0.23, P<0.01). EAT radiodensity (P<0.001), age (P<0.001), sex (P=0.03), and past smoking (P<0.01) were independent correlates of CAC in the multivariable linear regression model. Increased EAT radiodensity is independently associated with coronary atherosclerosis, which may reflect the unfavorable, proatherosclerotic metabolic properties of more radiodense epicardial fat. (author)

  17. Epicardial adipose tissue thickness and NGAL levels in women with polycystic ovary syndrome.

    Science.gov (United States)

    Sahin, Serap Baydur; Cure, Medine Cumhur; Ugurlu, Yavuz; Ergul, Elif; Gur, Emine Uslu; Alyildiz, Nese; Bostan, Mehmet

    2014-02-16

    Polycystic ovary syndrome (PCOS) is associated with an increased cardiovascular disease (CVD) risk and early atherosclerosis. Epicardial adipose tissue thickness (EATT) is clinically related to subclinical atherosclerosis. In the present study, considering the major role of neutrophil gelatinase-associated lipocalin (NGAL) which is an acute phase protein rapidly releasing upon inflammation and tissue injury, we aimed to evaluate NGAL levels and EATT in PCOS patients and assess their relationship with cardiometabolic factors. 64 patients with PCOS and 50 age- and body mass index-matched healthy controls were included in the study. We evaluated anthropometric, hormonal and metabolic parameters. EATT was measured by echocardiography above the free wall of the right ventricle. Serum NGAL and high-sensitive C- reactive protein (hsCRP) levels were measured by ELISA. Mean EATT was 0,38 +/-0,16 mm in the PCOS group and 0,34 +/-0,36 mm in the control group (p = 0,144). In the obese PCOS group (n = 44) EAT was thicker compared to the obese control group (n = 41) (p = 0.026). Mean NGAL levels of the patients with PCOS were 101,98 +/-21,53 pg/ml, while mean NGAL levels were 107,40 +/-26,44 pg/ml in the control group (p = 0,228). We found a significant positive correlation between EATT and age, BMI, waist circumference, fasting insulin, HOMA-IR, triglyceride and hsCRP levels in PCOS group. Thickness of the epicardial adipose tissue can be used to follow the risk of CVD development in obese PCOS cases. However serum NGAL levels do not differ in patients with PCOS and control group.

  18. Improving the performance and emission characteristics of a single cylinder diesel engine having reentrant combustion chamber using diesel and Jatropha methyl esters.

    Science.gov (United States)

    Premnath, S; Devaradjane, G

    2015-11-01

    The emissions from the Compression ignition (CI) engines introduce toxicity to the atmosphere. The undesirable carbon deposits from these engines are realized in the nearby static or dynamic systems such as vehicles, inhabitants, etc. The objective of this research work is to improve the performance and emission characteristics of a diesel engine in the modified re-entrant combustion chamber using a diesel and Jatropha methyl ester blend (J20) at three different injection pressures. From the literature, it is revealed that the shape of the combustion chamber and the fuel injection pressure have an impact on the performance and emission parameters of the CI engine. In this work, a re-entrant combustion chamber with three different fuel injection pressures (200, 220 and 240bars) has been used in the place of the conventional hemispherical combustion chamber for diesel and J20. From the experimental results, it is found that the re-entrant chamber improves the brake thermal efficiency of diesel and J20 in all the tested conditions. It is also found that the 20% blend of Jatropha methyl ester showed 4% improvement in the brake thermal efficiency in the re-entrant chamber at the maximum injection pressure. Environmental safety directly relates to the reduction in the undesirable effects on both living and non-living things. Currently environmental pollution is of major concern. Even with the stringent emission norms new methods are required to reduce the harmful effects from automobiles. The toxicity of carbon monoxide (CO) is well known. In the re-entrant combustion chamber, the amount of CO emission is reduced by 26% when compared with the conventional fuel operation of the engine. Moreover, the amount of smoke is reduced by 24% and hydrocarbons (HC) emission by 24%. Thus, the modified re-entrant combustion chamber reduces harmful pollutants such as unburned HC and CO as well as toxic smoke emissions. Copyright © 2015 Elsevier Inc. All rights reserved.

  19. 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

  20. Machine learning methods for locating re-entrant drivers from electrograms in a model of atrial fibrillation

    Science.gov (United States)

    McGillivray, Max Falkenberg; Cheng, William; Peters, Nicholas S.; Christensen, Kim

    2018-04-01

    Mapping resolution has recently been identified as a key limitation in successfully locating the drivers of atrial fibrillation (AF). Using a simple cellular automata model of AF, we demonstrate a method by which re-entrant drivers can be located quickly and accurately using a collection of indirect electrogram measurements. The method proposed employs simple, out-of-the-box machine learning algorithms to correlate characteristic electrogram gradients with the displacement of an electrogram recording from a re-entrant driver. Such a method is less sensitive to local fluctuations in electrical activity. As a result, the method successfully locates 95.4% of drivers in tissues containing a single driver, and 95.1% (92.6%) for the first (second) driver in tissues containing two drivers of AF. Additionally, we demonstrate how the technique can be applied to tissues with an arbitrary number of drivers. In its current form, the techniques presented are not refined enough for a clinical setting. However, the methods proposed offer a promising path for future investigations aimed at improving targeted ablation for AF.

  1. Spin freezing in the re-entrant spin glass FeNiMn close to the frustration limit

    Energy Technology Data Exchange (ETDEWEB)

    Pappas, Catherine [Hahn-Meitner-Institut, Glienickerstr. 100, 14109 Berlin (Germany); Klenke, Jens [Hahn-Meitner-Institut, Glienickerstr. 100, 14109 Berlin (Germany); Hesse, Juergen [Institut fuer Metallphysik und Nukleare Festkoerperphysik, Technische Universitaet Braunschweig, 38106 Braunschweig (Germany); Wagner, Volker [Physikalisch-Technische Bundesanstalt, Bundesallee 100, 38116 Braunschweig (Germany)]. E-mail: volker.wagner@ptb.de

    2007-07-15

    In the invar alloy (Fe{sub 0.65}Ni{sub 0.35}){sub 1-} {sub x} Mn {sub x} we measured the magnetic form factor s(Q) and the intermediate scattering function s(Q,t) for a sample close to the critical Mn concentration (x {sub c}=0.139), at which the sample turns to a re-entrant spin glass phase. The aim was to check whether the magnetic behaviour would approach the Q-independent relaxation behaviour of a classical spin glass when x=x {sub c}. The experiment showed a quite similar spin freezing as for a more ferromagnetic sample with x=0.113. The intermediate scattering function and the form factor were determined by paramagnetic NSE. The normalized scattering function S(Q,t)=s(Q,t)/s(Q)=exp[(-{gamma}t) {sup n}] was fitted by stretched exponential decay. As a function of temperature T<200 K the inverse time constant {gamma} showed the change of more than four orders of magnitude from frozen spin glass (T=60 K to T=100 K), where the ferromagnetic phase occurred. In general, the inverse time constant is higher than in the more ferromagnetic sample as the frustration of the spins became larger. In the ferromagnetic phase S(Q,t) depended on 0.3re-entrant spin glass down to at least 60 K.

  2. A Scheduling Model for the Re-entrant Manufacturing System and Its Optimization by NSGA-II

    Directory of Open Access Journals (Sweden)

    Masoud Rabbani

    2016-11-01

    Full Text Available In this study, a two-objective mixed-integer linear programming model (MILP for multi-product re-entrant flow shop scheduling problem has been designed. As a result, two objectives are considered. One of them is maximization of the production rate and the other is the minimization of processing time. The system has m stations and can process several products in a moment. The re-entrant flow shop scheduling problem is well known as NP-hard problem and its complexity has been discussed by several researchers. Given that NSGA-II algorithm is one of the strongest and most applicable algorithm in solving multi-objective optimization problems, it is used to solve this problem. To increase algorithm performance, Taguchi technique is used to design experiments for algorithm’s parameters. Numerical experiments are proposed to show the efficiency and effectiveness of the model. Finally, the results of NSGA-II are compared with SPEA2 algorithm (Strength Pareto Evolutionary Algorithm 2. The experimental results show that the proposed algorithm performs significantly better than the SPEA2.

  3. Ventricular tachycardia in ischemic heart disease substrates

    Directory of Open Access Journals (Sweden)

    Olujimi A. Ajijola

    2014-01-01

    This review will discuss the central role of the ischemic heart disease substrate in the development MMVT. Electrophysiologic characterization of the post-infarct myocardium using bipolar electrogram amplitudes to delineate scar border zones will be reviewed. Functional electrogram determinants of reentrant circuits such as isolated late potentials will be discussed. Strategies for catheter ablation of reentrant ventricular tachycardia, including structural and functional targets will also be examined, as will the role of the epicardial mapping and ablation in the management of recurrent MMVT.

  4. Ventricular filling slows epicardial conduction and increases action potential duration in an optical mapping study of the isolated rabbit heart

    Science.gov (United States)

    Sung, Derrick; Mills, Robert W.; Schettler, Jan; Narayan, Sanjiv M.; Omens, Jeffrey H.; McCulloch, Andrew D.; McCullough, A. D. (Principal Investigator)

    2003-01-01

    INTRODUCTION: Mechanical stimulation can induce electrophysiologic changes in cardiac myocytes, but how mechanoelectric feedback in the intact heart affects action potential propagation remains unclear. METHODS AND RESULTS: Changes in action potential propagation and repolarization with increased left ventricular end-diastolic pressure from 0 to 30 mmHg were investigated using optical mapping in isolated perfused rabbit hearts. With respect to 0 mmHg, epicardial strain at 30 mmHg in the anterior left ventricle averaged 0.040 +/- 0.004 in the muscle fiber direction and 0.032 +/- 0.006 in the cross-fiber direction. An increase in ventricular loading increased average epicardial activation time by 25%+/- 3% (P action potential duration at 20% repolarization (APD20) but did at 80% repolarization (APD80), from 179 +/- 7 msec to 207 +/- 5 msec (P action potential duration by a load-dependent mechanism that may not involve stretch-activated channels.

  5. Solid-state circuits

    CERN Document Server

    Pridham, G J

    2013-01-01

    Solid-State Circuits provides an introduction to the theory and practice underlying solid-state circuits, laying particular emphasis on field effect transistors and integrated circuits. Topics range from construction and characteristics of semiconductor devices to rectification and power supplies, low-frequency amplifiers, sine- and square-wave oscillators, and high-frequency effects and circuits. Black-box equivalent circuits of bipolar transistors, physical equivalent circuits of bipolar transistors, and equivalent circuits of field effect transistors are also covered. This volume is divided

  6. Circuit analysis for dummies

    CERN Document Server

    Santiago, John

    2013-01-01

    Circuits overloaded from electric circuit analysis? Many universities require that students pursuing a degree in electrical or computer engineering take an Electric Circuit Analysis course to determine who will ""make the cut"" and continue in the degree program. Circuit Analysis For Dummies will help these students to better understand electric circuit analysis by presenting the information in an effective and straightforward manner. Circuit Analysis For Dummies gives you clear-cut information about the topics covered in an electric circuit analysis courses to help

  7. Current limiter circuit system

    Science.gov (United States)

    Witcher, Joseph Brandon; Bredemann, Michael V.

    2017-09-05

    An apparatus comprising a steady state sensing circuit, a switching circuit, and a detection circuit. The steady state sensing circuit is connected to a first, a second and a third node. The first node is connected to a first device, the second node is connected to a second device, and the steady state sensing circuit causes a scaled current to flow at the third node. The scaled current is proportional to a voltage difference between the first and second node. The switching circuit limits an amount of current that flows between the first and second device. The detection circuit is connected to the third node and the switching circuit. The detection circuit monitors the scaled current at the third node and controls the switching circuit to limit the amount of the current that flows between the first and second device when the scaled current is greater than a desired level.

  8. Novel Percutaneous Epicardial Autonomic Modulation in the Canine for Atrial Fibrillation: Results of an Efficacy and Safety Study

    Science.gov (United States)

    Madhavan, Malini; Venkatachalam, K. L.; Swale, Matthew J.; DeSimone, Christopher V.; Gard, Joseph J.; Johnson, Susan B.; Suddendorf, Scott H.; Mikell, Susan B.; Ladewig, Dorothy J.; Nosbush, Toni Grabinger; Danielsen, Andrew J.; Knudson, Mark; Asirvatham, Samuel J.

    2016-01-01

    Background Endocardial ablation of atrial ganglionated plexi (GP) has been described for treatment of atrial fibrillation (AF). Our objective in this study was to develop percutaneous epicardial GP ablation in a canine model using novel energy sources and catheters. Methods Phase 1: The efficacy of several modalities to ablate the GP was tested in an open chest canine model (n=10). Phase 2: Percutaneous epicardial ablation of GP was done in 6 dogs using the most efficacious modality identified in phase 1 using 2 novel catheters. Results Phase 1: DC in varying doses [blocking (7 -12μA), electroporation (300-500μA), ablation (3000- 7500μA)], radiofrequency ablation (25–50 W), ultrasound (1.5MHz), and alcohol (2-5ml) injection were successful at 0/8, 4/12, 5/7, 3/8, 1/5 and 5/7 GP sites. DC (500–5000μA) along with alcohol irrigation was tested in phase 2. Phase 2: Percutaneous epicardial ablation of the right atrium, oblique sinus, vein of Marshall, and transverse sinus GP was successful in 5/6 dogs. One dog died of ventricular fibrillation (VF) during DC ablation at 5000 μA. Programmed stimulation induced AF in 6 dogs pre-ablation and no atrial arrhythmia in 3, flutter in 1 and AF in 1 post-ablation. Heart rate, blood pressure, effective atrial refractory period and local atrial electrogram amplitude did not change significantly post-ablation. Microscopic examination showed elimination of GP, and minimal injury to atrial myocardium. Conclusion Percutaneous epicardial ablation of GP using direct current and novel catheters is safe and feasible and may be used as an adjunct to pulmonary vein isolation in the treatment of atrial fibrillation in order to minimize additional atrial myocardial ablation. PMID:26854009

  9. Progressive epicardial coronary blood flow reduction fails to produce ST-segment depression at normal heart rates.

    Science.gov (United States)

    de Chantal, Marilyn; Diodati, Jean G; Nasmith, James B; Amyot, Robert; LeBlanc, A Robert; Schampaert, Erick; Pharand, Chantal

    2006-12-01

    ST-segment depression is commonly seen in patients with acute coronary syndromes. Most authors have attributed it to transient reductions in coronary blood flow due to nonocclusive thrombus formation on a disrupted atherosclerotic plaque and dynamic focal vasospasm at the site of coronary artery stenosis. However, ST-segment depression was never reproduced in classic animal models of coronary stenosis without the presence of tachycardia. We hypothesized that ST-segment depression occurring during acute coronary syndromes is not entirely explained by changes in epicardial coronary artery resistance and thus evaluated the effect of a slow, progressive epicardial coronary artery occlusion on the ECG and regional myocardial blood flow in anesthetized pigs. Slow, progressive occlusion over 72 min (SD 27) of the left anterior descending coronary artery in 20 anesthetized pigs led to a 90% decrease in coronary blood flow and the development of ST-segment elevation associated with homogeneous and transmural myocardial blood flow reductions, confirmed by microspheres and myocardial contrast echocardiography. ST-segment depression was not observed in any ECG lead before the development of ST-segment elevation. At normal heart rates, progressive epicardial stenosis of a coronary artery results in myocardial ischemia associated with homogeneous, transmural reduction in regional myocardial blood flow and ST-segment elevation, without preceding ST-segment depression. Thus, in coronary syndromes with ST-segment depression and predominant subendocardial ischemia, factors other than mere increases in epicardial coronary resistance must be invoked to explain the heterogeneous parietal distribution of flow and associated ECG changes.

  10. Association of Epicardial Adipose Tissue and High?Risk Plaque Characteristics: A Systematic Review and Meta?Analysis

    OpenAIRE

    Nerlekar, Nitesh; Brown, Adam J.; Muthalaly, Rahul G.; Talman, Andrew; Hettige, Thushan; Cameron, James D.; Wong, Dennis T. L.

    2017-01-01

    Background Epicardial adipose tissue (EAT) is hypothesized to alter atherosclerotic plaque composition, with potential development of high?risk plaque (HRP). EAT can be measured by volumetric assessment (EAT?v) or linear thickness (EAT?t). We performed a systematic review and random?effects meta?analysis to assess the association of EAT with HRP and whether this association is dependent on the measurement method used. Methods and Results Electronic databases were systematically searched up to...

  11. Increased vulnerability of human ventricle to re-entrant excitation in hERG-linked variant 1 short QT syndrome.

    Directory of Open Access Journals (Sweden)

    Ismail Adeniran

    2011-12-01

    Full Text Available The short QT syndrome (SQTS is a genetically heterogeneous condition characterized by abbreviated QT intervals and an increased susceptibility to arrhythmia and sudden death. This simulation study identifies arrhythmogenic mechanisms in the rapid-delayed rectifier K(+ current (I(Kr-linked SQT1 variant of the SQTS. Markov chain (MC models were found to be superior to Hodgkin-Huxley (HH models in reproducing experimental data regarding effects of the N588K mutation on KCNH2-encoded hERG. These ionic channel models were then incorporated into human ventricular action potential (AP models and into 1D and 2D idealised and realistic transmural ventricular tissue simulations and into a 3D anatomical model. In single cell models, the N588K mutation abbreviated ventricular cell AP duration at 90% repolarization (APD(90 and decreased the maximal transmural voltage heterogeneity (δV during APs. This resulted in decreased transmural heterogeneity of APD(90 and of the effective refractory period (ERP: effects that are anticipated to be anti-arrhythmic rather than pro-arrhythmic. However, with consideration of transmural heterogeneity of I(Kr density in the intact tissue model based on the ten Tusscher-Noble-Noble-Panfilov ventricular model, not only did the N588K mutation lead to QT-shortening and increases in T-wave amplitude, but δV was found to be augmented in some local regions of ventricle tissue, resulting in increased tissue vulnerability for uni-directional conduction block and predisposing to formation of re-entrant excitation waves. In 2D and 3D tissue models, the N588K mutation facilitated and maintained re-entrant excitation waves due to the reduced substrate size necessary for sustaining re-entry. Thus, in SQT1 the N588K-hERG mutation facilitates initiation and maintenance of ventricular re-entry, increasing the lifespan of re-entrant spiral waves and the stability of scroll waves in 3D tissue.

  12. Relationship between epicardial adipose tissue, coronary artery disease and adiponectin in a Mexican population.

    Science.gov (United States)

    Yañez-Rivera, Teresa G; Baños-Gonzalez, Manuel A; Ble-Castillo, Jorge L; Torres-Hernandez, Manuel E; Torres-Lopez, Jorge E; Borrayo-Sanchez, Gabriela

    2014-09-08

    The amount of epicardial adipose tissue (EAT) around the heart has been identified as an independent predictor of coronary artery disease (CAD), potentially through local release of inflammatory cytokines. Ethnic differences have been observed, but no studies have investigated this relationship in the Mexican population. The objective of the present study was to evaluate whether a relationship exist between EAT thickness assessed via echocardiography with CAD and adiponectin levels in a Mexican population. We studied 153 consecutive patients who underwent coronary angiography and transthoracic echocardiography (TTE). EAT thickness on the free wall of the right ventricle was measured at the end of systole from parasternal long and short axis views of three consecutive cardiac cycles. Coronary angiograms were analyzed for the presence, extent and severity of CAD. Serum adiponectin, lipids, glucose, C-reactive protein and fibrinogen were determined. EAT thickness was greater in patients with CAD than in those without CAD from both parasternal long (5.39 ± 1.75 mm vs 4.00 ± 1.67 mm p<0.0001) and short-axis views (5.23 ± 1.67 vs 4.12 ± 1.77, p=0.001). EAT thickness measured from parasternal long and short-axis showed a statistically significant positive correlation with age (r=0.354, p<0.001; r=0.286, p<0.001 respectively), and waist circumference (r=0.189, p=0.019; r=0.217, p=0.007 respectively). A significant negative correlation between EAT thickness from the parasternal long axis with cholesterol-HDL was observed (r=-0.163, p=0.045). No significant correlation was found between epicardial fat thickness and serum adiponectin or with the severity of CAD. EAT thickness was greater in patients with CAD. However, no correlation was observed with the severity of the disease or with serum adiponectin levels. EAT thickness measured by echocardiography might provide additional information for risk assessment and prediction of CAD.

  13. Epicardial fat volume and aortic stiffness in healthy individuals. A quantitative cardiac magnetic resonance study

    Energy Technology Data Exchange (ETDEWEB)

    Homsi, R.; Thomas, D.; Meier-Schroers, M.; Dabir, D.; Kuetting, D.; Luetkens, J.A.; Marx, C.; Schild, H.H. [Bonn University Hospital (Germany). Radiology; Gieseke, J. [Philips Healthcare, Hamburg (Germany); Sprinkart, A. [Bonn University Hospital (Germany). Radiology; Bochum Univ. (Germany). Inst. of Medical Engineering

    2016-09-15

    To determine epicardial fat volume (EFV) and aortic stiffness (assessed by aortic pulse wave velocity (PWV)) in healthy individuals, and to investigate the relationship of these parameters, and their association with body mass index (BMI) and age. 58 subjects (29 men, mean age 44.7 ± 13.9 years[y]) underwent a CMR exam at 1.5 Tesla. A 2 D velocity-encoded CMR scan was acquired to determine PWV. The EFV was measured based on a 3 D-mDixon sequence. Group comparisons were made between younger (age < 45y; n=30; mean age 33.4 ± 6.6y) and older (> 45y; n=28; 56.7 ± 8.4y) subjects and between subjects with a BMI < 25 kg/m{sup 2} (n=28; BMI 21.9 ± 2.5 kg/m{sup 2}) and a BMI > 25 kg/m{sup 2} (n=30; 28.7 ± 4.0 kg/m{sup 2}). Associations between the determined parameters were assessed by analyses of covariance (ANCOVAs). The mean values of PWV and EFV (normalized to body surface area) were 6.9 ±1.9 m/s and 44.2 ± 25.0 ml/m{sup 2}, respectively. The PWV and EFV were significantly higher in the older group (PWV=7.9 ± 2.0 m/s vs. 6.0 ± 1.2 m/s; EFV=54.7 ml/m{sup 2} vs. 34.5 ml/m{sup 2}; p < 0.01, each), with no significant differences in BMI or sex. In the overweighted group the EFV was significantly higher than in subjects with a BMI < 25kg/m{sup 2} (EFV=56.1 ± 27.1 ml/m{sup 2} vs. 31.5 ± 14.6 ml/m{sup 2}; p < 0.01) but without a significant difference in PWV. ANCOVA revealed a significant correlation between EFV and PWV, also after adjustment for age (p=0.025). An association was found between age and EFV as well as PWV. EFV and PWV were related to each other also after adjustment for age. The metabolic and pro-inflammatory activity found with increased epicardial fat volume may promote the development of atherosclerosis and aortic stiffness. CMR may be valuable for future studies investigating the relationship between EFV and PWV in patients with increased cardiovascular risk.

  14. Intuitive analog circuit design

    CERN Document Server

    Thompson, Marc

    2013-01-01

    Intuitive Analog Circuit Design outlines ways of thinking about analog circuits and systems that let you develop a feel for what a good, working analog circuit design should be. This book reflects author Marc Thompson's 30 years of experience designing analog and power electronics circuits and teaching graduate-level analog circuit design, and is the ideal reference for anyone who needs a straightforward introduction to the subject. In this book, Dr. Thompson describes intuitive and ""back-of-the-envelope"" techniques for designing and analyzing analog circuits, including transistor amplifi

  15. The circuit designer's companion

    CERN Document Server

    Williams, Tim

    1991-01-01

    The Circuit Designer's Companion covers the theoretical aspects and practices in analogue and digital circuit design. Electronic circuit design involves designing a circuit that will fulfill its specified function and designing the same circuit so that every production model of it will fulfill its specified function, and no other undesired and unspecified function.This book is composed of nine chapters and starts with a review of the concept of grounding, wiring, and printed circuits. The subsequent chapters deal with the passive and active components of circuitry design. These topics are foll

  16. Electronic devices and circuits

    CERN Document Server

    Pridham, Gordon John

    1972-01-01

    Electronic Devices and Circuits, Volume 3 provides a comprehensive account on electronic devices and circuits and includes introductory network theory and physics. The physics of semiconductor devices is described, along with field effect transistors, small-signal equivalent circuits of bipolar transistors, and integrated circuits. Linear and non-linear circuits as well as logic circuits are also considered. This volume is comprised of 12 chapters and begins with an analysis of the use of Laplace transforms for analysis of filter networks, followed by a discussion on the physical properties of

  17. Re-entrant spin glass and stepped magnetization in mixed-valence SrFe3(PO4)3

    International Nuclear Information System (INIS)

    Shang Mingyu; Chen Yan; Tian Ge; Yuan Hongming; Feng Shouhua

    2013-01-01

    The 2 D channel mixed-valent iron (II/III) monophosphate SrFe 3 (PO 4 ) 3 was synthesized via one step mild hydrothermal method at 210 °C and characterized by X-ray diffraction techniques and magnetization measurements. Coexistence of antiferromagnetic superexchange and ferromagnetic superexchange interactions was supposed to be in the lattice according to the Goodenough-Kanamori-Anderson rules. Temperature dependent DC magnetization measurement shows that SrFe 3 (PO 4 ) 3 is ferrimagnet with three magnetic transitions between 2 and 350 K. Through AC magnetization measurement, re-entrant spin glass was observed due to the competition between ferromagnetic and antiferromagnetic interactions. Furthermore, an interesting field induced stepped magnetization was observed in SrFe 3 (PO 4 ) 3 at 2 K with the saturation magnetization Ms=2.4 μ B /f.u. at 5 T.

  18. Minimizing makespan in a two-stage flow shop with parallel batch-processing machines and re-entrant jobs

    Science.gov (United States)

    Huang, J. D.; Liu, J. J.; Chen, Q. X.; Mao, N.

    2017-06-01

    Against a background of heat-treatment operations in mould manufacturing, a two-stage flow-shop scheduling problem is described for minimizing makespan with parallel batch-processing machines and re-entrant jobs. The weights and release dates of jobs are non-identical, but job processing times are equal. A mixed-integer linear programming model is developed and tested with small-scale scenarios. Given that the problem is NP hard, three heuristic construction methods with polynomial complexity are proposed. The worst case of the new constructive heuristic is analysed in detail. A method for computing lower bounds is proposed to test heuristic performance. Heuristic efficiency is tested with sets of scenarios. Compared with the two improved heuristics, the performance of the new constructive heuristic is superior.

  19. [The role of epicardial fat and obesity parameters in the prediction of coronary heart disease].

    Science.gov (United States)

    Prídavková, Dana; Kantárová, Daniela; Lišková, Renáta; Červeň, Peter; Kovář, František; Mokáň, Marián

    2016-04-01

    To assess the relationship of parameters of obesity in relationship to coronary angiography findings with correlation of epicardial fat (EF) thickness in uppermentioned context. There were 80 patients examined (43 males, 37 postmenopausal females) undergoing elective coronary angiography. We examined the regular obesity parameters - BMI, waist circumference (WC), neck circumference (NC), total body fat (TBF), and visceral fat (VF) using bioimpedance. We assessed the echocardiographically measured EF thickness. We added examination of lipidogram, glycaemia, HOMA-IR (insulin resistance index) and AIP (aterogenic index of plasma). The set was divided into group with coronarographically proved stenosis or stenoses (withCS), and a group without finding of quantifiable stenosis or stenoses (withoutCS). The average thickness of EF in withCS group was 6.3 vs 5.6 mm in group withoutCS (p obesity parameters in assessment of pre-clinical stages of coronary atherosclerosis and prediction of risk of coronary heart disease. In adipose parameters, EF thickness was correlated the most by WC. Risk stratification of coronary artery disease is supplemented by increased HOMA-IR and AIP.

  20. Automated quantification of epicardial adipose tissue using CT angiography: evaluation of a prototype software

    International Nuclear Information System (INIS)

    Spearman, James V.; Silverman, Justin R.; Krazinski, Aleksander W.; Costello, Philip; Meinel, Felix G.; Geyer, Lucas L.; Schoepf, U.J.; Apfaltrer, Paul; Canstein, Christian; De Cecco, Carlo Nicola

    2014-01-01

    This study evaluated the performance of a novel automated software tool for epicardial fat volume (EFV) quantification compared to a standard manual technique at coronary CT angiography (cCTA). cCTA data sets of 70 patients (58.6 ± 12.9 years, 33 men) were retrospectively analysed using two different post-processing software applications. Observer 1 performed a manual single-plane pericardial border definition and EFV M segmentation (manual approach). Two observers used a software program with fully automated 3D pericardial border definition and EFV A calculation (automated approach). EFV and time required for measuring EFV (including software processing time and manual optimization time) for each method were recorded. Intraobserver and interobserver reliability was assessed on the prototype software measurements. T test, Spearman's rho, and Bland-Altman plots were used for statistical analysis. The final EFV A (with manual border optimization) was strongly correlated with the manual axial segmentation measurement (60.9 ± 33.2 mL vs. 65.8 ± 37.0 mL, rho = 0.970, P 0.9). Automated EFV A quantification is an accurate and time-saving method for quantification of EFV compared to established manual axial segmentation methods. (orig.)

  1. Knockdown of Zebrafish Blood Vessel Epicardial Substance Results in Incomplete Retinal Lamination

    Directory of Open Access Journals (Sweden)

    Yu-Ching Wu

    2014-01-01

    Full Text Available Cell polarity during eye development determines the normal retinal lamination and differentiation of photoreceptor cells in the retina. In vertebrates, blood vessel epicardial substance (Bves is known to play an important role in the formation and maintenance of the tight junctions essential for epithelial cell polarity. In the current study, we generated a transgenic zebrafish Bves (zbves promoter-EGFP zebrafish line to investigate the expression pattern of Bves in the retina and to study the role of zbves in retinal lamination. Immunostaining with different specific antibodies from retinal cells and transmission electron microscopy were used to identify the morphological defects in normal and Bves knockdown zebrafish. In normal zebrafish, Bves is located at the apical junctions of embryonic retinal neuroepithelia during retinogenesis; later, it is strongly expressed around inner plexiform layer (IPL and retinal pigment epithelium (RPE. In contrast, a loss of normal retinal lamination and cellular polarity was found with undifferentiated photoreceptor cells in Bves knockdown zebrafish. Herein, our results indicated that disruption of Bves will result in a loss of normal retinal lamination.

  2. Effect of the Epicardial Adipose Tissue Volume on the Prevalence of Paroxysmal and Persistent Atrial Fibrillation.

    Science.gov (United States)

    Oba, Kageyuki; Maeda, Minetaka; Maimaituxun, Gulinu; Yamaguchi, Satoshi; Arasaki, Osamu; Fukuda, Daiju; Yagi, Shusuke; Hirata, Yukina; Nishio, Susumu; Iwase, Takashi; Takao, Shoichiro; Kusunose, Kenya; Yamada, Hirotsugu; Soeki, Takeshi; Wakatsuki, Tetsuzo; Harada, Masafumi; Masuzaki, Hiroaki; Sata, Masataka; Shimabukuro, Michio

    2018-05-25

    Although increasing evidence suggests that epicardial adipose tissue volume (EATV) is associated with atrial fibrillation (AF), it is controversial whether there is a dose-response relationship of increasing EATV along the continuum of AF. We evaluated the effect of the EATV on the prevalence of paroxysmal AF (PAF) and persistent AF (PeAF) and the relationships with cardiac structure and functional remodeling.Methods and Results:Subjects who underwent multidetector computed tomography (MDCT) coronary angiography because of symptoms suggestive of coronary artery disease were divided into sinus rhythm (SR) (n=112), PAF (n=133), and PeAF (n=71) groups. The EATV index (EATV/body surface area, mL/m 2 ) was strongly associated with the prevalence of PAF and PeAF on the model adjusted for known AF risk factors. The effect of the EATV index on the prevalence of PeAF, but not on that of PAF, was modified by the left atrial (LA) dimension, suggesting that extension of the LA dimension is related to EATV expansion in PeAF. The cutoff value of the EATV index for the prevalence was higher in PeAF than in PAF (64 vs. 55 mL/m 2 , PEATV index is associated with the prevalence of PAF and PeAF, and its cutoff values are predictive for PAF and PeAF development independently of other AF risk factors.

  3. Epicardial fat volume is correlated with coronary lesion and its severity.

    Science.gov (United States)

    Bo, Xiaohong; Ma, Likun; Fan, Jili; Jiang, Zhe; Zhou, Yuansong; Zhang, Lei; Li, Wanjun

    2015-01-01

    To evaluate the correlation of epicardial adipose tissue volume (EATV) with the coronary artery lesion and its severity. Inpatients with suspicious stable angina of coronary heart lesion were recruited. For patients with coronary artery lesions in CTA, further coronary angiography (CAG) was performed to evaluate the coronary artery lesion. Gensini scoring system was employed to assess the severity of coronary artery lesions. Patients were classified as coronary heart disease (CHD) group (n = 160). Results showed the mean EATV was 192.57 ± 30.32 cm(3) in CHD group, which was significantly larger than that in control group (138.56 ± 23.18 cm(3); P EATV among patients with different severities of coronary artery stenosis (P EATV (r = 0.285, P = 0.000). The EATV increased with the increase in the number of affected coronary arteries. Multivariate Logistic regression analysis showed EATV was an independent risk factor of CHD after adjusting other confounding factors (OR = 1.023, P = 0.013). EATV is closely related to the severity of coronary artery lesions: the larger the EATV, the more severe the coronary artery lesions. Moreover, EATV is an independent risk factor of CHD.

  4. Electrical Circuits and Water Analogies

    Science.gov (United States)

    Smith, Frederick A.; Wilson, Jerry D.

    1974-01-01

    Briefly describes water analogies for electrical circuits and presents plans for the construction of apparatus to demonstrate these analogies. Demonstrations include series circuits, parallel circuits, and capacitors. (GS)

  5. Electric circuits essentials

    CERN Document Server

    REA, Editors of

    2012-01-01

    REA's Essentials provide quick and easy access to critical information in a variety of different fields, ranging from the most basic to the most advanced. As its name implies, these concise, comprehensive study guides summarize the essentials of the field covered. Essentials are helpful when preparing for exams, doing homework and will remain a lasting reference source for students, teachers, and professionals. Electric Circuits I includes units, notation, resistive circuits, experimental laws, transient circuits, network theorems, techniques of circuit analysis, sinusoidal analysis, polyph

  6. Assessment of relationships between novel inflammatory markers and presence and severity of preeclampsia: Epicardial fat thickness, pentraxin-3, and neutrophil-to-lymphocyte ratio.

    Science.gov (United States)

    Cakmak, Huseyin Altug; Dincgez Cakmak, Burcu; Abide Yayla, Cigdem; Inci Coskun, Ebru; Erturk, Mehmet; Keles, Ibrahim

    2017-08-01

    The aim of this study was to evaluate the relation of three new inflammatory markers with presence and severity of preeclampsia and to compare the predictive values of all markers for presence of this setting. In this study, a total of 100 consecutive pregnants with a diagnosis of preeclampsia and 40 healthy pregnants between October 2014 and April 2015 were included. Epicardial fat tissue was calculated by two-dimensional transthoracic echocardiography, and pentraxin-3 and neutrophil-to-lymphocyte ratio were measured by using an enzyme-linked immunosorbent assay method and routine blood count analysis, respectively. Epicardial fat thickness (p preeclampsia as compared to the healthy pregnants. Furthermore, epicardial fat thickness (p = 0.002), pentraxin-3 (p preeclampsia compared to mild preeclampsia. In the multivariate analysis, epicardial fat thickness (p = 0.013), pentraxin-3 (p = 0.04), and neutrophil-to-lymphocyte ratio (p preeclampsia after adjusting for other risk factors. Epicardial fat thickness, neutrophil-to-lymphocyte ratio, and pentraxin-3 are important markers that provide an additional information beyond that provided by conventional methods in predicting presence and severity of preeclampsia.

  7. Piezoelectric drive circuit

    Science.gov (United States)

    Treu, C.A. Jr.

    1999-08-31

    A piezoelectric motor drive circuit is provided which utilizes the piezoelectric elements as oscillators and a Meacham half-bridge approach to develop feedback from the motor ground circuit to produce a signal to drive amplifiers to power the motor. The circuit automatically compensates for shifts in harmonic frequency of the piezoelectric elements due to pressure and temperature changes. 7 figs.

  8. Load testing circuit

    DEFF Research Database (Denmark)

    2009-01-01

    A load testing circuit a circuit tests the load impedance of a load connected to an amplifier. The load impedance includes a first terminal and a second terminal, the load testing circuit comprising a signal generator providing a test signal of a defined bandwidth to the first terminal of the load...

  9. Short-circuit logic

    NARCIS (Netherlands)

    Bergstra, J.A.; Ponse, A.

    2010-01-01

    Short-circuit evaluation denotes the semantics of propositional connectives in which the second argument is only evaluated if the first argument does not suffice to determine the value of the expression. In programming, short-circuit evaluation is widely used. A short-circuit logic is a variant of

  10. Signal sampling circuit

    NARCIS (Netherlands)

    Louwsma, S.M.; Vertregt, Maarten

    2011-01-01

    A sampling circuit for sampling a signal is disclosed. The sampling circuit comprises a plurality of sampling channels adapted to sample the signal in time-multiplexed fashion, each sampling channel comprising a respective track-and-hold circuit connected to a respective analogue to digital

  11. Signal sampling circuit

    NARCIS (Netherlands)

    Louwsma, S.M.; Vertregt, Maarten

    2010-01-01

    A sampling circuit for sampling a signal is disclosed. The sampling circuit comprises a plurality of sampling channels adapted to sample the signal in time-multiplexed fashion, each sampling channel comprising a respective track-and-hold circuit connected to a respective analogue to digital

  12. Feedback in analog circuits

    CERN Document Server

    Ochoa, Agustin

    2016-01-01

    This book describes a consistent and direct methodology to the analysis and design of analog circuits with particular application to circuits containing feedback. The analysis and design of circuits containing feedback is generally presented by either following a series of examples where each circuit is simplified through the use of insight or experience (someone else’s), or a complete nodal-matrix analysis generating lots of algebra. Neither of these approaches leads to gaining insight into the design process easily. The author develops a systematic approach to circuit analysis, the Driving Point Impedance and Signal Flow Graphs (DPI/SFG) method that does not require a-priori insight to the circuit being considered and results in factored analysis supporting the design function. This approach enables designers to account fully for loading and the bi-directional nature of elements both in the feedback path and in the amplifier itself, properties many times assumed negligible and ignored. Feedback circuits a...

  13. Epicardial clip occlusion of the left atrial appendage during cardiac surgery provides optimal surgical results and long-term stability.

    Science.gov (United States)

    Kurfirst, Vojtech; Mokrácek, Aleš; Canádyová, Júlia; Frána, Radim; Zeman, Petr

    2017-07-01

    Occlusion of the left atrial appendage (LAA) has become an integral and important part of the surgical treatment of atrial fibrillation. Different methods of surgical occlusion of the LAA have been associated with varying levels of short- and long-term success for closure. The purpose of this study was to evaluate long-term results of epicardial placement and endocardial occlusion in patients undergoing cardiac operative procedures. A total of 101 patients (average age 65.7 years) undergoing cardiac operative procedures with the epicardial AtriClip Exclusion System of the LAA were enrolled in the study. The AtriClip was placed via a sternotomy or a thoracotomy or from a thoracoscopic approach. Postoperative variables, such as thromboembolic events, clip stability and endocardial leakage around the device, were examined by transoesophageal echocardiography (TEE) and/or computed tomography. Perioperative clip implantation was achieved in 98% of patients. TEE and/or computed tomography conducted during the follow-up period, comprising 1873 patient-months with a mean duration of 18 ± 11 months, revealed no clip migration, no leakage around the device and no clot formation near the remnant cul-de-sac. During the follow-up period, 4 of the cardiac patients experienced transitory ischaemic attacks, whereas no patient experienced a cerebrovascular attack. The Epicardial AtriClip Exclusion System of the LAA appears to be a feasable and safe operative method with a high success rate. Long-term follow-up confirmed clip stability, complete occlussion of the LAA and absence of any atrial fibrilation-related thromboembolic events. These results need to be confirmed by a larger, multicentre study. © The Author 2017. Published by Oxford University Press on behalf of the European Association for Cardio-Thoracic Surgery. All rights reserved.

  14. Increased Regional Epicardial Fat Volume Associated with Reversible Myocardial Ischemia in Patients with Suspected Coronary Artery Disease

    Science.gov (United States)

    Khawaja, Tuba; Greer, Christine; Thadani, Samir R.; Kato, Tomoko S.; Bhatia, Ketan; Shimbo, Daichi; Konkak, Andrew; Bokhari, Sabahat; Einstein, Andrew J.; Schulze, P. Christian

    2015-01-01

    Epicardial adipose tissue is a source of pro-inflammatory cytokines and has been linked to the development of coronary artery disease. No study has systematically assessed the relationship between local epicardial fat volume (EFV) and myocardial perfusion defects. We analyzed EFV in patients undergoing SPECT myocardial perfusion imaging combined with computed tomography (CT) for attenuation correction. Low-dose CT without contrast was performed in 396 consecutive patients undergoing SPECT imaging for evaluation of coronary artery disease. Regional thickness, cross-sectional areas, and total EFV were assessed. 295 patients had normal myocardial perfusion scans and 101 had abnormal perfusion scans. Mean EFVs in normal, ischemic, and infarcted hearts were 99.8 ± 82.3 cm3, 156.4 ± 121.9 cm3, and 96.3 ± 102.1 cm3, respectively (P < 0.001). Reversible perfusion defects were associated with increased local EFV compared to normal perfusion in the distribution of the right (69.2 ± 51.5 vs 46.6 ± 32.0 cm3; P = 0.03) and left anterior descending coronary artery (87.1 ± 76.4 vs 46.7 ± 40.6 cm3; P = 0.005). Our results demonstrate increased regional epicardial fat in patients with active myocardial ischemia compared to patients with myocardial scar or normal perfusion on nuclear perfusion scans. Our results suggest a potential role for cardiac CT to improve risk stratification in patients with suspected coronary artery disease. PMID:25339129

  15. Role of miRNAs in Epicardial Adipose Tissue in CAD Patients with T2DM

    Directory of Open Access Journals (Sweden)

    Yang Liu

    2016-01-01

    Full Text Available Background. Epicardial adipose tissue (EAT is identified as an atypical fat depot surrounding the heart with a putative role in the involvement of metabolic disorders, including obesity, type-2 diabetes mellitus, and atherosclerosis. We profiled miRNAs in EAT of metabolic patients with coronary artery disease (CAD and type-2 diabetes mellitus (T2DM versus metabolically healthy patients by microarray. Compared to metabolically healthy patients, we identified forty-two miRNAs that are differentially expressed in patients with CAD and T2DM from Xinjiang, China. Eleven miRNAs were selected as potential novel miRNAs according to P value and fold change. Then the potential novel miRNAs targeted genes were predicted via TargetScan, PicTar, and miRTarbase, and the function of the target genes was predicted via Gene Ontology (GO analysis while the enriched KEGG pathway analyses of the miRNAs targeted genes were performed by bioinformatics software DAVID. Then protein-protein interaction networks of the targeted gene were conducted by online software STRING. Finally, using microarray, bioinformatics approaches revealed the possible molecular mechanisms pathogenesis of CAD and T2DM. A total of 11 differentially expressed miRNAs were identified and among them, hsa-miR-4687-3p drew specific attention. Bioinformatics analysis revealed that insulin signaling pathway is the central way involved in the progression of metabolic disorders. Conclusions. The current findings support the fact that miRNAs are involved in the pathogenesis of metabolic disorders in EAT of CAD patients with T2DM, and validation of the results of these miRNAs by independent and prospective study is certainly warranted.

  16. Association Between Epicardial Fat Thickness and Premature Coronary Artery Disease: A Case Control Study

    Science.gov (United States)

    Faghihi, Shadi; Vasheghani-Farahani, Ali; Parsaee, Mozhgan; Saedi, Sedigheh; Ghadrdoost, Behshid

    2015-01-01

    Background: The association between epicardial fat thickness (EFT) and premature coronary artery disease (CAD) has not been elaborately studied. Objectives: In the present study, we sought whether such a relationship between EFT and CAD exists. Patients and Methods: Sixty two consecutive subjects, under 50 years of age, who underwent coronary angiography (CAG) with the aspect of CAD, were included in this case control study. They were divided into two groups of 31 subjects, namely CAD (cases) and non-CAD (controls) group, according to CAG data. Presence of conventional coronary risk factors, drug history, and anthropometric data were recorded. Then, each subject underwent standard transthoracic echocardiography for measuring EFT in the proximal part of right ventricular outflow tract in the parasternal long axis view at end diastole, as well as other parameters of systolic and diastolic function, and left ventricle (LV) mass. Images were stored for offline analysis when the echocardiocardiographers were blind to CAG data. Results: Among baseline characteristics, waist circumference, triglyceride levels, cigarette smoking and history of statin use were significantly higher in the CAD group. The body mass index (BMI) was significantly higher in the non-CAD group. According to echocardiographic data, the EFT with a cut off value of 2.95 mm could well differentiate subjects in each group. The LV mass and E/e were significantly higher in CAD group, in addition to EFT. Also, there was a significant correlation between EFT and waist circumference, as well as LV mass. However, no significant relation was between EFT and LV systolic and diastolic function. Conclusions: The EFT, as measured by echocardiography, with a cut off value 2.95 mm has a strong association with premature CAD. PMID:26380819

  17. Automated quantification of epicardial adipose tissue using CT angiography: evaluation of a prototype software

    Energy Technology Data Exchange (ETDEWEB)

    Spearman, James V.; Silverman, Justin R.; Krazinski, Aleksander W.; Costello, Philip [Medical University of South Carolina, Department of Radiology and Radiological Science, Charleston, SC (United States); Meinel, Felix G.; Geyer, Lucas L. [Medical University of South Carolina, Department of Radiology and Radiological Science, Charleston, SC (United States); Ludwig-Maximilians-University Hospital, Institute for Clinical Radiology, Munich (Germany); Schoepf, U.J. [Medical University of South Carolina, Department of Radiology and Radiological Science, Charleston, SC (United States); Medical University of South Carolina, Division of Cardiology, Department of Medicine, Charleston, SC (United States); Apfaltrer, Paul [Medical University of South Carolina, Department of Radiology and Radiological Science, Charleston, SC (United States); University Medical Center Mannheim, Medical Faculty Mannheim - Heidelberg University, Institute of Clinical Radiology and Nuclear Medicine, Mannheim (Germany); Canstein, Christian [Siemens Medical Solutions USA, Inc., Malvern, PA (United States); De Cecco, Carlo Nicola [Medical University of South Carolina, Department of Radiology and Radiological Science, Charleston, SC (United States); University of Rome ' ' Sapienza' ' - Polo Pontino, Department of Radiological Sciences, Oncology and Pathology, Latina (Italy)

    2014-02-15

    This study evaluated the performance of a novel automated software tool for epicardial fat volume (EFV) quantification compared to a standard manual technique at coronary CT angiography (cCTA). cCTA data sets of 70 patients (58.6 ± 12.9 years, 33 men) were retrospectively analysed using two different post-processing software applications. Observer 1 performed a manual single-plane pericardial border definition and EFV{sub M} segmentation (manual approach). Two observers used a software program with fully automated 3D pericardial border definition and EFV{sub A} calculation (automated approach). EFV and time required for measuring EFV (including software processing time and manual optimization time) for each method were recorded. Intraobserver and interobserver reliability was assessed on the prototype software measurements. T test, Spearman's rho, and Bland-Altman plots were used for statistical analysis. The final EFV{sub A} (with manual border optimization) was strongly correlated with the manual axial segmentation measurement (60.9 ± 33.2 mL vs. 65.8 ± 37.0 mL, rho = 0.970, P < 0.001). A mean of 3.9 ± 1.9 manual border edits were performed to optimize the automated process. The software prototype required significantly less time to perform the measurements (135.6 ± 24.6 s vs. 314.3 ± 76.3 s, P < 0.001) and showed high reliability (ICC > 0.9). Automated EFV{sub A} quantification is an accurate and time-saving method for quantification of EFV compared to established manual axial segmentation methods. (orig.)

  18. Enhanced Electrical Integration of Engineered Human Myocardium via Intramyocardial versus Epicardial Delivery in Infarcted Rat Hearts.

    Directory of Open Access Journals (Sweden)

    Kaytlyn A Gerbin

    Full Text Available Cardiac tissue engineering is a promising approach to provide large-scale tissues for transplantation to regenerate the heart after ischemic injury, however, integration with the host myocardium will be required to achieve electromechanical benefits. To test the ability of engineered heart tissues to electrically integrate with the host, 10 million human embryonic stem cell (hESC-derived cardiomyocytes were used to form either scaffold-free tissue patches implanted on the epicardium or micro-tissue particles (~1000 cells/particle delivered by intramyocardial injection into the left ventricular wall of the ischemia/reperfusion injured athymic rat heart. Results were compared to intramyocardial injection of 10 million dispersed hESC-cardiomyocytes. Graft size was not significantly different between treatment groups and correlated inversely with infarct size. After implantation on the epicardial surface, hESC-cardiac tissue patches were electromechanically active, but they beat slowly and were not electrically coupled to the host at 4 weeks based on ex vivo fluorescent imaging of their graft-autonomous GCaMP3 calcium reporter. Histologically, scar tissue physically separated the patch graft and host myocardium. In contrast, following intramyocardial injection of micro-tissue particles and suspended cardiomyocytes, 100% of the grafts detected by fluorescent GCaMP3 imaging were electrically coupled to the host heart at spontaneous rate and could follow host pacing up to a maximum of 300-390 beats per minute (5-6.5 Hz. Gap junctions between intramyocardial graft and host tissue were identified histologically. The extensive coupling and rapid response rate of the human myocardial grafts after intramyocardial delivery suggest electrophysiological adaptation of hESC-derived cardiomyocytes to the rat heart's pacemaking activity. These data support the use of the rat model for studying electromechanical integration of human cardiomyocytes, and they

  19. Triiodothyronine promotes the proliferation of epicardial progenitor cells through the MAPK/ERK pathway.

    Science.gov (United States)

    Deng, Song-Bai; Jing, Xiao-Dong; Wei, Xiao-Ming; Du, Jian-Lin; Liu, Ya-Jie; Qin, Qin; She, Qiang

    2017-04-29

    Thyroid hormone has important functions in the development and physiological function of the heart. The aim of this study was to determine whether 3,5,3'-Triiodothyronine (T3) can promote the proliferation of epicardial progenitor cells (EPCs) and to investigate the potential underlying mechanism. Our results showed that T3 significantly promoted the proliferation of EPCs in a concentration- and time-dependent manner. The thyroid hormone nuclear receptor inhibitor bisphenol A (100 μmol/L) did not affect T3's ability to induce proliferation. Further studies showed that the mRNA expression levels of mitogen-activated protein kinase 1 (MAPK1), MAPK3, and Ki67 in EPCs in the T3 group (10 nmol/L) increased 2.9-, 3-, and 4.1-fold, respectively, compared with those in the control group (P < 0.05). In addition, the mRNA expression of the cell cycle protein cyclin D1 in the T3 group increased approximately 2-fold compared with the control group (P < 0.05), and there were more EPCs in the S phase of the cell cycle (20.6% vs. 12.0%, P < 0.05). The mitogen-activated protein kinase/extracellular signal-regulated kinase (MAPK/ERK) signaling pathway inhibitor U0126 (10 μmol/L) significantly inhibited the ability of T3 to promote the proliferation of EPCs and to alter cell cycle progression. This study suggested that T3 significantly promotes the proliferation of EPCs, and this effect may be achieved through activation of the MAPK/ERK signaling pathway. Copyright © 2017 Elsevier Inc. All rights reserved.

  20. Target vessel detection by epicardial ultrasound in off-pump coronary bypass surgery.

    Science.gov (United States)

    Hayakawa, Masato; Asai, Tohru; Kinoshita, Takeshi; Suzuki, Tomoaki; Shiraishi, Shoichiro

    2013-01-01

    The detection of embedded coronary arteries is difficult especially in off-pump coronary bypass surgery. From June 2010, we introduced high-frequency epicardial ultrasound (ECUS) to assess and evaluate embedded arteries during off-pump coronary bypass surgery. Between June 2010 and June 2011, a total of 89 consecutive patients underwent isolated coronary bypass surgery at our institution. The patients consisted of 72 men and 17 women with a mean age of 67.9 years. We routinely use the VeriQC system (MediStim, Oslo, Norway) to detect the target vessels in the operation. The patients were assigned to one of two groups, depending on whether ECUS was used in the operation (n = 10, ECUS group) or not (n = 79, non-ECUS group). We analyzed the impact of introducing the ECUS in terms of operative outcome. All patients underwent revascularization using the off-pump technique without emergent conversion to cardiopulmonary bypass during surgery. The total number of distal anastomoses was 299, and 12 target vessels could not be identified either visually or on palpation. Thus, the frequency of the embedded coronary arteries was 4.01% (12/299 cases). The preoperative profiles of the two groups were not significantly different. Operation time was significantly longer in the ECUS group (P = 0.02). There were no significant differences in postoperative outcome between the two groups. In the present study, in which the target coronary arteries could not be detected either visually or on palpation in 12 (4.01%) of 299 cases, the use of high-frequency ECUS allowed all patients to undergo off-pump coronary bypass surgery without conversion to cardiopulmonary bypass during the operation. High-frequency ECUS is therefore useful in off-pump coronary bypass surgery.

  1. Epicardial adipose tissue volume and adipocytokine imbalance are strongly linked to human coronary atherosclerosis.

    Science.gov (United States)

    Shimabukuro, Michio; Hirata, Yoichiro; Tabata, Minoru; Dagvasumberel, Munkhbaatar; Sato, Hiromi; Kurobe, Hirotsugu; Fukuda, Daiju; Soeki, Takeshi; Kitagawa, Tetsuya; Takanashi, Shuichiro; Sata, Masataka

    2013-05-01

    The impact of epicardial adipose tissue (EAT) over abdominal or overall adiposity on coronary artery disease (CAD) is currently unknown. We compared the association among EAT volume (EATV), cytokine/adipocytokine profiles in EAT and subcutaneous fat, and atherogenic CAD. Paired samples were obtained from EAT and subcutaneous adipose tissue during elective cardiac surgery for CAD (n=50) or non-CAD (n=50). EATV was the sum of cross-sectional EAT areas, and visceral and subcutaneous fat areas were determined at the umbilicus level on computed tomography scans. CD68(+), CD11c(+), and CD206(+) cells were counted using immunohistochemical staining. Cytokine/adipocytokine expression was evaluated using quantitative real-time polymerase chain reaction. Multivariate analysis indicated that male sex, age, diabetes mellitus, high triglycerides, and low high-density lipoprotein cholesterol, and EATV index (EATV/body surface area, cm(3)/m(2)) were significant CAD predictors (corrected R(2)=0.401; PEATV index positively correlated with the CD68(+) and CD11c(+) cell numbers and nucleotide-binding domain, leucine-rich-containing family, pyrin domain-containing-3 (NLRP3), interleukin-1β, and interleukin-1R expression; and negatively correlated with adiponectin expression in EAT. A multivariate analysis model, including CD68(+) cells and interleukin-1β, and adiponectin expression in EAT strongly predicted CAD (corrected R(2)=0.756; PEATV and macrophage and cytokine/adipocytokine signals in EAT strongly correlated with CAD. Our findings suggest that EATV and adipocytokine imbalance are strongly linked to human coronary atherosclerosis.

  2. Influence of technical parameters on epicardial fat volume quantification at cardiac CT.

    Science.gov (United States)

    Bucher, Andreas M; Joseph Schoepf, U; Krazinski, Aleksander W; Silverman, Justin; Spearman, James V; De Cecco, Carlo N; Meinel, Felix G; Vogl, Thomas J; Geyer, Lucas L

    2015-06-01

    To systematically analyze the influence of technical parameters on quantification of epicardial fat volume (EATV) at cardiac CT. 153 routine cardiac CT data sets were analyzed using three-dimensional pericardial border delineation. Three image series were reconstructed per patient: (a) CTAD: coronary CT angiography (CTA), diastolic phase; (b) CTAS: coronary CTA, systolic phase; (c) CaScD: non-contrast CT, diastolic phase. EATV was calculated using three different upper thresholds (-15HU, -30 HU, -45HU). Repeated measures ANOVA, Spearman's rho, and Bland Altman plots were used. Mean EATV differed between all three image series at a -30HU threshold (CTAD 87.2 ± 38.5 ml, CTAS 90.9 ± 37.7 ml, CaScD 130.7 ± 49.5 ml, PEATV of diastolic and systolic CTA reconstructions did not differ significantly (P=0.225). Mean EATV for contrast enhanced CTA at a -15HU threshold (CTAD15 102.4 ± 43.6 ml, CTAS15 105.3 ± 42.3 ml) could be approximated most closely by non-contrast CT at -45HU threshold (CaScD45 105.3 ± 40.8 ml). The correlation was excellent: CTAS15-CTAD15, rho=0.943; CTAD15-CaScD45, rho=0.905; CTAS15-CaScD45, rho=0.924; each PEATV can differ substantially between contrast enhanced and non-contrast CT studies, which can be reconciled by threshold modification. Heart cycle phase does not significantly influence EATV measurements. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  3. Lagrangian displacement tracking using a polar grid between endocardial and epicardial contours for cardiac strain imaging.

    Science.gov (United States)

    Ma, Chi; Varghese, Tomy

    2012-04-01

    Accurate cardiac deformation analysis for cardiac displacement and strain imaging over time requires Lagrangian description of deformation of myocardial tissue structures. Failure to couple the estimated displacement and strain information with the correct myocardial tissue structures will lead to erroneous result in the displacement and strain distribution over time. Lagrangian based tracking in this paper divides the tissue structure into a fixed number of pixels whose deformation is tracked over the cardiac cycle. An algorithm that utilizes a polar-grid generated between the estimated endocardial and epicardial contours for cardiac short axis images is proposed to ensure Lagrangian description of the pixels. Displacement estimates from consecutive radiofrequency frames were then mapped onto the polar grid to obtain a distribution of the actual displacement that is mapped to the polar grid over time. A finite element based canine heart model coupled with an ultrasound simulation program was used to verify this approach. Segmental analysis of the accumulated displacement and strain over a cardiac cycle demonstrate excellent agreement between the ideal result obtained directly from the finite element model and our Lagrangian approach to strain estimation. Traditional Eulerian based estimation results, on the other hand, show significant deviation from the ideal result. An in vivo comparison of the displacement and strain estimated using parasternal short axis views is also presented. Lagrangian displacement tracking using a polar grid provides accurate tracking of myocardial deformation demonstrated using both finite element and in vivo radiofrequency data acquired on a volunteer. In addition to the cardiac application, this approach can also be utilized for transverse scans of arteries, where a polar grid can be generated between the contours delineating the outer and inner wall of the vessels from the blood flowing though the vessel.

  4. Comparison of arrhythmogenicity and proinflammatory activity induced by intramyocardial or epicardial myoblast sheet delivery in a rat model of ischemic heart failure.

    Directory of Open Access Journals (Sweden)

    Tommi Pätilä

    Full Text Available Although cell therapy of the failing heart by intramyocardial injections of myoblasts to results in regenerative benefit, it has also been associated with undesired and prospectively fatal arrhythmias. We hypothesized that intramyocardial injections of myoblasts could enhance inflammatory reactivity and facilitate electrical cardiac abnormalities that can be reduced by epicardial myoblast sheet delivery. In a rat model of ischemic heart failure, myoblast therapy either by intramyocardial injections or epicardial cell sheets was given 2 weeks after occlusion of the coronary artery. Ventricular premature contractions (VPCs were assessed, using an implanted three-lead electrocardiograph at 1, 7, and 14 days after therapy, and 16-point epicardial electropotential mapping (EEPM was used to evaluate ventricular arrhythmogenicity under isoproterenol stress. Cardiac functioning was assessed by echocardiography. Both transplantation groups showed therapeutic benefit over sham therapy. However, VPCs were more frequent in the Injection group on day 1 and day 14 after therapy than in animals receiving epicardial or sham therapy (p < 0.05 and p < 0.01, respectively. EEPM under isoproterenol stress showed macroreentry at the infarct border area, leading to ventricular tachycardias in the Injection group, but not in the myoblast sheet- or sham-treated groups (p = 0.045. Both transplantation types modified the myocardial cytokine expression profile. In animals receiving epicardial myoblast therapy, selective reductions in the expressions of interferon gamma, interleukin (IL-1β and IL12 were observed, accompanied by reduced infiltration of inflammatory CD11b- and CD68-positive leukocytes, compared with animals receiving myoblasts as intramyocardial injections. Intramyocardial myoblast delivery was associated with enhanced inflammatory and immunomodulatory reactivity and increased frequency of VPCs. In comparison to intramyocardial injection, the epicardial

  5. Epicardial and Subcutaneous Adipose Tissue Fatty Acids Profiles in Diabetic and Non-Diabetic Patients Candidate for Coronary Artery Bypass Graft

    Directory of Open Access Journals (Sweden)

    Masoud Pezeshkian

    2013-01-01

    Full Text Available Introduction: We have recently shown that in high cholesterol-fed rabbits, the sensitivity of epicardial adipose tissue to changes in dietary fat is higher than that of subcutaneous adipose tissue. Although the effects of diabetes on epicardial adipose tissue thickness have been studied, the influence of diabetes on profile of epicardial free fatty acids (FFAs has not been studied. The aim of this study is to investigate the effect of diabetes on the FFAs composition in serum and in the subcutaneous and epicardial adipose tissues in patients undergoing coronary artery bypass graft (CABG. Methods: Forty non-diabetic and twenty eight diabetic patients candidate for CABG with > 75% stenosis participated in this study.Fasting blood sugar (FBS and lipid profiles were assayed by auto analyzer. Phospholipids and non-estrified FFA of serum and the fatty acids profile of epicardial and subcutaneous adipose tissues were determined using gas chromatography method. Results: In the phospholipid fraction of diabetic patients’ serum, the percentage of 16:0, 18:3n-9, 18:2n-6 and monounsaturated fatty acids (MUFAs was lower than the corresponding values of the non-diabetics; whereas, 18:0 value was higher. A 100% increase in the amount of 18:0 and 35% decrease in the level of 18:1n-11 was observed in the diabetic patients’ subcutaneous adipose tissue. In epicardial adipose tissue, the increase of 18:0 and conjugated linolenic acid (CLA and decrease of 18:1n-11, ω3 (20:5n-3 and 22:6n-3 were significant; but, the contents of arachidonic acid and its precursor linoleic acid were not affected by diabetes. Conclusion: The fatty acids’ profile of epicardial and subcutaneous adipose tissues is not equally affected by diabetes. The significant decrease of 16:0 and ω3 fatty acids and increase of trans and conjugated fatty acids in epicardial adipose tissue in the diabetic patients may worsen the formation of atheroma in the related arteries.

  6. [The reentrant binomial model of nuclear anomalies growth in rhabdomyosarcoma RA-23 cell populations under increasing doze of rare ionizing radiation].

    Science.gov (United States)

    Alekseeva, N P; Alekseev, A O; Vakhtin, Iu B; Kravtsov, V Iu; Kuzovatov, S N; Skorikova, T I

    2008-01-01

    Distributions of nuclear morphology anomalies in transplantable rabdomiosarcoma RA-23 cell populations were investigated under effect of ionizing radiation from 0 to 45 Gy. Internuclear bridges, nuclear protrusions and dumbbell-shaped nuclei were accepted for morphological anomalies. Empirical distributions of the number of anomalies per 100 nuclei were used. The adequate model of reentrant binomial distribution has been found. The sum of binomial random variables with binomial number of summands has such distribution. Averages of these random variables were named, accordingly, internal and external average reentrant components. Their maximum likelihood estimations were received. Statistical properties of these estimations were investigated by means of statistical modeling. It has been received that at equally significant correlation between the radiation dose and the average of nuclear anomalies in cell populations after two-three cellular cycles from the moment of irradiation in vivo the irradiation doze significantly correlates with internal average reentrant component, and in remote descendants of cell transplants irradiated in vitro - with external one.

  7. Electric circuits and signals

    CERN Document Server

    Sabah, Nassir H

    2007-01-01

    Circuit Variables and Elements Overview Learning Objectives Electric Current Voltage Electric Power and Energy Assigned Positive Directions Active and Passive Circuit Elements Voltage and Current Sources The Resistor The Capacitor The Inductor Concluding Remarks Summary of Main Concepts and Results Learning Outcomes Supplementary Topics on CD Problems and Exercises Basic Circuit Connections and Laws Overview Learning Objectives Circuit Terminology Kirchhoff's Laws Voltage Division and Series Connection of Resistors Current Division and Parallel Connection of Resistors D-Y Transformation Source Equivalence and Transformation Reduced-Voltage Supply Summary of Main Concepts and Results Learning Outcomes Supplementary Topics and Examples on CD Problems and Exercises Basic Analysis of Resistive Circuits Overview Learning Objectives Number of Independent Circuit Equations Node-Voltage Analysis Special Considerations in Node-Voltage Analysis Mesh-Current Analysis Special Conside...

  8. [Shunt and short circuit].

    Science.gov (United States)

    Rangel-Abundis, Alberto

    2006-01-01

    Shunt and short circuit are antonyms. In French, the term shunt has been adopted to denote the alternative pathway of blood flow. However, in French, as well as in Spanish, the word short circuit (court-circuit and cortocircuito) is synonymous with shunt, giving rise to a linguistic and scientific inconsistency. Scientific because shunt and short circuit made reference to a phenomenon that occurs in the field of the physics. Because shunt and short circuit are antonyms, it is necessary to clarify that shunt is an alternative pathway of flow from a net of high resistance to a net of low resistance, maintaining the stream. Short circuit is the interruption of the flow, because a high resistance impeaches the flood. This concept is applied to electrical and cardiovascular physiology, as well as to the metabolic pathways.

  9. Analog circuits cookbook

    CERN Document Server

    Hickman, Ian

    2013-01-01

    Analog Circuits Cookbook presents articles about advanced circuit techniques, components and concepts, useful IC for analog signal processing in the audio range, direct digital synthesis, and ingenious video op-amp. The book also includes articles about amplitude measurements on RF signals, linear optical imager, power supplies and devices, and RF circuits and techniques. Professionals and students of electrical engineering will find the book informative and useful.

  10. Analog circuit design

    CERN Document Server

    Dobkin, Bob

    2012-01-01

    Analog circuit and system design today is more essential than ever before. With the growth of digital systems, wireless communications, complex industrial and automotive systems, designers are being challenged to develop sophisticated analog solutions. This comprehensive source book of circuit design solutions aids engineers with elegant and practical design techniques that focus on common analog challenges. The book's in-depth application examples provide insight into circuit design and application solutions that you can apply in today's demanding designs. <

  11. Regenerative feedback resonant circuit

    Science.gov (United States)

    Jones, A. Mark; Kelly, James F.; McCloy, John S.; McMakin, Douglas L.

    2014-09-02

    A regenerative feedback resonant circuit for measuring a transient response in a loop is disclosed. The circuit includes an amplifier for generating a signal in the loop. The circuit further includes a resonator having a resonant cavity and a material located within the cavity. The signal sent into the resonator produces a resonant frequency. A variation of the resonant frequency due to perturbations in electromagnetic properties of the material is measured.

  12. CMOS circuits manual

    CERN Document Server

    Marston, R M

    1995-01-01

    CMOS Circuits Manual is a user's guide for CMOS. The book emphasizes the practical aspects of CMOS and provides circuits, tables, and graphs to further relate the fundamentals with the applications. The text first discusses the basic principles and characteristics of the CMOS devices. The succeeding chapters detail the types of CMOS IC, including simple inverter, gate and logic ICs and circuits, and complex counters and decoders. The last chapter presents a miscellaneous collection of two dozen useful CMOS circuits. The book will be useful to researchers and professionals who employ CMOS circu

  13. Timergenerator circuits manual

    CERN Document Server

    Marston, R M

    2013-01-01

    Timer/Generator Circuits Manual is an 11-chapter text that deals mainly with waveform generator techniques and circuits. Each chapter starts with an explanation of the basic principles of its subject followed by a wide range of practical circuit designs. This work presents a total of over 300 practical circuits, diagrams, and tables.Chapter 1 outlines the basic principles and the different types of generator. Chapters 2 to 9 deal with a specific type of waveform generator, including sine, square, triangular, sawtooth, and special waveform generators pulse. These chapters also include pulse gen

  14. Electronic devices and circuits

    CERN Document Server

    Pridham, Gordon John

    1968-01-01

    Electronic Devices and Circuits, Volume 1 deals with the design and applications of electronic devices and circuits such as passive components, diodes, triodes and transistors, rectification and power supplies, amplifying circuits, electronic instruments, and oscillators. These topics are supported with introductory network theory and physics. This volume is comprised of nine chapters and begins by explaining the operation of resistive, inductive, and capacitive elements in direct and alternating current circuits. The theory for some of the expressions quoted in later chapters is presented. Th

  15. Maximum Acceleration Recording Circuit

    Science.gov (United States)

    Bozeman, Richard J., Jr.

    1995-01-01

    Coarsely digitized maximum levels recorded in blown fuses. Circuit feeds power to accelerometer and makes nonvolatile record of maximum level to which output of accelerometer rises during measurement interval. In comparison with inertia-type single-preset-trip-point mechanical maximum-acceleration-recording devices, circuit weighs less, occupies less space, and records accelerations within narrower bands of uncertainty. In comparison with prior electronic data-acquisition systems designed for same purpose, circuit simpler, less bulky, consumes less power, costs and analysis of data recorded in magnetic or electronic memory devices. Circuit used, for example, to record accelerations to which commodities subjected during transportation on trucks.

  16. MOS integrated circuit design

    CERN Document Server

    Wolfendale, E

    2013-01-01

    MOS Integral Circuit Design aims to help in the design of integrated circuits, especially large-scale ones, using MOS Technology through teaching of techniques, practical applications, and examples. The book covers topics such as design equation and process parameters; MOS static and dynamic circuits; logic design techniques, system partitioning, and layout techniques. Also featured are computer aids such as logic simulation and mask layout, as well as examples on simple MOS design. The text is recommended for electrical engineers who would like to know how to use MOS for integral circuit desi

  17. Circuits and filters handbook

    CERN Document Server

    Chen, Wai-Kai

    2003-01-01

    A bestseller in its first edition, The Circuits and Filters Handbook has been thoroughly updated to provide the most current, most comprehensive information available in both the classical and emerging fields of circuits and filters, both analog and digital. This edition contains 29 new chapters, with significant additions in the areas of computer-aided design, circuit simulation, VLSI circuits, design automation, and active and digital filters. It will undoubtedly take its place as the engineer's first choice in looking for solutions to problems encountered in the design, analysis, and behavi

  18. Security electronics circuits manual

    CERN Document Server

    MARSTON, R M

    1998-01-01

    Security Electronics Circuits Manual is an invaluable guide for engineers and technicians in the security industry. It will also prove to be a useful guide for students and experimenters, as well as providing experienced amateurs and DIY enthusiasts with numerous ideas to protect their homes, businesses and properties.As with all Ray Marston's Circuits Manuals, the style is easy-to-read and non-mathematical, with the emphasis firmly on practical applications, circuits and design ideas. The ICs and other devices used in the practical circuits are modestly priced and readily available ty

  19. Thickening of the epicardial adipose tissue can be alleviated by thyroid hormone replacement therapy in patients with subclinical hypothyroidism.

    Science.gov (United States)

    Sayin, Irmak; Erkan, Aycan Fahri; Ekici, Berkay; Kutuk, Utku; Corakci, Ahmet; Tore, Hasan Fehmi

    2016-01-01

    Subclinical hypothyroidism (SCH) is a common disorder which has adverse cardiovascular effects. Epicardial adipose tissue (EAT), a novel marker of cardiovascular risk, is increased in SCH. We aimed to investigate whether L-thyroxine treatment can reverse the thickening of EAT in SCH. Forty-four patients with SCH and 42 euthyroid control subjects were included. EAT thickness was measured using transthoracic echocardiography at baseline and after restoration of the euthyroid status with 3 months of L-thyroxine treatment. At baseline, mean EAT thickness was significantly greater in the SCH group when compared to the control group (6.3 ± 1.7 mm vs. 4.1 ± 0.9 mm, respectively, p treatment (6.3 ± 1.7 mm vs. 5.1 ± 1.4 mm, p treatment when compared to baseline (DEAT) significantly correlated to the difference in TSH levels before and after treatment (DTSH; r = 0.323; p = 0.032). Epicardial adipose tissue thickness is increased in patients with SCH. This thickening was alleviated with restoration of the euthyroid status with L-thyroxine treatment in our study population of predominantly male, relatively old subjects with greater baseline EAT thickness.

  20. Aborted Sudden Cardiac Death in a Female Patient Presenting with Takotsubo-Like Cardiomyopathy due to Epicardial Coronary Vasospasm

    Directory of Open Access Journals (Sweden)

    Sorin Giusca

    2017-01-01

    Full Text Available Takotsubo cardiomyopathy is characterized by apical ballooning of the left ventricle (LV in the absence of relevant coronary artery stenosis, which typically occurs in elderly women after emotional stress. Catecholamine cardiotoxicity, metabolic disturbance, and coronary microvascular impairment have previously been proposed as underlying pathophysiologic mechanisms of takotsubo cardiomyopathy, whereas myocardial stunning resulting from epicardial coronary artery vasospasm is not generally accepted as a cause of takotsubo cardiomyopathy. The prognosis of takotsubo cardiomyopathy is generally more favourable compared to myocardial infarction; however, severe complications such as rupture of the LV and life-threatening arrhythmias may occur. Herein, we describe a case of an 84-year-old female, who presented with aborted sudden cardiac death due to ventricular fibrillation. Echocardiography suggested LV apical ballooning with severely impaired LV-function, so that takotsubo cardiomyopathy was suspected. However, coronary angiography revealed epicardial spasm of the left anterior ascending, which resolved after intracoronary injection of 0.2 mg nitroglycerine. Cardiac magnetic resonance exhibited subendocardial late enhancement and echocardiography showed normalization of LV dysfunction during follow-up. The patient was put on conservative treatment with nitrates and calcium inhibitors and ICD implantation were deferred.

  1. Increased epicardial fat is independently associated with the presence and chronicity of atrial fibrillation and radiofrequency ablation outcome

    Energy Technology Data Exchange (ETDEWEB)

    Stojanovska, Jadranka; Kazerooni, Ella A.; Gross, Barry H.; Patel, Smita [University of Michigan Health System, Department of Radiology, Division of Cardiothoracic Radiology, UH B1-132 Taubman/Box 0302, Ann Arbor, MI (United States); Sinno, Mohamad; Oral, Hakan [University of Michigan Health System, Department of Internal Medicine, Cardiovascular Medicine, Electrophysiology Laboratory, Cardiovascular Center, Ann Arbor, MI (United States); Watcharotone, Kuanwong [University of Michigan, Michigan Institute for Clinical and Health Research (MICHR), Ann Arbor, MI (United States); Jacobson, Jon A. [University of Michigan Health System, Department of Radiology, Division of Musculoskeletal Radiology, Ann Arbor, MI (United States)

    2015-08-15

    To determine whether intrathoracic fat volumes are associated with presence and chronicity of atrial fibrillation (AF) and radiofrequency ablation (RFA) treatment outcome. IRB approval was obtained and patient consent was waived for this HIPAA-compliant retrospective study. 169 patients with AF (75 non-paroxysmal and 94 paroxysmal) and 62 control patients underwent cardiac CT examination. Extrapericardial (EPFV) and epicardial fat volumes (EFV) were measured on CT, the sum of which is the total intrathoracic fat volume. Associations between these three fat volumes and presence and chronicity of AF, and outcome after RFA, were evaluated using logistic regression analysis. EFV was significantly associated with presence [OR 1.01 (95 % CI 1.003-1.03), p = 0.01], chronicity of AF [1.008 (1.001-1.020), p = 0.03] and AF recurrence after RFA [1.009 (1.001-1.01), p = 0.02] after adjustment for age, gender and BMI. Patients with a larger EFV had a shorter time to AF recurrence (p = 0.017) and a higher rate of recurrence (54 % vs 46 %) (p = 0.002) after RFA. EPFV had no significant associations. Increased epicardial fat is associated with the presence and chronicity of AF, a higher probability of AF recurrence after RFA and a shorter AF-free interval. (orig.)

  2. Adipogenesis and epicardial adipose tissue: a novel fate of the epicardium induced by mesenchymal transformation and PPARγ activation.

    Science.gov (United States)

    Yamaguchi, Yukiko; Cavallero, Susana; Patterson, Michaela; Shen, Hua; Xu, Jian; Kumar, S Ram; Sucov, Henry M

    2015-02-17

    The hearts of many mammalian species are surrounded by an extensive layer of fat called epicardial adipose tissue (EAT). The lineage origins and determinative mechanisms of EAT development are unclear, in part because mice and other experimentally tractable model organisms are thought to not have this tissue. In this study, we show that mouse hearts have EAT, localized to a specific region in the atrial-ventricular groove. Lineage analysis indicates that this adipose tissue originates from the epicardium, a multipotent epithelium that until now is only established to normally generate cardiac fibroblasts and coronary smooth muscle cells. We show that adoption of the adipocyte fate in vivo requires activation of the peroxisome proliferator activated receptor gamma (PPARγ) pathway, and that this fate can be ectopically induced in mouse ventricular epicardium, either in embryonic or adult stages, by expression and activation of PPARγ at times of epicardium-mesenchymal transformation. Human embryonic ventricular epicardial cells natively express PPARγ, which explains the abundant presence of fat seen in human hearts at birth and throughout life.

  3. Increased epicardial fat volume quantified by 64-multidetector computed tomography is associated with coronary atherosclerosis and totally occlusive lesions

    International Nuclear Information System (INIS)

    Ueno, Koji; Anzai, Toshihisa; Jinzaki, Masahiro

    2009-01-01

    The relationship between the epicardial fat volume measured by 64-slice multidetector computed tomography (MDCT) and the extension and severity of coronary atherosclerosis was investigated. Both MDCT and conventional coronary angiography (CAG) were performed in 71 consecutive patients who presented with effort angina. The volume of epicardial adipose tissue (EAT) was measured by MDCT. The severity of coronary atherosclerosis was assessed by evaluating the extension of coronary plaques in 790 segments using MDCT data, and the percentage diameter stenosis in 995 segments using CAG data. The estimated volume of EAT indexed by body surface area was defined as VEAT. Increased VEAT was associated with advanced age, male sex, degree of metabolic alterations, a history of acute coronary syndrome (ACS) and the presence of total occlusions, and showed positive correlation with the stenosis score r=0.28, P=0.02) and the atheromatosis score (r=0.67, P 3 /m 2 ) to be the strongest independent determinant of the presence of total occlusions odds ratio 4.64. P=0.02). VEAT correlates with the degree of metabolic alterations and coronary atheromatosis. Excessive accumulation of EAT might contribute to the development of ACS and coronary total occlusions. (author)

  4. Epicardial distribution of ST segment and T wave changes produced by stimulation of intrathoracic ganglia or cardiopulmonary nerves in dogs.

    Science.gov (United States)

    Savard, P; Cardinal, R; Nadeau, R A; Armour, J A

    1991-06-01

    Sixty-three ventricular epicardial electrograms were recorded simultaneously in 8 atropinized dogs during stimulation of acutely decentralized intrathoracic autonomic ganglia or cardiopulmonary nerves. Three variables were measured: (1) isochronal maps representing the epicardial activation sequence, (2) maps depicting changes in areas under the QRS complex and T wave (regional inhomogeneity of repolarization), and (3) local and total QT intervals. Neural stimulations did not alter the activation sequence but induced changes in the magnitude and polarity of the ST segments and T waves as well as in QRST areas. Stimulation of the same neural structure in different dogs induced electrical changes with different amplitudes and in different regions of the ventricles, except for the ventral lateral cardiopulmonary nerve which usually affected the dorsal wall of the left ventricle. Greatest changes occurred when the right recurrent, left intermediate medial, left caudal pole, left ventral lateral cardiopulmonary nerves and stellate ganglia were stimulated. Local QT durations either decreased or did not change, whereas total QT duration as measured using a root-mean-square signal did not change, indicating the regional nature of repolarization changes. Taken together, these data indicate that intrathoracic efferent sympathetic neurons can induce regional inhomogeneity of repolarization without prolonging the total QT interval.

  5. Changes in arterial stiffness, carotid intima-media thickness, and epicardial fat after L-thyroxine replacement therapy in hypothyroidism.

    Science.gov (United States)

    del Busto-Mesa, Abdel; Cabrera-Rego, Julio Oscar; Carrero-Fernández, Lisván; Hernández-Roca, Cristina Victoria; González-Valdés, Jorge Luis; de la Rosa-Pazos, José Eduardo

    2015-01-01

    To assess the relationship between primary hypothyroidism and subclinical atherosclerosis and its potential changes with L-thyroxine replacement therapy. A prospective cohort study including 101 patients with primary hypothyroidism and 101 euthyroid patients as controls was conducted from July 2011 to December 2013. Clinical, anthropometrical, biochemical, and ultrasonographic parameters were assessed at baseline and after one year of L-thyroxine replacement therapy. At baseline, hypothyroid patients had significantly greater values of blood pressure, total cholesterol, VLDL cholesterol, left ventricular mass, epicardial fat, and carotid intima-media thickness as compared to controls. Total cholesterol, VLDL cholesterol, ventricular diastolic function, epicardial fat, carotid intima-media thickness, carotid local pulse wave velocity, pressure strain elastic modulus, and β arterial stiffness index showed a significant and positive correlation with TSH levels. After one year of replacement therapy, patients with hypothyroidism showed changes in total cholesterol, VLDL cholesterol, TSH, carotid intima-media thickness, and arterial stiffness parameters. Primary hypothyroidism is characterized by an increased cardiovascular risk. In these patients, L-thyroxine replacement therapy for one year is related to decreased dyslipidemia and improvement in markers of subclinical carotid atherosclerosis. Copyright © 2014 SEEN. Published by Elsevier España, S.L.U. All rights reserved.

  6. Evidence for reentrant spin glass behavior in transition metal substituted Co-Ga alloys near critical concentration

    Science.gov (United States)

    Yasin, Sk. Mohammad; Srinivas, V.; Kasiviswanathan, S.; Vagadia, Megha; Nigam, A. K.

    2018-04-01

    In the present study magnetic and electrical transport properties of transition metal substituted Co-Ga alloys (near critical cobalt concentration) have been investigated. Analysis of temperature and field dependence of dc magnetization and ac susceptibility (ACS) data suggests an evidence of reentrant spin glass (RSG) phase in Co55.5TM3Ga41.5 (TM = Co, Cr, Fe, Cu). The magnetic transition temperatures (TC and Tf) are found to depend on the nature of TM element substitution with the exchange coupling strength Co-Fe > Co-Co > Co-Cu > Co-Cr. From magnetization dynamics precise transition temperatures for the glassy phases are estimated. It is found that characteristic relaxation times are higher than that of spin glasses with minimal spin-cluster formation. The RSG behavior has been further supported by the temperature dependence of magnetotransport studies. From the magnetic field and substitution effects it has been established that the magnetic and electrical transport properties are correlated in this system.

  7. Reentrant spin glass behavior in polycrystalline La0.7Sr0.3Mn1-XFeXO 3

    Directory of Open Access Journals (Sweden)

    Xavier Jr. M.M.

    2004-01-01

    Full Text Available The magnetic and transport properties of the compound La0.7Sr0.3Mn1-xFe xO 3 (0.1 < x <0.4 have been studied by means of electrical resistivity, AC magnetic susceptibility, and DC magnetization. At low concentrations (x <0.1, the system displays essentially para-to-ferromagnetic transitions as the temperature is decreased, although a decrease in the magnetic moment has been observed in previous studies at temperatures a little below T C. This ferromagnetism is explained by double exchange theory in terms of the formation of Mn+3/Mn+4 ions pairs in the system. At concentrations in the range 0.1 < x <0.4 the system is more complex. Increased Fe doping not only weakens the ferromagnetic (FM order and augments the resistivity of the samples, but also induces the appearance of a reentrant spin glass phase at low temperatures (T < 60 K. Irreversibility of the magnetization measured with zero field cooling and with field cooling has been observed. In addition, the AC susceptibility peak position varies with frequency. All these effects are characteristic of spin glass behavior. The results have been interpreted based in an increase of frustration due to increasing competition between FM Mn+3/Mn+4 interactions and antiferromagnetic interactions between ions at the boundaries of Fe clusters.

  8. Outcome of slow pathway modulation for atrioventricular nodal reentrant tachycardia with 50 versus 30 watts-more power, more effect?

    Science.gov (United States)

    Dechering, Dirk G; Schleberger, Ruben; Greiser, Eva; Dickow, Jannis; Koebe, Julia; Frommeyer, Gerrit; Willems, Stephan; Eckardt, Lars; Hoffmann, Boris A; Wasmer, Kristina

    2018-03-19

    Slow pathway modulation is the treatment of choice in patients with atrioventricular nodal reentrant tachycardia (AVNRT). No comparative data on ablation strategies exist. Therefore, we sought to compare two common ablation approaches. We analyzed prospective ablation databases of two high-volume tertiary centers (> 1000 ablations/year) using either 30 or 50 W for slow pathway modulation from 2012 to 2013. We analyzed procedural characteristics as well as short- and long-term outcomes. Mean follow-up was 36 ± 9 months. Six hundred thirty-four patients (50 W center: n = 342, 30 W center: n = 292) were ablated. Slow pathway modulation was successful in 99% in both groups (p = ns). Periprocedural AV block occurred in nine patients (2.6%) in the 50 W and five patients (1.7%) in the 30 W group (p = 0.59), respectively. We documented no permanent higher-degree AV block. The number of RF lesions and seconds of RF delivery was significantly less in the 50 W group (p = 0.04 for number of lesions; p modulation are highly effective and safe. Significantly, fewer RF duration was necessary to modulate the slow pathway with higher power output (50 W). Our subgroup analysis suggests that males and females might benefit most from different modulation approaches.

  9. Controlling and modelling the wetting properties of III-V semiconductor surfaces using re-entrant nanostructures.

    Science.gov (United States)

    Ng, Wing H; Lu, Yao; Liu, Huiyun; Carmalt, Claire J; Parkin, Ivan P; Kenyon, Anthony J

    2018-02-23

    Inorganic semiconductors such as III-V materials are very important in our everyday life as they are used for manufacturing optoelectronic and microelectronic components with important applications span from energy harvesting to telecommunications. In some applications, these components are required to operate in harsh environments. In these cases, having waterproofing capability is essential. Here we demonstrate design and control of the wettability of indium phosphide based multilayer material (InP/InGaAs/InP) using re-entrant structures fabricated by a fast electron beam lithography technique. This patterning technique enabled us to fabricate highly uniform nanostructure arrays with at least one order of magnitude shorter patterning times compared to conventional electron beam lithography methods. We reduced the surface contact fraction significantly such that the water droplets may be completely removed from our nanostructured surface. We predicted the wettability of our patterned surface by modelling the adhesion energies between the water droplet and both the patterned surface and the dispensing needle. This is very useful for the development of coating-free waterproof optoelectronic and microelectronic components where the coating may hinder the performance of such devices and cause problems with semiconductor fabrication compatibility.

  10. Technology use in linking criminal justice reentrants to HIV care in the community: a qualitative formative research study.

    Science.gov (United States)

    Peterson, James; Cota, Michelle; Gray, Holly; Bazerman, Lauri; Kuo, Irene; Kurth, Ann; Beckwith, Curt

    2015-01-01

    Innovative interventions increasing linkage, adherence, and retention in care among HIV-infected persons in the criminal justice system are needed. The authors conducted a qualitative study to investigate technology-based tools to facilitate linkage to community-based care and viral suppression for HIV-infected jail detainees on antiretroviral medications being released to the community. The authors conducted 24 qualitative interview-12 in Rhode Island and 12 in Washington, DC-among recently incarcerated HIV-infected persons to elicit their perceptions on the use of technology tools to support linkage to HIV care among criminal justice populations. This article discusses participants' perceptions of the acceptability of technological tools such as (a) a computer-based counseling and (b) text messaging interventions. The participants reported positive experiences when previewing the technology-based tools to facilitate linkage to HIV care and adherence to HIV medications. Successful linkage to care has been shown to improve HIV-associated and non-HIV-associated health outcomes, as well as prevent criminal recidivism and facilitate reentrants' successful and meaningful transition. These findings can be used to inform the implementation of interventions aimed at promoting adherence to antiretroviral medications and linkage to care for HIV-infected persons being released from the correctional setting.

  11. Circuits on Cylinders

    DEFF Research Database (Denmark)

    Hansen, Kristoffer Arnsfelt; Miltersen, Peter Bro; Vinay, V

    2006-01-01

    We consider the computational power of constant width polynomial size cylindrical circuits and nondeterministic branching programs. We show that every function computed by a Pi2 o MOD o AC0 circuit can also be computed by a constant width polynomial size cylindrical nondeterministic branching pro...

  12. CMOS analog circuit design

    CERN Document Server

    Allen, Phillip E

    1987-01-01

    This text presents the principles and techniques for designing analog circuits to be implemented in a CMOS technology. The level is appropriate for seniors and graduate students familiar with basic electronics, including biasing, modeling, circuit analysis, and some familiarity with frequency response. Students learn the methodology of analog integrated circuit design through a hierarchically-oriented approach to the subject that provides thorough background and practical guidance for designing CMOS analog circuits, including modeling, simulation, and testing. The authors' vast industrial experience and knowledge is reflected in the circuits, techniques, and principles presented. They even identify the many common pitfalls that lie in the path of the beginning designer--expert advice from veteran designers. The text mixes the academic and practical viewpoints in a treatment that is neither superficial nor overly detailed, providing the perfect balance.

  13. Epicardial adipose tissue and pericoronary fat thickness measured with 64-multidetector computed tomography: potential predictors of the severity of coronary artery disease

    Directory of Open Access Journals (Sweden)

    Muhammed Bora Demircelik

    2014-06-01

    Full Text Available OBJECTIVE:The aim of the present study was to investigate the relationship between pericoronary fat and the severity and extent of atherosclerosis, quantified using 64-multidetector computed tomography, in patients with suspected coronary artery disease.METHODS:The study population consisted of 131 patients who were clinically referred for noninvasive multislice computed tomography coronary angiography for the evaluation of coronary artery disease. Patients were classified as follows: no atherosclerosis, Group 1; nonobstructive atherosclerosis (luminal narrowing <50% in diameter, Group 2; and obstructive atherosclerosis (luminal narrowing ≥50% in a single vessel or obstructive atherosclerosis in the left main coronary artery and/or multiple vessels, Group 3. Epicardial adipose tissue was defined as the adipose tissue between the surface of the heart and the visceral layer of the pericardium (visceral epicardium. Epicardial adipose tissue thickness (mm was determined in the right ventricular anterior free wall. The mean thickness of the pericoronary fat surrounding the three coronary arteries was used for the analyses.RESULTS:The average thickness over all three regions was 13.2 ± 2.1 mm. The pericoronary fat thickness was significantly increased in Group 3 compared with Groups 2 and 1. The epicardial adipose tissue thickness was significantly increased in Group 3 compared with Groups 2 and 1. A receiver operating characteristic curve for obstructive coronary artery disease was assessed to verify the optimum cut-off point for pericoronary fat thickness, which was 13.8 mm. A receiver operating characteristic curve for obstructive coronary artery disease was also assessed to verify the optimum cut-off point for epicardial adipose tissue, which was 6.8 cm.CONCLUSION:We showed that the epicardial adipose tissue and pericoronary fat thickness scores were higher in patients with obstructive coronary artery diseases.

  14. Epicardial adipose tissue and pericoronary fat thickness measured with 64-multidetector computed tomography: potential predictors of the severity of coronary artery disease

    Energy Technology Data Exchange (ETDEWEB)

    Demircelik, Muhammed Bora; Gurel, Ozgul Malcok; Selcoki, Yusuf; Atar, Inci Asli; Eryonucu, Beyhan, E-mail: drdemircelik@yahoo.com [Turgut Ozal Univercity, Department of Cardiology, Ankara (Turkey); Bozkurt, Alper; Akin, Kayihan [Turgut Ozal Univercity, Department of Radiology, Ankara (Turkey); Yilmaz, Omer Caglar [Ankara Occupational Diseases Hospital, Department of Cardiology, Ankara (Turkey)

    2014-06-15

    Objective: the aim of the present study was to investigate the relationship between pericoronary fat and the severity and extent of atherosclerosis, quantified using 64-multidetector computed tomography, in patients with suspected coronary artery disease. Methods: the study population consisted of 131 patients who were clinically referred for noninvasive multislice computed tomography coronary angiography for the evaluation of coronary artery disease. Patients were classified as follows: no atherosclerosis, Group 1; nonobstructive atherosclerosis (luminal narrowing < 50% in diameter), Group 2; and obstructive atherosclerosis (luminal narrowing ≧ 50%) in a single vessel or obstructive atherosclerosis in the left main coronary artery and/or multiple vessels, Group 3. Epicardial adipose tissue was defined as the adipose tissue between the surface of the heart and the visceral layer of the pericardium (visceral epicardium). Epicardial adipose tissue thickness (mm) was determined in the right ventricular anterior free wall. The mean thickness of the pericoronary fat surrounding the three coronary arteries was used for the analyses. Results: the average thickness over all three regions was 13.2 ± 2.1 mm. The pericoronary fat thickness was significantly increased in Group 3 compared with Groups 2 and 1. The epicardial adipose tissue thickness was significantly increased in Group 3 compared with Groups 2 and 1. A receiver operating characteristic curve for obstructive coronary artery disease was assessed to verify the optimum cut-off point for pericoronary fat thickness, which was 13.8 mm. A receiver operating characteristic curve for obstructive coronary artery disease was also assessed to verify the optimum cut-off point for epicardial adipose tissue, which was 6.8 cm. Conclusion: we showed that the epicardial adipose tissue and pericoronary fat thickness scores were higher in patients with obstructive coronary artery diseases. (author)

  15. Epicardial adipose tissue and pericoronary fat thickness measured with 64-multidetector computed tomography: potential predictors of the severity of coronary artery disease

    International Nuclear Information System (INIS)

    Demircelik, Muhammed Bora; Gurel, Ozgul Malcok; Selcoki, Yusuf; Atar, Inci Asli; Eryonucu, Beyhan; Bozkurt, Alper; Akin, Kayihan; Yilmaz, Omer Caglar

    2014-01-01

    Objective: the aim of the present study was to investigate the relationship between pericoronary fat and the severity and extent of atherosclerosis, quantified using 64-multidetector computed tomography, in patients with suspected coronary artery disease. Methods: the study population consisted of 131 patients who were clinically referred for noninvasive multislice computed tomography coronary angiography for the evaluation of coronary artery disease. Patients were classified as follows: no atherosclerosis, Group 1; nonobstructive atherosclerosis (luminal narrowing < 50% in diameter), Group 2; and obstructive atherosclerosis (luminal narrowing ≧ 50%) in a single vessel or obstructive atherosclerosis in the left main coronary artery and/or multiple vessels, Group 3. Epicardial adipose tissue was defined as the adipose tissue between the surface of the heart and the visceral layer of the pericardium (visceral epicardium). Epicardial adipose tissue thickness (mm) was determined in the right ventricular anterior free wall. The mean thickness of the pericoronary fat surrounding the three coronary arteries was used for the analyses. Results: the average thickness over all three regions was 13.2 ± 2.1 mm. The pericoronary fat thickness was significantly increased in Group 3 compared with Groups 2 and 1. The epicardial adipose tissue thickness was significantly increased in Group 3 compared with Groups 2 and 1. A receiver operating characteristic curve for obstructive coronary artery disease was assessed to verify the optimum cut-off point for pericoronary fat thickness, which was 13.8 mm. A receiver operating characteristic curve for obstructive coronary artery disease was also assessed to verify the optimum cut-off point for epicardial adipose tissue, which was 6.8 cm. Conclusion: we showed that the epicardial adipose tissue and pericoronary fat thickness scores were higher in patients with obstructive coronary artery diseases. (author)

  16. The relationship between epicardial fat and indices of obesity and the metabolic syndrome: a systematic review and meta-analysis.

    Science.gov (United States)

    Rabkin, Simon W

    2014-02-01

    Epicardial fat (epicardial adipose tissue, EAT) has been implicated in the pathogenesis of coronary artery disease (CAD). The objective of this study was to examine the relationship between EAT and generalized obesity, central or visceral adipose tissue (VAT), and the components of the metabolic syndrome--systolic blood pressure (SBP), triglycerides (TGs), high-density lipoprotein cholesterol (HDL-C), and fasting blood glucose (FBG)--that are linked to CAD. A systematic review of the literature, following meta-analysis guidelines, was conducted until May, 2013, using the search strategy "Obesity" OR "abdominal obesity" OR "metabolic syndrome" OR "metabolic syndrome X" AND "epicardial fat". Thirty-eight studies fulfilled the criteria. There was a highly significant (Pcorrelation between EAT and body mass index (BMI), waist circumference (WC), or VAT. The correlation between EAT and VAT was significantly (Pcorrelation between EAT and WC, which in turn was significantly greater than the correlation between EAT and BMI. Overall, EAT was 7.5 ± 0.1 mm in thickness in the metabolic syndrome (n=427) compared to 4.0 ± 0.1 mm in controls (n=301). EAT correlated significantly (PHDL, and FBG, but the strength of the association was less than one-half of the relationship of EAT to indices of obesity. The results of multivariate analysis were less consistent but show a relationship between EAT and metabolic syndrome independent of BMI. In summary, the very strong correlation between EAT and VAT suggests a relationship between these two adipose tissue depots. Measurement of EAT can be useful to indicate VAT. Whereas EAT correlates significantly with each of the components of the metabolic syndrome- SBP, TGs, HDL, or FBG-the magnitude of the relationship is considerably and significantly less than the relationship of EAT to BMI. These data show the strong relationship between EAT and BMI but especially with WC and VAT. They also demonstrate the smaller magnitude of the

  17. Approximate circuits for increased reliability

    Science.gov (United States)

    Hamlet, Jason R.; Mayo, Jackson R.

    2015-08-18

    Embodiments of the invention describe a Boolean circuit having a voter circuit and a plurality of approximate circuits each based, at least in part, on a reference circuit. The approximate circuits are each to generate one or more output signals based on values of received input signals. The voter circuit is to receive the one or more output signals generated by each of the approximate circuits, and is to output one or more signals corresponding to a majority value of the received signals. At least some of the approximate circuits are to generate an output value different than the reference circuit for one or more input signal values; however, for each possible input signal value, the majority values of the one or more output signals generated by the approximate circuits and received by the voter circuit correspond to output signal result values of the reference circuit.

  18. Troubleshooting analog circuits

    CERN Document Server

    Pease, Robert A

    1991-01-01

    Troubleshooting Analog Circuits is a guidebook for solving product or process related problems in analog circuits. The book also provides advice in selecting equipment, preventing problems, and general tips. The coverage of the book includes the philosophy of troubleshooting; the modes of failure of various components; and preventive measures. The text also deals with the active components of analog circuits, including diodes and rectifiers, optically coupled devices, solar cells, and batteries. The book will be of great use to both students and practitioners of electronics engineering. Other

  19. Modern TTL circuits manual

    CERN Document Server

    Marston, R M

    2013-01-01

    Modern TTL Circuits Manual provides an introduction to the basic principles of Transistor-Transistor Logic (TTL). This book outlines the major features of the 74 series of integrated circuits (ICs) and introduces the various sub-groups of the TTL family.Organized into seven chapters, this book begins with an overview of the basics of digital ICs. This text then examines the symbology and mathematics of digital logic. Other chapters consider a variety of topics, including waveform generator circuitry, clocked flip-flop and counter circuits, special counter/dividers, registers, data latches, com

  20. Circuit analysis with Multisim

    CERN Document Server

    Baez-Lopez, David

    2011-01-01

    This book is concerned with circuit simulation using National Instruments Multisim. It focuses on the use and comprehension of the working techniques for electrical and electronic circuit simulation. The first chapters are devoted to basic circuit analysis.It starts by describing in detail how to perform a DC analysis using only resistors and independent and controlled sources. Then, it introduces capacitors and inductors to make a transient analysis. In the case of transient analysis, it is possible to have an initial condition either in the capacitor voltage or in the inductor current, or bo

  1. Optoelectronics circuits manual

    CERN Document Server

    Marston, R M

    2013-01-01

    Optoelectronics Circuits Manual covers the basic principles and characteristics of the best known types of optoelectronic devices, as well as the practical applications of many of these optoelectronic devices. The book describes LED display circuits and LED dot- and bar-graph circuits and discusses the applications of seven-segment displays, light-sensitive devices, optocouplers, and a variety of brightness control techniques. The text also tackles infrared light-beam alarms and multichannel remote control systems. The book provides practical user information and circuitry and illustrations.

  2. 'Speedy' superconducting circuits

    International Nuclear Information System (INIS)

    Holst, T.

    1994-01-01

    The most promising concept for realizing ultra-fast superconducting digital circuits is the Rapid Single Flux Quantum (RSFQ) logic. The basic physical principle behind RSFQ logic, which include the storage and transfer of individual magnetic flux quanta in Superconducting Quantum Interference Devices (SQUIDs), is explained. A Set-Reset flip-flop is used as an example of the implementation of an RSFQ based circuit. Finally, the outlook for high-temperature superconducting materials in connection with RSFQ circuits is discussed in some details. (au)

  3. Quasi-elastic neutron scattering study of a re-entrant side-chain liquid-crystal polyacrylate

    Science.gov (United States)

    Benguigui, L.; Noirez, L.; Kahn, R.; Keller, P.; Lambert, M.; Cohen de Lara, E.

    1991-04-01

    We present a first investigation of the dynamics of a side chain liquid crystal polyacrylate in the isotropic (I), nematic (N), smectic A (SA), and re-entrant nematic (NRe) phases by means of quasi-elastic neutron scattering. The motion or/and the mobility of the mesogen protons decreases as soon as the temperature decreases after the isotropic-nematic transition. The I-N and SA-NRe transitions corrspond to a jump in the curve of the Elastic Incoherent Structure Factor (ratio: elastic scattering/ total scattering) versus temperature, on the other hand the transition N-SA occurs without any change of slope. We conclude that the local order is very similar in the nematic and the smectic A phases. Nous présentons une première étude dynamique par diffusion quasi-élastique des neutrons, d'un échantillon de polyacrylate mésomorphe en peigne dans chacune des phases : isotrope, nématique, smectique et nématique rentrante. On montre que le mouvement et/ou la mobilité des protons du mésogène se restreint à mesure que la température diminue après la transition isotrope-nématique. Contrairement à la transition N-SA, les transitions I-N et SA-NRe correspondent à une discontinuité dans la courbe du Facteur de Structure Incohérent Elastique (rapport : intensité élastique/intensité totale) en fonction de la température ; l'ordre local semble donc très proche pour les phases nématique et smectique.

  4. Test Characteristics of Neck Fullness and Witnessed Neck Pulsations in the Diagnosis of Typical AV Nodal Reentrant Tachycardia

    Science.gov (United States)

    Sakhuja, Rahul; Smith, Lisa M; Tseng, Zian H; Badhwar, Nitish; Lee, Byron K; Lee, Randall J; Scheinman, Melvin M; Olgin, Jeffrey E; Marcus, Gregory M

    2011-01-01

    Summary Background Claims in the medical literature suggest that neck fullness and witnessed neck pulsations are useful in the diagnosis of typical AV nodal reentrant tachycardia (AVNRT). Hypothesis Neck fullness and witnessed neck pulsations have a high positive predictive value in the diagnosis of typical AVNRT. Methods We performed a cross sectional study of consecutive patients with palpitations presenting to a single electrophysiology (EP) laboratory over a 1 year period. Each patient underwent a standard questionnaire regarding neck fullness and/or witnessed neck pulsations during their palpitations. The reference standard for diagnosis was determined by electrocardiogram and invasive EP studies. Results Comparing typical AVNRT to atrial fibrillation (AF) or atrial flutter (AFL) patients, the proportions with neck fullness and witnessed neck pulsations did not significantly differ: in the best case scenario (using the upper end of the 95% confidence interval [CI]), none of the positive or negative predictive values exceeded 79%. After restricting the population to those with supraventricular tachycardia other than AF or AFL (SVT), neck fullness again exhibited poor test characteristics; however, witnessed neck pulsations exhibited a specificity of 97% (95% CI 90–100%) and a positive predictive value of 83% (95% CI 52–98%). After adjustment for potential confounders, SVT patients with witnessed neck pulsations had a 7 fold greater odds of having typical AVNRT, p=0.029. Conclusions Although neither neck fullness nor witnessed neck pulsations are useful in distinguishing typical AVNRT from AF or AFL, witnessed neck pulsations are specific for the presence of typical AVNRT among those with SVT. PMID:19479968

  5. Dynamics of Endo- and Epicardial Focal Fibrillation Waves at the Right Atrium in a Patient With Advanced Atrial Remodelling.

    Science.gov (United States)

    van der Does, Lisette J M E; Kik, Charles; Bogers, Ad J J C; Allessie, Maurits A; de Groot, Natasja M S

    2016-10-01

    Focal waves appear frequently at the epicardium during persistent atrial fibrillation (AF), however, the origin of these waves is under debate. We performed simultaneous endo-epicardial mapping of the right atrial wall during longstanding persistent AF in a patient undergoing cardiac surgery. During 10 seconds 53 and 59 focal waves appeared at random at respectively the endocardium and epicardium. Repetitive focal activity did not last longer than 3 cycles. Transmural asynchrony and conduction might be the origin of focal waves. Asynchronous propagation of fibrillation waves in 3 dimensions would stabilize the arrhythmia and could explain the limited success of persistent AF ablation. Copyright © 2016 Canadian Cardiovascular Society. Published by Elsevier Inc. All rights reserved.

  6. Comparison of fatty acid composition of subcutaneous, pericardial and epicardial adipose tissue and atrial tissue in patients with heart disease

    DEFF Research Database (Denmark)

    Eschen, Rikke Bülow; Gu, Jiwei; Andreasen, Jan Jesper

    2016-01-01

    (EPA) and docosahexaenoic acid (DHA), from three different adipose tissue compartments [epicardial (EAT), pericardial (PAT) and subcutaneous (SAT)]. Furthermore, we studied the correlation between the content of EPA and DHA in these compartments and in atrial tissue (AT). METHODS We obtained AT from......OBJECTIVES The content in adipose tissue of marine n-3 polyunsaturated fatty acids (PUFAs) is a marker of long-term fish consumption and data suggest an antiarrhythmic effect of n-3 PUFAs. We investigated the correlation between adipose tissue content of the major n-3 PUFAs, eicosapentaenoic acid...... auricles, EAT above the right ventricle, PAT, and SAT below the sternum from 50 patients undergoing cardiac surgery. Samples were frozen at -80°C and the content of n-3 PUFAs determined by gas chromatography with results given in relative weight%. RESULTS EPA and DHA were significantly correlated in EAT...

  7. Analogue circuits simulation

    Energy Technology Data Exchange (ETDEWEB)

    Mendo, C

    1988-09-01

    Most analogue simulators have evolved from SPICE. The history and description of SPICE-like simulators are given. From a mathematical formulation of the electronic circuit the following analysis are possible: DC, AC, transient, noise, distortion, Worst Case and Statistical.

  8. Printed circuit for ATLAS

    CERN Multimedia

    Laurent Guiraud

    1999-01-01

    A printed circuit board made by scientists in the ATLAS collaboration for the transition radiaton tracker (TRT). This will read data produced when a high energy particle crosses the boundary between two materials with different electrical properties.

  9. Magnonic logic circuits

    International Nuclear Information System (INIS)

    Khitun, Alexander; Bao Mingqiang; Wang, Kang L

    2010-01-01

    We describe and analyse possible approaches to magnonic logic circuits and basic elements required for circuit construction. A distinctive feature of the magnonic circuitry is that information is transmitted by spin waves propagating in the magnetic waveguides without the use of electric current. The latter makes it possible to exploit spin wave phenomena for more efficient data transfer and enhanced logic functionality. We describe possible schemes for general computing and special task data processing. The functional throughput of the magnonic logic gates is estimated and compared with the conventional transistor-based approach. Magnonic logic circuits allow scaling down to the deep submicrometre range and THz frequency operation. The scaling is in favour of the magnonic circuits offering a significant functional advantage over the traditional approach. The disadvantages and problems of the spin wave devices are also discussed.

  10. Value of epicardial potential maps in localizing pre-excitation sites for radiofrequency ablation. A simulation study

    Science.gov (United States)

    Hren, Rok

    1998-06-01

    Using computer simulations, we systematically investigated the limitations of an inverse solution that employs the potential distribution on the epicardial surface as an equivalent source model in localizing pre-excitation sites in Wolff-Parkinson-White syndrome. A model of the human ventricular myocardium that features an anatomically accurate geometry, an intramural rotating anisotropy and a computational implementation of the excitation process based on electrotonic interactions among cells, was used to simulate body surface potential maps (BSPMs) for 35 pre-excitation sites positioned along the atrioventricular ring. Two individualized torso models were used to account for variations in torso boundaries. Epicardial potential maps (EPMs) were computed using the L-curve inverse solution. The measure for accuracy of the localization was the distance between a position of the minimum in the inverse EPMs and the actual site of pre-excitation in the ventricular model. When the volume conductor properties and lead positions of the torso were precisely known and the measurement noise was added to the simulated BSPMs, the minimum in the inverse EPMs was at 12 ms after the onset on average within cm of the pre-excitation site. When the standard torso model was used to localize the sites of onset of the pre-excitation sequence initiated in individualized male and female torso models, the mean distance between the minimum and the pre-excitation site was cm for the male torso and cm for the female torso. The findings of our study indicate that a location of the minimum in EPMs computed using the inverse solution can offer non-invasive means for pre-interventional planning of the ablative treatment.

  11. Atrial Heterogeneity Generates Re-entrant Substrate during Atrial Fibrillation and Anti-arrhythmic Drug Action: Mechanistic Insights from Canine Atrial Models

    Science.gov (United States)

    Varela, Marta; Hancox, Jules C.; Aslanidi, Oleg V.

    2016-01-01

    Anti-arrhythmic drug therapy is a frontline treatment for atrial fibrillation (AF), but its success rates are highly variable. This is due to incomplete understanding of the mechanisms of action of specific drugs on the atrial substrate at different stages of AF progression. We aimed to elucidate the role of cellular, tissue and organ level atrial heterogeneities in the generation of a re-entrant substrate during AF progression, and their modulation by the acute action of selected anti-arrhythmic drugs. To explore the complex cell-to-organ mechanisms, a detailed biophysical models of the entire 3D canine atria was developed. The model incorporated atrial geometry and fibre orientation from high-resolution micro-computed tomography, region-specific atrial cell electrophysiology and the effects of progressive AF-induced remodelling. The actions of multi-channel class III anti-arrhythmic agents vernakalant and amiodarone were introduced in the model by inhibiting appropriate ionic channel currents according to experimentally reported concentration-response relationships. AF was initiated by applied ectopic pacing in the pulmonary veins, which led to the generation of localized sustained re-entrant waves (rotors), followed by progressive wave breakdown and rotor multiplication in both atria. The simulated AF scenarios were in agreement with observations in canine models and patients. The 3D atrial simulations revealed that a re-entrant substrate was typically provided by tissue regions of high heterogeneity of action potential duration (APD). Amiodarone increased atrial APD and reduced APD heterogeneity and was more effective in terminating AF than vernakalant, which increased both APD and APD dispersion. In summary, the initiation and sustenance of rotors in AF is linked to atrial APD heterogeneity and APD reduction due to progressive remodelling. Our results suggest that anti-arrhythmic strategies that increase atrial APD without increasing its dispersion are

  12. Peak reading detector circuit

    International Nuclear Information System (INIS)

    Courtin, E.; Grund, K.; Traub, S.; Zeeb, H.

    1975-01-01

    The peak reading detector circuit serves for picking up the instants during which peaks of a given polarity occur in sequences of signals in which the extreme values, their time intervals, and the curve shape of the signals vary. The signal sequences appear in measuring the foetal heart beat frequence from amplitude-modulated ultrasonic, electrocardiagram, and blood pressure signals. In order to prevent undesired emission of output signals from, e. g., disturbing intermediate extreme values, the circuit consists of the series connections of a circuit to simulate an ideal diode, a strong unit, a discriminator for the direction of charging current, a time-delay circuit, and an electronic switch lying in the decharging circuit of the storage unit. The time-delay circuit thereby causes storing of a preliminary maximum value being used only after a certain time delay for the emission of the output signal. If a larger extreme value occurs during the delay time the preliminary maximum value is cleared and the delay time starts running anew. (DG/PB) [de

  13. Color Coding of Circuit Quantities in Introductory Circuit Analysis Instruction

    Science.gov (United States)

    Reisslein, Jana; Johnson, Amy M.; Reisslein, Martin

    2015-01-01

    Learning the analysis of electrical circuits represented by circuit diagrams is often challenging for novice students. An open research question in electrical circuit analysis instruction is whether color coding of the mathematical symbols (variables) that denote electrical quantities can improve circuit analysis learning. The present study…

  14. Project Circuits in a Basic Electric Circuits Course

    Science.gov (United States)

    Becker, James P.; Plumb, Carolyn; Revia, Richard A.

    2014-01-01

    The use of project circuits (a photoplethysmograph circuit and a simple audio amplifier), introduced in a sophomore-level electric circuits course utilizing active learning and inquiry-based methods, is described. The development of the project circuits was initiated to promote enhanced engagement and deeper understanding of course content among…

  15. AV nodal reentrant tachycardia with a 2:1 right bundle branch block missed as bidirectional ventricular tachycardia in the first superficial evaluation

    Directory of Open Access Journals (Sweden)

    Akbarzadeh Mohammad Ali

    2017-06-01

    Full Text Available A 95-year old woman was admitted to our emergency unit because of acute abdominal pain. After urgent surgery according to the acute abdomen, she was referred to intensive care unit (ICU of the emergency unit as she was intubated. It was developed a run of new arrhythmia which was diagnosed by cardiology resident as bidirectional ventricular tachycardia due to beat to beat changing the axis of the QRS. However, a second and more precise evaluation of the abnormal ECG suggested a narrow supraventricular tachycardia, most probably AV nodal reentrant tachycardia with a 2:1 right bundle branch block.

  16. Low latency asynchronous interface circuits

    Science.gov (United States)

    Sadowski, Greg

    2017-06-20

    In one form, a logic circuit includes an asynchronous logic circuit, a synchronous logic circuit, and an interface circuit coupled between the asynchronous logic circuit and the synchronous logic circuit. The asynchronous logic circuit has a plurality of asynchronous outputs for providing a corresponding plurality of asynchronous signals. The synchronous logic circuit has a plurality of synchronous inputs corresponding to the plurality of asynchronous outputs, a stretch input for receiving a stretch signal, and a clock output for providing a clock signal. The synchronous logic circuit provides the clock signal as a periodic signal but prolongs a predetermined state of the clock signal while the stretch signal is active. The asynchronous interface detects whether metastability could occur when latching any of the plurality of the asynchronous outputs of the asynchronous logic circuit using said clock signal, and activates the stretch signal while the metastability could occur.

  17. Reentrant metal-insulator transition in the Cu-doped manganites La1-x Pbx MnO3 (x˜0.14) single crystals

    Science.gov (United States)

    Zhao, B. C.; Song, W. H.; Ma, Y. Q.; Ang, R.; Zhang, S. B.; Sun, Y. P.

    2005-10-01

    Single crystals of La1-x Pbx Mn1-y-z Cuy O3 ( x˜0.14 ; y=0 ,0.01,0.02,0.04,0.06; z=0.02 ,0.08,0.11,0.17,0.20) are grown by the flux growth technique. The effect of Cu doping at the Mn-site on magnetic and transport properties is studied. All studied samples undergo a paramagnetic-ferromagnetic transition. The Curie temperature TC decreases and the transition becomes broader with increasing Cu-doping level. The high-temperature insulator-metal (I-M) transition moves to lower temperature with increasing Cu-doping level. A reentrant M-I transition at the low temperature T* is observed for samples with y⩾0.02 . In addition, T* increases with increasing Cu-doping level and is not affected by applied magnetic fields. Accompanying the appearance of T* , there exists a large, almost constant magnetoresistance (MR) below T* except for a large MR peak near TC . This reentrant M-I transition is ascribed to charge carrier localization due to lattice distortion caused by the Cu doping at Mn sites.

  18. Junction and circuit fabrication

    International Nuclear Information System (INIS)

    Jackel, L.D.

    1980-01-01

    Great strides have been made in Josephson junction fabrication in the four years since the first IC SQUID meeting. Advances in lithography have allowed the production of devices with planar dimensions as small as a few hundred angstroms. Improved technology has provided ultra-high sensitivity SQUIDS, high-efficiency low-noise mixers, and complex integrated circuits. This review highlights some of the new fabrication procedures. The review consists of three parts. Part 1 is a short summary of the requirements on junctions for various applications. Part 2 reviews intergrated circuit fabrication, including tunnel junction logic circuits made at IBM and Bell Labs, and microbridge radiation sources made at SUNY at Stony Brook. Part 3 describes new junction fabrication techniques, the major emphasis of this review. This part includes a discussion of small oxide-barrier tunnel junctions, semiconductor barrier junctions, and microbridge junctions. Part 3 concludes by considering very fine lithography and limitations to miniaturization. (orig.)

  19. Endocardial-epicardial distribution of myocardial perfusion reserve assessed by multidetector computed tomography in symptomatic patients without significant coronary artery disease

    DEFF Research Database (Denmark)

    Kühl, Jørgen Tobias; George, Richard T; Mehra, Vishal C

    2016-01-01

    (MPR) in humans. We aimed to test the hypothesis that MPR in all myocardial layers is determined by age, gender, and cardiovascular risk profile in patients with ischaemic symptoms or equivalent but without obstructive coronary artery disease (CAD). METHODS AND RESULTS: A total of 149 patients enrolled...... in endocardial-epicardial distribution of perfusion reserve may be demonstrated with static CT perfusion. Low MPR in all myocardial layers was observed specifically in obese patients....

  20. Gender-linked impact of epicardial adipose tissue volume in patients who underwent coronary artery bypass graft surgery or non-coronary valve surgery

    OpenAIRE

    Maimaituxun, Gulinu; Shimabukuro, Michio; Salim, Hotimah Masdan; Tabata, Minoru; Yuji, Daisuke; Morimoto, Yoshihisa; Akasaka, Takeshi; Matsuura, Tomomi; Yagi, Shusuke; Fukuda, Daiju; Yamada, Hirotsugu; Soeki, Takeshi; Sugimoto, Takaki; Tanaka, Masashi; Takanashi, Shuichiro

    2017-01-01

    Background Traditional and non-traditional risk factors for atherosclerotic cardiovascular disease (ASCVD) are different between men and women. Gender-linked impact of epicardial adipose tissue volume (EATV) in patients undergoing coronary artery bypass grafting (CABG) remains unknown. Methods Gender-linked impact of EATV, abdominal fat distribution and other traditional ASCVD risk factors were compared in 172 patients (men: 115; women: 57) who underwent CABG or non-coronary valvular surgery ...

  1. Gender disparities in the association between epicardial adipose tissue volume and coronary atherosclerosis: A 3-dimensional cardiac computed tomography imaging study in Japanese subjects

    OpenAIRE

    Dagvasumberel Munkhbaatar; Shimabukuro Michio; Nishiuchi Takeshi; Ueno Junji; Takao Shoichiro; Fukuda Daiju; Hirata Yoichiro; Kurobe Hirotsugu; Soeki Takeshi; Iwase Takashi; Kusunose Kenya; Niki Toshiyuki; Yamaguchi Koji; Taketani Yoshio; Yagi Shusuke

    2012-01-01

    Abstract Background Growing evidence suggests that epicardial adipose tissue (EAT) may contribute to the development of coronary artery disease (CAD). In this study, we explored gender disparities in EAT volume (EATV) and its impact on coronary atherosclerosis. Methods The study population consisted of 90 consecutive subjects (age: 63 ± 12 years; men: 47, women: 43) who underwent 256-slice multi-detector computed tomography (MDCT) coronary angiography. EATV was measured as the sum of cross-se...

  2. Accumulation of epicardial fat rather than visceral fat is an independent risk factor for left ventricular diastolic dysfunction in patients undergoing peritoneal dialysis

    OpenAIRE

    Lin, Heng-Hsu; Lee, Jen-Kuang; Yang, Chung-Yi; Lien, Yu-Chung; Huang, Jenq-Wen; Wu, Cho-Kai

    2013-01-01

    Background Symptoms of heart failure with preserved left ventricular systolic function are common among patients undergoing peritoneal dialysis (PD). Epicardial fat (EpF) is an ectopic fat depot with possible paracrine or mechanical effects on myocardial function. The aim of our current study is to assess the association between EpF and Left ventricular diastolic dysfunction (LVDD) in patients undergoing PD and to clarify the relationships among EpF, inflammation, and LVDD in this population....

  3. Small circuits for cryptography.

    Energy Technology Data Exchange (ETDEWEB)

    Torgerson, Mark Dolan; Draelos, Timothy John; Schroeppel, Richard Crabtree; Miller, Russell D.; Anderson, William Erik

    2005-10-01

    This report examines a number of hardware circuit design issues associated with implementing certain functions in FPGA and ASIC technologies. Here we show circuit designs for AES and SHA-1 that have an extremely small hardware footprint, yet show reasonably good performance characteristics as compared to the state of the art designs found in the literature. Our AES performance numbers are fueled by an optimized composite field S-box design for the Stratix chipset. Our SHA-1 designs use register packing and feedback functionalities of the Stratix LE, which reduce the logic element usage by as much as 72% as compared to other SHA-1 designs.

  4. Silicon integrated circuit process

    International Nuclear Information System (INIS)

    Lee, Jong Duck

    1985-12-01

    This book introduces the process of silicon integrated circuit. It is composed of seven parts, which are oxidation process, diffusion process, ion implantation process such as ion implantation equipment, damage, annealing and influence on manufacture of integrated circuit and device, chemical vapor deposition process like silicon Epitaxy LPCVD and PECVD, photolithography process, including a sensitizer, spin, harden bake, reflection of light and problems related process, infrared light bake, wet-etch, dry etch, special etch and problems of etching, metal process like metal process like metal-silicon connection, aluminum process, credibility of aluminum and test process.

  5. Primer printed circuit boards

    CERN Document Server

    Argyle, Andrew

    2009-01-01

    Step-by-step instructions for making your own PCBs at home. Making your own printed circuit board (PCB) might seem a daunting task, but once you master the steps, it's easy to attain professional-looking results. Printed circuit boards, which connect chips and other components, are what make almost all modern electronic devices possible. PCBs are made from sheets of fiberglass clad with copper, usually in multiplelayers. Cut a computer motherboard in two, for instance, and you'll often see five or more differently patterned layers. Making boards at home is relatively easy

  6. Silicon integrated circuit process

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Jong Duck

    1985-12-15

    This book introduces the process of silicon integrated circuit. It is composed of seven parts, which are oxidation process, diffusion process, ion implantation process such as ion implantation equipment, damage, annealing and influence on manufacture of integrated circuit and device, chemical vapor deposition process like silicon Epitaxy LPCVD and PECVD, photolithography process, including a sensitizer, spin, harden bake, reflection of light and problems related process, infrared light bake, wet-etch, dry etch, special etch and problems of etching, metal process like metal process like metal-silicon connection, aluminum process, credibility of aluminum and test process.

  7. Circuit design for reliability

    CERN Document Server

    Cao, Yu; Wirth, Gilson

    2015-01-01

    This book presents physical understanding, modeling and simulation, on-chip characterization, layout solutions, and design techniques that are effective to enhance the reliability of various circuit units.  The authors provide readers with techniques for state of the art and future technologies, ranging from technology modeling, fault detection and analysis, circuit hardening, and reliability management. Provides comprehensive review on various reliability mechanisms at sub-45nm nodes; Describes practical modeling and characterization techniques for reliability; Includes thorough presentation of robust design techniques for major VLSI design units; Promotes physical understanding with first-principle simulations.

  8. Electronic circuits fundamentals & applications

    CERN Document Server

    Tooley, Mike

    2015-01-01

    Electronics explained in one volume, using both theoretical and practical applications.New chapter on Raspberry PiCompanion website contains free electronic tools to aid learning for students and a question bank for lecturersPractical investigations and questions within each chapter help reinforce learning Mike Tooley provides all the information required to get to grips with the fundamentals of electronics, detailing the underpinning knowledge necessary to appreciate the operation of a wide range of electronic circuits, including amplifiers, logic circuits, power supplies and oscillators. The

  9. The Influence of Epicardial Fat and Nonalcoholic Fatty Liver Disease on Heart Rate Recovery in Metabolic Syndrome.

    Science.gov (United States)

    Cho, Kyoung Im; Jo, Eun Ah; Cho, Sang Hoon; Kim, Bo Hyun

    2017-06-01

    Epicardial adipose tissues reflecting visceral fat accumulations of the heart are associated with metabolic syndrome (MetS) and can be a predictor of other cardiometabolic diseases. It can adversely influence autonomic nervous system (ANS) of heart. Heart rate recovery (HRR) is an easy method for measuring ANS dysfunction. The purpose of this study was to determine whether epicardial fat thickness (EFT) and nonalcoholic fatty liver disease (NAFLD) are related to HRR in patients with MetS. We enrolled 772 consecutive patients from a health-screening center who underwent abdominal ultrasonography, treadmill test, and cardiac echocardiography. EFT using echocardiography and HRR by symptom-limited exercise testing was assessed. According to the presence of MetS and NAFLD, patients were classified into the four groups. In NAFLD patients, EFT was higher and HRR was lower, especially in patients with MetS and NAFLD, compared to non-MetS participants without NAFLD (MetS with NAFLD, EFT 7.5 ± 4.4 mm, HRR 31.9 ± 12.7; MetS without NAFLD, EFT 4.9 ± 3.0 mm, HRR 39.5 ± 11.1; non-MetS with NAFLD, EFT 5.9 ± 3.6 mm, HRR 36.6 ± 12.7; and non-MetS without NAFLD, EFT 4.4 ± 3.5 mm, HRR 43.4 ± 14.5, p < 0.001). Patients with severe liver steatosis (LS) showed significantly higher EFT than those with moderate LS (14.2 ± 2.0 vs. 7.5 ± 3.1 mm, P < 0.001), and EFT was positively correlated with severity of LS (r = 0.431, P < 0.001). HRR was significantly correlated with EFT (r = -0.386, P < 0.001) and severity of LS (r = -0.324, P < 0.001). EFT and NAFLD were significantly correlated with HRR in patients with MetS and they may be highly related to increased cardiovascular risk. These results suggest a cross-link among EFT, NAFLD, and cardiac autonomic dysfunction in patients with MetS.

  10. Impact of Ischemic and Valvular Heart Disease on Atrial Excitation:A High-Resolution Epicardial Mapping Study.

    Science.gov (United States)

    Mouws, Elisabeth M J P; Lanters, Eva A H; Teuwen, Christophe P; van der Does, Lisette J M E; Kik, Charles; Knops, Paul; Yaksh, Ameeta; Bekkers, Jos A; Bogers, Ad J J C; de Groot, Natasja M S

    2018-03-08

    The influence of underlying heart disease or presence of atrial fibrillation (AF) on atrial excitation during sinus rhythm (SR) is unknown. We investigated atrial activation patterns and total activation times of the entire atrial epicardial surface during SR in patients with ischemic and/or valvular heart disease with or without AF. Intraoperative epicardial mapping (N=128/192 electrodes, interelectrode distances: 2 mm) of the right atrium, Bachmann's bundle (BB), left atrioventricular groove, and pulmonary vein area was performed during SR in 253 patients (186 male [74%], age 66±11 years) with ischemic heart disease (N=132, 52%) or ischemic valvular heart disease (N=121, 48%). As expected, SR origin was located at the superior intercaval region of the right atrium in 232 patients (92%). BB activation occurred via 1 wavefront from right-to-left (N=163, 64%), from the central part (N=18, 7%), or via multiple wavefronts (N=72, 28%). Left atrioventricular groove activation occurred via (1) BB: N=108, 43%; (2) pulmonary vein area: N=9, 3%; or (3) BB and pulmonary vein area: N=136, 54%; depending on which route had the shortest interatrial conduction time ( P <0.001). Ischemic valvular heart disease patients more often had central BB activation and left atrioventricular groove activation via pulmonary vein area compared with ischemic heart disease patients (N=16 [13%] versus N=2 [2%]; P =0.009 and N=86 [71%] versus N=59 [45%]; P <0.001, respectively). Total activation times were longer in patients with AF (AF: 136±20 [92-186] ms; no AF: 114±17 [74-156] ms; P <0.001), because of prolongation of right atrium ( P =0.018) and BB conduction times ( P <0.001). Atrial excitation during SR is affected by underlying heart disease and AF, resulting in alternative routes for BB and left atrioventricular groove activation and prolongation of total activation times. Knowledge of atrial excitation patterns during SR and its electropathological variations, as demonstrated in

  11. Epicardial, Biatrial Ablation With Integrated Uni-bipolar Radiofrequency Technology in Stand-alone Persistent Atrial Fibrillation.

    Science.gov (United States)

    Rosati, Fabrizio; Muneretto, Claudio; Merati, Elisa; Polvani, Gianluca; Moltrasio, Massimo; Tondo, Claudio; Curnis, Antonio; Cerini, Manuel; Metras, Alexandre; Bisleri, Gianluigi

    Although minimally invasive approaches for surgical treatment of stand-alone atrial fibrillation have gained popularity for the past decade, ablation technology and extensive lesion sets play a major role in the achievement of a successful procedure, especially in presence of persistent and long-standing persistent atrial fibrillation. We evaluated clinical outcomes after totally endoscopic biatrial epicardial ablation of persistent atrial fibrillation with a novel integrated uni-bipolar radiofrequency device. Forty-nine (49) consecutive patients with stand-alone atrial fibrillation underwent right-sided monolateral thoracoscopic surgical ablation with a novel integrated uni-bipolar radiofrequency energy delivery and temperature-controlled technology. Atrial fibrillation was persistent in 13 (26.5%) of 49 and long-standing persistent in 36 (73.5%) of 49 patients. Mean ± SD age was 60.6 ± 10.3 years. Median duration of atrial fibrillation was 74 months. Mean ± SD left atrial diameter was 44.7 ± 4.0 mm. Epicardial en bloc isolation of all pulmonary veins (box lesion) and additional ablation of the right atrial free wall was successfully performed via minimally invasive approach without any intraoperative and postoperative major complications. Intraoperative entrance and exit block was achieved in 77.5% (38/49) and 91.8% (45/49) of patients, respectively. Mean ± SD ablation time was 16.3 ± 4.8 minutes. No intensive care unit stay was required. Postoperative sinus rhythm was achieved in 93.8% (30/32) patients, and no pacemaker implantation was required. At 13 months, 87.7% (43/49) of patients were in sinus rhythm; 71.4% (35/49) were free from antiarrhythmic drugs and 75.5% (37/49) from oral anticoagulation. Integrated uni-bipolar radiofrequency ablation technology showed to be effective for the surgical treatment of atrial fibrillation with a total endoscopic approach. A versapolar suction device with extensive right-left atrial lesion set may further improve

  12. [Association of human epicardial adipose tissue volume and inflammatory mediators with atherosclerosis and vulnerable coronary atherosclerotic plaque].

    Science.gov (United States)

    Zhou, Liangliang; Gong, Jianbin; Li, Demin; Lu, Guangming; Chen, Dong; Wang, Jing

    2015-02-01

    To investigate the relation of epicardial adipose tissue volume (EATV) determined by dual-source CT (DSCT) cardiac angiography and EAT-derived inflammatory factors to coronary heart disease (CHD) and vulnerable plaque. A total of 260 patients underwent cardiac computed tomography to evaluate stenosis of coronary artery, and blood samples were obtained from each patient. CHD was confirmed in 180 patients by DSA and CHD was excluded in the remaining 80 patients (NCHD). Vascular remodeling index and plaque vulnerability parameters (fatty volume, fibrous volume and calcification volume and fiber volume) were measured in CHD patients and correlation with EATV was analyzed. Epicardial adipose tissue (EAT) and intrathoracic adipose tissue (TAT) were collected from 40 CHD patients undergoing CABG surgery, and, mRNA and protein expressions of leptin and MMP9 were detected by RT-PCR and Western blot analysis. (1) The EATV was significantly higher in the CHD group than in NCHD group ((121.2 ± 40.6) mm³ vs. (74.7 ± 18.1) mm³, P = 0.01). (2) Subgroup analysis of the CHD patients demonstrated that EATV was significantly higher in patients with positive remodeling than in patients without positive remodeling ((97.6 ± 42.0) cm³ vs. (75.5 ± 25.4) cm³, P = 0.01). Lipid plaque volume was positively correlated with EATV (r = 0.34, P = 0.002); however, fiber plaque volume was negatively correlated with EATV (r = -0.30, P = 0.008). (3) Logistic regression analysis indicated that EATV was an independent risk factor for positive vascular remodeling (OR = 2.01, 95% CI: 1.30-2.32, P = 0.01). (4) mRNA and protein expression of leptin and MMP9 in EAT was significantly upregulated in 40 CHD patients who received CABG surgery compared to 40 NCHD patients (P 0.05) in mRNA and protein expression of leptin and MMP9 from the SAT between CHD and NCHD patients. (5) In the CHD group, leptin and MMP9 levels in EAT and EATV were positively correlated with lipid plaque volume and fibrous plaque

  13. ESD analog circuits and design

    CERN Document Server

    Voldman, Steven H

    2014-01-01

    A comprehensive and in-depth review of analog circuit layout, schematic architecture, device, power network and ESD design This book will provide a balanced overview of analog circuit design layout, analog circuit schematic development, architecture of chips, and ESD design.  It will start at an introductory level and will bring the reader right up to the state-of-the-art. Two critical design aspects for analog and power integrated circuits are combined. The first design aspect covers analog circuit design techniques to achieve the desired circuit performance. The second and main aspect pres

  14. Unstable oscillators based hyperchaotic circuit

    DEFF Research Database (Denmark)

    Murali, K.; Tamasevicius, A.; G. Mykolaitis, A.

    1999-01-01

    A simple 4th order hyperchaotic circuit with unstable oscillators is described. The circuit contains two negative impedance converters, two inductors, two capacitors, a linear resistor and a diode. The Lyapunov exponents are presented to confirm hyperchaotic nature of the oscillations in the circ...... in the circuit. The performance of the circuit is investigated by means of numerical integration of appropriate differential equations, PSPICE simulations, and hardware experiment.......A simple 4th order hyperchaotic circuit with unstable oscillators is described. The circuit contains two negative impedance converters, two inductors, two capacitors, a linear resistor and a diode. The Lyapunov exponents are presented to confirm hyperchaotic nature of the oscillations...

  15. The test of VLSI circuits

    Science.gov (United States)

    Baviere, Ph.

    Tests which have proven effective for evaluating VLSI circuits for space applications are described. It is recommended that circuits be examined after each manfacturing step to gain fast feedback on inadequacies in the production system. Data from failure modes which occur during operational lifetimes of circuits also permit redefinition of the manufacturing and quality control process to eliminate the defects identified. Other tests include determination of the operational envelope of the circuits, examination of the circuit response to controlled inputs, and the performance and functional speeds of ROM and RAM memories. Finally, it is desirable that all new circuits be designed with testing in mind.

  16. Electronic Circuit Analysis Language (ECAL)

    Science.gov (United States)

    Chenghang, C.

    1983-03-01

    The computer aided design technique is an important development in computer applications and it is an important component of computer science. The special language for electronic circuit analysis is the foundation of computer aided design or computer aided circuit analysis (abbreviated as CACD and CACA) of simulated circuits. Electronic circuit analysis language (ECAL) is a comparatively simple and easy to use circuit analysis special language which uses the FORTRAN language to carry out the explanatory executions. It is capable of conducting dc analysis, ac analysis, and transient analysis of a circuit. Futhermore, the results of the dc analysis can be used directly as the initial conditions for the ac and transient analyses.

  17. An integrated circuit switch

    Science.gov (United States)

    Bonin, E. L.

    1969-01-01

    Multi-chip integrated circuit switch consists of a GaAs photon-emitting diode in close proximity with S1 phototransistor. A high current gain is obtained when the transistor has a high forward common-emitter current gain.

  18. Automatic sweep circuit

    International Nuclear Information System (INIS)

    Keefe, D.J.

    1980-01-01

    An automatically sweeping circuit for searching for an evoked response in an output signal in time with respect to a trigger input is described. Digital counters are used to activate a detector at precise intervals, and monitoring is repeated for statistical accuracy. If the response is not found then a different time window is examined until the signal is found

  19. Automatic sweep circuit

    Science.gov (United States)

    Keefe, Donald J.

    1980-01-01

    An automatically sweeping circuit for searching for an evoked response in an output signal in time with respect to a trigger input. Digital counters are used to activate a detector at precise intervals, and monitoring is repeated for statistical accuracy. If the response is not found then a different time window is examined until the signal is found.

  20. "Printed-circuit" rectenna

    Science.gov (United States)

    Dickinson, R. M.

    1977-01-01

    Rectifying antenna is less bulky structure for absorbing transmitted microwave power and converting it into electrical current. Printed-circuit approach, using microstrip technology and circularly polarized antenna, makes polarization orientation unimportant and allows much smaller arrays for given performance. Innovation is particularly useful with proposed electric vehicles powered by beam microwaves.

  1. Het onzichtbare circuit

    NARCIS (Netherlands)

    Nauta, Bram

    2013-01-01

    De chip, of geïntegreerde schakeling, heeft in een razend tempo ons leven ingrijpend veranderd. Het lijkt zo vanzelfsprekend dat er weer een nieuwe generatie smartphones, tablets of computers is. Maar dat is het niet. Prof.dr.ir. Bram Nauta, hoogleraar Integrated Circuit Design, laat in zijn rede

  2. Voltage regulating circuit

    NARCIS (Netherlands)

    2005-01-01

    A voltage regulating circuit comprising a rectifier (2) for receiving an AC voltage (Vmains) and for generating a rectified AC voltage (vrec), and a capacitor (3) connected in parallel with said rectified AC voltage for providing a DC voltage (VDC) over a load (5), characterized by a unidirectional

  3. Streaming Reduction Circuit

    NARCIS (Netherlands)

    Gerards, Marco Egbertus Theodorus; Kuper, Jan; Kokkeler, Andre B.J.; Molenkamp, Egbert

    2009-01-01

    Reduction circuits are used to reduce rows of floating point values to single values. Binary floating point operators often have deep pipelines, which may cause hazards when many consecutive rows have to be reduced. We present an algorithm by which any number of consecutive rows of arbitrary lengths

  4. A Magnetic Circuit Demonstration.

    Science.gov (United States)

    Vanderkooy, John; Lowe, June

    1995-01-01

    Presents a demonstration designed to illustrate Faraday's, Ampere's, and Lenz's laws and to reinforce the concepts through the analysis of a two-loop magnetic circuit. Can be made dramatic and challenging for sophisticated students but is suitable for an introductory course in electricity and magnetism. (JRH)

  5. The LMT circuit and SPICE

    DEFF Research Database (Denmark)

    Lindberg, Erik; Murali, K.; Tamacevicius, Arunas

    2006-01-01

    The state equations of the LMT circuit are modeled as a dedicated analogue computer circuit and solved by means of PSpice. The nonlinear part of the system is studied. Problems with the PSpice program are presented....

  6. Resistor Combinations for Parallel Circuits.

    Science.gov (United States)

    McTernan, James P.

    1978-01-01

    To help simplify both teaching and learning of parallel circuits, a high school electricity/electronics teacher presents and illustrates the use of tables of values for parallel resistive circuits in which total resistances are whole numbers. (MF)

  7. Detecting short circuits during assembly

    Science.gov (United States)

    Deboo, G. J.

    1980-01-01

    Detector circuit identifies shorts between bus bars of electronic equipment being wired. Detector sounds alarm and indicates which planes are shorted. Power and ground bus bars are scanned continuously until short circuit occurs.

  8. BR-5 primary circuit decontamination

    International Nuclear Information System (INIS)

    Efimov, I.A.; Nikulin, M.P.; Smirnov-Averin, A.P.; Tymosh, B.S.; Shereshkov, V.S.

    1976-01-01

    Results and methodology of steam-water and acid decontamination of the primary coolant circuit SBR-5 reactor in 1971 are discussed. Regeneration process in a cold trap of the primary coolant circuit is discussed

  9. Localization of heart vectors produced by epicardial burns and ectopic stimuli; validation of a dipole ranging method.

    Science.gov (United States)

    Ideker, R E; Bandura, J P; Larsen, R A; Cox, J W; Keller, F W; Brody, D A

    1975-01-01

    Location of the equivalent cardiac dipole has been estimated but not fully verified in several laboratories. To test the accuracy of such a procedure, injury vectors were produced in 14 isolated, perfused rabbit hearts by epicardial searing. Strongly dipolar excitation fronts were produced in 6 additional hearts by left ventricular pacing. Twenty computer-processed signals, derived from surface electrodes on a spherical electrolyte-filled tank containing the test preparation, were optimally fitted with a locatable cardiac dipole that accounted for over 99% of the root-mean-square surface potential. For the 14 burns (mean radius 5.0 mm), the S-T injury dipole was located 3.4 plus or minus 0.7 (SD) mm from the burn center. For the 6 paced hearts, the dipole early in the ectopic beat was located 3.7 mm (range 2.6 to 4.6 mm) from the stimulating electrode. Phase inhomogeneities within the chamber appeared to have a small but predictable effect on dipole site determination. The study demonstrates that equivalent dipole location can be determined with acceptable accuracy from potential measurements of the external cardiac field.

  10. Left ventricular epicardial activation increases transmural dispersion of repolarization in healthy, long QT, and dilated cardiomyopathy dogs.

    Science.gov (United States)

    Bai, Rong; Lü, Jiagao; Pu, Jun; Liu, Nian; Zhou, Qiang; Ruan, Yanfei; Niu, Huiyan; Zhang, Cuntai; Wang, Lin; Kam, Ruth

    2005-10-01

    Benefits of cardiac resynchronization therapy (CRT) are well established. However, less is understood concerning its effects on myocardial repolarization and the potential proarrhythmic risk. Healthy dogs (n = 8) were compared to a long QT interval (LQT) model (n = 8, induced by cesium chloride, CsCl) and a dilated cardiomyopathy with congestive heart failure (DCM-CHF, induced by rapid ventricular pacing, n = 5). Monophasic action potential (MAP) recordings were obtained from the subendocardium, midmyocardium, subepicardium, and the transmural dispersion of repolarization (TDR) was calculated. The QT interval and the interval from the peak to the end of the T wave (T(p-e)) were measured. All these characteristics were compared during left ventricular epicardial (LV-Epi), right ventricular endocardial (RV-Endo), and biventricular (Bi-V) pacing. In healthy dogs, TDR prolonged to 37.54 ms for Bi-V pacing and to 47.16 ms for LV-Epi pacing as compared to 26.75 ms for RV-Endo pacing (P canine models in addition to their intrinsic transmural heterogeneity in the intact heart. This mechanism may contribute to the development of malignant ventricular arrhythmias, such as torsades de pointes (TdP) in congestive heart failure (CHF) patients treated with CRT.

  11. Subclinical atherosclerosis and hyperandrogenemia are independent risk factors for increased epicardial fat thickness in patients with PCOS and idiopathic hirsutism.

    Science.gov (United States)

    Cakir, Evrim; Doğan, Mehmet; Topaloglu, Oya; Ozbek, Mustafa; Cakal, Erman; Vural, Mustafa Gokhan; Yeter, Ekrem; Delibasi, Tuncay

    2013-01-01

    Polycystic ovary syndrome (PCOS) is one of the most common endocrine disorders affecting reproductive-age women and is reported to be associated with an increased risk of cardiovascular disease and early atherosclerosis. Epicardial fat thickness (EF) is clinically related to subclinical atherosclerosis and visceral fat changes. Therefore, the objective of this study is to compare the carotid artery intima-media thickness (CIMT), EF and cardiometabolic risk factors in patients with PCOS, patients with idiopathic hirsutism (IH) and healthy controls. This cross-sectional controlled study was conducted in a training and research hospital. The study population consisted of 50 reproductive-age PCOS women, 34 women with IH and 39 control subjects. We evaluated anthropometric, hormonal and metabolic parameters as well as CIMT and EF measurements in PCOS patients, IH patients and controls. The mean fasting insulin, HOMA-IR, hsCRP, GGT, CIMT, and EF levels were significantly higher in patients with PCOS and IH (p cardiometabolic response in patients with PCOS and IH, even at an early stage. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

  12. Role of galectin 3 and epicardial fat thickness in the development of atrial fibrillation in patients with metabolic syndrome

    Directory of Open Access Journals (Sweden)

    V. A. Ionin

    2015-01-01

    Full Text Available Objective. To evaluate the epicardial fat thickness (EFT in patients with metabolic syndrome (MS, including paroxysmal and persistent atrial fibrillation (AF. To relate EFT to the fibroid heart marker, i.e. galectin 3. Materials and methods. We examined 100 patients with MS (50 with AF, and 50 healthy persons made the control group. Serum galectin 3 was measured by ELISA method. The EFT was measured with echocardiography. Results. EFT in patients with MS was twofold higher than in healthy persons. EFT in patients with MS and AF didn't differ significantly from that in patients with MS without AF. Positive correlation between the levels of EFT and galectin 3 in serum was revealed. Serum galectin 3 and EFT were associated with atrial fibrillation in patients with MS (OR:1,27, 95% CI 1,02-1,58 and OR:1,73, 95% CI 1,37-2,19, correspondingly.Conclusion. Definition of EFT at echocardiography can be used in the assessment of risk AF in patients with MS.

  13. Epicardial Adipose Tissue Thickness in Patients With Subclinical Hypothyroidism and the Relationship Thereof With Visceral Adipose Tissue Thickness.

    Science.gov (United States)

    Arpaci, Dilek; Gurkan Tocoglu, Aysel; Yilmaz, Sabiye; Korkmaz, Sumeyye; Ergenc, Hasan; Gunduz, Huseyin; Keser, Nurgul; Tamer, Ali

    2016-03-01

    Subclinical hypothyroidism (SH) is associated with cardiovascular metabolic syndromes, especially dislipidemia and abdominal obesity. Visceral abdominal adipose tissue (VAAT) and epicardial adipose tissue (EAT) have the same ontogenic origin and produce many proinflammatory and proatherogenic cytokines. We evaluated EAT and VAAT thickness in patients with SH. Forty-one patients with SH and 35 controls were included in the study. Demographical and anthropometric features of both patients and controls were recorded. Thyroid and metabolic parameters were measured. EAT was measured using 2D-transthoracic echocardiography. The age and gender distributions were similar in the two groups (P = 0.998 and P = 0.121, respectively). Body mass index (BMI), fat mass, waist circumference (WC), hip circumference (HC), the WC/HC ratio, and the thicknesses of VAAT and abdominal subcutaneous adipose tissue were higher in the case group than the control group (all P values 0.05). We found no difference between the two groups in fasting plasma glucose (FPG) level (P = 0.780), but the levels of LDL-C and TG differed significantly (P = 0.002 and P = 0.026, respectively). The serum TSH level was higher and the FT4 level was lower in the case than the control group (both P values <0.01). Increased abdominal adipose tissue thickness in patients with SH is associated with atherosclerosis. To detemine the risk of atherosclerosis in such patients, EAT measurements are valuable; such assessment is simple to perform.

  14. MOS voltage automatic tuning circuit

    OpenAIRE

    李, 田茂; 中田, 辰則; 松本, 寛樹

    2004-01-01

    Abstract ###Automatic tuning circuit adjusts frequency performance to compensate for the process variation. Phase locked ###loop (PLL) is a suitable oscillator for the integrated circuit. It is a feedback system that compares the input ###phase with the output phase. It can make the output frequency equal to the input frequency. In this paper, PLL ###fomed of MOSFET's is presented.The presented circuit consists of XOR circuit, Low-pass filter and Relaxation ###Oscillator. On PSPICE simulation...

  15. Behavioral synthesis of asynchronous circuits

    DEFF Research Database (Denmark)

    Nielsen, Sune Fallgaard

    2005-01-01

    This thesis presents a method for behavioral synthesis of asynchronous circuits, which aims at providing a synthesis flow which uses and tranfers methods from synchronous circuits to asynchronous circuits. We move the synchronous behavioral synthesis abstraction into the asynchronous handshake...... is idle. This reduces unnecessary switching activity in the individual functional units and therefore the energy consumption of the entire circuit. A collection of behavioral synthesis algorithms have been developed allowing the designer to perform time and power constrained design space exploration...

  16. Selected collection of circuit drawings

    International Nuclear Information System (INIS)

    1977-01-01

    The many electronics circuits have been constracted in the Electronics Shop for use in nuclear experiments or other purposes of this Institute. The types of these circuits amount to about 500 items in total since 1968. This report describes the electronics circuit diagrams selected from this collection. The circuit details are not presented in this report, because these are already been published in the other technical reports. (auth.)

  17. Diode, transistor & fet circuits manual

    CERN Document Server

    Marston, R M

    2013-01-01

    Diode, Transistor and FET Circuits Manual is a handbook of circuits based on discrete semiconductor components such as diodes, transistors, and FETS. The book also includes diagrams and practical circuits. The book describes basic and special diode characteristics, heat wave-rectifier circuits, transformers, filter capacitors, and rectifier ratings. The text also presents practical applications of associated devices, for example, zeners, varicaps, photodiodes, or LEDs, as well as it describes bipolar transistor characteristics. The transistor can be used in three basic amplifier configuration

  18. Analysis of Bernstein's factorization circuit

    NARCIS (Netherlands)

    Lenstra, A.K.; Shamir, A.; Tomlinson, J.; Tromer, E.; Zheng, Y.

    2002-01-01

    In [1], Bernstein proposed a circuit-based implementation of the matrix step of the number field sieve factorization algorithm. These circuits offer an asymptotic cost reduction under the measure "construction cost x run time". We evaluate the cost of these circuits, in agreement with [1], but argue

  19. High voltage MOSFET switching circuit

    Science.gov (United States)

    McEwan, Thomas E.

    1994-01-01

    The problem of source lead inductance in a MOSFET switching circuit is compensated for by adding an inductor to the gate circuit. The gate circuit inductor produces an inductive spike which counters the source lead inductive drop to produce a rectangular drive voltage waveform at the internal gate-source terminals of the MOSFET.

  20. Neuromorphic Silicon Neuron Circuits

    Science.gov (United States)

    Indiveri, Giacomo; Linares-Barranco, Bernabé; Hamilton, Tara Julia; van Schaik, André; Etienne-Cummings, Ralph; Delbruck, Tobi; Liu, Shih-Chii; Dudek, Piotr; Häfliger, Philipp; Renaud, Sylvie; Schemmel, Johannes; Cauwenberghs, Gert; Arthur, John; Hynna, Kai; Folowosele, Fopefolu; Saighi, Sylvain; Serrano-Gotarredona, Teresa; Wijekoon, Jayawan; Wang, Yingxue; Boahen, Kwabena

    2011-01-01

    Hardware implementations of spiking neurons can be extremely useful for a large variety of applications, ranging from high-speed modeling of large-scale neural systems to real-time behaving systems, to bidirectional brain–machine interfaces. The specific circuit solutions used to implement silicon neurons depend on the application requirements. In this paper we describe the most common building blocks and techniques used to implement these circuits, and present an overview of a wide range of neuromorphic silicon neurons, which implement different computational models, ranging from biophysically realistic and conductance-based Hodgkin–Huxley models to bi-dimensional generalized adaptive integrate and fire models. We compare the different design methodologies used for each silicon neuron design described, and demonstrate their features with experimental results, measured from a wide range of fabricated VLSI chips. PMID:21747754

  1. Neuromorphic silicon neuron circuits

    Directory of Open Access Journals (Sweden)

    Giacomo eIndiveri

    2011-05-01

    Full Text Available Hardware implementations of spiking neurons can be extremely useful for a large variety of applications, ranging from high-speed modeling of large-scale neural systems to real-time behaving systems, to bidirectional brain-machine interfaces. The specific circuit solutions used to implement silicon neurons depend on the application requirements. In this paper we describe the most common building blocks and techniques used to implement these circuits, and present an overview of a wide range of neuromorphic silicon neurons, which implement different computational models, ranging from biophysically realistic and conductance based Hodgkin-Huxley models to bi-dimensional generalized adaptive Integrate and Fire models. We compare the different design methodologies used for each silicon neuron design described, and demonstrate their features with experimental results, measured from a wide range of fabricated VLSI chips.

  2. Integrated circuit structure

    International Nuclear Information System (INIS)

    1981-01-01

    The invention describes the fabrication of integrated circuit structures, such as read-only memory components of field-effect transistors, which may be fabricated and then maintained in inventory, and later selectively modified in accordance with a desired pattern. It is claimed that MOS depletion-mode devices in accordance with the invention can be fabricated at lower cost and at higher yields. (U.K.)

  3. Integrated Circuit Immunity

    Science.gov (United States)

    Sketoe, J. G.; Clark, Anthony

    2000-01-01

    This paper presents a DOD E3 program overview on integrated circuit immunity. The topics include: 1) EMI Immunity Testing; 2) Threshold Definition; 3) Bias Tee Function; 4) Bias Tee Calibration Set-Up; 5) EDM Test Figure; 6) EMI Immunity Levels; 7) NAND vs. and Gate Immunity; 8) TTL vs. LS Immunity Levels; 9) TP vs. OC Immunity Levels; 10) 7805 Volt Reg Immunity; and 11) Seventies Chip Set. This paper is presented in viewgraph form.

  4. Integrated coincidence circuits

    International Nuclear Information System (INIS)

    Borejko, V.F.; Grebenyuk, V.M.; Zinov, V.G.

    1976-01-01

    The description is given of two coincidence units employing integral circuits in the VISHNYA standard. The units are distinguished for the coincidence selection element which is essentially a combination of a tunnel diode and microcircuits. The output fast response of the units is at least 90 MHz in the mode of the output signal unshaped in duration and 50 MHz minimum in the mode of the output signal shaping. The resolution time of the units is dependent upon the duration of input signals

  5. Semiconductor integrated circuits

    International Nuclear Information System (INIS)

    Michel, A.E.; Schwenker, R.O.; Ziegler, J.F.

    1979-01-01

    An improved method involving ion implantation to form non-epitaxial semiconductor integrated circuits. These are made by forming a silicon substrate of one conductivity type with a recessed silicon dioxide region extending into the substrate and enclosing a portion of the silicon substrate. A beam of ions of opposite conductivity type impurity is directed at the substrate at an energy and dosage level sufficient to form a first region of opposite conductivity within the silicon dioxide region. This impurity having a concentration peak below the surface of the substrate forms a region of the one conductivity type which extends from the substrate surface into the first opposite type region to a depth between the concentration peak and the surface and forms a second region of opposite conductivity type. The method, materials and ion beam conditions are detailed. Vertical bipolar integrated circuits can be made this way when the first opposite type conductivity region will function as a collector. Also circuits with inverted bipolar devices when this first region functions as a 'buried'' emitter region. (U.K.)

  6. Observation of linear spin wave dispersion in the reentrant spin glass Fe sub 0 sub . sub 7 Al sub 0 sub . sub 3

    CERN Document Server

    Shapiro, S M; Raymond, S; Lee, S H; Motoya, K

    2002-01-01

    Fe sub 0 sub . sub 7 Al sub 0 sub . sub 3 is a reentrant spin glass, which undergoes a transition from a paramagnet to a disordered ferromagnet at T sub c propor to 500 K; at a lower temperature the spins progressively freeze and it exhibits a spin-glass-like behavior. In the ferromagnetic phase spin waves with a q sup 2 dispersion are observed at small q, which broaden rapidly and become diffusive beyond a critical wave vector q sub 0. On cooling the spin waves also disappear and a strong elastic central peak develops. For measurements around the (1,1,1) Bragg peak, a new sharp excitation is observed which has a linear dispersion behavior. It disappears above T sub c , but persists throughout the spin-glass phase. It is not present in the stoichiometric Fe sub 3 Al material. (orig.)

  7. Interface Circuit For Printer Port

    Science.gov (United States)

    Tucker, Jerry H.; Yadlowsky, Ann B.

    1991-01-01

    Electronic circuit, called printer-port interface circuit (PPI) developed to overcome certain disadvantages of previous methods for connecting IBM PC or PC-compatible computer to other equipment. Has both reading and writing modes of operation. Very simple, requiring only six integrated circuits. Provides for moderately fast rates of transfer of data and uses existing unmodified circuit card in IBM PC. When used with appropriate software, circuit converts printer port on IBM PC, XT, AT, or compatible personal computer to general purpose, 8-bit-data, 16-bit address bus that connects to multitude of devices.

  8. Changes to the shuttle circuits

    CERN Multimedia

    GS Department

    2011-01-01

    To fit with passengers expectation, there will be some changes to the shuttle circuits as from Monday 10 October. See details on http://cern.ch/ShuttleService (on line on 7 October). Circuit No. 5 is cancelled as circuit No. 1 also stops at Bldg. 33. In order to guarantee shorter travel times, circuit No. 1 will circulate on Meyrin site only and circuit No. 2, with departures from Bldg. 33 and 500, on Prévessin site only. Site Services Section

  9. Thermionic integrated circuits: electronics for hostile environments

    International Nuclear Information System (INIS)

    Lynn, D.K.; McCormick, J.B.; MacRoberts, M.D.J.; Wilde, D.K.; Dooley, G.R.; Brown, D.R.

    1985-01-01

    Thermionic integrated circuits combine vacuum tube technology with integrated circuit techniques to form integrated vacuum triode circuits. These circuits are capable of extended operation in both high-temperature and high-radiation environments

  10. Power system with an integrated lubrication circuit

    Science.gov (United States)

    Hoff, Brian D [East Peoria, IL; Akasam, Sivaprasad [Peoria, IL; Algrain, Marcelo C [Peoria, IL; Johnson, Kris W [Washington, IL; Lane, William H [Chillicothe, IL

    2009-11-10

    A power system includes an engine having a first lubrication circuit and at least one auxiliary power unit having a second lubrication circuit. The first lubrication circuit is in fluid communication with the second lubrication circuit.

  11. Integrated coherent matter wave circuits

    International Nuclear Information System (INIS)

    Ryu, C.; Boshier, M. G.

    2015-01-01

    An integrated coherent matter wave circuit is a single device, analogous to an integrated optical circuit, in which coherent de Broglie waves are created and then launched into waveguides where they can be switched, divided, recombined, and detected as they propagate. Applications of such circuits include guided atom interferometers, atomtronic circuits, and precisely controlled delivery of atoms. We report experiments demonstrating integrated circuits for guided coherent matter waves. The circuit elements are created with the painted potential technique, a form of time-averaged optical dipole potential in which a rapidly moving, tightly focused laser beam exerts forces on atoms through their electric polarizability. Moreover, the source of coherent matter waves is a Bose-Einstein condensate (BEC). Finally, we launch BECs into painted waveguides that guide them around bends and form switches, phase coherent beamsplitters, and closed circuits. These are the basic elements that are needed to engineer arbitrarily complex matter wave circuitry

  12. Dynamic pulse difference circuit

    International Nuclear Information System (INIS)

    Erickson, G.L.

    1978-01-01

    A digital electronic circuit of especial use for subtracting background activity pulses in gamma spectrometry is disclosed which comprises an up-down counter connected to count up with signal-channel pulses and to count down with background-channel pulses. A detector responsive to the count position of the up-down counter provides a signal when the up-down counter has completed one scaling sequence cycle of counts in the up direction. In an alternate embodiment, a detector responsive to the count position of the up-down counter provides a signal upon overflow of the counter

  13. Electronics circuits and systems

    CERN Document Server

    Bishop, Owen

    2007-01-01

    The material in Electronics - Circuits and Systems is a truly up-to-date textbook, with coverage carefully matched to the electronics units of the 2007 BTEC National Engineering and the latest AS and A Level specifications in Electronics from AQA, OCR and WJEC. The material has been organized with a logical learning progression, making it ideal for a wide range of pre-degree courses in electronics. The approach is student-centred and includes: numerous examples and activities; web research topics; Self Test features, highlighted key facts, formulae and definitions. Each chapter ends with a set

  14. Electric circuits problem solver

    CERN Document Server

    REA, Editors of

    2012-01-01

    Each Problem Solver is an insightful and essential study and solution guide chock-full of clear, concise problem-solving gems. All your questions can be found in one convenient source from one of the most trusted names in reference solution guides. More useful, more practical, and more informative, these study aids are the best review books and textbook companions available. Nothing remotely as comprehensive or as helpful exists in their subject anywhere. Perfect for undergraduate and graduate studies.Here in this highly useful reference is the finest overview of electric circuits currently av

  15. Digital logic circuit test

    Energy Technology Data Exchange (ETDEWEB)

    Yun, Gil Jung; Yang, Hong Young

    2011-03-15

    This book is about digital logic circuit test, which lists the digital basic theory, basic gate like and, or And Not gate, NAND/NOR gate such as NAND gate, NOR gate, AND and OR, logic function, EX-OR gate, adder and subtractor, decoder and encoder, multiplexer, demultiplexer, flip-flop, counter such as up/down counter modulus N counter and Reset type counter, shift register, D/A and A/D converter and two supplements list of using components and TTL manual and CMOS manual.

  16. Photonic Integrated Circuits

    Science.gov (United States)

    Krainak, Michael; Merritt, Scott

    2016-01-01

    Integrated photonics generally is the integration of multiple lithographically defined photonic and electronic components and devices (e.g. lasers, detectors, waveguides passive structures, modulators, electronic control and optical interconnects) on a single platform with nanometer-scale feature sizes. The development of photonic integrated circuits permits size, weight, power and cost reductions for spacecraft microprocessors, optical communication, processor buses, advanced data processing, and integrated optic science instrument optical systems, subsystems and components. This is particularly critical for small spacecraft platforms. We will give an overview of some NASA applications for integrated photonics.

  17. Integrated circuit cell library

    Science.gov (United States)

    Whitaker, Sterling R. (Inventor); Miles, Lowell H. (Inventor)

    2005-01-01

    According to the invention, an ASIC cell library for use in creation of custom integrated circuits is disclosed. The ASIC cell library includes some first cells and some second cells. Each of the second cells includes two or more kernel cells. The ASIC cell library is at least 5% comprised of second cells. In various embodiments, the ASIC cell library could be 10% or more, 20% or more, 30% or more, 40% or more, 50% or more, 60% or more, 70% or more, 80% or more, 90% or more, or 95% or more comprised of second cells.

  18. Nano integrated circuit process

    International Nuclear Information System (INIS)

    Yoon, Yung Sup

    2004-02-01

    This book contains nine chapters, which are introduction of manufacture of semiconductor chip, oxidation such as Dry-oxidation, wet oxidation, oxidation model and oxide film, diffusion like diffusion process, diffusion equation, diffusion coefficient and diffusion system, ion implantation, including ion distribution, channeling, multiimplantation and masking and its system, sputtering such as CVD and PVD, lithography, wet etch and dry etch, interconnection and flattening like metal-silicon connection, silicide, multiple layer metal process and flattening, an integrated circuit process, including MOSFET and CMOS.

  19. Electronic logic circuits

    CERN Document Server

    Gibson, J

    2013-01-01

    Most branches of organizing utilize digital electronic systems. This book introduces the design of such systems using basic logic elements as the components. The material is presented in a straightforward manner suitable for students of electronic engineering and computer science. The book is also of use to engineers in related disciplines who require a clear introduction to logic circuits. This third edition has been revised to encompass the most recent advances in technology as well as the latest trends in components and notation. It includes a wide coverage of application specific integrate

  20. Linear integrated circuits

    CERN Document Server

    Carr, Joseph

    1996-01-01

    The linear IC market is large and growing, as is the demand for well trained technicians and engineers who understand how these devices work and how to apply them. Linear Integrated Circuits provides in-depth coverage of the devices and their operation, but not at the expense of practical applications in which linear devices figure prominently. This book is written for a wide readership from FE and first degree students, to hobbyists and professionals.Chapter 1 offers a general introduction that will provide students with the foundations of linear IC technology. From chapter 2 onwa

  1. Nano integrated circuit process

    Energy Technology Data Exchange (ETDEWEB)

    Yoon, Yung Sup

    2004-02-15

    This book contains nine chapters, which are introduction of manufacture of semiconductor chip, oxidation such as Dry-oxidation, wet oxidation, oxidation model and oxide film, diffusion like diffusion process, diffusion equation, diffusion coefficient and diffusion system, ion implantation, including ion distribution, channeling, multiimplantation and masking and its system, sputtering such as CVD and PVD, lithography, wet etch and dry etch, interconnection and flattening like metal-silicon connection, silicide, multiple layer metal process and flattening, an integrated circuit process, including MOSFET and CMOS.

  2. Electronics circuits and systems

    CERN Document Server

    Bishop, Owen

    2011-01-01

    The material in Electronics - Circuits and Systems is a truly up-to-date textbook, with coverage carefully matched to the electronics units of the 2007 BTEC National Engineering and the latest AS and A Level specifications in Electronics from AQA, OCR and WJEC. The material has been organized with a logical learning progression, making it ideal for a wide range of pre-degree courses in electronics. The approach is student-centred and includes: numerous examples and activities; web research topics; Self Test features, highlighted key facts, formulae and definitions. Ea

  3. Optoelectronics circuits manual

    CERN Document Server

    Marston, R M

    1999-01-01

    This manual is a useful single-volume guide specifically aimed at the practical design engineer, technician, and experimenter, as well as the electronics student and amateur. It deals with the subject in an easy to read, down to earth, and non-mathematical yet comprehensive manner, explaining the basic principles and characteristics of the best known devices, and presenting the reader with many practical applications and over 200 circuits. Most of the ICs and other devices used are inexpensive and readily available types, with universally recognised type numbers.The second edition

  4. Optically controllable molecular logic circuits

    International Nuclear Information System (INIS)

    Nishimura, Takahiro; Fujii, Ryo; Ogura, Yusuke; Tanida, Jun

    2015-01-01

    Molecular logic circuits represent a promising technology for observation and manipulation of biological systems at the molecular level. However, the implementation of molecular logic circuits for temporal and programmable operation remains challenging. In this paper, we demonstrate an optically controllable logic circuit that uses fluorescence resonance energy transfer (FRET) for signaling. The FRET-based signaling process is modulated by both molecular and optical inputs. Based on the distance dependence of FRET, the FRET pathways required to execute molecular logic operations are formed on a DNA nanostructure as a circuit based on its molecular inputs. In addition, the FRET pathways on the DNA nanostructure are controlled optically, using photoswitching fluorescent molecules to instruct the execution of the desired operation and the related timings. The behavior of the circuit can thus be controlled using external optical signals. As an example, a molecular logic circuit capable of executing two different logic operations was studied. The circuit contains functional DNAs and a DNA scaffold to construct two FRET routes for executing Input 1 AND Input 2 and Input 1 AND NOT Input 3 operations on molecular inputs. The circuit produced the correct outputs with all possible combinations of the inputs by following the light signals. Moreover, the operation execution timings were controlled based on light irradiation and the circuit responded to time-dependent inputs. The experimental results demonstrate that the circuit changes the output for the required operations following the input of temporal light signals

  5. The impact of obesity on the relationship between epicardial adipose tissue, left ventricular mass and coronary microvascular function

    International Nuclear Information System (INIS)

    Bakkum, M.J.; Danad, I.; Romijn, M.A.J.; Stuijfzand, W.J.A.; Leonora, R.M.; Rossum, A.C. van; Knaapen, P.; Tulevski, I.I.; Somsen, G.A.; Lammertsma, A.A.; Kuijk, C. van; Raijmakers, P.G.

    2015-01-01

    Epicardial adipose tissue (EAT) has been linked to coronary artery disease (CAD) and coronary microvascular dysfunction. However, its injurious effect may also impact the underlying myocardium. This study aimed to determine the impact of obesity on the quantitative relationship between left ventricular mass (LVM), EAT and coronary microvascular function. A total of 208 (94 men, 45 %) patients evaluated for CAD but free of coronary obstructions underwent quantitative [ 15 O]H 2 O hybrid positron emission tomography (PET)/CT imaging. Coronary microvascular resistance (CMVR) was calculated as the ratio of mean arterial pressure to hyperaemic myocardial blood flow. Obese patients [body mass index (BMI) > 25, n = 133, 64 % of total] had more EAT (125.3 ± 47.6 vs 93.5 ± 42.1 cc, p < 0.001), a higher LVM (130.1 ± 30.4 vs 114.2 ± 29.3 g, p < 0.001) and an increased CMVR (26.6 ± 9.1 vs 22.3 ± 8.6 mmHg x ml -1 x min -1 x g -1 , p < 0.01) as compared to nonobese patients. Male gender (β = 40.7, p < 0.001), BMI (β = 1.61, p < 0.001), smoking (β = 6.29, p = 0.03) and EAT volume (β = 0.10, p < 0.01) were identified as independent predictors of LVM. When grouped according to BMI status, EAT was only independently associated with LVM in nonobese patients. LVM, hypercholesterolaemia and coronary artery calcium score were independent predictors of CMVR. EAT volume is associated with LVM independently of BMI and might therefore be a better predictor of cardiovascular risk than BMI. However, EAT volume was not related to coronary microvascular function after adjustments for LVM and traditional risk factors. (orig.)

  6. The impact of obesity on the relationship between epicardial adipose tissue, left ventricular mass and coronary microvascular function

    Energy Technology Data Exchange (ETDEWEB)

    Bakkum, M.J.; Danad, I.; Romijn, M.A.J.; Stuijfzand, W.J.A.; Leonora, R.M.; Rossum, A.C. van; Knaapen, P. [VU University Medical Center, Department of Cardiology, Amsterdam (Netherlands); Tulevski, I.I.; Somsen, G.A. [Cardiology Centers of the Netherlands, Amsterdam (Netherlands); Lammertsma, A.A.; Kuijk, C. van; Raijmakers, P.G. [VU University Medical Center, Department of Radiology and Nuclear Medicine, Amsterdam (Netherlands)

    2015-09-15

    Epicardial adipose tissue (EAT) has been linked to coronary artery disease (CAD) and coronary microvascular dysfunction. However, its injurious effect may also impact the underlying myocardium. This study aimed to determine the impact of obesity on the quantitative relationship between left ventricular mass (LVM), EAT and coronary microvascular function. A total of 208 (94 men, 45 %) patients evaluated for CAD but free of coronary obstructions underwent quantitative [{sup 15}O]H{sub 2}O hybrid positron emission tomography (PET)/CT imaging. Coronary microvascular resistance (CMVR) was calculated as the ratio of mean arterial pressure to hyperaemic myocardial blood flow. Obese patients [body mass index (BMI) > 25, n = 133, 64 % of total] had more EAT (125.3 ± 47.6 vs 93.5 ± 42.1 cc, p < 0.001), a higher LVM (130.1 ± 30.4 vs 114.2 ± 29.3 g, p < 0.001) and an increased CMVR (26.6 ± 9.1 vs 22.3 ± 8.6 mmHg x ml{sup -1} x min{sup -1} x g{sup -1}, p < 0.01) as compared to nonobese patients. Male gender (β = 40.7, p < 0.001), BMI (β = 1.61, p < 0.001), smoking (β = 6.29, p = 0.03) and EAT volume (β = 0.10, p < 0.01) were identified as independent predictors of LVM. When grouped according to BMI status, EAT was only independently associated with LVM in nonobese patients. LVM, hypercholesterolaemia and coronary artery calcium score were independent predictors of CMVR. EAT volume is associated with LVM independently of BMI and might therefore be a better predictor of cardiovascular risk than BMI. However, EAT volume was not related to coronary microvascular function after adjustments for LVM and traditional risk factors. (orig.)

  7. Epicardial fat thickness: distribution and association with diabetes mellitus, hypertension and the metabolic syndrome in the ELSA-Brasil study.

    Science.gov (United States)

    Graeff, Daniela Bertol; Foppa, Murilo; Pires, Julio Cesar Gall; Vigo, Alvaro; Schmidt, Maria Ines; Lotufo, Paulo Andrade; Mill, Jose Geraldo; Duncan, Bruce Bartholow

    2016-04-01

    Epicardial fat thickness (EFT) has emerged as a marker of cardiometabolic risk, but its clinical use warrants proper knowledge of its distribution and associations in populations. We aimed to describe the distribution of EFT, its demographic correlates and independent associations with diabetes, hypertension and metabolic syndrome (MS) in free-living Brazilian adults. From the baseline echocardiography of the Brazilian Longitudinal Study of Adult Health (ELSA-Brasil)-a cohort study of civil servants aged 35-74 years-EFT was measured from a randomly selected sample of 998 participants as the mean of two paraesternal windows obtained at end systole (EFTsyst) and end diastole (EFTdiast). From the 421 individuals free of diabetes, hypertension and MS, we defined EFT reference values and the EFTsyst 75th percentile cut-off. Median EFTsyst was 1.5 (IQR 0-2.6) mm; a large proportion (84 %) had EFTdiast = 0. EFT was higher in women and lower in blacks, and increased with age and BMI. Although EFT was higher in those with diabetes, hypertension, and MS, EFT associations were reduced when adjusted for age, sex and ethnicity, and were non-significant after adjusting for obesity measures. In conclusion, the amount of EFT in this large multiethnic population is smaller than reported in other populations. EFT reference values varied across demographic and clinical variables, EFT associations with cardiometabolic variables being largely explained by age, sex, ethnicity and central obesity. Although EFT can help identify individuals at increased cardiometabolic risk, it will likely have a limited additional role compared to current risk stratification strategies.

  8. Association between epicardial adipose tissue volumes on 3-dimensional reconstructed CT images and recurrence of atrial fibrillation after catheter ablation

    International Nuclear Information System (INIS)

    Nagashima, Koichi; Okumura, Yasuo; Watanabe, Ichiro

    2011-01-01

    Whether epicardial adipose tissue (EAT) is independently associated with atrial fibrillation (AF) and outcome after catheter ablation (CA) for AF remains unclear. Three-dimensional volume-rendering reconstructed images of EAT (total EAT) and EAT surrounding the left atrium (LA-EAT) were measured on 320-row multidetector computed tomography in 40 patients with AF (paroxysmal AF [PAF], n=24; persistent AF [PerAF], n=16) who underwent CA, and in 37 age-matched control patients. EAT volumes were as follows for the control, PAF and PerAF patients: total EAT, 138.3±45.2 cm 3 vs. 158.3±47.2 cm 3 vs. 226.4±93.3 cm 3 (P 3 vs. 41.3±15.3 cm 3 vs. 66.8±35.1 cm 3 (P 3 vs. 106.2±27.3 cm 3 , P=0.021; LA-EAT: 34.0±10.6 cm 3 vs. 21.8±6.9 cm 3 , P=0.0006). EAT volumes were greater in the 15 AF patients (37.5%) with post-ablation recurrence than in patients without recurrence (total EAT: 239.0±90.2 cm 3 vs. 153.5±42.7 cm 3 , P=0.0002; LA-EAT: 69.6±35.5 cm 3 vs. 40.7±13.9 cm 3 , P=0.0008). EAT volume increases in AF patients independent of conventional risk factors and is greater in patients with lone AF than in non-AF patients. EAT volume might be useful for predicting AF recurrence after CA. (author)

  9. Total and interatrial epicardial adipose tissues are independently associated with left atrial remodeling in patients with atrial fibrillation.

    Science.gov (United States)

    Shin, Seung Yong; Yong, Hwan Seok; Lim, Hong Euy; Na, Jin Oh; Choi, Cheol Ung; Choi, Jong Il; Kim, Seong Hwan; Kim, Jin Won; Kim, Eung Ju; Park, Sang Weon; Rha, Seung-Woon; Park, Chang Gyu; Seo, Hong Seog; Oh, Dong Joo; Kim, Young-Hoon

    2011-06-01

    As epicardial adipose tissue (EAT) is a metabolically active visceral fat, potential interaction between EAT and myocardium is strongly suggested. The aims of this study were to determine whether the amount and regional distribution of EAT are related to the chronicity of atrial fibrillation (AF) and left atrial (LA) remodeling. This study consisted of 40 subjects with paroxysmal AF (PAF) and 40 with persistent AF (PeAF). Eighty subjects with no history of AF were enrolled as controls. Total volume of EAT (EAT(total)), regional thickness of EAT, and LA volume (LAV) were measured by multislice computed tomography. In the AF group, blood samples were drawn from coronary sinus for analysis of inflammatory cytokines including adiponectin. Compared with controls, AF subjects had larger LAV, EAT(total), and the thicknesses of periatrial EAT including interatrial septum (IAS). However, the thicknesses of periventricular EAT were not different between the groups. The PeAF subjects had larger LAV, EAT(total), and periatrial EAT thicknesses, higher levels of inflammatory cytokines, and lower level of adiponectin than did the PAF subjects. Adiponection level was significantly associated with EAT(total) and IAS thickness. Multivariate analysis revealed that EAT(total) (P = 0.004) and IAS thickness (P = 0.016) were independently associated with LAV. EAT(total) and thickness of periatrial EAT were significantly larger in AF subjects compared to those of the matched controls and were closely related to the chronicity of AF. Moreover, EAT(total) and IAS thickness were independently associated with LAV in subjects with AF. © 2011 Wiley Periodicals, Inc.

  10. Does quantifying epicardial and intrathoracic fat with noncontrast computed tomography improve risk stratification beyond calcium scoring alone?

    Science.gov (United States)

    Forouzandeh, Farshad; Chang, Su Min; Muhyieddeen, Kamil; Zaid, Rashid R; Trevino, Alejandro R; Xu, Jiaqiong; Nabi, Faisal; Mahmarian, John J

    2013-01-01

    Noncontrast cardiac computed tomography allows calculation of coronary artery calcium score (CACS) and measurement of epicardial adipose tissue (EATv) and intrathoracic fat (ITFv) volumes. It is unclear whether fat volume information contributes to risk stratification. Cardiac computed tomography was performed in 760 consecutive patients with acute chest pain admitted thorough the emergency department. None had prior coronary artery disease. CACS was calculated using the Agatston method. EATv and ITFv were semiautomatically calculated. Median patient follow-up was 3.3 years. Mean patient age was 54.4±13.7 years and Framingham risk score 8.2±8.2. The 45 patients (5.9%) with major acute cardiac events (MACE) were older (64.8±13.9 versus 53.7±13.4 years), more frequently male (60% versus 40%), and had a higher median Framingham risk score (16 versus 4) and CACS (268 versus 0) versus those without events (all PEATv (154 versus 116 mL) and ITFv (330 versus 223 mL), and a higher prevalence of EATv >125 mL (67% versus 44%) and ITFv >250 mL (64% versus 42%) (all PEATv, and ITFv were all independently associated with MACE. CACS was associated with MACE after adjustment for fat volumes (PEATv and ITFv improved the risk model only in patients with CACS >400. CACS and fat volumes are independently associated with MACE in acute chest pain patients and beyond that provided by clinical information alone. Although fat volumes may add prognostic value in patients with CACS >400, CACS is most strongly correlated with outcome.

  11. [Relationship between epicardial adipose tissue and clinical prognosis of patients with coronary heart disease after percutaneous coronary intervention].

    Science.gov (United States)

    Zhang, Y Y; Li, X; Lin, W H; Liu, J J; Jing, R; Lu, Y J; Di, C Y; Shi, H Y; Gao, P

    2018-01-16

    Objective: To further evaluate the clinical value of epicardial adipose tissue volume (EATV) in predicting the prognosis of coronary heart disease (CHD) after percutaneous coronary intervention (PCI). Methods: From July 2013 to July 2016 in TEDA International Cardiovascular Disease Hospital, a total of 474 patients diagnosed with CHD were included in this study.According to the result of EATV, patients were divided into three groups, group A (EATV≤75 ml), group B (75 mlEATVEATV≥150 ml). Then the level of body mass index (BMI), hypersensitive c-reactive protein (hs-CRP), interleukin (IL)-6 and tumor necrosis factor (TNF)-α were tested for all the three groups.All the patients were followed up for 1 year for major adverse cardiovascular events (MACE). The clinical value of EATV in predicting the occurrence of MACE events was evaluated. Results: The BMI, level of hs-CRP, TNF-α in group B were higher than group A, group C were significantly higher than group B, with statistically significant difference across all the comparisons ( P EATV was positively correlated with hs-CRP, IL-6, TNF-α ( r =0.675-0.700, P EATV level was 120.39 ml to predict MACE (area under cure: 0.751, 95% CI : 0.634-0.868, P EATV>120.39 ml can be used as an independent risk factor for predicting the occurrence of MACE. Conclusion: The level of EATV is closely related to the occurrence of MACE events, and EATV>120.39 ml is an independent risk factor for MACE in patients with CHD after PCI.

  12. Effect of interconnection between cervical vagus trunk, epicardial fat pad on sinus node function, and atrial fibrillation.

    Science.gov (United States)

    Zhou, Qina; Zhang, Ling; Wang, Kun; Xu, Xiaoxia; Ji, Meng; Zhang, Feng; Wang, Hongli; Hou, Yuemei

    2014-03-01

    The epicardial fat pad (FP) integrates the autonomic innervation between the extrinsic and intrinsic cardiac autonomic nervous system and affects atrial electrophysiology and pathophysiology. Eighteen dogs were divided into two groups: sequential ablation of sinoatrial node FP (SAN-FP) and atrioventricular node FP (AVN-FP). Sinus rate (SR), atrial fibrillation (AF) inducibility, and effective refractory period (ERP) changes during electrical stimulation of the vagus trunk were detected before and after ablation. In the SAN-FP group, the SR slowing, increasing AF inducibility, and ERP shortening that induced by vagus trunk stimulation were significantly attenuated by isolated SAN-FP ablation, compared with the same group prior to ablation (all P AVN-FP ablation following SAN-FP ablation almost cannot produce further attenuation during vagus trunk stimulation, compared with isolated SAN-FP ablation (P > 0.05). In the AVN-FP group, SR slowing, increasing AF inducibility, and ERP shortening that induced by vagus trunk stimulation were completely eliminated by isolated AVN-FP ablation, compared with the same group prior to ablation (all P AVN-FP ablation produced no further attenuation, compared with isolated AVN-FP ablation (P > 0.05). A neural pathway from the cervical vagus trunk to the sinus node and atrium runs through the SAN-FP, but eventually converges at the AVN-FP and also suggested that the AVN-FP serves as an "integration center" for the SAN-FP to modulate sinus node function. The AVN-FP may play a more critical role in the initiation and maintenance of AF. ©2013 First Affilated Hospital of Xingiang Medical University Pacing and Clinical Electrophysiology ©2013 Wiley Periodicals, Inc.

  13. Epicardial fat tissue thickness is increased in patients with lichen planus and is linked to inflammation and dyslipidemia.

    Science.gov (United States)

    Ertem, Ahmet Goktug; Erdogan, Mehmet; Koseoglu, Cemal; Akoglu, Gulsen; Ozdemir, Elcin; Koseoglu, Gamze; Sivri, Serkan; Keles, Telat; Durmaz, Tahir; Aktas, Akın; Bozkurt, Engin

    2016-10-01

    Lichen planus (LP) is a mucocutaneous inflammatory disease. Inflammation plays a major role in the progression of atherosclerosis. Epicardial fat tissue (EFT) has been shown to produce and secrete various proatherogenic and proinflammatory hormones and cytokines. The aim of this study was to assess EFT in patients with lichen planus. Fifty-four patients with LP and 50 controls were enrolled in the study. LP was diagnosed according to the World Health Organization criteria. EFT was measured on the free wall of the right ventricle in parasternal long-axis view, as previously described and validated. There were positive correlations between EFT thickness and platelet/lymphocyte ratio, neutrophil/lymphocyte ratio, duration of LP, and high-sensitivity C-reactive protein (hsCRP) (p<0.001, p<0.001, p=0.002 and p<0.001, respectively). In multivariate analysis, after adjustments for relevant confounders, LDL cholesterol, hsCRP, platelet/lymphocyte ratio and duration of LP were independent predictors of EFT thickness in patients with LP (β=0.231, p=0.014; β=0.205, p=0.037; β=0.361, p=0.001 and β=0.133, p=0.047, respectively). EFT is increased in patients with LP compared to control subjects. Duration of LP is correlated with EFT, and duration of LP is also an independent predictor of increased EFT, which is a predictor of subclinical atherosclerosis. Copyright © 2016 Sociedade Portuguesa de Cardiologia. Publicado por Elsevier España, S.L.U. All rights reserved.

  14. Sequential circuit design for radiation hardened multiple voltage integrated circuits

    Science.gov (United States)

    Clark, Lawrence T [Phoenix, AZ; McIver, III, John K.

    2009-11-24

    The present invention includes a radiation hardened sequential circuit, such as a bistable circuit, flip-flop or other suitable design that presents substantial immunity to ionizing radiation while simultaneously maintaining a low operating voltage. In one embodiment, the circuit includes a plurality of logic elements that operate on relatively low voltage, and a master and slave latches each having storage elements that operate on a relatively high voltage.

  15. Simple Cell Balance Circuit

    Science.gov (United States)

    Johnson, Steven D.; Byers, Jerry W.; Martin, James A.

    2012-01-01

    A method has been developed for continuous cell voltage balancing for rechargeable batteries (e.g. lithium ion batteries). A resistor divider chain is provided that generates a set of voltages representing the ideal cell voltage (the voltage of each cell should be as if the cells were perfectly balanced). An operational amplifier circuit with an added current buffer stage generates the ideal voltage with a very high degree of accuracy, using the concept of negative feedback. The ideal voltages are each connected to the corresponding cell through a current- limiting resistance. Over time, having the cell connected to the ideal voltage provides a balancing current that moves the cell voltage very close to that ideal level. In effect, it adjusts the current of each cell during charging, discharging, and standby periods to force the cell voltages to be equal to the ideal voltages generated by the resistor divider. The device also includes solid-state switches that disconnect the circuit from the battery so that it will not discharge the battery during storage. This solution requires relatively few parts and is, therefore, of lower cost and of increased reliability due to the fewer failure modes. Additionally, this design uses very little power. A preliminary model predicts a power usage of 0.18 W for an 8-cell battery. This approach is applicable to a wide range of battery capacities and voltages.

  16. Quantum-Circuit Refrigerator

    Science.gov (United States)

    MöTtöNen, Mikko; Tan, Kuan Y.; Masuda, Shumpei; Partanen, Matti; Lake, Russell E.; Govenius, Joonas; Silveri, Matti; Grabert, Hermann

    Quantum technology holds great potential in providing revolutionizing practical applications. However, fast and precise cooling of the functional quantum degrees of freedom on demand remains a major challenge in many solid-state implementations, such as superconducting circuits. We demonstrate direct cooling of a superconducting resonator mode using voltage-controllable quantum tunneling of electrons in a nanoscale refrigerator. In our first experiments on this type of a quantum-circuit refrigerator, we measure the drop in the mode temperature by electron thermometry at a resistor which is coupled to the resonator mode through ohmic losses. To eliminate unwanted dissipation, we remove the probe resistor and directly observe the power spectrum of the resonator output in agreement with the so-called P(E) theory. We also demonstrate in microwave reflection experiments that the internal quality factor of the resonator can be tuned by orders of magnitude. In the future, our refrigerator can be integrated with different quantum electric devices, potentially enhancing their performance. For example, it may prove useful in the initialization of superconducting quantum bits and in dissipation-assisted quantum annealing. We acknowledge European Research Council Grant SINGLEOUT (278117) and QUESS (681311) for funding.

  17. Quasi-Linear Circuit

    Science.gov (United States)

    Bradley, William; Bird, Ross; Eldred, Dennis; Zook, Jon; Knowles, Gareth

    2013-01-01

    This work involved developing spacequalifiable switch mode DC/DC power supplies that improve performance with fewer components, and result in elimination of digital components and reduction in magnetics. This design is for missions where systems may be operating under extreme conditions, especially at elevated temperature levels from 200 to 300 degC. Prior art for radiation-tolerant DC/DC converters has been accomplished utilizing classical magnetic-based switch mode converter topologies; however, this requires specific shielding and component de-rating to meet the high-reliability specifications. It requires complex measurement and feedback components, and will not enable automatic re-optimization for larger changes in voltage supply or electrical loading condition. The innovation is a switch mode DC/DC power supply that eliminates the need for processors and most magnetics. It can provide a well-regulated voltage supply with a gain of 1:100 step-up to 8:1 step down, tolerating an up to 30% fluctuation of the voltage supply parameters. The circuit incorporates a ceramic core transformer in a manner that enables it to provide a well-regulated voltage output without use of any processor components or magnetic transformers. The circuit adjusts its internal parameters to re-optimize its performance for changes in supply voltage, environmental conditions, or electrical loading at the output

  18. Arithmetic circuits for DSP applications

    CERN Document Server

    Stouraitis, Thanos

    2017-01-01

    Arithmetic Circuits for DSP Applications is a complete resource on arithmetic circuits for digital signal processing (DSP). It covers the key concepts, designs and developments of different types of arithmetic circuits, which can be used for improving the efficiency of implementation of a multitude of DSP applications. Each chapter includes various applications of the respective class of arithmetic circuits along with information on the future scope of research. Written for students, engineers, and researchers in electrical and computer engineering, this comprehensive text offers a clear understanding of different types of arithmetic circuits used for digital signal processing applications. The text includes contributions from noted researchers on a wide range of topics, including a review o circuits used in implementing basic operations like additions and multiplications; distributed arithmetic as a technique for the multiplier-less implementation of inner products for DSP applications; discussions on look ...

  19. Integrated circuit cooled turbine blade

    Science.gov (United States)

    Lee, Ching-Pang; Jiang, Nan; Um, Jae Y.; Holloman, Harry; Koester, Steven

    2017-08-29

    A turbine rotor blade includes at least two integrated cooling circuits that are formed within the blade that include a leading edge circuit having a first cavity and a second cavity and a trailing edge circuit that includes at least a third cavity located aft of the second cavity. The trailing edge circuit flows aft with at least two substantially 180-degree turns at the tip end and the root end of the blade providing at least a penultimate cavity and a last cavity. The last cavity is located along a trailing edge of the blade. A tip axial cooling channel connects to the first cavity of the leading edge circuit and the penultimate cavity of the trailing edge circuit. At least one crossover hole connects the penultimate cavity to the last cavity substantially near the tip end of the blade.

  20. Control circuit for transformer relay

    International Nuclear Information System (INIS)

    Wyatt, G.A.

    1984-01-01

    A control circuit for a transformer relay which will automatically momentarily control the transformer relay to a selected state upon energization of the control circuit. The control circuit has an energy storage element and a current director coupled in series and adapted to be coupled with the secondary winding of the transformer relay. A device for discharge is coupled across the energy storage element. The energy storage element and current director will momentarily allow a unidirectional flow of current in the secondary winding of the transformer relay upon application of energy to the control circuit. When energy is not applied to the control circuit the device for discharge will allow the energy storage element to discharge and be available for another operation of the control circuit

  1. Source-circuit design overview

    Science.gov (United States)

    Ross, R. G., Jr.

    1983-01-01

    The source circuit is the fundamental electrical building block of a large central-station array; it consists of a series-parallel network of solar cells that develops full system voltage. The array field is generally made up of a large number of parallel source circuits. Source-circuit electrical configuration is driven by a number of design considerations, which must be considered simultaneously. Array fault tolerance and hot spot heating endurance are examined in detail.

  2. Radiation-sensitive switching circuits

    Energy Technology Data Exchange (ETDEWEB)

    Moore, J.H.; Cockshott, C.P.

    1976-03-16

    A radiation-sensitive switching circuit has a light emitting diode which supplies light to a photo-transistor, the light being interrupted from time to time. When the photo-transistor is illuminated, current builds up and when this current reaches a predetermined value, a trigger circuit changes state. The peak output of the photo-transistor is measured and the trigger circuit is arranged to change state when the output of the device is a set proportion of the peak output, so as to allow for aging of the components. The circuit is designed to control the ignition system in an automobile engine.

  3. Four-junction superconducting circuit

    Science.gov (United States)

    Qiu, Yueyin; Xiong, Wei; He, Xiao-Ling; Li, Tie-Fu; You, J. Q.

    2016-01-01

    We develop a theory for the quantum circuit consisting of a superconducting loop interrupted by four Josephson junctions and pierced by a magnetic flux (either static or time-dependent). In addition to the similarity with the typical three-junction flux qubit in the double-well regime, we demonstrate the difference of the four-junction circuit from its three-junction analogue, including its advantages over the latter. Moreover, the four-junction circuit in the single-well regime is also investigated. Our theory provides a tool to explore the physical properties of this four-junction superconducting circuit. PMID:27356619

  4. Memristor Circuits and Systems

    KAUST Repository

    Zidan, Mohammed A.

    2015-05-01

    Current CMOS-based technologies are facing design challenges related to the continuous scaling down of the minimum feature size, according to Moore’s law. Moreover, conventional computing architecture is no longer an effective way of fulfilling modern applications demands, such as big data analysis, pattern recognition, and vector processing. Therefore, there is an exigent need to shift to new technologies, at both the architecture and the device levels. Recently, memristor devices and structures attracted attention for being promising candidates for this job. Memristor device adds a new dimension for designing novel circuits and systems. In addition, high-density memristor-based crossbar is widely considered to be the essential element for future memory and bio-inspired computing systems. However, numerous challenges need to be addressed before the memristor genuinely replaces current memory and computing technologies, which is the motivation behind this research effort. In order to address the technology challenges, we begin by fabricating and modeling the memristor device. The devices fabricated at our local clean room enriched our understanding of the memristive phenomenon and enabled the experimental testing for our memristor-based circuits. Moreover, our proposed mathematical modeling for memristor behavior is an essential element for the theoretical circuit design stage. Designing and addressing the challenges of memristor systems with practical complexity, however, requires an extra step, which takes the form of a reliable and modular simulation platform. We, therefore, built a new simulation platform for the resistive crossbar, which can simulate realistic size arrays filled with real memory data. In addition, this simulation platform includes various crossbar nonidealities in order to obtain accurate simulation results. Consequently, we were able to address the significant challenges facing the high density memristor crossbar, as the building block for

  5. Basic electronic circuits

    CERN Document Server

    Buckley, P M

    1980-01-01

    In the past, the teaching of electricity and electronics has more often than not been carried out from a theoretical and often highly academic standpoint. Fundamentals and basic concepts have often been presented with no indication of their practical appli­ cations, and all too frequently they have been illustrated by artificially contrived laboratory experiments bearing little relationship to the outside world. The course comes in the form of fourteen fairly open-ended constructional experiments or projects. Each experiment has associated with it a construction exercise and an explanation. The basic idea behind this dual presentation is that the student can embark on each circuit following only the briefest possible instructions and that an open-ended approach is thereby not prejudiced by an initial lengthy encounter with the theory behind the project; this being a sure way to dampen enthusiasm at the outset. As the investigation progresses, questions inevitably arise. Descriptions of the phenomena encounte...

  6. ECCS control circuit

    International Nuclear Information System (INIS)

    Sato, Takashi.

    1986-01-01

    Purpose: To afford a sufficient margin to pressure vibrations upon starting of an automatic depressurization system by dispersing pressure vibration in suppression water due to the opening action of an automatic releaf valve in the automatic depressurization system thereby reducing the dynamic load exerted to the surface of the suppression walls. Constitution: Upon occurrence of loss of coolant accidents, an automatic releaf valve for automatic depressurization is opened to deliver the steams in the pressure vessel into the suppression pool. Since a plurality of automatic releaf valves have usually been disposed, if they are opened simultaneously, excess dynamic loads are exerted due to the pressure vibrations to the wall surface of the suppression pool. In this invention, a control circuit is disposed such that the opening timing for each of the automatic releaf valves is deviated upon occurrence of a driving signal for the automatic depressurization system to thereby disperse the pressure vibrations in the suppression water. (Kamimura, M.)

  7. A dishwasher for circuits

    CERN Multimedia

    Rosaria Marraffino

    2014-01-01

    You have always been told that electronic devices fear water. However, at the Surface Mount Devices (SMD) Workshop here at CERN all the electronic assemblies are cleaned with a machine that looks like a… dishwasher.   The circuit dishwasher. Credit: Clara Nellist.  If you think the image above shows a dishwasher, you wouldn’t be completely wrong. Apart from the fact that the whole pumping system and the case itself are made entirely from stainless steel and chemical resistant materials, and the fact that it washes electrical boards instead of dishes… it works exactly like a dishwasher. It’s a professional machine (mainly used in the pharmaceutical industry) designed to clean everything that can be washed with a water-based chemical soap. This type of treatment increases the lifetime of the electronic boards and therefore the LHC's reliability by preventing corrosion problems in the severe radiation and ozone environment of the LHC tunn...

  8. Modeling cortical circuits.

    Energy Technology Data Exchange (ETDEWEB)

    Rohrer, Brandon Robinson; Rothganger, Fredrick H.; Verzi, Stephen J.; Xavier, Patrick Gordon

    2010-09-01

    The neocortex is perhaps the highest region of the human brain, where audio and visual perception takes place along with many important cognitive functions. An important research goal is to describe the mechanisms implemented by the neocortex. There is an apparent regularity in the structure of the neocortex [Brodmann 1909, Mountcastle 1957] which may help simplify this task. The work reported here addresses the problem of how to describe the putative repeated units ('cortical circuits') in a manner that is easily understood and manipulated, with the long-term goal of developing a mathematical and algorithmic description of their function. The approach is to reduce each algorithm to an enhanced perceptron-like structure and describe its computation using difference equations. We organize this algorithmic processing into larger structures based on physiological observations, and implement key modeling concepts in software which runs on parallel computing hardware.

  9. Inductive circuit arrangements

    International Nuclear Information System (INIS)

    Mansfield, Peter; Coxon, R.J.

    1987-01-01

    A switched coil arrangement is connected in a bridge configuration of four switches S 1 , S 2 , S 3 and S 4 which are each shunted by diodes D 1 , D 2 , D 3 and D 4 so that current can flow in either direction through a coil L depending on the setting of the switches. A capacitor C is connected across the bridge through a switch S 5 to receive the inductive energy stored in coil L on breaking the current flow path through the coil. The electrostatic energy stored in capacitor C can then be used to supply current through the coil in the reverse direction either immediately or after a time delay. Coil L may be a superconductive coil. Losses in the circuit can be made up by a trickle charge of capacitor C from a separate supply V 2 . The device may be used in nuclear magnetic resonance imaging. (author)

  10. Gender disparities in the association between epicardial adipose tissue volume and coronary atherosclerosis: a 3-dimensional cardiac computed tomography imaging study in Japanese subjects.

    Science.gov (United States)

    Dagvasumberel, Munkhbaatar; Shimabukuro, Michio; Nishiuchi, Takeshi; Ueno, Junji; Takao, Shoichiro; Fukuda, Daiju; Hirata, Yoichiro; Kurobe, Hirotsugu; Soeki, Takeshi; Iwase, Takashi; Kusunose, Kenya; Niki, Toshiyuki; Yamaguchi, Koji; Taketani, Yoshio; Yagi, Shusuke; Tomita, Noriko; Yamada, Hirotsugu; Wakatsuki, Tetsuzo; Harada, Masafumi; Kitagawa, Tetsuya; Sata, Masataka

    2012-09-10

    Growing evidence suggests that epicardial adipose tissue (EAT) may contribute to the development of coronary artery disease (CAD). In this study, we explored gender disparities in EAT volume (EATV) and its impact on coronary atherosclerosis. The study population consisted of 90 consecutive subjects (age: 63 ± 12 years; men: 47, women: 43) who underwent 256-slice multi-detector computed tomography (MDCT) coronary angiography. EATV was measured as the sum of cross-sectional epicardial fat area on CT images, from the lower surface of the left pulmonary artery origin to the apex. Subjects were segregated into the CAD group (coronary luminal narrowing > 50%) and non-CAD group. EATV/body surface area (BSA) was higher among men in the CAD group than in the non-CAD group (62 ± 13 vs. 33 ± 10 cm3/m2, p EATV/BSA was the single predictor for >50% coronary luminal narrowing in men (p EATV is strongly associated with coronary atherosclerosis in men.

  11. Gender disparities in the association between epicardial adipose tissue volume and coronary atherosclerosis: A 3-dimensional cardiac computed tomography imaging study in Japanese subjects

    Directory of Open Access Journals (Sweden)

    Dagvasumberel Munkhbaatar

    2012-09-01

    Full Text Available Abstract Background Growing evidence suggests that epicardial adipose tissue (EAT may contribute to the development of coronary artery disease (CAD. In this study, we explored gender disparities in EAT volume (EATV and its impact on coronary atherosclerosis. Methods The study population consisted of 90 consecutive subjects (age: 63 ± 12 years; men: 47, women: 43 who underwent 256-slice multi-detector computed tomography (MDCT coronary angiography. EATV was measured as the sum of cross-sectional epicardial fat area on CT images, from the lower surface of the left pulmonary artery origin to the apex. Subjects were segregated into the CAD group (coronary luminal narrowing > 50% and non-CAD group. Results EATV/body surface area (BSA was higher among men in the CAD group than in the non-CAD group (62 ± 13 vs. 33 ± 10 cm3/m2, p 3/m2, not significant. Multivariate logistic analysis showed that EATV/BSA was the single predictor for >50% coronary luminal narrowing in men (p Conclusions Increased EATV is strongly associated with coronary atherosclerosis in men.

  12. Compact Circuit Preprocesses Accelerometer Output

    Science.gov (United States)

    Bozeman, Richard J., Jr.

    1993-01-01

    Compact electronic circuit transfers dc power to, and preprocesses ac output of, accelerometer and associated preamplifier. Incorporated into accelerometer case during initial fabrication or retrofit onto commercial accelerometer. Made of commercial integrated circuits and other conventional components; made smaller by use of micrologic and surface-mount technology.

  13. Comminution circuits for compact itabirites

    Directory of Open Access Journals (Sweden)

    Pedro Ferreira Pinto

    Full Text Available Abstract In the beneficiation of compact Itabirites, crushing and grinding account for major operational and capital costs. As such, the study and development of comminution circuits have a fundamental importance for feasibility and optimization of compact Itabirite beneficiation. This work makes a comparison between comminution circuits for compact Itabirites from the Iron Quadrangle. The circuits developed are: a crushing and ball mill circuit (CB, a SAG mill and ball mill circuit (SAB and a single stage SAG mill circuit (SSSAG. For the SAB circuit, the use of pebble crushing is analyzed (SABC. An industrial circuit for 25 million tons of run of mine was developed for each route from tests on a pilot scale (grinding and industrial scale. The energy consumption obtained for grinding in the pilot tests was compared with that reported by Donda and Bond. The SSSAG route had the lowest energy consumption, 11.8kWh/t and the SAB route had the highest energy consumption, 15.8kWh/t. The CB and SABC routes had a similar energy consumption of 14.4 kWh/t and 14.5 kWh/t respectively.

  14. Current-mode minimax circuit

    NARCIS (Netherlands)

    Wassenaar, R.F.

    1992-01-01

    The minimum-maximum (minimax) circuit selects the minimum and maximum of two input currents. Four transistors in matched pairs are operated in the saturation region. Because the behavior of the circuit is based on matched devices and is independent of the relationship between the drain current and

  15. Short-circuit impedance measurement

    DEFF Research Database (Denmark)

    Pedersen, Knud Ole Helgesen; Nielsen, Arne Hejde; Poulsen, Niels Kjølstad

    2003-01-01

    Methods for estimating the short-circuit impedance in the power grid are investigated for various voltage levels and situations. The short-circuit impedance is measured, preferably from naturally occurring load changes in the grid, and it is shown that such a measurement system faces different...

  16. Cell short circuit, preshort signature

    Science.gov (United States)

    Lurie, C.

    1980-01-01

    Short-circuit events observed in ground test simulations of DSCS-3 battery in-orbit operations are analyzed. Voltage signatures appearing in the data preceding the short-circuit event are evaluated. The ground test simulation is briefly described along with performance during reconditioning discharges. Results suggest that a characteristic signature develops prior to a shorting event.

  17. Enhancement of Linear Circuit Program

    DEFF Research Database (Denmark)

    Gaunholt, Hans; Dabu, Mihaela; Beldiman, Octavian

    1996-01-01

    In this report a preliminary user friendly interface has been added to the LCP2 program making it possible to describe an electronic circuit by actually drawing the circuit on the screen. Component values and other options and parameters can easily be set by the aid of the interface. The interface...

  18. Patients ≥ 75 years with acute coronary syndrome but without critical epicardial coronary disease: prevalence, characteristics, and outcome

    Science.gov (United States)

    Wong, Vincent; Farah, Ahmed; von Korn, Hubertus; Memisevic, Nedim; Richter, Stefan; Tukhiashvili, Ketevan; Lauer, Bernward; Ohlow, Marc-Alexander

    2015-01-01

    Objective Absence of significant epicardial coronary artery disease (CAD) in patients with acute onset of chest pain and elevation of myocardial necrosis markers is occasionally observed. The aim of this study was to analyse the clinical characteristics and outcome of such patients with advanced age. Methods We retrospectively analysed 4,311 patients with acute onset of chest pain plus necrosis marker elevation. Two hundred and seventy two patients without CAD on angiogram (6.3%) were identified. Out of them, 50 (1.2%) patients ≥ 75 years (Group I) were compared with (1) 222 acute coronary syndrome (ACS) patients without CAD on angiogram < 75 years (Group II), and (2) 610 consecutive patients ≥ 75 years with Non-ST-elevation Myocardial Infarction (NSTEMI) undergoing percutaneous coronary intervention (Group III). Results Group I compared to Group III patients made up for more females (64.0% vs. 49.2%; P < 0.0001), and had more severe anginal symptoms on presentation [Canadian Cardiovascular Society (CCS) class I/II, 26.0% vs. 49.8%; P = 0.02]. Group I patients also had lower troponin levels (0.62 ± 0.8 ng/mL vs. 27 ± 74 ng/mL; P < 0.02), lower leukocyte count (9.4 ± 3.13 × 109 vs. 12 ± 5.1 × 109; P = 0.001) and better preserved left ventricular function (56.7% ± 14.3% vs. 45% ± 11%; P < 0.0001). Event-free survival (cardiac death, myocardial infarction, recurrent angina, and re-hospitalisation) was more frequent in Group I and II patients compared to Group III patients (64.9%, 66.7%, and 41.6%, respectively; P < 0.0001). Conclusions ACS in patients ≥ 75 years without CAD is very infrequent, associated with a (1) similar outcome compared to ACS patients < 75 years without CAD, and (2) significant better outcome compared to NSTEMI patients ≥ 75 years. PMID:25678899

  19. Epicardial Adipose Tissue (EAT Thickness Is Associated with Cardiovascular and Liver Damage in Nonalcoholic Fatty Liver Disease.

    Directory of Open Access Journals (Sweden)

    Anna Ludovica Fracanzani

    Full Text Available Epicardial adipose tissue (EAT has been proposed as a cardiometabolic and hepatic fibrosis risk factor in patients with non alcoholic fatty liver disease (NAFLD. Aim of this study was to evaluate the role of EAT in NAFLD by analyzing 1 the association between EAT, the other metabolic parameters and the severity of steatosis 2 the relationship between cardiovascular (cIMT, cplaques, E/A, liver (presence of NASH and significant fibrosis damage and metabolic risk factors including EAT 3 the relationship between EAT and genetic factors strongly influencing liver steatosis.In a cross-sectional study, we considered 512 consecutive patients with NAFLD (confirmed by biopsy in 100. EAT, severity of steatosis, carotid intima-media thickness (cIMT and plaques were evaluated by ultrasonography and results analysed by multiple linear and logistic regression models. Variables independently associated with EAT (mm were female gender (p = 0.003, age (p = 0.001, BMI (p = 0.01, diastolic blood pressure (p = 0.009, steatosis grade 2 (p = 0.01 and 3 (p = 0.04, fatty liver index (p = 0.001 and statin use (p = 0.03. Variables independently associated with carotid IMT were age (p = 0.0001, hypertension (p = 0.009, diabetes (p = 0.04, smoking habits (p = 0.04 and fatty liver index (p = 0.02, with carotid plaques age (p = 0.0001, BMI (p = 0.03, EAT (p = 0.02, and hypertension (p = 0.02, and with E/A age (p = 0.0001, diabetes (p = 0.005, hypertension (p = 0.04 and fatty liver index (p = 0.004. In the 100 patients with available liver histology non alcoholic steatohepatitis (NASH was independently associated with EAT (p = 0.04 and diabetes (p = 0.054 while significant fibrosis with EAT (p = 0.02, diabetes (p = 0.01 and waist circumference (p = 0.05. No association between EAT and PNPLA3 and TM6SF2 polymorphisms was found.In patients with NAFLD, EAT is associated with the severity of liver and vascular damage besides with the known metabolic risk factors.

  20. Myocardial blood flow reserve is impaired in patients with aortic valve calcification and unobstructed epicardial coronary arteries.

    Science.gov (United States)

    Nel, Karen; Nam, Michael C Y; Anstey, Chris; Boos, Christopher J; Carlton, Edward; Senior, Roxy; Kaski, Juan Carlos; Khattab, Ahmed; Shamley, Delva; Byrne, Christopher D; Stanton, Tony; Greaves, Kim

    2017-12-01

    Although calcific aortic valve disease (CAVD) is associated with coronary atherosclerosis, it is not known whether early CAVD is associated with coronary microcirculatory dysfunction (CMD). We sought to investigate the relationship between myocardial blood flow reserve (MBFR) - a measure of CMD, and early CAVD in the absence of obstructive epicardial coronary artery disease. We also determined whether this relationship was independent of coronary artery disease (CAD) and hs-CRP, a marker of systemic inflammation. 183 patients with chest pain and unobstructed coronary arteries were studied. Aortic valve calcification score (AVCS), coronary total plaque length (TPL), and coronary calcium score were quantified from multislice CT. MBFR was assessed using vasodilator myocardial contrast echocardiography. Hs-CRP was measured from venous blood using a particle-enhanced immunoassay. Mean (±SD) participant age was 59.8 (9.6) years. Mean AVCS was 68 (258) AU, TPL was 15.6 (22.2) mm, and median coronary calcification score was 43.5AU. Mean MBFR was 2.20 (0.52). Mean hs-CRP was 2.52 (3.86) mg/l. Multivariable linear regression modelling incorporating demographics, coronary plaque characteristics, MBFR, and inflammatory markers, demonstrated that age (β=0.05, 95% CI: 0.02, 0.08, P=0.007), hs-CRP (β=0.09, CI: 0.02, 0.16, P=0.010) and diabetes (β=1.03, CI: 0.08, 1.98, P=0.033), were positively associated with AVCS. MBFR (β=-0.87, CI: -1.44, -0.30, P=0.003), BMI (β=-0.11, CI: -0.21, -0.01, P=0.033), and LDL (β=-0.32, CI: -0.61, -0.03, P=0.029) were negatively associated with AVCS. TPL and coronary calcium score were not independently associated with AVCS when included in the regression model. Coronary microvascular function as determined by measurement of myocardial blood flow reserve is independently associated with early CAVD. This effect is independent of the presence of coronary artery disease and also systemic inflammation. Copyright © 2017 Elsevier B.V. All rights

  1. Automatic circuit analysis based on mask information

    International Nuclear Information System (INIS)

    Preas, B.T.; Lindsay, B.W.; Gwyn, C.W.

    1976-01-01

    The Circuit Mask Translator (CMAT) code has been developed which converts integrated circuit mask information into a circuit schematic. Logical operations, pattern recognition, and special functions are used to identify and interconnect diodes, transistors, capacitors, and resistances. The circuit topology provided by the translator is compatible with the input required for a circuit analysis program

  2. A re-entrant resonator for the measurement of phase boundaries: dew points for {0.4026CH4 + 0.5974C3H8}

    International Nuclear Information System (INIS)

    Kandil, Mohamed E.; Marsh, Kenneth N.; Goodwin, Anthony R.H.

    2005-01-01

    For a natural gas and, especially, retrograde condensates, it is important for exploration and production that the (liquid + gas) phase boundary be known along with the ratio of liquid-to-gas volumes within the (liquid + gas) two-phase region. These fluid properties can be measured by a plethora of methods and here we report a method based on the measurement of the resonance frequency of the lowest order inductive-capacitance mode of a re-entrant cavity capable of operating at temperatures up to 473 K and pressures below 20 MPa. This instrument has been used to measure, at T 4 + 0.5974C 3 H 8 }. The measured dew pressures differ by less than 0.5 % from values obtained by interpolation of those reported in the literature, which were determined from measurements with experimental techniques that suffer from quite different potential sources of systematic error than the radio-frequency resonator used here. Dew pressures estimated from both NIST 14 and the Peng-Robinson equation of state lie within <±1 % of our results at temperature between (315 and 337) K while predictions obtained from the Soave Redlich Kwong cubic equation of state deviate from our results by 0.4 % at T = 315 K and these absolute differences increase smoothly with increasing temperature to be -2.4 % at T = 337 K

  3. Re-entrant lithium local environments and defect driven electrochemistry of Li- and Mn-rich Li-ion battery cathodes.

    Science.gov (United States)

    Dogan, Fulya; Long, Brandon R; Croy, Jason R; Gallagher, Kevin G; Iddir, Hakim; Russell, John T; Balasubramanian, Mahalingam; Key, Baris

    2015-02-18

    Direct observations of structure-electrochemical activity relationships continue to be a key challenge in secondary battery research. (6)Li magic angle spinning (MAS) nuclear magnetic resonance (NMR) spectroscopy is the only structural probe currently available that can quantitatively characterize local lithium environments on the subnanometer scale that dominates the free energy for site occupation in lithium-ion (Li-ion) intercalation materials. In the present study, we use this local probe to gain new insights into the complex electrochemical behavior of activated 0.5(6)Li2MnO3·0.5(6)LiMn(0.5)Ni(0.5)O2, lithium- and manganese-rich transition-metal (TM) oxide intercalation electrodes. We show direct evidence of path-dependent lithium site occupation, correlated to structural reorganization of the metal oxide and the electrochemical hysteresis, during lithium insertion and extraction. We report new (6)Li resonances centered at ∼1600 ppm that are assigned to LiMn6-TM(tet) sites, specifically, a hyperfine shift related to a small fraction of re-entrant tetrahedral TMs (Mn(tet)), located above or below lithium layers, coordinated to LiMn6 units. The intensity of the TM layer lithium sites correlated with tetrahedral TMs loses intensity after cycling, indicating limited reversibility of TM migrations upon cycling. These findings reveal that defect sites, even in dilute concentrations, can have a profound effect on the overall electrochemical behavior.

  4. Nanofluidic Transistor Circuits

    Science.gov (United States)

    Chang, Hsueh-Chia; Cheng, Li-Jing; Yan, Yu; Slouka, Zdenek; Senapati, Satyajyoti

    2012-02-01

    Non-equilibrium ion/fluid transport physics across on-chip membranes/nanopores is used to construct rectifying, hysteretic, oscillatory, excitatory and inhibitory nanofluidic elements. Analogs to linear resistors, capacitors, inductors and constant-phase elements were reported earlier (Chang and Yossifon, BMF 2009). Nonlinear rectifier is designed by introducing intra-membrane conductivity gradient and by asymmetric external depletion with a reverse rectification (Yossifon and Chang, PRL, PRE, Europhys Lett 2009-2011). Gating phenomenon is introduced by functionalizing polyelectrolytes whose conformation is field/pH sensitive (Wang, Chang and Zhu, Macromolecules 2010). Surface ion depletion can drive Rubinstein's microvortex instability (Chang, Yossifon and Demekhin, Annual Rev of Fluid Mech, 2012) or Onsager-Wien's water dissociation phenomenon, leading to two distinct overlimiting I-V features. Bipolar membranes exhibit an S-hysteresis due to water dissociation (Cheng and Chang, BMF 2011). Coupling the hysteretic diode with some linear elements result in autonomous ion current oscillations, which undergo classical transitions to chaos. Our integrated nanofluidic circuits are used for molecular sensing, protein separation/concentration, electrospray etc.

  5. Experimental Device for Learning of Logical Circuit Design using Integrated Circuits

    OpenAIRE

    石橋, 孝昭

    2012-01-01

    This paper presents an experimental device for learning of logical circuit design using integrated circuits and breadboards. The experimental device can be made at a low cost and can be used for many subjects such as logical circuits, computer engineering, basic electricity, electrical circuits and electronic circuits. The proposed device is effective to learn the logical circuits than the usual lecture.

  6. Variational integrators for electric circuits

    International Nuclear Information System (INIS)

    Ober-Blöbaum, Sina; Tao, Molei; Cheng, Mulin; Owhadi, Houman; Marsden, Jerrold E.

    2013-01-01

    In this contribution, we develop a variational integrator for the simulation of (stochastic and multiscale) electric circuits. When considering the dynamics of an electric circuit, one is faced with three special situations: 1. The system involves external (control) forcing through external (controlled) voltage sources and resistors. 2. The system is constrained via the Kirchhoff current (KCL) and voltage laws (KVL). 3. The Lagrangian is degenerate. Based on a geometric setting, an appropriate variational formulation is presented to model the circuit from which the equations of motion are derived. A time-discrete variational formulation provides an iteration scheme for the simulation of the electric circuit. Dependent on the discretization, the intrinsic degeneracy of the system can be canceled for the discrete variational scheme. In this way, a variational integrator is constructed that gains several advantages compared to standard integration tools for circuits; in particular, a comparison to BDF methods (which are usually the method of choice for the simulation of electric circuits) shows that even for simple LCR circuits, a better energy behavior and frequency spectrum preservation can be observed using the developed variational integrator

  7. Integrated circuits, and design and manufacture thereof

    Science.gov (United States)

    Auracher, Stefan; Pribbernow, Claus; Hils, Andreas

    2006-04-18

    A representation of a macro for an integrated circuit layout. The representation may define sub-circuit cells of a module. The module may have a predefined functionality. The sub-circuit cells may include at least one reusable circuit cell. The reusable circuit cell may be configured such that when the predefined functionality of the module is not used, the reusable circuit cell is available for re-use.

  8. Radiation-sensitive switching circuits

    Energy Technology Data Exchange (ETDEWEB)

    Moore, J.H.; Cockshott, C.P.

    1976-03-16

    A radiation-sensitive switching circuit includes a light emitting diode which from time to time illuminates a photo-transistor, the photo-transistor serving when its output reaches a predetermined value to operate a trigger circuit. In order to allow for aging of the components, the current flow through the diode is increased when the output from the transistor falls below a known level. Conveniently, this is achieved by having a transistor in parallel with the diode, and turning the transistor off when the output from the phototransistor becomes too low. The circuit is designed to control the ignition system in an automobile engine.

  9. The Maplin electronic circuits handbook

    CERN Document Server

    Tooley, Michael

    1990-01-01

    The Maplin Electronic Circuits Handbook provides pertinent data, formula, explanation, practical guidance, theory and practical guidance in the design, testing, and construction of electronic circuits. This book discusses the developments in electronics technology techniques.Organized into 11 chapters, this book begins with an overview of the common types of passive component. This text then provides the reader with sufficient information to make a correct selection of passive components for use in the circuits. Other chapters consider the various types of the most commonly used semiconductor

  10. Secure integrated circuits and systems

    CERN Document Server

    Verbauwhede, Ingrid MR

    2010-01-01

    On any advanced integrated circuit or 'system-on-chip' there is a need for security. In many applications the actual implementation has become the weakest link in security rather than the algorithms or protocols. The purpose of the book is to give the integrated circuits and systems designer an insight into the basics of security and cryptography from the implementation point of view. As a designer of integrated circuits and systems it is important to know both the state-of-the-art attacks as well as the countermeasures. Optimizing for security is different from optimizations for speed, area,

  11. INTEGRATED SENSOR EVALUATION CIRCUIT AND METHOD FOR OPERATING SAID CIRCUIT

    OpenAIRE

    Krüger, Jens; Gausa, Dominik

    2015-01-01

    WO15090426A1 Sensor evaluation device and method for operating said device Integrated sensor evaluation circuit for evaluating a sensor signal (14) received from a sensor (12), having a first connection (28a) for connection to the sensor and a second connection (28b) for connection to the sensor. The integrated sensor evaluation circuit comprises a configuration data memory (16) for storing configuration data which describe signal properties of a plurality of sensor control signals (26a-c). T...

  12. Quantum circuit behaviour

    International Nuclear Information System (INIS)

    Poulton, D.

    1989-09-01

    Single electron tunnelling in multiply connected weak link systems is considered. Using a second quantised approach the tunnel current, in both normal and superconducting systems, using perturbation theory, is derived. The tunnel currents are determined as a function of an Aharanov-Bohm phase (acquired by the electrons). Using these results, the multiply connected system is then discussed when coupled to a resonant LC circuit. The resulting dynamics of this composite system are then determined. In the superconducting case the results are compared and contrasted with flux mode behaviour seen in large superconducting weak link rings. Systems in which the predicted dynamics may be seen are also discussed. In analogy to the electron tunnelling analysis, the tunnelling of magnetic flux quanta through the weak link is also considered. Here, the voltage across the weak link, due to flux tunnelling, is determined as a function of an externally applied current. This is done for both singly and multiply connected flux systems. The results are compared and contrasted with charge mode behaviour seen in superconducting weak link systems. Finally, the behaviour of simple quantum fluids is considered when subject to an external rotation. Using a microscopic analysis it is found that the microscopic quantum behaviour of the particles is manifest on a macroscopic level. Results are derived for bosonic, fermionic and BCS pair-type systems. The connection between flux quantisation in electromagnetic systems is also made. Using these results, the dynamics of such a quantum fluid is considered when coupled to a rotating torsional oscillator. The results are compared with those found in SQUID devices. A model is also presented which discusses the possible excited state dynamics of such a fluid. (author)

  13. Transistor and integrated circuit manufacture

    International Nuclear Information System (INIS)

    Colman, D.

    1978-01-01

    This invention relates to the manufacture of transistors and integrated circuits by ion bombardment techniques and is particularly, but not exclusively, of value in the manufacture of so-called integrated injection logic circuitry. (author)

  14. Time domain analog circuit simulation

    NARCIS (Netherlands)

    Fijnvandraat, J.G.; Houben, S.H.M.J.; Maten, ter E.J.W.; Peters, J.M.F.

    2006-01-01

    Recent developments of new methods for simulating electric circuits are described. Emphasis is put on methods that fit existing datastructures for backward differentiation formulae methods. These methods can be modified to apply to hierarchically organized datastructures, which allows for efficient

  15. Circuit design on plastic foils

    CERN Document Server

    Raiteri, Daniele; Roermund, Arthur H M

    2015-01-01

    This book illustrates a variety of circuit designs on plastic foils and provides all the information needed to undertake successful designs in large-area electronics.  The authors demonstrate architectural, circuit, layout, and device solutions and explain the reasons and the creative process behind each. Readers will learn how to keep under control large-area technologies and achieve robust, reliable circuit designs that can face the challenges imposed by low-cost low-temperature high-throughput manufacturing.   • Discusses implications of problems associated with large-area electronics and compares them to standard silicon; • Provides the basis for understanding physics and modeling of disordered material; • Includes guidelines to quickly setup the basic CAD tools enabling efficient and reliable designs; • Illustrates practical solutions to cope with hard/soft faults, variability, mismatch, aging and bias stress at architecture, circuit, layout, and device levels.

  16. Discharge quenching circuit for counters

    International Nuclear Information System (INIS)

    Karasik, A.S.

    1982-01-01

    A circuit for quenching discharges in gas-discharge detectors with working voltage of 3-5 kV based on transistors operating in the avalanche mode is described. The quenching circuit consists of a coordinating emitter follower, amplifier-shaper for avalanche key cascade control which changes potential on the counter electrodes and a shaper of discharge quenching duration. The emitter follower is assembled according to a widely used flowsheet with two transistors. The circuit permits to obtain a rectangular quenching pulse with front of 100 ns and an amplitude of up to 3.2 kV at duration of 500 μm-8 ms. Application of the quenching circuit described permits to obtain countering characteristics with the slope less than or equal to 0.02%/V and plateau extent greater than or equal to 300 V [ru

  17. Transistor and integrated circuit manufacture

    Energy Technology Data Exchange (ETDEWEB)

    Colman, D

    1978-09-27

    This invention relates to the manufacture of transistors and integrated circuits by ion bombardment techniques and is particularly, but not exclusively, of value in the manufacture of so-called integrated injection logic circuitry.

  18. Ignition circuit for combustion engines

    Energy Technology Data Exchange (ETDEWEB)

    Becker, H W

    1977-05-26

    The invention refers to the ignition circuit for combustion engines, which are battery fed. The circuit contains a transistor and an oscillator to produce an output voltage on the secondary winding of an output transformer to supply an ignition current. The plant is controlled by an interrupter. The purpose of the invention is to form such a circuit that improved sparks for ignition are produced, on the one hand, and that on the other hand, the plant can continue to function after loss of the oscillator. The problem is solved by the battery and the secondary winding of the output transformers of the oscillator are connected via a rectifier circuit to produce a resultant total voltage with the ignition coil from the battery voltage and the rectified pulsating oscillator output.

  19. Reverse engineering of integrated circuits

    Science.gov (United States)

    Chisholm, Gregory H.; Eckmann, Steven T.; Lain, Christopher M.; Veroff, Robert L.

    2003-01-01

    Software and a method therein to analyze circuits. The software comprises several tools, each of which perform particular functions in the Reverse Engineering process. The analyst, through a standard interface, directs each tool to the portion of the task to which it is most well suited, rendering previously intractable problems solvable. The tools are generally used iteratively to produce a successively more abstract picture of a circuit, about which incomplete a priori knowledge exists.

  20. Is the epicardial left ventricular lead implantation an alternative approach to percutaneous attempt in patients with Steinert disease? A case report

    Science.gov (United States)

    PAPA, ANDREA ANTONIO; RAGO, ANNA; PETILLO, ROBERTA; D’AMBROSIO, PAOLA; SCUTIFERO, MARIANNA; FEO, MARISA DE; MAIELLO, CIRO; PALLADINO, ALBERTO

    2017-01-01

    Steinert’s disease or Myotonic Dystrophy type 1 (DM1) is an autosomal dominant multisystemic disorder characterized by myotonia, muscle and facial weakness, cataracts, cognitive, endocrine and gastrointestinal involvement, and cardiac conduction abnormalities. Although mild myocardial dysfunction may be detected in this syndrome with age, overt myocardial dysfunction with heart failure is not frequent. Cardiac resynchronization therapy is an effective treatment to improve morbidity and reduce mortality in patients with DM1 showing intra-ventricular conduction delay and/or congestive heart failure. We report the case of a patient with Steinert disease showing an early onset ventricular dysfunction due to chronic right ventricular apical pacing, in which an epicardial left ventricular lead implantation was performed following the failure of the percutaneous attempt. As no relief in symptoms of heart failure, nor an improvement of left ventricular ejection fraction and reverse remodelling was observed six months later, the patient was addressed to the heart transplantation.

  1. Receiver Gain Modulation Circuit

    Science.gov (United States)

    Jones, Hollis; Racette, Paul; Walker, David; Gu, Dazhen

    2011-01-01

    A receiver gain modulation circuit (RGMC) was developed that modulates the power gain of the output of a radiometer receiver with a test signal. As the radiometer receiver switches between calibration noise references, the test signal is mixed with the calibrated noise and thus produces an ensemble set of measurements from which ensemble statistical analysis can be used to extract statistical information about the test signal. The RGMC is an enabling technology of the ensemble detector. As a key component for achieving ensemble detection and analysis, the RGMC has broad aeronautical and space applications. The RGMC can be used to test and develop new calibration algorithms, for example, to detect gain anomalies, and/or correct for slow drifts that affect climate-quality measurements over an accelerated time scale. A generalized approach to analyzing radiometer system designs yields a mathematical treatment of noise reference measurements in calibration algorithms. By treating the measurements from the different noise references as ensemble samples of the receiver state, i.e. receiver gain, a quantitative description of the non-stationary properties of the underlying receiver fluctuations can be derived. Excellent agreement has been obtained between model calculations and radiometric measurements. The mathematical formulation is equivalent to modulating the gain of a stable receiver with an externally generated signal and is the basis for ensemble detection and analysis (EDA). The concept of generating ensemble data sets using an ensemble detector is similar to the ensemble data sets generated as part of ensemble empirical mode decomposition (EEMD) with exception of a key distinguishing factor. EEMD adds noise to the signal under study whereas EDA mixes the signal with calibrated noise. It is mixing with calibrated noise that permits the measurement of temporal-functional variability of uncertainty in the underlying process. The RGMC permits the evaluation of EDA by

  2. Coronary microembolization with normal epicardial coronary arteries and no visible infarcts on nitrobluetetrazolium chloride-stained specimens: Evaluation with cardiac magnetic resonance imaging in a swine model

    Energy Technology Data Exchange (ETDEWEB)

    Jin, Hang; Yun, Hong; Zeng, Meng Su [Dept. of Radiology, Zhongshan Hospital, Fudan University and Shanghai Institute of Medical Imaging, Shanghai (China); Ma, Jian Ying; Chen, Zhang Wei; Chang, Shu Fu [Dept. of Cardiology, Zhongshan Hospital, Fudan University and Shanghai Institute of Cardiovascular Diseases, Shanghai (China)

    2016-02-15

    To assess magnetic resonance imaging (MRI) features of coronary microembolization in a swine model induced by small-sized microemboli, which may cause microinfarcts invisible to the naked eye. Eleven pigs underwent intracoronary injection of small-sized microspheres (42 µm) and catheter coronary angiography was obtained before and after microembolization. Cardiac MRI and measurement of cardiac troponin T (cTnT) were performed at baseline, 6 hours, and 1 week after microembolization. Postmortem evaluation was performed after completion of the imaging studies. Coronary angiography pre- and post-microembolization revealed normal epicardial coronary arteries. Systolic wall thickening of the microembolized regions decreased significantly from 42.6 ± 2.0% at baseline to 20.3 ± 2.3% at 6 hours and 31.5 ± 2.1% at 1 week after coronary microembolization (p < 0.001 for both). First-pass perfusion defect was visualized at 6 hours but the extent was largely decreased at 1 week. Delayed contrast enhancement MRI (DE-MRI) demonstrated hyperenhancement within the target area at 6 hours but not at 1 week. The microinfarcts on gross specimen stained with nitrobluetetrazolium chloride were invisible to the naked eye and only detectable microscopically. Increased cTnT was observed at 6 hours and 1 week after microembolization. Coronary microembolization induced by a certain load of small-sized microemboli may result in microinfarcts invisible to the naked eye with normal epicardial coronary arteries. MRI features of myocardial impairment secondary to such microembolization include the decline in left ventricular function and myocardial perfusion at cine and first-pass perfusion imaging, and transient hyperenhancement at DE-MRI.

  3. Cardiac magnetic resonance based evaluation of aortic stiffness and epicardial fat volume in patients with hypertension, diabetes mellitus, and myocardial infarction.

    Science.gov (United States)

    Homsi, Rami; Sprinkart, Alois M; Gieseke, Juergen; Meier-Schroers, Michael; Yuecel, Seyrani; Fischer, Stefan; Nadal, Jennifer; Dabir, Darius; Luetkens, Julian A; Kuetting, Daniel L; Schild, Hans H; Thomas, Daniel K

    2018-01-01

    Background Aortic stiffness and epicardial fat relate to cardiovascular risk. Their relationship with each other and their role with hypertension, diabetes mellitus (DM), and myocardial infarction (MI) can be evaluated by cardiac magnetic resonance (CMR). Purpose To explore an association between aortic stiffness and epicardial as well as paracardial fat volume (EFV and ParaFV, respectively) in hypertensive patients and to relate the results to the presence of DM and MI. Material and Methods A total of 156 hypertensive and 20 non-hypertensive participants were examined at 1.5 Tesla. A 2D-velocity-encoded sequence was acquired to assess aortic pulse wave velocity (PWV in m/s) as a measure of aortic stiffness. A 3D-Dixon sequence was used to determine EFV and ParaFV. Results PWV correlated with EFV (R = 0.474; P hypertensive controls compared to hypertensive patients. EFV and PWV were significantly higher in diabetic hypertensive patients without MI (n = 19; PWV: 10.4 ± 2.9; EFV: 92.5 ± 19.3) compared to hypertension-only patients (n = 84 [no DM or MI]; EFV: 64.8 ± 25.1, PWV: 9.0 ± 2.6; P hypertensive patients. Both were increased in the presence of DM; however, only EFV was increased in the presence of MI. This may relate to the PWV lowering effect of the antihypertensive medication used by hypertensive patients and underscores the benefit of EFV assessment in this regard.

  4. Epicardial fat thickness in stable coronary artery disease: its relationship with high-sensitive cardiac troponin T and N-terminal pro-brain natriuretic peptide.

    Science.gov (United States)

    Börekçi, Abdurrezzak; Gür, Mustafa; Özaltun, Betül; Baykan, Ahmet Oytun; Harbalioğlu, Hazar; Seker, Taner; Sen, Ömer; Acele, Armağan; Gözükara, Mehmet Yavuz; Kuloğlu, Osman; Koç, Mevlüt; Çayli, Murat

    2014-12-01

    Epicardial adipose tissue is related to coronary atherosclerosis, left ventricle hypertrophy, myocardial dysfunction, cardiomyopathy, and inflammation, which produces a variety of cytokines that influence key pathogenic mechanisms of atherogenesis. The main goal of this study is to examine the relationship between epicardial fat thickness (EFT) and cardiovascular risk markers as well as the complexity of coronary artery disease (CAD) in patients with stable CAD. We prospectively included 439 stable CAD patients undergoing coronary angiography in the present study (mean age: 62.2±10.7 years). Patients were divided into two groups (EFTlow and EFThigh groups) according to their median EFT values. EFT was evaluated by two-dimensional echocardiography before angiography. The SYNTAX score was calculated in all patients. N-terminal pro-brain natriuretic peptide (NT-proBNP), high-sensitive C-reactive protein (hs-CRP), high-sensitive cardiac troponin T (hs-cTnT), uric acid, and other biochemical markers were also measured. Age, SYNTAX score, frequencies of diabetes, hyperlipidemia, and hypertension, NT-proBNP, hs-CRP, hs-cTnT, and uric acid levels were higher in EFThigh group compared with the EFTlow group (P<0.05 for all). EFT was associated independently with age (β=-0.102, P=0.001), diabetes (β=-0.083, P=0.011), SYNTAX score (β=0.352, P<0.001), hs-CRP level (β=0.217, P<0.001), hs-cTnT level (β=0.197, P<0.001), and NT-proBNP level (β=0.300, P<0.001) in multivariate analysis. EFT obtained by echocardiograpy may not only be an easy tool but also an important tool for early detection of increased cardiac risk as well as the extent and complexity of CAD in patients with stable CAD.

  5. Gender-linked impact of epicardial adipose tissue volume in patients who underwent coronary artery bypass graft surgery or non-coronary valve surgery.

    Directory of Open Access Journals (Sweden)

    Gulinu Maimaituxun

    Full Text Available Traditional and non-traditional risk factors for atherosclerotic cardiovascular disease (ASCVD are different between men and women. Gender-linked impact of epicardial adipose tissue volume (EATV in patients undergoing coronary artery bypass grafting (CABG remains unknown.Gender-linked impact of EATV, abdominal fat distribution and other traditional ASCVD risk factors were compared in 172 patients (men: 115; women: 57 who underwent CABG or non-coronary valvular surgery (non-CABG.In men, EATV, EATV index (EATV/body surface area and the markers of adiposity such as body mass index, waist circumference and visceral fat area were higher in the CABG group than in the non-CABG group. Traditional ASCVD risk factors were also prevalent in the CABG group. In women, EATV and EATV index were higher in the CABG group, but other adiposity markers were comparable between CABG and non-CABG groups. Multivariate logistic regression analysis showed that in men, CABG was determined by EATV Index and other ASCVD risk factors including hypertension, dyslipidemia, adiponectin, high sensitive C-reactive protein (hsCRP and type 2 diabetes mellitus (Corrected R2 = 0.262, p < 0.0001, while in women, type 2 diabetes mellitus is a single strong predictor for CABG, excluding EATV Index (Corrected R2 = 0.266, p = 0.005.Our study found that multiple risk factors, including epicardial adipose tissue volume and traditional ASCVD factors are determinants for CABG in men, but type 2 diabetes mellitus was the sole determinant in women. Gender-specific disparities in risk factors of CABG prompt us to evaluate new diagnostic and treatment strategies and to seek underlying mechanisms.

  6. Gender-linked impact of epicardial adipose tissue volume in patients who underwent coronary artery bypass graft surgery or non-coronary valve surgery.

    Science.gov (United States)

    Maimaituxun, Gulinu; Shimabukuro, Michio; Salim, Hotimah Masdan; Tabata, Minoru; Yuji, Daisuke; Morimoto, Yoshihisa; Akasaka, Takeshi; Matsuura, Tomomi; Yagi, Shusuke; Fukuda, Daiju; Yamada, Hirotsugu; Soeki, Takeshi; Sugimoto, Takaki; Tanaka, Masashi; Takanashi, Shuichiro; Sata, Masataka

    2017-01-01

    Traditional and non-traditional risk factors for atherosclerotic cardiovascular disease (ASCVD) are different between men and women. Gender-linked impact of epicardial adipose tissue volume (EATV) in patients undergoing coronary artery bypass grafting (CABG) remains unknown. Gender-linked impact of EATV, abdominal fat distribution and other traditional ASCVD risk factors were compared in 172 patients (men: 115; women: 57) who underwent CABG or non-coronary valvular surgery (non-CABG). In men, EATV, EATV index (EATV/body surface area) and the markers of adiposity such as body mass index, waist circumference and visceral fat area were higher in the CABG group than in the non-CABG group. Traditional ASCVD risk factors were also prevalent in the CABG group. In women, EATV and EATV index were higher in the CABG group, but other adiposity markers were comparable between CABG and non-CABG groups. Multivariate logistic regression analysis showed that in men, CABG was determined by EATV Index and other ASCVD risk factors including hypertension, dyslipidemia, adiponectin, high sensitive C-reactive protein (hsCRP) and type 2 diabetes mellitus (Corrected R2 = 0.262, p EATV Index (Corrected R2 = 0.266, p = 0.005). Our study found that multiple risk factors, including epicardial adipose tissue volume and traditional ASCVD factors are determinants for CABG in men, but type 2 diabetes mellitus was the sole determinant in women. Gender-specific disparities in risk factors of CABG prompt us to evaluate new diagnostic and treatment strategies and to seek underlying mechanisms.

  7. Sensitivity of reentrant driver localization to electrophysiological parameter variability in image-based computational models of persistent atrial fibrillation sustained by a fibrotic substrate

    Science.gov (United States)

    Deng, Dongdong; Murphy, Michael J.; Hakim, Joe B.; Franceschi, William H.; Zahid, Sohail; Pashakhanloo, Farhad; Trayanova, Natalia A.; Boyle, Patrick M.

    2017-09-01

    Atrial fibrillation (AF) is the most common sustained cardiac arrhythmia, causing morbidity and mortality in millions worldwide. The atria of patients with persistent AF (PsAF) are characterized by the presence of extensive and distributed atrial fibrosis, which facilitates the formation of persistent reentrant drivers (RDs, i.e., spiral waves), which promote fibrillatory activity. Targeted catheter ablation of RD-harboring tissues has shown promise as a clinical treatment for PsAF, but the outcomes remain sub-par. Personalized computational modeling has been proposed as a means of non-invasively predicting optimal ablation targets in individual PsAF patients, but it remains unclear how RD localization dynamics are influenced by inter-patient variability in the spatial distribution of atrial fibrosis, action potential duration (APD), and conduction velocity (CV). Here, we conduct simulations in computational models of fibrotic atria derived from the clinical imaging of PsAF patients to characterize the sensitivity of RD locations to these three factors. We show that RDs consistently anchor to boundaries between fibrotic and non-fibrotic tissues, as delineated by late gadolinium-enhanced magnetic resonance imaging, but those changes in APD/CV can enhance or attenuate the likelihood that an RD will anchor to a specific site. These findings show that the level of uncertainty present in patient-specific atrial models reconstructed without any invasive measurements (i.e., incorporating each individual's unique distribution of fibrotic tissue from medical imaging alongside an average representation of AF-remodeled electrophysiology) is sufficiently high that a personalized ablation strategy based on targeting simulation-predicted RD trajectories alone may not produce the desired result.

  8. Spectral Purity Enhancement via Polyphase Multipath Circuits

    NARCIS (Netherlands)

    Mensink, E.; Klumperink, Eric A.M.; Nauta, Bram

    2004-01-01

    The central question of this paper is: can we enhance the spectral purity of nonlinear circuits by using polyphase multipath circuits? The basic idea behind polyphase multipath circuits is to split the nonlinear circuits into two or more paths and exploit phase differences between these paths to

  9. Distortion Cancellation via Polyphase Multipath Circuits

    NARCIS (Netherlands)

    Mensink, E.; Klumperink, Eric A.M.; Nauta, Bram

    The central question of this paper is: can we enhance the spectral purity of nonlinear circuits with the help of polyphase multipath circuits. Polyphase multipath circuits are circuits with two or more paths that exploit phase differences between the paths to cancel unwanted signals. It turns out

  10. Dynamic theory for the mesoscopic electric circuit

    International Nuclear Information System (INIS)

    Chen Bin; Shen Xiaojuan; Li Youquan; Sun LiLy; Yin Zhujian

    2005-01-01

    The quantum theory for mesoscopic electric circuit with charge discreteness is briefly described. The minibands of quasienergy in LC design mesoscopic electric circuit have been found. In the mesoscopic 'pure' inductance design circuit, just like in the mesoscopic metallic rings, the quantum dynamic characteristics have been obtained explicitly. In the 'pure' capacity design circuit, the Coulomb blockade had also been addressed

  11. Multi-Layer E-Textile Circuits

    Science.gov (United States)

    Dunne, Lucy E.; Bibeau, Kaila; Mulligan, Lucie; Frith, Ashton; Simon, Cory

    2012-01-01

    Stitched e-textile circuits facilitate wearable, flexible, comfortable wearable technology. However, while stitched methods of e-textile circuits are common, multi-layer circuit creation remains a challenge. Here, we present methods of stitched multi-layer circuit creation using accessible tools and techniques.

  12. Instrumentation and test gear circuits manual

    CERN Document Server

    Marston, R M

    2013-01-01

    Instrumentation and Test Gear Circuits Manual provides diagrams, graphs, tables, and discussions of several types of practical circuits. The practical circuits covered in this book include attenuators, bridges, scope trace doublers, timebases, and digital frequency meters. Chapter 1 discusses the basic instrumentation and test gear principles. Chapter 2 deals with the design of passive attenuators, and Chapter 3 with passive and active filter circuits. The subsequent chapters tackle 'bridge' circuits, analogue and digital metering techniques and circuitry, signal and waveform generation, and p

  13. Logic circuits from zero forcing.

    Science.gov (United States)

    Burgarth, Daniel; Giovannetti, Vittorio; Hogben, Leslie; Severini, Simone; Young, Michael

    We design logic circuits based on the notion of zero forcing on graphs; each gate of the circuits is a gadget in which zero forcing is performed. We show that such circuits can evaluate every monotone Boolean function. By using two vertices to encode each logical bit, we obtain universal computation. We also highlight a phenomenon of "back forcing" as a property of each function. Such a phenomenon occurs in a circuit when the input of gates which have been already used at a given time step is further modified by a computation actually performed at a later stage. Finally, we show that zero forcing can be also used to implement reversible computation. The model introduced here provides a potentially new tool in the analysis of Boolean functions, with particular attention to monotonicity. Moreover, in the light of applications of zero forcing in quantum mechanics, the link with Boolean functions may suggest a new directions in quantum control theory and in the study of engineered quantum spin systems. It is an open technical problem to verify whether there is a link between zero forcing and computation with contact circuits.

  14. Installations having pressurised fluid circuits

    International Nuclear Information System (INIS)

    Rigg, S.; Grant, J.

    1977-01-01

    Reference is made to nuclear installations having pressurised coolant flow circuits. Breaches in such circuits may quickly result in much damage to the plant. Devices such as non-return valves, orifice plates, and automatically operated shut-off valves have been provided to prevent or reduce fluid flow through a breached pipe line, but such devices have several disadvantages; they may present large restrictions to normal flow of coolant, and may depend on the operation of ancillary equipment, with consequent delay in bringing them into operation in an emergency. Other expedients that have been adopted to prevent or reduce reverse flow through an upstream breach comprise various forms of hydraulic counter flow brakes. The arrangement described has at least one variable fluid brake comprising a fluidic device connected into a duct in the pressurised circuit, the device having an inlet, an outlet, a vortex chamber between the inlet and outlet, a control jet for introducing fluid into the vortex chamber, connections communicating the inlet and the outlet into one part of the circuit and the control jet into another region at a complementary pressure so that, in the event of a breach in the circuit in one region, fluid passes from the other region to enter the vortex chamber to stimulate pressure to create a flow restricting vortex in the chamber that reduces flow through the breach. The system finds particular application to stream generating pressure tube reactors, such as the steam generating heavy water reactor at UKAEA, Winfrith. (U.K.)

  15. 30 CFR 75.601-1 - Short circuit protection; ratings and settings of circuit breakers.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Short circuit protection; ratings and settings... Trailing Cables § 75.601-1 Short circuit protection; ratings and settings of circuit breakers. Circuit breakers providing short circuit protection for trailing cables shall be set so as not to exceed the...

  16. 30 CFR 77.506 - Electric equipment and circuits; overload and short-circuit protection.

    Science.gov (United States)

    2010-07-01

    ... short-circuit protection. 77.506 Section 77.506 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION... circuits; overload and short-circuit protection. Automatic circuit-breaking devices or fuses of the correct type and capacity shall be installed so as to protect all electric equipment and circuits against short...

  17. 30 CFR 75.518 - Electric equipment and circuits; overload and short circuit protection.

    Science.gov (United States)

    2010-07-01

    ... short circuit protection. 75.518 Section 75.518 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION... Equipment-General § 75.518 Electric equipment and circuits; overload and short circuit protection... installed so as to protect all electric equipment and circuits against short circuit and overloads. Three...

  18. Type A Wolff-Parkinson-White Syndrome Generating an Antidromic Atrioventricular (AV Reentrant Tachycardia (AVRT and an Orthodromic AVRT with a Long RP Interval Initiated only after Incomplete Impairment of an AV Accessory Pathway

    Directory of Open Access Journals (Sweden)

    Kazushi Tanaka, MD PhD

    2011-01-01

    Full Text Available We report on a case of a 23-year-old male with Wolff-Parkinson-White syndrome. At baseline, constant right atrial pacing induced antidromic atrioventricular reentrant tachycardia (AVRT, whereas constant right ventricular (RV pacing only revealed a normal His-Purkinje system. Mapping below the mitral annulus during sinus rhythm revealed fusion of atrial and ventricular potentials at multiple lateral sites. After unsuccessful ablation at these sites, constant RV pacing induced a long RP interval, orthodromic AVRT with the earliest atrial site being located at an anterior aspect, where successful ablation was later achieved. These phenomena may indicate an unexpected arrhythmogenic effect of initial ablations.

  19. In-field X-ray and neutron diffraction studies of re-entrant charge-ordering and field induced metastability in La0.175Pr0.45Ca0.375MnO3-δ

    Science.gov (United States)

    Sharma, Shivani; Shahee, Aga; Yadav, Poonam; da Silva, Ivan; Lalla, N. P.

    2017-11-01

    Low-temperature high-magnetic field (2 K, 8 T) (LTHM) powder X-ray diffraction (XRD) and time of flight powder neutron diffraction (NPD), low-temperature transmission electron microscopic (TEM), and resistivity and magnetization measurements have been carried out to investigate the re-entrant charge ordering (CO), field induced structural phase transitions, and metastability in phase-separated La0.175Pr0.45Ca0.375MnO3-δ (LPCMO). Low-temperature TEM and XRD studies reveal that on cooling under zero-field, paramagnetic Pnma phase transforms to P21/m CO antiferromagnetic (AFM) insulating phase below ˜233 K. Unlike reported literature, no structural signature of CO AFM P21/m to ferromagnetic (FM) Pnma phase-transition during cooling down to 2 K under zero-field was observed. However, the CO phase was found to undergo a re-entrant transition at ˜40 K. Neutron diffraction studies revealed a pseudo CE type spin arrangement of the observed CO phase. The low-temperature resistance, while cooled under zero-field, shows insulator to metal like transition below ˜105 K with minima at ˜25 K. On application of field, the CO P21/m phase was found to undergo field-induced transition to FM Pnma phase, which shows irreversibility on field removal below ˜40 K. Zero-field warming XRD and NPD studies reveal that field-induced FM Pnma phase is a metastable phase, which arise due to the arrest of kinetics of the first-order phase transition of FM Pnma to CO-AFM P21/m phase, below 40 K. Thus, a strong magneto-structural coupling is observed for this system. A field-temperature (H-T) phase-diagram has been constructed based on the LTHM-XRD, which matches very nicely with the reported H-T phase-diagram constructed based on magnetic measurements. Due to the occurrence of gradual growth of the re-entrant CO phase and the absence of a clear structural signature of phase-separation of CO-AFM P21/m and FM Pnma phases, the H-T minima in the phase-diagram of the present LPCMO sample has been

  20. Interpretation of specific-heat and spontaneous-magnetization anomalies at the reentrant superconducting - ferromagnetic transition in (Ho0.6Er0.4)Rh4B4

    International Nuclear Information System (INIS)

    Woolf, L.D.; Johnston, D.C.; Mook, H.A.; Koehler, W.C.; Maple, M.B.; Fisk, Z.

    1981-09-01

    Analysis of neutron-diffraction data on the compound (Ho 0 . 6 Er 0 . 4 )Rh 4 B 4 indicates that the Curie temperature is depressed by about 0.2 K due to the occurrence of superconductivity, in agreement with theoretical predictions. The temperature dependence of the specific heat in the vicinity of the first-order reentrant superconducting - ferromagnetic transition was computed by means of a simple model from the temperature dependence of the spontaneous magnetization of the Ho ions and was found to be in good agreement with the experimental data

  1. Multiplication circuit for particle identification

    International Nuclear Information System (INIS)

    Gerlier, Jean

    1962-01-01

    After having commented some characteristics of the particles present in a cyclotron, and their interactions, this report addresses the development and the implementation of a method and a device for selecting and counting particles. The author presents the principle and existing techniques of selection. In comparison with an existing device, the proportional counter and the scintillator are replaced by junctions: a surface barrier type junction (a silicon N layer with a very thin oxygen layer playing the role of the P layer), and lithium-based junction (a silicon P type layer made intrinsic by migration of lithium). The author then describes the developed circuit and assembly (background of the choice of a multiplication circuit), and their operation. In the next part, he presents the performed tests and discuses the obtained results. He finally outlines the benefits of the herein presented circuit [fr

  2. Wiring of electronic evaluation circuits

    International Nuclear Information System (INIS)

    Bauer, R.; Svoboda, Z.

    1977-01-01

    The wiring is described of electronic evaluation circuits for the automatic viewing of photographic paper strip negatives on which line tracks with an angular scatter relative to the spectrograph longitudinal axis were recorded during the oblique flight of nuclear particles during exposure in the spectrograph. In coincidence evaluation, the size of the angular scatter eventually requires that evaluation dead time be increased. The equipment consists of minimally two fixed registers and a block of logic circuits whose output is designed such as will allow connection to equipment for recording signals corresponding to the number of tracks on the film. The connection may be implemented using integrated circuits guaranteeing high operating reliability and life. (J.B.)

  3. Counterpulse railgun energy recovery circuit

    International Nuclear Information System (INIS)

    Honig, E.M.

    1986-01-01

    This patent describes a counterpulse railgun energy recovery circuit for propelling a projectile along a railgun the counterpulse railgun energy recovery circuit consists of: a railgun having an effective inductance; a source inductor initially charged to an initial current; current means for initially charging the source inductor to the initial current; first current-zero type switching means; second current-zero type switching; third current-zero type switching; muzzle current-zero type switching means; transfer capacitor, the transfer capacitor is for cooperating with the first, second, third, and muzzle current-zero type switching means for providing a resonant circuit for transferring current from the source inductor to the effective inductance of the railgun during the propelling of a projectile along the railgun and for returning current from the effective inductance of the railgun to the source inductance after the projectile has exited the railgun

  4. Vertically Integrated Circuits at Fermilab

    International Nuclear Information System (INIS)

    Deptuch, Grzegorz; Demarteau, Marcel; Hoff, James; Lipton, Ronald; Shenai, Alpana; Trimpl, Marcel; Yarema, Raymond; Zimmerman, Tom

    2009-01-01

    The exploration of the vertically integrated circuits, also commonly known as 3D-IC technology, for applications in radiation detection started at Fermilab in 2006. This paper examines the opportunities that vertical integration offers by looking at various 3D designs that have been completed by Fermilab. The emphasis is on opportunities that are presented by through silicon vias (TSV), wafer and circuit thinning and finally fusion bonding techniques to replace conventional bump bonding. Early work by Fermilab has led to an international consortium for the development of 3D-IC circuits for High Energy Physics. The consortium has submitted over 25 different designs for the Fermilab organized MPW run organized for the first time.

  5. Fermionic models with superconducting circuits

    Energy Technology Data Exchange (ETDEWEB)

    Las Heras, Urtzi; Garcia-Alvarez, Laura; Mezzacapo, Antonio; Lamata, Lucas [University of the Basque Country UPV/EHU, Department of Physical Chemistry, Bilbao (Spain); Solano, Enrique [University of the Basque Country UPV/EHU, Department of Physical Chemistry, Bilbao (Spain); IKERBASQUE, Basque Foundation for Science, Bilbao (Spain)

    2015-12-01

    We propose a method for the efficient quantum simulation of fermionic systems with superconducting circuits. It consists in the suitable use of Jordan-Wigner mapping, Trotter decomposition, and multiqubit gates, be with the use of a quantum bus or direct capacitive couplings. We apply our method to the paradigmatic cases of 1D and 2D Fermi-Hubbard models, involving couplings with nearest and next-nearest neighbours. Furthermore, we propose an optimal architecture for this model and discuss the benchmarking of the simulations in realistic circuit quantum electrodynamics setups. (orig.)

  6. Circuit modeling for electromagnetic compatibility

    CERN Document Server

    Darney, Ian B

    2013-01-01

    Very simply, electromagnetic interference (EMI) costs money, reduces profits, and generally wreaks havoc for circuit designers in all industries. This book shows how the analytic tools of circuit theory can be used to simulate the coupling of interference into, and out of, any signal link in the system being reviewed. The technique is simple, systematic and accurate. It enables the design of any equipment to be tailored to meet EMC requirements. Every electronic system consists of a number of functional modules interconnected by signal links and power supply lines. Electromagnetic interference

  7. Relative ultrasound energy measurement circuit

    OpenAIRE

    Gustafsson, E.Martin I.; Johansson, Jonny; Delsing, Jerker

    2005-01-01

    A relative ultrasound energy estimation circuit has been designed in a standard 0.35-μm CMOS process, to be a part of a thumb size internet connected wireless ultrasound measurement system. This circuit measures the relative energy between received ultrasound pulses, and presents an output signal that is linear to the received energy. Post-layout simulations indicate 7 bit linearity for 500 mV input signals, 5 μsec startup and stop times, 2.6 mW power consumption during active state. The acti...

  8. Simplified design of filter circuits

    CERN Document Server

    Lenk, John

    1999-01-01

    Simplified Design of Filter Circuits, the eighth book in this popular series, is a step-by-step guide to designing filters using off-the-shelf ICs. The book starts with the basic operating principles of filters and common applications, then moves on to describe how to design circuits by using and modifying chips available on the market today. Lenk's emphasis is on practical, simplified approaches to solving design problems.Contains practical designs using off-the-shelf ICsStraightforward, no-nonsense approachHighly illustrated with manufacturer's data sheets

  9. Programming languages for circuit design.

    Science.gov (United States)

    Pedersen, Michael; Yordanov, Boyan

    2015-01-01

    This chapter provides an overview of a programming language for Genetic Engineering of Cells (GEC). A GEC program specifies a genetic circuit at a high level of abstraction through constraints on otherwise unspecified DNA parts. The GEC compiler then selects parts which satisfy the constraints from a given parts database. GEC further provides more conventional programming language constructs for abstraction, e.g., through modularity. The GEC language and compiler is available through a Web tool which also provides functionality, e.g., for simulation of designed circuits.

  10. Endogenous money, circuits and financialization

    OpenAIRE

    Malcolm Sawyer

    2013-01-01

    This paper locates the endogenous money approach in a circuitist framework. It argues for the significance of the credit creation process for the evolution of the economy and the absence of any notion of ‘neutrality of money’. Clearing banks are distinguished from other financial institutions as the providers of initial finance in a circuit whereas other financial institutions operate in a final finance circuit. Financialization is here viewed in terms of the growth of financial assets an...

  11. Implementation of Chua's circuit using simulated inductance

    Science.gov (United States)

    Gopakumar, K.; Premlet, B.; Gopchandran, K. G.

    2011-05-01

    In this study we describe how to build an inductorless version of the classic Chua's circuit. A suitable inductor for Chua's circuit is often hard to procure. The required inductor for the circuit is designed using simple circuit elements such as resistors, capacitors and operational amplifiers. The complete circuit can be implemented by using off-the-shelf components, and it can readily be integrated on a single chip. This design of Chua's circuit allows the original dynamics to be slowed down to just a few hertz, enabling implementation of sophisticated control schemes without severe time restrictions. Another novel feature of the circuit is that losses associated with capacitors due to leakages can easily be compensated by providing negative resistance using the same setup. The chaotic behaviour of the circuit is verified by PSpice and Multisim simulation and also by experimental study on a circuit breadboard. The results give excellent agreement with each other and with the results of previous investigators.

  12. Mechanism-specific effects of adenosine on ventricular tachycardia.

    Science.gov (United States)

    Lerman, Bruce B; Ip, James E; Shah, Bindi K; Thomas, George; Liu, Christopher F; Ciaccio, Edward J; Wit, Andrew L; Cheung, Jim W; Markowitz, Steven M

    2014-12-01

    There is no universally accepted method by which to diagnose clinical ventricular tachycardia (VT) due to cAMP-mediated triggered activity. Based on cellular and clinical data, adenosine termination of VT is thought to be consistent with a diagnosis of triggered activity. However, a major gap in evidence mitigates the validity of this proposal, namely, defining the specificity of adenosine response in well-delineated reentrant VT circuits. To this end, we systematically studied the effects of adenosine in a model of canine reentrant VT and in human reentrant VT, confirmed by 3-dimensional, pace- and substrate mapping. Adenosine (12 mg [IQR 12-24]) failed to terminate VT in 31 of 31 patients with reentrant VT due to structural heart disease, and had no effect on VT cycle length (age, 67 years [IQR 53-74]); ejection fraction, 35% [IQR 20-55]). In contrast, adenosine terminated VT in 45 of 50 (90%) patients with sustained focal right or left outflow tract tachycardia. The sensitivity of adenosine for identifying VT due to triggered activity was 90% (95% CI, 0.78-0.97) and its specificity was 100% (95% CI, 0.89-1.0). Additionally, reentrant circuits were mapped in the epicardial border zone of 4-day-old infarcts in mongrel dogs. Adenosine (300-400 μg/kg) did not terminate sustained VT or have any effect on VT cycle length. These data support the concept that adenosine's effects on ventricular myocardium are mechanism specific, such that termination of VT in response to adenosine is diagnostic of cAMP-mediated triggered activity. © 2014 Wiley Periodicals, Inc.

  13. Advanced circuit simulation using Multisim workbench

    CERN Document Server

    Báez-López, David; Cervantes-Villagómez, Ofelia Delfina

    2012-01-01

    Multisim is now the de facto standard for circuit simulation. It is a SPICE-based circuit simulator which combines analog, discrete-time, and mixed-mode circuits. In addition, it is the only simulator which incorporates microcontroller simulation in the same environment. It also includes a tool for printed circuit board design.Advanced Circuit Simulation Using Multisim Workbench is a companion book to Circuit Analysis Using Multisim, published by Morgan & Claypool in 2011. This new book covers advanced analyses and the creation of models and subcircuits. It also includes coverage of transmissi

  14. Digital circuit boards mach 1 GHz

    CERN Document Server

    Morrison, Ralph

    2012-01-01

    A unique, practical approach to the design of high-speed digital circuit boards The demand for ever-faster digital circuit designs is beginning to render the circuit theory used by engineers ineffective. Digital Circuit Boards presents an alternative to the circuit theory approach, emphasizing energy flow rather than just signal interconnection to explain logic circuit behavior. The book shows how treating design in terms of transmission lines will ensure that the logic will function, addressing both storage and movement of electrical energy on these lines. It cove

  15. Clocking Scheme for Switched-Capacitor Circuits

    DEFF Research Database (Denmark)

    Steensgaard-Madsen, Jesper

    1998-01-01

    A novel clocking scheme for switched-capacitor (SC) circuits is presented. It can enhance the understanding of SC circuits and the errors caused by MOSFET (MOS) switches. Charge errors, and techniques to make SC circuits less sensitive to them are discussed.......A novel clocking scheme for switched-capacitor (SC) circuits is presented. It can enhance the understanding of SC circuits and the errors caused by MOSFET (MOS) switches. Charge errors, and techniques to make SC circuits less sensitive to them are discussed....

  16. Unbalanced Neuronal Circuits in Addiction

    OpenAIRE

    Volkow, Nora D.; Wang, Gen-Jack; Tomasi, Dardo; Baler, Ruben D.

    2013-01-01

    Through sequential waves of drug-induced neurochemical stimulation, addiction co-opts the brain's neuronal circuits that mediate reward, motivation, , to behavioral inflexibility and a severe disruption of self-control and compulsive drug intake. Brain imaging technologies have allowed neuroscientists to map out the neural landscape of addiction in the human brain and to understand how drugs modify it.

  17. A Low Noise Electronic Circuit

    NARCIS (Netherlands)

    Annema, Anne J.; Leenaerts, Dominicus M.W.; de Vreede, Petrus W.H.

    2002-01-01

    An electronic circuit, which can be used as a Low Noise Amplifier (LNA), comprises two complementary Field Effect Transistors (M1, M2; M5, M6), each having a gate, a source and a drain. The gates are connected together as a common input terminal, and the drains are connected together as a

  18. Circuit design for RF transceivers

    CERN Document Server

    Leenaerts, Domine; Vaucher, Cicero S

    2007-01-01

    Second edition of this successful 2001 RF Circuit Design book, has been updated, latest technology reviews have been added as well as several actual case studies. Due to the authors being active in industry as well as academia, this should prove to be an essential guide on RF Transceiver Design for students and engineers.

  19. Integrated Circuit Stellar Magnitude Simulator

    Science.gov (United States)

    Blackburn, James A.

    1978-01-01

    Describes an electronic circuit which can be used to demonstrate the stellar magnitude scale. Six rectangular light-emitting diodes with independently adjustable duty cycles represent stars of magnitudes 1 through 6. Experimentally verifies the logarithmic response of the eye. (Author/GA)

  20. Simulated annealing and circuit layout

    NARCIS (Netherlands)

    Aarts, E.H.L.; Laarhoven, van P.J.M.

    1991-01-01

    We discuss the problem of approximately sotvlng circuit layout problems by simulated annealing. For this we first summarize the theoretical concepts of the simulated annealing algorithm using Ihe theory of homogeneous and inhomogeneous Markov chains. Next we briefly review general aspects of the

  1. Multicenter, randomized comparison between magnetically navigated and manually guided radiofrequency ablation of atrioventricular nodal reentrant tachycardia (the MagMa-AVNRT-trial).

    Science.gov (United States)

    Reents, Tilko; Jilek, Clemens; Schuster, Peter; Nölker, Georg; Koch-Büttner, Katharina; Ammar-Busch, Sonia; Semmler, Verena; Bourier, Felix; Kottmaier, Marc; Kornmayer, Marie; Brooks, Stephanie; Fichtner, Stephanie; Kolb, Christof; Deisenhofer, Isabel; Hessling, Gabriele

    2017-12-01

    Remote magnetic navigation (RMN) is attributed to diminish radiation exposure for both patient and operator performing catheter ablation for different arrhythmia substrates. The purpose of this prospective, randomized study was to compare RMN with manually guided catheter ablation for AV nodal reentrant tachycardia (AVNRT) regarding fluoroscopy time/dosage, acute and long-term efficacy as well as safety. A total of 218 patients with AVNRT undergoing catheter ablation at three centers (male 34%, mean age 50 ± 17 years) were randomized to a manual approach (n = 113) or RMN (n = 105) using the Niobe ® magnetic navigation system. The primary study endpoint was total fluoroscopy time/dosage for patient and operator at the end of the procedure. Secondary endpoints included acute success, procedure duration, complications and success rate after 6 months. Fluoroscopy time and dosage for the patient were significantly reduced in the RMN group compared to the manual group (6 ± 6 vs. 11 ± 10 min; p < 0.001 and 425 ± 558 vs. 751 ± 900 cGycm 2 , p = 0.002). A reduction in fluoroscopy time/dose also applied to the operator (3 ± 5 vs. 7 ± 9 min 209 ± 444 vs. 482 ± 689 cGycm 2 , p < 0.001). Procedure duration was significantly longer in the RMN group (88 ± 29 vs. 79 ± 29 min; p = 0.03) and crossover from the RMN group to manual ablation occurred in 7.6% of patients (7.6 vs. 0.1%; p = 0.02). Acute success was achieved in 100% of patients in both groups. Midterm success after 6 months was 97 vs. 98% (p = 0.67). No complications occurred in both groups. The use of RMN for catheter ablation of AVNRT compared to a manual approach results in a reduction of fluoroscopy time and dosage of about 50% for both patients and physicians. Acute and midterm success and safety are comparable. RMN is a good alternative to a manual approach for AVNRT ablation.

  2. The voltage—current relationship and equivalent circuit implementation of parallel flux-controlled memristive circuits

    International Nuclear Information System (INIS)

    Bao Bo-Cheng; Feng Fei; Dong Wei; Pan Sai-Hu

    2013-01-01

    A flux-controlled memristor characterized by smooth cubic nonlinearity is taken as an example, upon which the voltage—current relationships (VCRs) between two parallel memristive circuits — a parallel memristor and capacitor circuit (the parallel MC circuit), and a parallel memristor and inductor circuit (the parallel ML circuit) — are investigated. The results indicate that the VCR between these two parallel memristive circuits is closely related to the circuit parameters, and the frequency and amplitude of the sinusoidal voltage stimulus. An equivalent circuit model of the memristor is built, upon which the circuit simulations and experimental measurements of both the parallel MC circuit and the parallel ML circuit are performed, and the results verify the theoretical analysis results

  3. Association of epicardial adipose tissue thickness and inflammation parameters with CHA2DS2-VASc score in patients with nonvalvular atrial fibrillation

    Directory of Open Access Journals (Sweden)

    Akdag S

    2015-11-01

    Full Text Available Serkan Akdag, Hakki Simsek, Musa Sahin, Aytac Akyol, Ramazan Duz, Naci Babat Department of Cardiology, Yuzuncu Yil University Medical Faculty, Van, Turkey Background: Epicardial adipose tissue (EAT, mean platelet volume (MPV, platelet-to- lymphocyte ratio (PLR, and neutrophil-to-lymphocyte ratio (NLR have been shown to be helpful in predicting adverse cardiovascular events. However, to date, in the literature, there have been no studies demonstrating the relationship between EAT, MPV, PLR, NLR, and thromboembolism risk in atrial fibrillation (AF. Therefore, we examined the relationship between EAT, MPV, PLR, NLR, and CHA2DS2-VASc score used for the evaluation of thromboembolism risk in patients with AF.Methods: The study included 96 consecutive patients with AF and 52 age- and sex-matched control subjects. We calculated CHA2DS2-VASc risk score for each patient and measured baseline EAT thickness, MPV, PLR, NLR, left atrial volume index, and left ventricular ejection fraction.Results: The group with high CHA2DS2-VASc score had higher EAT (7.2±1.5 vs 5.9±1.2 mm, P<0.001, MPV (9.1±1.1 vs 8.4±1.0 fL, P=0.004, PLR (152.3±28.4 vs 126.7±25.4, P=0.001, and NLR (4.0±1.6 vs 3.2±1.3, P<0.001 compared to group with low-intermediate CHA2DS2-VASc score. Moreover, CHA2DS2-VASc score was found to be positively correlated with EAT (r=0.623, P<0.001, MPV (r=0.350, P=0.004, PLR (r=0.398, P=0.001, and NLR (r=0.518, P<0.001.Conclusion: Our study results demonstrated that EAT thickness, MPV, PLR, and NLR were associated with the thromboembolic risk exhibited by CHA2DS2-VASc score in patients with nonvalvular AF. Keywords: atrial fibrillation, epicardial adipose tissue, platelet, neutrophil, mean platelet volume

  4. Fabric circuits and method of manufacturing fabric circuits

    Science.gov (United States)

    Chu, Andrew W. (Inventor); Dobbins, Justin A. (Inventor); Scully, Robert C. (Inventor); Trevino, Robert C. (Inventor); Lin, Greg Y. (Inventor); Fink, Patrick W. (Inventor)

    2011-01-01

    A flexible, fabric-based circuit comprises a non-conductive flexible layer of fabric and a conductive flexible layer of fabric adjacent thereto. A non-conductive thread, an adhesive, and/or other means may be used for attaching the conductive layer to the non-conductive layer. In some embodiments, the layers are attached by a computer-driven embroidery machine at pre-determined portions or locations in accordance with a pre-determined attachment layout before automated cutting. In some other embodiments, an automated milling machine or a computer-driven laser using a pre-designed circuit trace as a template cuts the conductive layer so as to separate an undesired portion of the conductive layer from a desired portion of the conductive layer. Additional layers of conductive fabric may be attached in some embodiments to form a multi-layer construct.

  5. Investigation of Equivalent Circuit for PEMFC Assessment

    International Nuclear Information System (INIS)

    Myong, Kwang Jae

    2011-01-01

    Chemical reactions occurring in a PEMFC are dominated by the physical conditions and interface properties, and the reactions are expressed in terms of impedance. The performance of a PEMFC can be simply diagnosed by examining the impedance because impedance characteristics can be expressed by an equivalent electrical circuit. In this study, the characteristics of a PEMFC are assessed using the AC impedance and various equivalent circuits such as a simple equivalent circuit, equivalent circuit with a CPE, equivalent circuit with two RCs, and equivalent circuit with two CPEs. It was found in this study that the characteristics of a PEMFC could be assessed using impedance and an equivalent circuit, and the accuracy was highest for an equivalent circuit with two CPEs

  6. Sustainability issues in circuit board recycling

    DEFF Research Database (Denmark)

    Legarth, Jens Brøbech; Alting, Leo; Baldo, Gian Luca

    1995-01-01

    The resource recovery and environmental impact issues of printed circuit board recycling by secondary copper smelters are discussed. Guidelines concerning material selection for circuit board manufacture and concerning the recycling processes are given to enhance recovery efficiency and to lower...

  7. Developing a Domain Model for Relay Circuits

    DEFF Research Database (Denmark)

    Haxthausen, Anne Elisabeth

    2009-01-01

    In this paper we stepwise develop a domain model for relay circuits as used in railway control systems. First we provide an abstract, property-oriented model of networks consisting of components that can be glued together with connectors. This model is strongly inspired by a network model...... for railways madeby Bjørner et.al., however our model is more general: the components can be of any kind and can later be refined to e.g. railway components or circuit components. Then we show how the abstract network model can be refined into an explicit model for relay circuits. The circuit model describes...... the statics as well as the dynamics of relay circuits, i.e. how a relay circuit can be composed legally from electrical components as well as how the components may change state over time. Finally the circuit model is transformed into an executable model, and we show how a concrete circuit can be defined...

  8. Telecommunications Circuit Allocation Programs - Kansas City Area

    National Research Council Canada - National Science Library

    Thomas, William

    1994-01-01

    The overall objective of the audit was to determine whether DoD circuit allocation programs identified and used the most effective configurations for leased long-haul, special-purpose telecommunications circuits...

  9. Circuit QED lattices: Towards quantum simulation with superconducting circuits

    Energy Technology Data Exchange (ETDEWEB)

    Schmidt, Sebastian [Institute for Theoretical Physics, ETH Zurich, 8093, Zurich (Switzerland); Koch, Jens [Department of Physics and Astronomy, Northwestern University, Evanston, IL, 60208 (United States)

    2013-06-15

    The Jaynes-Cummings model describes the coupling between photons and a single two-level atom in a simplified representation of light-matter interactions. In circuit QED, this model is implemented by combining microwave resonators and superconducting qubits on a microchip with unprecedented experimental control. Arranging qubits and resonators in the form of a lattice realizes a new kind of Hubbard model, the Jaynes-Cummings-Hubbard model, in which the elementary excitations are polariton quasi-particles. Due to the genuine openness of photonic systems, circuit QED lattices offer the possibility to study the intricate interplay of collective behavior, strong correlations and non-equilibrium physics. Thus, turning circuit QED into an architecture for quantum simulation, i.e., using a well-controlled system to mimic the intricate quantum behavior of another system too daunting for a theorist to tackle head-on, is an exciting idea which has served as theorists' playground for a while and is now also starting to catch on in experiments. This review gives a summary of the most recent theoretical proposals and experimental efforts. (copyright 2013 by WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  10. What's new about generator circuit breakers

    International Nuclear Information System (INIS)

    Kolarik, P.L.

    1979-01-01

    The need for updating ANSI C37 Standards for AC high-voltage circuit breakers has become necessary because of the increased interest in power circuit breakers for generator application. These circuit breakers, which have continuous current ratings and rated short-circuit currents that are much higher than those presently covered by existing C37 Standards, take on added importance because they are being installed in critical AC power supplies at nuclear power stations

  11. Trip electrical circuit of the gyrotion

    International Nuclear Information System (INIS)

    Rossi, J.O.

    1987-09-01

    The electron cyclotron resonance heating system of INPE/LAP is shown and the trip electrical circuit of the gyrotron is described, together with its fundamental aspects. The trip electrical circuit consists basically of a series regulator circuit which regulates the output voltage level and controls the pulse width time. Besides that, a protection circuit for both tubes, regulator and gyrotron, against faults in the system. (author) [pt

  12. Hybdrid integral circuit for proportional chambers

    International Nuclear Information System (INIS)

    Yanik, R.; Khudy, M.; Povinets, P.; Strmen', P.; Grabachek, Z.; Feshchenko, A.A.

    1978-01-01

    Outlined briefly are a hybrid integrated circuit of the channel. One channel contains an input amplifier, delay circuit, and memory register on the base of the D-type flip-flop and controlled by the recording gate pulse. Provided at the output of the channel is a readout gating circuit. Presented are the flowsheet of the channel, the shaper amplifier and logical channel. At present the logical circuit was accepted for manufacture

  13. A Fault Tolerant Integrated Circuit Memory

    OpenAIRE

    Barton, Anthony Francis

    1980-01-01

    Most commercially produced integrated circuits are incapable of tolerating manufacturing defects. The area and function of the circuits is thus limited by the probability of faults occurring within the circuit. This thesis examines techniques for using redundancy in memory circuits to provide fault tolerance and to increase storage capacity. A hierarchical memory architecture using multiple Hamming codes is introduced and analysed to determine its resistance to manufa...

  14. Development of a pulse shape discrimination circuit

    International Nuclear Information System (INIS)

    Ye Bangjiao; Fan Wei; Fan Yangmei; Yu Xiaoqi; Mei Wen; Wang Zhongmin; Han Rongdian; Xiao Zhenxi

    1994-01-01

    A pulse shape discrimination circuit was designed and used in an experiment measuring double-differential cross sections of (n, charged particle) reaction; to identify p, α and γ. The performance of the circuit was tested. With this circuit, excellent identification of p, α and γ was obtained. ((orig.))

  15. Circuit card failures and industry mitigation strategy

    Energy Technology Data Exchange (ETDEWEB)

    Mondal, U. [Candu Owners Group, Toronto, Ontario (Canada)

    2012-07-01

    In recent years the nuclear industry has experienced an increase in circuit card failures due to ageing of components, inadequate Preventive Maintenance (PM), lack of effective circuit card health monitoring, etc. Circuit card failures have caused loss of critical equipment, e.g., electro hydraulic governors, Safety Systems, resulting in loss of function and in some cases loss of generation. INPO completed a root cause analysis of 40 Reactor Trips/Scrams in US reactors and has recommended several actions to mitigate Circuit Card failures. Obsolescence of discrete components has posed many challenges in conducting effective preventative maintenance on circuit cards. In many cases, repairs have resulted in installation of components that compromise performance of the circuit cards. Improper termination and worn edge connectors have caused intermittent contacts contributing to circuit card failures. Traditionally, little attention is paid to relay functions and preventative maintenance of relay. Relays contribute significantly to circuit card failures and have dominated loss of generation across the power industry. The INPO study recommended a number of actions to mitigate circuit card failures, such as; identification of critical components and single point vulnerabilities; strategic preventative maintenance; protection of circuit boards against electrostatic discharge; limiting power cycles; performing an effective burn-in prior to commissioning of the circuit cards; monitoring performance of DC power supplies; limiting cabinet temperatures; managing of component aging/degradation mechanism, etc. A subcommittee has been set up under INPO sponsorship to understand the causes of circuit card failure and to develop an effective mitigation strategy. (author)

  16. Improvements in or relating to transistor circuits

    International Nuclear Information System (INIS)

    Richards, R.F.; Williamson, P.W.

    1978-01-01

    This invention relates to transistor circuits and in particular to integrated transistor circuits formed on a substrate of semi-conductor material such as silicon. The invention is concerned with providing integrated circuits in which malfunctions caused by the effects of ionising, e.g. nuclear, radiations are reduced. (author)

  17. CMOS digital integrated circuits a first course

    CERN Document Server

    Hawkins, Charles; Zarkesh-Ha, Payman

    2016-01-01

    This book teaches the fundamentals of modern CMOS technology and covers equal treatment to both types of MOSFET transistors that make up computer circuits; power properties of logic circuits; physical and electrical properties of metals; introduction of timing circuit electronics and introduction of layout; real-world examples and problem sets.

  18. Piezo pump and pressurized circuit provided therewith

    NARCIS (Netherlands)

    Van Es, Johannes; Wits, Wessel Willems

    2015-01-01

    A piezo pump for use in a pressurized circuit includes a pump chamber with an inlet provided with a one way inlet valve, for connection to a feeding line of the pressurized circuit and an outlet provided with a one way outlet valve, for connection to a discharge line of the pressurized circuit and a

  19. 49 CFR 236.721 - Circuit, control.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Circuit, control. 236.721 Section 236.721..., MAINTENANCE, AND REPAIR OF SIGNAL AND TRAIN CONTROL SYSTEMS, DEVICES, AND APPLIANCES Definitions § 236.721 Circuit, control. An electrical circuit between a source of electric energy and a device which it operates. ...

  20. Superconducting flux flow digital circuits

    International Nuclear Information System (INIS)

    Martens, J.S.; Zipperian, T.E.; Hietala, V.M.; Ginley, D.S.; Tigges, C.P.; Phillips, J.M.; Siegal, M.P.

    1993-01-01

    The authors have developed a family of digital logic circuits based on superconducting flux flow transistors that show high speed, reasonable signal levels, large fan-out, and large noise margins. The circuits are made from high-temperature superconductors (HTS) and have been shown to operate at over 90 K. NOR gates have been demonstrated with fan-outs of more than 5 and fully loaded switching times less than a fixture-limited 50 ps. Ring-oscillator data suggest inverter delay times of about 40ps when using a 3-μm linewidths. Simple flip-flops have also been demonstrated showing large noise margins, response times of less than 30 ps, and static power dissipation on the order of 30 nW. Among other uses, this logic family is appropriate as an interface between logic families such as single flux quantum and conventional semiconductor logic

  1. Advanced Microwave Circuits and Systems

    DEFF Research Database (Denmark)

    This book is based on recent research work conducted by the authors dealing with the design and development of active and passive microwave components, integrated circuits and systems. It is divided into seven parts. In the first part comprising the first two chapters, alternative concepts...... amplifier architectures. In addition, distortion analysis and power combining techniques are considered. Another key element in most microwave systems is a signal generator. It forms the heart of all kinds of communication and radar systems. The fourth part of this book is dedicated to signal generators...... push currently available technologies to the limits. Some considerations to meet the growing requirements are provided in the fifth part of this book. The following part deals with circuits based on LTCC and MEMS technologies. The book concludes with chapters considering application of microwaves...

  2. Electron commutator on integrated circuits

    International Nuclear Information System (INIS)

    Demidenko, V.V.

    1975-01-01

    The scheme and the parameters of an electron 16-channel contactless commutator based entirely on integrated circuits are described. The device consists of a unit of analog keys based on field-controlled metal-insulator-semiconductor (m.i.s.) transistors, operation amplifier comparators controlling these keys, and a level distributor. The distributor is based on a ''matrix'' scheme and comprises two ring-shaped shift registers plugged in series and a decoder base on two-input logical elements I-NE. The principal dynamical parameters of the circuit are as follows: the control signal delay in the distributor. 50 nsec; the total channel switch-over time, 500-600 nsec. The commutator transmits both constant signals and pulses whose duration reaches tens of nsec. The commutator can be used in data acquisition and processing systems, for shaping complicated signals (for example), (otherwise signals), for simultaneous oscillographing of several signals, and so forth [ru

  3. Smart Circuit Breaker Communication Infrastructure

    Directory of Open Access Journals (Sweden)

    Octavian Mihai MACHIDON

    2017-11-01

    Full Text Available The expansion of the Internet of Things has fostered the development of smart technologies in fields such as power transmission and distribution systems (as is the Smart Grid and also in regard to home automation (the Smart Home concept. This paper addresses the network communication infrastructure for a Smart Circuit Breaker system, a novel application at the edge of the two afore-mentioned systems (Smart Grid and Smart Home. Such a communication interface has high requirements from functionality, performance and security point of views, given the large amount of distributed connected elements and the real-time information transmission and system management. The paper describes the design and implementation of the data server, Web interface and the embedded networking capabilities of the smart circuit breakers, underlining the protocols and communication technologies used.

  4. Foundations for microstrip circuit design

    CERN Document Server

    Edwards, Terry

    2016-01-01

    Building on the success of the previous three editions, Foundations for Microstrip Circuit Design offers extensive new, updated and revised material based upon the latest research. Strongly design-oriented, this fourth edition provides the reader with a fundamental understanding of this fast expanding field making it a definitive source for professional engineers and researchers and an indispensable reference for senior students in electronic engineering. Topics new to this edition: microwave substrates, multilayer transmission line structures, modern EM tools and techniques, microstrip and planar transmision line design, transmission line theory, substrates for planar transmission lines, Vias, wirebonds, 3D integrated interposer structures, computer-aided design, microstrip and power-dependent effects, circuit models, microwave network analysis, microstrip passive elements, and slotline design fundamentals.

  5. Unbalanced neuronal circuits in addiction.

    Science.gov (United States)

    Volkow, Nora D; Wang, Gen-Jack; Tomasi, Dardo; Baler, Ruben D

    2013-08-01

    Through sequential waves of drug-induced neurochemical stimulation, addiction co-opts the brain's neuronal circuits that mediate reward, motivation to behavioral inflexibility and a severe disruption of self-control and compulsive drug intake. Brain imaging technologies have allowed neuroscientists to map out the neural landscape of addiction in the human brain and to understand how drugs modify it. Published by Elsevier Ltd.

  6. Monolithic readout circuits for RHIC

    International Nuclear Information System (INIS)

    O'Connor, P.; Harder, J.; Sippach, W.

    1991-10-01

    Several CMOS ASICs have been developed for a proposed RHIC experiment. This paper discusses why ASIC implementation was chosen for certain functions, circuit specifications and the design techniques used to meet them, and results of simulations and early prototypes. By working closely together from an early stage in the planning process, in-house ASIC designers and detector and data acquisition experimenters can achieve optimal use of this important technology

  7. Circuit complexity of regular languages

    Czech Academy of Sciences Publication Activity Database

    Koucký, Michal

    2009-01-01

    Roč. 45, č. 4 (2009), s. 865-879 ISSN 1432-4350 R&D Projects: GA ČR GP201/07/P276; GA MŠk(CZ) 1M0545 Institutional research plan: CEZ:AV0Z10190503 Keywords : regular languages * circuit complexity * upper and lower bounds Subject RIV: BA - General Mathematics Impact factor: 0.726, year: 2009

  8. Realistic Realizations Of Threshold Circuits

    Science.gov (United States)

    Razavi, Hassan M.

    1987-08-01

    Threshold logic, in which each input is weighted, has many theoretical advantages over the standard gate realization, such as reducing the number of gates, interconnections, and power dissipation. However, because of the difficult synthesis procedure and complicated circuit implementation, their use in the design of digital systems is almost nonexistant. In this study, three methods of NMOS realizations are discussed, and their advantages and shortcomings are explored. Also, the possibility of using the methods to realize multi-valued logic is examined.

  9. Microcontroller based Integrated Circuit Tester

    OpenAIRE

    Yousif Taha Yousif Elamin; Abdelrasoul Jabar Alzubaidi

    2015-01-01

    The digital integrated circuit (IC) tester is implemented by using the ATmega32 microcontroller . The microcontroller processes the inputs and outputs and displays the results on a Liquid Crystal Display (LCD). The basic function of the digital IC tester is to test a digital IC for correct logical functioning as described in the truth table and/or function table. The designed model can test digital ICs having 14 pins. Since it is programmable, any number of ICs can be tested . Thi...

  10. Monolithic readout circuits for RHIC

    Energy Technology Data Exchange (ETDEWEB)

    O`Connor, P.; Harder, J. [Brookhaven National Laboratory, Upton, NY (United States)

    1991-12-31

    Several CMOS ASICs have been developed for a proposed RHIC experiment. This paper discusses why ASIC implementation was chosen for certain functions, circuit specifications and the design techniques used to meet them, and results of simulations and early prototypes. By working closely together from an early stage in the planning process, in-house ASIC designers and detector and data acquisition experimenters can achieve optimal use of this important technology.

  11. Root finding with threshold circuits

    Czech Academy of Sciences Publication Activity Database

    Jeřábek, Emil

    2012-01-01

    Roč. 462, Nov 30 (2012), s. 59-69 ISSN 0304-3975 R&D Projects: GA AV ČR IAA100190902; GA MŠk(CZ) 1M0545 Institutional support: RVO:67985840 Keywords : root finding * threshold circuit * power series Subject RIV: BA - General Mathematics Impact factor: 0.489, year: 2012 http://www.sciencedirect.com/science/article/pii/S0304397512008006#

  12. Refractory silicides for integrated circuits

    International Nuclear Information System (INIS)

    Murarka, S.P.

    1980-01-01

    Transition metal silicides have, in the past, attracted attention because of their usefulness as high temperature materials and in integrated circuits as Schottky barrier and ohmic contacts. More recently, with the increasing silicon integrated circuits (SIC) packing density, the line widths get narrower and the sheet resistance contribution to the RC delay increases. The possibility of using low resistivity silicides, which can be formed directly on the polysilicon, makes these silicides highly attractive. The usefulness of a silicide metallization scheme for integrated circuits depends, not only on the desired low resistivity, but also on the ease with which the silicide can be formed and patterned and on the stability of the silicides throughout device processing and during actual device usage. In this paper, various properties and the formation techniques of the silicides have been reviewed. Correlations between the various properties and the metal or silicide electronic or crystallographic structure have been made to predict the more useful silicides for SIC applications. Special reference to the silicide resistivity, stress, and oxidizability during the formation and subsequent processing has been given. Various formation and etching techniques are discussed

  13. Epicardial adipose tissue volume a diagnostic study for independent predicting disorder of circadian rhythm of blood pressure in patients with essential hypertension.

    Science.gov (United States)

    Zhou, L; Deng, Y; Gong, J; Chen, X; Zhang, Q; Wang, J

    2016-05-30

    The aim of the study was to determine whether epicardial adipose tissue volume (EATV), a new cardiometabolic risk factor, is associated with circadian changes of blood pressure (BP) in patients with newly diagnosed essential hypertension. Ninety patients with newly diagnosed essential hypertension underwent ambulatory blood pressure monitoring for 24 h. EATV was measured using cardiac computed tomography. These patients were categorized into three groups according to their BP patterns (group 1, n=46, dipper hypertension, also called normal pattern; group 2, n=24, non-dipper hypertension; group 3, n=20, anti-dipper hypertension; group 2 and 3 are also called abnormal pattern). Data were collected retrospectively and compared between hypertensive patients with normal pattern and abnormal pattern. The normal pattern hypertensive patient had significant lower mean EATV and BP ((EATV, 91.3±29.4 cm3) than those of abnormal pattern patients including group 2 (EATV, 116.2±31.06cm3, EATV, 124.8±28.5cm3, PEATV with abnormal blood pressure mode was 0.500 (pEATV was elevated in newly diagnosed and untreated patients with non-dipper hypertension and anti-dipper hypertension. EATV measured by cardiac computed tomography can be used to indicate the increased risk of circadian rhythm of blood pressure.

  14. Epicardial fat thickness correlates with P-wave duration, left atrial size and decreased left ventricular systolic function in morbid obesity.

    Science.gov (United States)

    Fernandes-Cardoso, A; Santos-Furtado, M; Grindler, J; Ferreira, L A; Andrade, J L; Santo, M A

    2017-08-01

    Epicardial fat (EF) is increased in obesity and has important interactions with atrial and ventricular myocardium. Most of the evidence in this scenario can be confused by the presence of comorbidities such as hypertension, diabetes and dyslipidemia, which are very common in this population. The influence of EF on atrial remodeling and cardiac function demands further investigation on morbidly obese without these comorbidities. We prospectively recruited 20 metabolically healthy morbidly obese and 20 normo-weights controls. The maximum P-wave duration (PWD) was analyzed by 12-lead electrocardiogram. Left atrial diameter (LAD), left ventricular ejection fraction (LVEF) and EF thickness (EFT) were evaluated by two-dimensional echocardiography. The mean of maximum PWD and LAD were significantly larger in the obese group as compared to the control group: 109.55 ± 11.52 ms × 89.38 ± 11.19 ms and 36.12 ± 3.46 mm × 31.45 ± 2.64 mm, (p function. Copyright © 2017 The Italian Society of Diabetology, the Italian Society for the Study of Atherosclerosis, the Italian Society of Human Nutrition, and the Department of Clinical Medicine and Surgery, Federico II University. Published by Elsevier B.V. All rights reserved.

  15. Impact of Body Mass Index on the relationship of epicardial adipose tissue to metabolic syndrome and coronary artery disease in an Asian population

    Directory of Open Access Journals (Sweden)

    Yoon Myeong-Ho

    2010-07-01

    Full Text Available Abstract Background In a previous study, we demonstrated that the thickness of epicardial adipose tissue (EAT, measured by echocardiography, was increased in patients with metabolic syndrome (MS and coronary artery disease (CAD. Several studies on obese patients, however, failed to demonstrate any relationship between EAT and CAD. We hypothesized that body mass index (BMI affected the link between EAT and MS and CAD. Methods We consecutively enrolled 643 patients (302 males, 341 females; 59 ± 11 years, who underwent echocardiography and coronary angiography. The EAT thickness was measured on the free wall of the right ventricle at the end of diastole. All patients were divided into two groups: high BMI group, ≥27 kg/m2 (n = 165, and non-high BMI group, 2 (n = 478. Results The median and mean EAT thickness of 643 patients were 3.0 mm and 3.1 ± 2.4 mm, respectively. In the non-high BMI group, the median EAT thickness was significantly increased in patients with MS compared to those without MS (3.5 vs. 1.9 mm, p Conclusions While EAT thickness was significantly increased in patients with MS and CAD, the power of EAT thickness to predict MS and CAD was stronger in patients with BMI 2. These findings showed that the measurement of EAT thickness by echocardiography might be especially useful in an Asian population with a non-high BMI, less than 27 kg/m2.

  16. Ultra-low power integrated circuit design circuits, systems, and applications

    CERN Document Server

    Li, Dongmei; Wang, Zhihua

    2014-01-01

    This book describes the design of CMOS circuits for ultra-low power consumption including analog, radio frequency (RF), and digital signal processing circuits (DSP). The book addresses issues from circuit and system design to production design, and applies the ultra-low power circuits described to systems for digital hearing aids and capsule endoscope devices. Provides a valuable introduction to ultra-low power circuit design, aimed at practicing design engineers; Describes all key building blocks of ultra-low power circuits, from a systems perspective; Applies circuits and systems described to real product examples such as hearing aids and capsule endoscopes.

  17. CMOS circuit design, layout and simulation

    CERN Document Server

    Baker, R Jacob

    2010-01-01

    The Third Edition of CMOS Circuit Design, Layout, and Simulation continues to cover the practical design of both analog and digital integrated circuits, offering a vital, contemporary view of a wide range of analog/digital circuit blocks including: phase-locked-loops, delta-sigma sensing circuits, voltage/current references, op-amps, the design of data converters, and much more. Regardless of one's integrated circuit (IC) design skill level, this book allows readers to experience both the theory behind, and the hands-on implementation of, complementary metal oxide semiconductor (CMOS) IC design via detailed derivations, discussions, and hundreds of design, layout, and simulation examples.

  18. Design of analog integrated circuits and systems

    CERN Document Server

    Laker, Kenneth R

    1994-01-01

    This text is designed for senior or graduate level courses in analog integrated circuits or design of analog integrated circuits. This book combines consideration of CMOS and bipolar circuits into a unified treatment. Also included are CMOS-bipolar circuits made possible by BiCMOS technology. The text progresses from MOS and bipolar device modelling to simple one and two transistor building block circuits. The final two chapters present a unified coverage of sample-data and continuous-time signal processing systems.

  19. Graphene radio frequency receiver integrated circuit.

    Science.gov (United States)

    Han, Shu-Jen; Garcia, Alberto Valdes; Oida, Satoshi; Jenkins, Keith A; Haensch, Wilfried

    2014-01-01

    Graphene has attracted much interest as a future channel material in radio frequency electronics because of its superior electrical properties. Fabrication of a graphene integrated circuit without significantly degrading transistor performance has proven to be challenging, posing one of the major bottlenecks to compete with existing technologies. Here we present a fabrication method fully preserving graphene transistor quality, demonstrated with the implementation of a high-performance three-stage graphene integrated circuit. The circuit operates as a radio frequency receiver performing signal amplification, filtering and downconversion mixing. All circuit components are integrated into 0.6 mm(2) area and fabricated on 200 mm silicon wafers, showing the unprecedented graphene circuit complexity and silicon complementary metal-oxide-semiconductor process compatibility. The demonstrated circuit performance allow us to use graphene integrated circuit to perform practical wireless communication functions, receiving and restoring digital text transmitted on a 4.3-GHz carrier signal.

  20. Characterisation of a microwave re-entrant cavity resonator for phase-equilibrium measurements and new dew-point data for a (0.25 argon + 0.75 carbon dioxide) mixture

    International Nuclear Information System (INIS)

    Tsankova, Gergana; Richter, Markus; Madigan, Adele; Stanwix, Paul L.; May, Eric F.; Span, Roland

    2016-01-01

    Highlights: • A microwave reentrant cavity resonator was refurbished and extensively characterised. • Vacuum resonance frequencies and Q-factors were modelled and experimentally validated. • Whispering gallery-type modes first-time reported for present cavity geometry. • Dew points of a (0.2491 argon + 0.7509 carbon dioxide) mixture were measured. • Measurements were carried out from T = (252–280) K at pressures up to 6.9 MPa. - Abstract: An apparatus based on a microwave re-entrant cavity resonator, originally built for accurate measurements of the dielectric permittivity of natural gas mixtures, was refurbished and extensively characterised. This was done to enable the future investigation of phase equilibria and (p, ρ, T, x) behaviour of fluid mixtures utilizing the present experimental technique. Vacuum resonance frequencies and Q-factors of the resonator’s modes were modelled using both analytic and finite element methods, and found to compare well with experimental values. The finite element models helped to identify two whispering gallery-type modes not previously reported for such cavity geometries. The models also predict distributions of the electric and magnetic fields in the re-entrant cavity resonator useful for identifying regions in the cavity more sensitive to the presence of a liquid. Following the resonator’s characterisation, its ability to measure dew points was tested using a gravimetrically prepared (0.2501 argon + 0.7499 carbon dioxide) mixture over the temperature range from (252 to 280) K at pressures from (2.8 to 6.9) MPa. The combined expanded uncertainty with a level of confidence of approximately 95% (k = 2) in dew-point temperature and pressure ranged between (0.025 and 0.044) K and from (0.009 to 0.015) MPa, respectively. We compared the experimental dew-point pressures with the recently developed multi-parameter equation of state optimised for combustion gases (EOS-CG), showing relative deviations in the range of (0

  1. Optimal planning of series resistor to control time constant of test circuit for high-voltage AC circuit-breakers

    OpenAIRE

    Yoon-Ho Kim; Jung-Hyeon Ryu; Jin-Hwan Kim; Kern-Joong Kim

    2016-01-01

    The equivalent test circuit that can deliver both short-circuit current and recovery voltage is used to verify the performance of high-voltage circuit breakers. Most of the parameters in this circuit can be obtained by using a simple calculation or a simulation program. The ratings of the circuit breaker include rated short-circuit breaking current, rated short-circuit making current, rated operating sequence of the circuit breaker and rated short-time current. Among these ratings, the short-...

  2. Circuit for Driving Piezoelectric Transducers

    Science.gov (United States)

    Randall, David P.; Chapsky, Jacob

    2009-01-01

    The figure schematically depicts an oscillator circuit for driving a piezoelectric transducer to excite vibrations in a mechanical structure. The circuit was designed and built to satisfy application-specific requirements to drive a selected one of 16 such transducers at a regulated amplitude and frequency chosen to optimize the amount of work performed by the transducer and to compensate for both (1) temporal variations of the resonance frequency and damping time of each transducer and (2) initially unknown differences among the resonance frequencies and damping times of different transducers. In other words, the circuit is designed to adjust itself to optimize the performance of whichever transducer is selected at any given time. The basic design concept may be adaptable to other applications that involve the use of piezoelectric transducers in ultrasonic cleaners and other apparatuses in which high-frequency mechanical drives are utilized. This circuit includes three resistor-capacitor networks that, together with the selected piezoelectric transducer, constitute a band-pass filter having a peak response at a frequency of about 2 kHz, which is approximately the resonance frequency of the piezoelectric transducers. Gain for generating oscillations is provided by a power hybrid operational amplifier (U1). A junction field-effect transistor (Q1) in combination with a resistor (R4) is used as a voltage-variable resistor to control the magnitude of the oscillation. The voltage-variable resistor is part of a feedback control loop: Part of the output of the oscillator is rectified and filtered for use as a slow negative feedback to the gate of Q1 to keep the output amplitude constant. The response of this control loop is much slower than 2 kHz and, therefore, does not introduce significant distortion of the oscillator output, which is a fairly clean sine wave. The positive AC feedback needed to sustain oscillations is derived from sampling the current through the

  3. Coherent defects in superconducting circuits

    International Nuclear Information System (INIS)

    Mueller, Clemens

    2011-01-01

    The interaction of superconducting circuits with additional quantum systems is a topic that has found extensive study in the recent past. In the limit where the added system are incoherent, this is the standard field of decoherence and the system dynamics can be described by a simple master equation. In the other limit however, when the additional parts are coherent, the resulting time-evolution can become more complicated. In this thesis we have investigated the interaction of superconducting circuits with coherent and incoherent two-level defects. We have shown theoretical calculations characterizing this interaction for all relevant parameter regimes. In the weak coupling limit, the interaction can be described in an effective bath picture, where the TLS act as parts of a large, decohering environment. For strong coupling, however, the coherent dynamics of the full coupled system has to be considered. We show the calculations of the coupled time-evolution and again characterize the interaction by an effective decoherence rate. We also used experimental data to characterize the microscopic origin of the defects and the details of their interaction with the circuits. The results obtained by analyzing spectroscopic data allow us to place strong constraint on several microscopic models for the observed TLS. However, these calculations are not yet fully conclusive as to the physical nature of the TLS. We propose additional experiments to fully characterize the interaction part of the Hamiltonian, thus providing the answer to the question of the physical origin of the coupling. Additionally we have developed a method to directly drive individual defect states via virtual excitation of the qubit. This method allows one to directly probe the properties of single TLS and possibly make use of their superior coherence times for quantum information purposes. The last part of this thesis provided a way for a possible implementation of geometric quantum computation in

  4. Miniaturization of Josephson logic circuits

    International Nuclear Information System (INIS)

    Ko, H.; Van Duzer, T.

    1985-01-01

    The performances of Current Injection Logic (CIL) and Resistor Coupled Josephson Logic (RCJL) have been evaluated for minimum features sizes ranging from 5 μm to 0.2 μm. The logic delay is limited to about 10 ps for both the CIL AND gate and the RCJL OR gate biased at 70% of maximum bias current. The maximum circuit count on an 6.35 x 6.35 chip is 13,000 for CIL gates and 20,000 for RCJL gates. Some suggestions are given for further improvements

  5. Integrated circuits for multimedia applications

    DEFF Research Database (Denmark)

    Vandi, Luca

    2007-01-01

    , and it is applied to a broad-band dual-loop receiver architecture in order to boost the linearity performances of the stage. A simplified noise- and linearity analysis of the circuit is derived, and a comparison is provided with a more traditional dual-loop topology (a broad-band stage based on shunt...... the impact of substrate-induced currents. Basic models are derived in the design phase, and the technological limits of the device are considered. Measurement results show that a very compact coil can provide ~1nH inductance up to 20GHz (physical limit for the measurement equipment), with a peak quality...

  6. Model reduction for circuit simulation

    CERN Document Server

    Hinze, Michael; Maten, E Jan W Ter

    2011-01-01

    Simulation based on mathematical models plays a major role in computer aided design of integrated circuits (ICs). Decreasing structure sizes, increasing packing densities and driving frequencies require the use of refined mathematical models, and to take into account secondary, parasitic effects. This leads to very high dimensional problems which nowadays require simulation times too large for the short time-to-market demands in industry. Modern Model Order Reduction (MOR) techniques present a way out of this dilemma in providing surrogate models which keep the main characteristics of the devi

  7. HF radio systems and circuits

    CERN Document Server

    Sabin, William

    1998-01-01

    A comprehensive reference for the design of high frequency communications systems and equipment. This revised edition is loaded with practical data, much of which cannot be found in other reference books. Its approach to the subject follows the needs of an engineer from system definition and performance requirements down to the individual circuit elements that make up radio transmitters and receivers. The accompanying disk contains updated software on filters, matching networks and receiver analysis. SciTech Publishing also provides many other products related to Communication Systems Design.

  8. Polysilicon photoconductor for integrated circuits

    Science.gov (United States)

    Hammond, R.B.; Bowman, D.R.

    1989-04-11

    A photoconductive element of polycrystalline silicon is provided with intrinsic response time which does not limit overall circuit response. An undoped polycrystalline silicon layer is deposited by LPCVD to a selected thickness on silicon dioxide. The deposited polycrystalline silicon is then annealed at a selected temperature and for a time effective to obtain crystal sizes effective to produce an enhanced current output. The annealed polycrystalline layer is subsequently exposed and damaged by ion implantation to a damage factor effective to obtain a fast photoconductive response. 6 figs.

  9. Wideband 4-diode sampling circuit

    Science.gov (United States)

    Wojtulewicz, Andrzej; Radtke, Maciej

    2016-09-01

    The objective of this work was to develop a wide-band sampling circuit. The device should have the ability to collect samples of a very fast signal applied to its input, strengthen it and prepare for further processing. The study emphasizes the method of sampling pulse shaping. The use of ultrafast pulse generator allows sampling signals with a wide frequency spectrum, reaching several gigahertzes. The device uses a pulse transformer to prepare symmetrical pulses. Their final shape is formed with the help of the step recovery diode, two coplanar strips and Schottky diode. Made device can be used in the sampling oscilloscope, as well as other measurement system.

  10. Circuit QED with transmon qubits

    Energy Technology Data Exchange (ETDEWEB)

    Wulschner, Karl Friedrich; Puertas, Javier; Baust, Alexander; Eder, Peter; Fischer, Michael; Goetz, Jan; Haeberlein, Max; Schwarz, Manuel; Xie, Edwar; Zhong, Ling; Deppe, Frank; Fedorov, Kirill; Marx, Achim; Menzel, Edwin; Gross, Rudolf [Walther-Meissner-Institut, Bayerische Akademie der Wissenschaften, Garching (Germany); Physik-Department, TU Muenchen, Garching (Germany); Nanosystems Initiative Munich (NIM), Muenchen (Germany); Huebl, Hans [Walther-Meissner-Institut, Bayerische Akademie der Wissenschaften, Garching (Germany); Nanosystems Initiative Munich (NIM), Muenchen (Germany); Weides, Martin [Karlsruhe Institute of Technology (KIT), Karlsruhe (Germany)

    2015-07-01

    Superconducting quantum bits are basic building blocks for circuit QED systems. Applications in the fields of quantum computation and quantum simulation require long coherence times. We have fabricated and characterized superconducting transmon qubits which are designed to operate at a high ratio of Josephson energy and charging energy. Due to their low sensitivity to charge noise transmon qubits show good coherence properties. We couple transmon qubits to coplanar waveguide resonators and coplanar slotline resonators and characterize the devices at mK-temperatures. From the experimental data we derive the qubit-resonator coupling strength, the qubit relaxation time and calibrate the photon number in the resonator via Stark shifts.

  11. Early Forming a Hummingbird-like Hovering Neural Network Circuitry Pattern with Reentrant Spatiotemporal Energy-Sensory Orientation Privileged to Avoid “Epilepsy” Based on a Biomimetic Acetylcholinesterase Memcapacitor Prosthesis

    Directory of Open Access Journals (Sweden)

    Ellen T. Chen

    2015-08-01

    Full Text Available The hummingbird’s significant asymmetry hovering flight with energy conservation pattern is remarkable among all vertebrates. However, little is known to human’s neuronal network circuitry current flow pattern for whether or not has this privilege during slow wave sleeping (SWS. What is the advantage in order to avoid diseases if we have this network pattern ? A memory device was developed with nanostructured biomimetic acetylcholinesterase (ACHE gorge membrane on gold chips as memcapacitor 1, served as a normal brain network prosthesis, compared with a mutated ACHE prosthesis as device 2, for evaluation of neuronal network circuitry integrity in the presence of Amyloid- beta (Ab under the conditions of free from tracers and antibodies in spiked NIST SRM 965A human serum. Three categories of Reentrant Energy-Sensory images are presented based on infused brain pulse energies in a matrix of “Sensory Biomarkers” having frequencies over 0.25-333 Hz at free and fixed Ab levels, respectively. Early non-symptomatic epilepsy was indentified and predicted by device 2 due to Pathological High Frequency Oscillation (pHFO and large areas of 38 µM Ab re-depositions. Device 1 sensitively “feels” Ab damage because of its Frequency Oscillation (HFO enhanced the hummingbird- like hovering pattern with higher reentrant energy sensitivity of 0.12 pj/bit/s/µm3 without Ab compared with Ab, 13 aj/bit/s/µm3/nM over 3.8-471 nM range over 0.003-4s. Device 1 reliably detected early CR dysfunction privileged to avoid epilepsy.

  12. Realizing a supercapacitor in an electrical circuit

    International Nuclear Information System (INIS)

    Fukuhara, Mikio; Kuroda, Tomoyuki; Hasegawa, Fumihiko

    2014-01-01

    Capacitors are commonly used in electronic resonance circuits; however, capacitors have not been used for storing large amounts of electrical energy in electrical circuits. Here, we report a superior RC circuit which serves as an electrical storage system characterized by quick charging and long-term discharging of electricity. The improved energy storage characteristics in this mixed electric circuit (R 1  + R 2 C 1 ) with small resistor R 1 , large resistor R 2 , and large capacitor C 1 are derived from the damming effect by large R 2 in simple parallel R 2 C 1 circuit. However, no research work has been carried out previously on the use of capacitors as electrical energy storage devices in circuits. Combined with nanotechnology, we hope that our finding will play a remarkable role in a variety of applications such as hybrid electric vehicles and backup power supplies

  13. Feasibility of epicardial adipose tissue quantification in non-ECG-gated low-radiation-dose CT: comparison with prospectively ECG-gated cardiac CT

    Energy Technology Data Exchange (ETDEWEB)

    Simon-Yarza, Isabel; Viteri-Ramirez, Guillermo; Saiz-Mendiguren, Ramon; Slon-Roblero, Pedro J.; Paramo, Maria [Dept. of Radiology, Clinica Univ. de Navarra, Pamplona (Spain); Bastarrika, Gorka [Dept. of Radiology, Clinica Univ. de Navarra, Pamplona (Spain); Cardiac Imaging Unit, Clinica Univ. de Navarra, Pamplona (Spain)], e-mail: bastarrika@unav.es

    2012-06-15

    Background: Epicardial adipose tissue (EAT) is an important indicator of cardiovascular risk. This parameter is generally assessed on ECG-gated computed tomography (CT) images. Purpose: To evaluate feasibility and reliability of EAT quantification on non-gated thoracic low-radiation-dose CT examinations with respect to prospectively ECG-gated cardiac CT acquisition. Material and Methods: Sixty consecutive asymptomatic smokers (47 men; mean age 64 {+-} 9.8 years) underwent low-dose CT of the chest and prospectively ECG-gated cardiac CT acquisitions (64-slice dual-source CT). The two examinations were reconstructed with the same range, field of view, slice thickness, and convolution algorithm. Two independent observers blindly quantified EAT volume using commercially available software. Data were compared with paired sample Student t-test, concordance correlation coefficients (CCC), and Bland-Altman plots. Results: No statistically significant difference was observed for EAT volume quantification with low-dose-CT (141.7 {+-} 58.3 mL) with respect to ECG-gated CT (142.7 {+-} 57.9 mL). Estimation of CCC showed almost perfect concordance between the two techniques for EAT-volume assessment (CCC, 0.99; mean difference, 0.98 {+-} 5.1 mL). Inter-observer agreement for EAT volume estimation was CCC: 0.96 for low-dose-CT examinations and 0.95 for ECG-gated CT. Conclusion: Non-gated low-dose CT allows quantifying EAT with almost the same concordance and reliability as using dedicated prospectively ECG-gated cardiac CT acquisition protocols.

  14. Expression of Sterol Regulatory Element-Binding Proteins in epicardial adipose tissue in patients with coronary artery disease and diabetes mellitus: preliminary study

    Science.gov (United States)

    Pérez-Belmonte, Luis M.; Moreno-Santos, Inmaculada; Cabrera-Bueno, Fernando; Sánchez-Espín, Gemma; Castellano, Daniel; Such, Miguel; Crespo-Leiro, María G; Carrasco-Chinchilla, Fernando; Alonso-Pulpón, Luis; López-Garrido, Miguel; Ruiz-Salas, Amalio; Becerra-Muñoz, Víctor M.; Gómez-Doblas, Juan J.; de Teresa-Galván, Eduardo; Jiménez-Navarro, Manuel

    2017-01-01

    Objectives: Sterol regulatory element-binding proteins (SREBP) genes are crucial in lipid biosynthesis and cardiovascular homeostasis. Their expression in epicardial adipose tissue (EAT) and their influence in the development of coronary artery disease (CAD) and type-2 diabetes mellitus remain to be determined. The aim of our study was to evaluate the expression of SREBP genes in EAT in patients with CAD according to diabetes status and its association with clinical and biochemical data. Methods: SREBP-1 and SREBP-2 mRNA expression levels were measured in EAT from 49 patients with CAD (26 with diabetes) and 23 controls without CAD or diabetes. Results: Both SREBPs mRNA expression were significantly higher in patients with CAD and diabetes (pcardiovascular risk factor for coronary artery disease in patients with type-2 diabetes (SREBP-1: OR 1.7, 95%CI 1.1-2.5, p=0.02; SREBP-2: OR 1.6, 95%CI 1.2-3, p=0.02) and were independently associated with the presence of multivessel CAD, left main and anterior descending artery stenosis, and higher total and LDL cholesterol levels, and lower HDL cholesterol levels, in patients with CAD and diabetes. Conclusions: SREBP genes are expressed in EAT and were higher in CAD patients with diabetes than those patients without CAD or diabetes. SREBP expression was associated as cardiovascular risk factor for the severity of CAD and the poor lipid control. In this preliminary study we suggest the importance of EAT in the lipid metabolism and cardiovascular homeostasis for coronary atherosclerosis of patients with diabetes and highlight a future novel therapeutic target. PMID:28367087

  15. Feasibility of epicardial adipose tissue quantification in non-ECG-gated low-radiation-dose CT: comparison with prospectively ECG-gated cardiac CT

    International Nuclear Information System (INIS)

    Simon-Yarza, Isabel; Viteri-Ramirez, Guillermo; Saiz-Mendiguren, Ramon; Slon-Roblero, Pedro J.; Paramo, Maria; Bastarrika, Gorka

    2012-01-01

    Background: Epicardial adipose tissue (EAT) is an important indicator of cardiovascular risk. This parameter is generally assessed on ECG-gated computed tomography (CT) images. Purpose: To evaluate feasibility and reliability of EAT quantification on non-gated thoracic low-radiation-dose CT examinations with respect to prospectively ECG-gated cardiac CT acquisition. Material and Methods: Sixty consecutive asymptomatic smokers (47 men; mean age 64 ± 9.8 years) underwent low-dose CT of the chest and prospectively ECG-gated cardiac CT acquisitions (64-slice dual-source CT). The two examinations were reconstructed with the same range, field of view, slice thickness, and convolution algorithm. Two independent observers blindly quantified EAT volume using commercially available software. Data were compared with paired sample Student t-test, concordance correlation coefficients (CCC), and Bland-Altman plots. Results: No statistically significant difference was observed for EAT volume quantification with low-dose-CT (141.7 ± 58.3 mL) with respect to ECG-gated CT (142.7 ± 57.9 mL). Estimation of CCC showed almost perfect concordance between the two techniques for EAT-volume assessment (CCC, 0.99; mean difference, 0.98 ± 5.1 mL). Inter-observer agreement for EAT volume estimation was CCC: 0.96 for low-dose-CT examinations and 0.95 for ECG-gated CT. Conclusion: Non-gated low-dose CT allows quantifying EAT with almost the same concordance and reliability as using dedicated prospectively ECG-gated cardiac CT acquisition protocols

  16. Transesophageal Echocardiography-Guided Epicardial Left Ventricular Lead Placement by Video-Assisted Thoracoscopic Surgery in Nonresponders to Biventricular Pacing and Previous Chest Surgery.

    Science.gov (United States)

    Schroeder, Carsten; Chung, Jane M; Mackall, Judith A; Cakulev, Ivan T; Patel, Aaron; Patel, Sunny J; Hoit, Brian D; Sahadevan, Jayakumar

    2018-06-14

    The aim of the study was to study the feasibility, safety, and efficacy of transesophageal echocardiography-guided intraoperative left ventricular lead placement via a video-assisted thoracoscopic surgery approach in patients with failed conventional biventricular pacing. Twelve patients who could not have the left ventricular lead placed conventionally underwent epicardial left ventricular lead placement by video-assisted thoracoscopic surgery. Eight patients had previous chest surgery (66%). Operative positioning was a modified far lateral supine exposure with 30-degree bed tilt, allowing for groin and sternal access. To determine the optimal left ventricular location for lead placement, the left ventricular surface was divided arbitrarily into nine segments. These segments were transpericardially paced using a hand-held malleable pacing probe identifying the optimal site verified by transesophageal echocardiography. The pacing leads were screwed into position via a limited pericardiotomy. The video-assisted thoracoscopic surgery approach was successful in all patients. Biventricular pacing was achieved in all patients and all reported symptomatic benefit with reduction in New York Heart Association class from III to I-II (P = 0.016). Baseline ejection fraction was 23 ± 3%; within 1-year follow-up, the ejection fraction increased to 32 ± 10% (P = 0.05). The mean follow-up was 566 days. The median length of hospital stay was 7 days with chest tube removal between postoperative days 2 and 5. In patients who are nonresponders to conventional biventricular pacing, intraoperative left ventricular lead placement using anatomical and functional characteristics via a video-assisted thoracoscopic surgery approach is effective in improving heart failure symptoms. This optimized left ventricular lead placement is feasible and safe. Previous chest surgery is no longer an exclusion criterion for a video-assisted thoracoscopic surgery approach.

  17. Accumulation of epicardial fat rather than visceral fat is an independent risk factor for left ventricular diastolic dysfunction in patients undergoing peritoneal dialysis.

    Science.gov (United States)

    Lin, Heng-Hsu; Lee, Jen-Kuang; Yang, Chung-Yi; Lien, Yu-Chung; Huang, Jenq-Wen; Wu, Cho-Kai

    2013-08-30

    Symptoms of heart failure with preserved left ventricular systolic function are common among patients undergoing peritoneal dialysis (PD). Epicardial fat (EpF) is an ectopic fat depot with possible paracrine or mechanical effects on myocardial function. The aim of our current study is to assess the association between EpF and Left ventricular diastolic dysfunction (LVDD) in patients undergoing PD and to clarify the relationships among EpF, inflammation, and LVDD in this population. This was a cross-sectional study of 149 patients with preserved left ventricular systolic function who were undergoing PD. LVDD was diagnosed (according to the European Society of Cardiology guidelines) and EpF thickness measured by echocardiography. The patients without LVDD were used as controls. The serum inflammatory biomarker high-sensitivity C-reactive protein (hsCRP) was measured. The location and amount of adipose tissue were assessed by computed tomography (CT) at the level of the fourth lumbar vertebra. Subjects with LVDD had higher levels of hsCRP, more visceral and peritoneal fat, and thicker EpF (all p EpF all correlated significantly (p EpF was the most powerful determinant of LVDD (odds ratio = 2.41, 95% confidence interval = 1.43-4.08, p EpF thickness also correlated significantly with the ratio of transmitral Doppler early filling velocity to tissue Doppler early diastolic mitral annular velocity (E/e'; r = 0.27, p EpF thickness is significantly independently associated with LVDD in patients undergoing PD and may be involved in its pathogenesis.

  18. The analysis and design of linear circuits

    CERN Document Server

    Thomas, Roland E; Toussaint, Gregory J

    2009-01-01

    The Analysis and Design of Linear Circuits, 6e gives the reader the opportunity to not only analyze, but also design and evaluate linear circuits as early as possible. The text's abundance of problems, applications, pedagogical tools, and realistic examples helps engineers develop the skills needed to solve problems, design practical alternatives, and choose the best design from several competing solutions. Engineers searching for an accessible introduction to resistance circuits will benefit from this book that emphasizes the early development of engineering judgment.

  19. Test and Diagnosis of Integrated Circuits

    OpenAIRE

    Bosio , Alberto

    2015-01-01

    The ever-increasing growth of the semiconductor market results in an increasing complexity of digital circuits. Smaller, faster, cheaper and low-power consumption are the main challenges in semiconductor industry. The reduction of transistor size and the latest packaging technology (i.e., System-On-a-Chip, System-In-Package, Trough Silicon Via 3D Integrated Circuits) allows the semiconductor industry to satisfy the latest challenges. Although producing such advanced circuits can benefit users...

  20. An analog integrated circuit design laboratory

    OpenAIRE

    Mondragon-Torres, A.F.; Mayhugh, Jr.; Pineda de Gyvez, J.; Silva-Martinez, J.; Sanchez-Sinencio, E.

    2003-01-01

    We present the structure of an analog integrated circuit design laboratory to instruct at both, senior undergraduate and entry graduate levels. The teaching material includes: a laboratory manual with analog circuit design theory, pre-laboratory exercises and circuit design specifications; a reference web page with step by step instructions and examples; the use of mathematical tools for automation and analysis; and state of the art CAD design tools in use by industry. Upon completion of the ...

  1. Logarithmic current-measuring transistor circuits

    DEFF Research Database (Denmark)

    Højberg, Kristian Søe

    1967-01-01

    Describes two transistorized circuits for the logarithmic measurement of small currents suitable for nuclear reactor instrumentation. The logarithmic element is applied in the feedback path of an amplifier, and only one dual transistor is used as logarithmic diode and temperature compensating...... transistor. A simple one-amplifier circuit is compared with a two-amplifier system. The circuits presented have been developed in connexion with an amplifier using a dual m.o.s. transistor input stage with diode-protected gates....

  2. Electronic circuits for communications systems: A compilation

    Science.gov (United States)

    1972-01-01

    The compilation of electronic circuits for communications systems is divided into thirteen basic categories, each representing an area of circuit design and application. The compilation items are moderately complex and, as such, would appeal to the applications engineer. However, the rationale for the selection criteria was tailored so that the circuits would reflect fundamental design principles and applications, with an additional requirement for simplicity whenever possible.

  3. Instrumentation for Sodium Circuits; Instrumentation des Circuits de Sodium

    Energy Technology Data Exchange (ETDEWEB)

    Cambillard, E. [CEA, Centre d' Etudes Nucleaires de Fontenay-aux-Roses (France); Lions, N. [CEA, Centre d' Etudes Nucleaires de Cadarache (France)

    1967-06-15

    Electromagnetic flow meters, level gauges and differential pressure gauges are among the main measurement instruments designed and tested at the Commissariat a l'Energie Atomique (CEA) for sodium reactors. The main characteristics of the flow meters used with RAPSODIE are indicated. The instruments used in this connection are of the permanent -magnet or electromagnet type (in the primary circuits). A description is given of the calibration methods employed - use is made of diaphragms or Venturi tubes as standard flow meters - and information is given on the results measured for maximum sodium flows of 400 m{sup 3}/h. Three types of continuous level gauge have been studied. Resistance gauge. Two varieties used for the 1 - and 10-MW test circuits of RAPSODIE are described. In one there is a compensation resistance along the whole height of the measuring element (the continuous gauges used with the RAPSODIE reactor are at present of this type). In the other type of gauge a device is incorporated to heat the measurement element and prevent the formation of conducting deposits (prototype sodium tests have been completed). Induction gauge. This type has two coupled coils and is fitted with a device to compensate for temperature effects. A description is given of a prototype which has been built and the results obtained in the course of sodium tests are described. Ultrasonic gauge. With this type, a transmitter is fitted on top of the outside of the sodium container; there is also a vertical wave guide, the bottom of which is immersed in the liquid metal and possesses a reflector system which returns the ultrasonic beam towards the surface. Fixed reference marks provide a permanent means of calibration and the whole apparatus is welded. This type of gauge is now being constructed. The differential pressure gauges that have been built, and used in particular with Venturi tube flow meters, are modified versions of the devices employed with the 1 - and 10-MW test circuits of

  4. Analog circuit design art, science, and personalities

    CERN Document Server

    Williams, Jim

    1991-01-01

    Analog Circuit Design: Art, Science, and Personalities discusses the many approaches and styles in the practice of analog circuit design. The book is written in an informal yet informative manner, making it easily understandable to those new in the field. The selection covers the definition, history, current practice, and future direction of analog design; the practice proper; and the styles in analog circuit design. The book also includes the problems usually encountered in analog circuit design; approach to feedback loop design; and other different techniques and applications. The text is

  5. Circuit For Control Of Electromechanical Prosthetic Hand

    Science.gov (United States)

    Bozeman, Richard J., Jr.

    1995-01-01

    Proposed circuit for control of electromechanical prosthetic hand derives electrical control signals from shoulder movements. Updated, electronic version of prosthesis, that includes two hooklike fingers actuated via cables from shoulder harness. Circuit built around favored shoulder harness, provides more dexterous movement, without incurring complexity of computer-controlled "bionic" or hydraulically actuated devices. Additional harness and potentiometer connected to similar control circuit mounted on other shoulder. Used to control stepping motor rotating hand about prosthetic wrist to one of number of angles consistent with number of digital outputs. Finger-control signals developed by circuit connected to first shoulder harness transmitted to prosthetic hand via sliprings at prosthetic wrist joint.

  6. Model Order Reduction for Electronic Circuits:

    DEFF Research Database (Denmark)

    Hjorth, Poul G.; Shontz, Suzanne

    Electronic circuits are ubiquitous; they are used in numerous industries including: the semiconductor, communication, robotics, auto, and music industries (among many others). As products become more and more complicated, their electronic circuits also grow in size and complexity. This increased...... in the semiconductor industry. Circuit simulation proceeds by using Maxwell’s equations to create a mathematical model of the circuit. The boundary element method is then used to discretize the equations, and the variational form of the equations are then solved on the graph network....

  7. Radiation-hardened CMOS integrated circuits

    International Nuclear Information System (INIS)

    Derbenwick, G.F.; Hughes, R.C.

    1977-01-01

    Electronic circuits that operate properly after exposure to ionizing radiation are necessary for nuclear weapon systems, satellites, and apparatus designed for use in radiation environments. The program to develop and theoretically model radiation-tolerant integrated circuit components has resulted in devices that show an improvement in hardness up to a factor of ten thousand over earlier devices. An inverter circuit produced functions properly after an exposure of 10 6 Gy (Si) which, as far as is known, is the record for an integrated circuit

  8. Hyperchaotic circuit with damped harmonic oscillators

    DEFF Research Database (Denmark)

    Lindberg, Erik; Murali, K.; Tamasevicius, A.

    2001-01-01

    A simple fourth-order hyperchaotic circuit with damped harmonic oscillators is described. ANP3 and PSpice simulations including an eigenvalue study of the linearized Jacobian are presented together with a hardware implementation. The circuit contains two inductors with series resistance, two ideal...... capacitors and one nonlinear active conductor. The Lyapunov exponents are presented to confirm the hyperchaotic nature of the oscillations of the circuit. The nonlinear conductor is realized with a diode. A negative impedance converter and a linear resistor. The performance of the circuit is investigated...... by means of numerical integration of the appropriate differential equations....

  9. Electronic circuit for control rod attracting electromagnet

    International Nuclear Information System (INIS)

    Ito, Koji.

    1991-01-01

    The present invention provides a discharging circuit for control rod attracting electromagnet used for a reactor which is highly reliable and has high performance. The resistor of the circuit comprises a non-linear resistor element and a blocking rectification element connected in series. The discharging circuit can be prevented from short-circuit by selecting a resistor having a resistance value about ten times as great as the coil resistance, even in a case where the blocking rectification element and the non-linear resistor element are failed. Accordingly, reduction of attracting force and the increase of scream releasing time can be minimized. (I.S.)

  10. Electric circuit theory applied electricity and electronics

    CERN Document Server

    Yorke, R

    1981-01-01

    Electric Circuit Theory provides a concise coverage of the framework of electrical engineering. Comprised of six chapters, this book emphasizes the physical process of electrical engineering rather than abstract mathematics. Chapter 1 deals with files, circuits, and parameters, while Chapter 2 covers the natural and forced response of simple circuit. Chapter 3 talks about the sinusoidal steady state, and Chapter 4 discusses the circuit analysis. The fifth chapter tackles frequency response of networks, and the last chapter covers polyphase systems. This book will be of great help to electrical

  11. Intrinsic neuromodulation: altering neuronal circuits from within.

    Science.gov (United States)

    Katz, P S; Frost, W N

    1996-02-01

    There are two sources of neuromodulation for neuronal circuits: extrinsic inputs and intrinsic components of the circuits themselves. Extrinsic neuromodulation is known to be pervasive in nervous systems, but intrinsic neuromodulation is less recognized, despite the fact that it has now been demonstrated in sensory and neuromuscular circuits and in central pattern generators. By its nature, intrinsic neuromodulation produces local changes in neuronal computation, whereas extrinsic neuromodulation can cause global changes, often affecting many circuits simultaneously. Studies in a number of systems are defining the different properties of these two forms of neuromodulation.

  12. The Software Reliability of Large Scale Integration Circuit and Very Large Scale Integration Circuit

    OpenAIRE

    Artem Ganiyev; Jan Vitasek

    2010-01-01

    This article describes evaluation method of faultless function of large scale integration circuits (LSI) and very large scale integration circuits (VLSI). In the article there is a comparative analysis of factors which determine faultless of integrated circuits, analysis of already existing methods and model of faultless function evaluation of LSI and VLSI. The main part describes a proposed algorithm and program for analysis of fault rate in LSI and VLSI circuits.

  13. Electrical circuit theory and technology

    CERN Document Server

    Bird, John

    2014-01-01

    This much-loved textbook explains the principles of electrical circuit theory and technology so that students of electrical and mechanical engineering can master the subject. Real-world situations and engineering examples put the theory into context. The inclusion of worked problems with solutions help you to learn and further problems then allow you to test and confirm you have fully understood each subject. In total the book contains 800 worked problems, 1000 further problems and 14 revision tests with answers online. This an ideal text for foundation and undergraduate degree students and those on upper level vocational engineering courses, in particular electrical and mechanical. It provides a sound understanding of the knowledge required by technicians in fields such as electrical engineering, electronics and telecommunications. This edition has been updated with developments in key areas such as semiconductors, transistors, and fuel cells, along with brand new material on ABCD parameters and Fourier's An...

  14. Scaling of graphene integrated circuits.

    Science.gov (United States)

    Bianchi, Massimiliano; Guerriero, Erica; Fiocco, Marco; Alberti, Ruggero; Polloni, Laura; Behnam, Ashkan; Carrion, Enrique A; Pop, Eric; Sordan, Roman

    2015-05-07

    The influence of transistor size reduction (scaling) on the speed of realistic multi-stage integrated circuits (ICs) represents the main performance metric of a given transistor technology. Despite extensive interest in graphene electronics, scaling efforts have so far focused on individual transistors rather than multi-stage ICs. Here we study the scaling of graphene ICs based on transistors from 3.3 to 0.5 μm gate lengths and with different channel widths, access lengths, and lead thicknesses. The shortest gate delay of 31 ps per stage was obtained in sub-micron graphene ROs oscillating at 4.3 GHz, which is the highest oscillation frequency obtained in any strictly low-dimensional material to date. We also derived the fundamental Johnson limit, showing that scaled graphene ICs could be used at high frequencies in applications with small voltage swing.

  15. Shapeable short circuit resistant capacitor

    Science.gov (United States)

    Taylor, Ralph S.; Myers, John D.; Baney, William J.

    2015-10-06

    A ceramic short circuit resistant capacitor that is bendable and/or shapeable to provide a multiple layer capacitor that is extremely compact and amenable to desirable geometries. The capacitor that exhibits a benign failure mode in which a multitude of discrete failure events result in a gradual loss of capacitance. Each event is a localized event in which localized heating causes an adjacent portion of one or both of the electrodes to vaporize, physically cleaning away electrode material from the failure site. A first metal electrode, a second metal electrode, and a ceramic dielectric layer between the electrodes are thin enough to be formed in a serpentine-arrangement with gaps between the first electrode and the second electrode that allow venting of vaporized electrode material in the event of a benign failure.

  16. [Migratory circuits in western Mexico].

    Science.gov (United States)

    Durand, J

    1986-11-01

    The author examines patterns of internal and international migration in western Mexico. "Drawing on data from different sources and statistics, the essay demonstrates the importance of both types of migration, the changes in endogenous and exogenous factors which have affected the life and the migratory patterns of the population of this region. The migratory circuit being a flow not only of persons, but of goods and capital as well, the cities, specifically that of Guadalajara, have a strategic importance. They fulfill various functions and have become the backbone of the migratory process: they serve as centers for attracting and 'hosting' internal migrants as well as places of origin for other migrants; jumping-off points for international migrants; and the milieu in which many returning migrants of rural origin settle." (SUMMARY IN ENG AND FRE) excerpt

  17. TIME CALIBRATED OSCILLOSCOPE SWEEP CIRCUIT

    Science.gov (United States)

    Smith, V.L.; Carstensen, H.K.

    1959-11-24

    An improved time calibrated sweep circuit is presented, which extends the range of usefulness of conventional oscilloscopes as utilized for time calibrated display applications in accordance with U. S. Patent No. 2,832,002. Principal novelty resides in the provision of a pair of separate signal paths, each of which is phase and amplitude adjustable, to connect a high-frequency calibration oscillator to the output of a sawtooth generator also connected to the respective horizontal deflection plates of an oscilloscope cathode ray tube. The amplitude and phase of the calibration oscillator signals in the two signal paths are adjusted to balance out feedthrough currents capacitively coupled at high frequencies of the calibration oscillator from each horizontal deflection plate to the vertical plates of the cathode ray tube.

  18. Integrated Circuit Electromagnetic Immunity Handbook

    Science.gov (United States)

    Sketoe, J. G.

    2000-08-01

    This handbook presents the results of the Boeing Company effort for NASA under contract NAS8-98217. Immunity level data for certain integrated circuit parts are discussed herein, along with analytical techniques for applying the data to electronics systems. This handbook is built heavily on the one produced in the seventies by McDonnell Douglas Astronautics Company (MDAC, MDC Report E1929 of 1 August 1978, entitled Integrated Circuit Electromagnetic Susceptibility Handbook, known commonly as the ICES Handbook, which has served countless systems designers for over 20 years). Sections 2 and 3 supplement the device susceptibility data presented in section 4 by presenting information on related material required to use the IC susceptibility information. Section 2 concerns itself with electromagnetic susceptibility analysis and serves as a guide in using the information contained in the rest of the handbook. A suggested system hardening requirements is presented in this chapter. Section 3 briefly discusses coupling and shielding considerations. For conservatism and simplicity, a worst case approach is advocated to determine the maximum amount of RF power picked up from a given field. This handbook expands the scope of the immunity data in this Handbook is to of 10 MHz to 10 GHz. However, the analytical techniques provided are applicable to much higher frequencies as well. It is expected however, that the upper frequency limit of concern is near 10 GHz. This is due to two factors; the pickup of microwave energy on system cables and wiring falls off as the square of the wavelength, and component response falls off at a rapid rate due to the effects of parasitic shunt paths for the RF energy. It should be noted also that the pickup on wires and cables does not approach infinity as the frequency decreases (as would be expected by extrapolating the square law dependence of the high frequency roll-off to lower frequencies) but levels off due to mismatch effects.

  19. Short circuit in deep brain stimulation.

    Science.gov (United States)

    Samura, Kazuhiro; Miyagi, Yasushi; Okamoto, Tsuyoshi; Hayami, Takehito; Kishimoto, Junji; Katano, Mitsuo; Kamikaseda, Kazufumi

    2012-11-01

    The authors undertook this study to investigate the incidence, cause, and clinical influence of short circuits in patients treated with deep brain stimulation (DBS). After the incidental identification of a short circuit during routine follow-up, the authors initiated a policy at their institution of routinely evaluating both therapeutic impedance and system impendence at every outpatient DBS follow-up visit, irrespective of the presence of symptoms suggesting possible system malfunction. This study represents a report of their findings after 1 year of this policy. Implanted DBS leads exhibiting short circuits were identified in 7 patients (8.9% of the patients seen for outpatient follow-up examinations during the 12-month study period). The mean duration from DBS lead implantation to the discovery of the short circuit was 64.7 months. The symptoms revealing short circuits included the wearing off of therapeutic effect, apraxia of eyelid opening, or dysarthria in 6 patients with Parkinson disease (PD), and dystonia deterioration in 1 patient with generalized dystonia. All DBS leads with short circuits had been anchored to the cranium using titanium miniplates. Altering electrode settings resulted in clinical improvement in the 2 PD cases in which patients had specific symptoms of short circuits (2.5%) but not in the other 4 cases. The patient with dystonia underwent repositioning and replacement of a lead because the previous lead was located too anteriorly, but did not experience symptom improvement. In contrast to the sudden loss of clinical efficacy of DBS caused by an open circuit, short circuits may arise due to a gradual decrease in impedance, causing the insidious development of neurological symptoms via limited or extended potential fields as well as shortened battery longevity. The incidence of short circuits in DBS may be higher than previously thought, especially in cases in which DBS leads are anchored with miniplates. The circuit impedance of DBS

  20. Design of an improved RCD buffer circuit for full bridge circuit

    Science.gov (United States)

    Yang, Wenyan; Wei, Xueye; Du, Yongbo; Hu, Liang; Zhang, Liwei; Zhang, Ou

    2017-05-01

    In the full bridge inverter circuit, when the switch tube suddenly opened or closed, the inductor current changes rapidly. Due to the existence of parasitic inductance of the main circuit. Therefore, the surge voltage between drain and source of the switch tube can be generated, which will have an impact on the switch and the output voltage. In order to ab sorb the surge voltage. An improve RCD buffer circuit is proposed in the paper. The peak energy will be absorbed through the buffer capacitor of the circuit. The part energy feedback to the power supply, another part release through the resistor in the form of heat, and the circuit can absorb the voltage spikes. This paper analyzes the process of the improved RCD snubber circuit, According to the specific parameters of the main circuit, a reasonable formula for calculating the resistance capacitance is given. A simulation model will be modulated in Multisim, which compared the waveform of tube voltage and the output waveform of the circuit without snubber circuit with the improved RCD snubber circuit. By comparing and analyzing, it is proved that the improved buffer circuit can absorb surge voltage. Finally, experiments are demonstrated to validate that the correctness of the RC formula and the improved RCD snubber circuit.