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Sample records for cardiac electrical storm

  1. Electrical storm: Incidence, Prognosis and Therapy

    Science.gov (United States)

    Proietti, Riccardo; Sagone, Antonio

    2011-01-01

    Implantable defibrillators are lifesavers and have improved mortality rates in patients at risk of sudden death, both in primary and secondary prevention. However, they are unable to modify the myocardial substrate, which remains susceptible to life-threatening ventricular arrhythmias. Electrical storm is a clinical entity characterized the recurrence of hemodynamically unstable ventricular tachycardia and/or ventricular fibrillation, twice or more in 24 hours, requiring electrical cardioversion or defibrillation. With the arrival of the implantable cardioverter-defibrillator, this definition was broadened, and electrical storm is now defined as the occurrence of three or more distinct episodes of ventricular tachycardia or ventricular fibrillation in 24 hours, requiring the intervention of the defibrillator (anti-tachycardia pacing or shock). Clinical presentation can be very dramatic, with multiple defibrillator shocks and hemodynamic instability. Managing its acute presentation is a challenge, and mortality is high both in the acute phase and in the long term. In large clinical trials involving patients implanted with a defibrillator both for primary and secondary prevention, electrical storm appears to be a harbinger of cardiac death, with notably high mortality soon after the event. In most cases, the storm can be interrupted by medical therapy, though transcatheter radiofrequency ablation of ventricular arrhythmias may be an effective treatment for refractory cases. This narrative literature review outlines the main clinical characteristics of electrical storm and emphasises critical points in approaching and managing this peculiar clinical entity. Finally focus is given to studies that consider transcatheter ablation therapy in cases refractory to medical treatment. PMID:21468247

  2. A case of thyroid storm with cardiac arrest

    Directory of Open Access Journals (Sweden)

    Nakashima Y

    2014-05-01

    Full Text Available Yutaka Nakashima,1 Tsuneaki Kenzaka,2 Masanobu Okayama,3 Eiji Kajii31Department for Support of Rural Medicine, Yamaguchi Grand Medical Center, 2Division of General Medicine, Center for Community Medicine, Jichi Medical University School of Medicine, Shimotsuke, Japan; 3Division of Community and Family Medicine, Center for Community Medicine, Jichi Medical University School of Medicine, Shimotsuke, JapanAbstract: A 23-year-old man became unconscious while jogging. He immediately received basic life support from a bystander and was transported to our hospital. On arrival, his spontaneous circulation had returned from a state of ventricular fibrillation and pulseless electrical activity. Following admission, hyperthyroidism led to a suspicion of thyroid storm, which was then diagnosed as a possible cause of the cardiac arrest. Although hyperthyroidism-induced cardiac arrest including ventricular fibrillation is rare, it should be considered when diagnosing the cause of treatable cardiac arrest.Keywords: hyperthyroidism, ventricular fibrillation, treatable cardiac arrest, cardiac arrest, cardiopulmonary arrest

  3. Electrical storm: A clinical and electrophysiological overview

    Institute of Scientific and Technical Information of China (English)

    Sergio; Conti; Salvatore; Pala; Viviana; Biagioli; Giuseppe; Del; Giorno; Martina; Zucchetti; Eleonora; Russo; Vittoria; Marino; Antonio; Dello; Russo; Michela; Casella; Francesca; Pizzamiglio; Valentina; Catto; Claudio; Tondo; Corrado; Carbucicchio

    2015-01-01

    Electrical storm(ES) is a clinical condition characterized by three or more ventricular arrhythmia episodes leading to appropriate implantable cardioverterdefibrillator(ICD) therapies in a 24 h period. Mostly, arrhythmias responsible of ES are multiple morphologies of monomorphic ventricular tachycardia(VT), but polymorphic VT and ventricular fibrillation can also result in ES. Clinical presentation is very dramatic in most cases, strictly related to the cardiac disease that may worsen electrical and hemodynamic decompensation. Therefore ES management is challenging in the majority of cases and a high mortality is the rule both in the acute and in the long-term phases. Different underlying cardiomyopathies provide significant clues into the mechanism of ES, which can arise in the setting of structural arrhythmogenic cardiomyopathies or rarely in patients with inherited arrhythmic syndrome, impacting on pharmacological treatment, on ICD programming, and on the opportunity to apply strategies of catheter ablation. This latter has become a pivotal form of treatment due to its high efficacy in modifying the arrhythmogenic substrate and in achieving rhythm stability, aiming at reducing recurrences of ventricular arrhythmia and at improving overall survival. In this review, the most relevant epidemiological and clinical aspects of ES, with regard to the acute and long-term follow-up implications, were evaluated, focusing on these novel therapeutic strategies of treatment.

  4. Electrical storm: Incidence, Prognosis and Therapy

    OpenAIRE

    PROIETTI, RICCARDO; Sagone, Antonio

    2011-01-01

    Implantable defibrillators are lifesavers and have improved mortality rates in patients at risk of sudden death, both in primary and secondary prevention. However, they are unable to modify the myocardial substrate, which remains susceptible to life-threatening ventricular arrhythmias. Electrical storm is a clinical entity characterized the recurrence of hemodynamically unstable ventricular tachycardia and/or ventricular fibrillation, twice or more in 24 hours, requiring electrical cardiovers...

  5. Electrical storm in systemic sclerosis: Inside the electroanatomic substrate

    Institute of Scientific and Technical Information of China (English)

    Michela; Casella; Corrado; Carbucicchio; Eleonora; Russo; Francesca; Pizzamiglio; Paolo; Golia; Sergio; Conti; Fabrizio; Costa; Antonio; Dello; Russo; Claudio; Tondo

    2014-01-01

    We report the case of a 63-year-old woman affected by a severe form of systemic scleroderma with pul-monary involvement(interstitial fibrosis diagnosed by biopsy and moderate pulmonary hypertension) and cardiac involvement(paroxysmal atrial fibrillation, right atrial flutter treated by catheter ablation, ventricular tachyarrhythmias, previous dual chamber implantable cardioverter defibrillator implant). Because of recurrent electrical storms refractory to iv antiarrhythmic drugs the patient was referred to our institution to undergo catheter ablation. During electrophysiological proce-dure a 3D shell of cardiac anatomy was created with intracardiac echocardiography pointing out a significant right ventricular dilatation with a complex aneurysmal lesion characterized by thin walls and irregular multiple trabeculae. A substrate-guided strategy of catheter ab-lation was accomplished leading to a complete electri-cal isolation of the aneurism and to the abolishment of all abnormal electrical activities. The use of advanced strategies of imaging together with electroanatomical mapping added important information to the complex arrhythmogenic substrate and improved efficacy and safety.

  6. Valves replacement operation in treatment of electrical storm induced by rheumatic valves disease

    Institute of Scientific and Technical Information of China (English)

    Zhenqiang Chen; Hui Zhang; Yang Zhao; Haiji Yang; Sheng'ai Ye; Liang Cheng; Ying Zhang

    2007-01-01

    Objective: To present a case of electrical storm (ES) in a female patient with rheumatic valve disease. Methods: A female patient with severe rheumatic valve disease suffered an unexpected ES. She received more than 50 electrical shocks for repeated cardiac arrests due to ES over 16 hours. Then she received beta-blocking agent treatment and had an operation of double valves replacement. Results: ES was suppressed by sympathetic blockade with beta-receptor blocker and finally disappeared after the double pathological valves had been replaced. Conclusion: Increased sympathetic activity plays an important role in the genesis of electrical storm and sympathetic blockade may effectively suppress ES. However, the most important thing in the treatment of ES is to identify and eliminate the underlying cause of ES.

  7. Historically Large Geomagnetic Storms and Potential Electric Power Grid Impacts

    Science.gov (United States)

    Kappenman, J. G.

    2004-05-01

    While recent work has been done to examine the possible Dst Intensity of historically large geomagnetic storms, the impacts caused to modern day electric power grids from these storms occurs due to rapid rate-of-change of regional geomagnetic fields which in most cases are driven by large ionospheric electrojet current intensifications. These temporally and spatially dynamic disturbance morphologies are not well-characterized by Dst or other broad geomagnetic storm indices. For estimates of storm intensity that correctly scale the threat potential to electric power grids, it is necessary to describe the rate-of-change of geomagnetic field. The rate-of-change of the geomagnetic field (dB/dt usually measured in nT/min) creates at ground level a geoelectric field that causes the flow of geomagnetically-induced currents (GIC) through ground connection points in electric power grids. Therefore in general, the larger the dB/dt, the larger the resulting geo-electric field and GIC in exposed power grid infrastructures and the greater the operational impact these induced currents will have on the power grid. Both extensive modeling analysis and recent operational experience suggests that power grids are becoming more vulnerable to geomagnetic storms as they grow in size and complexity. Also, large power grid blackouts have occurred at relatively low geomagnetic storm intensities. For example, the regional disturbance intensity that triggered the Hydro Quebec collapse during the March 13, 1989 Superstorm only reached an intensity of 479 nT/min. Large numbers of power system impacts in the United States were also observed for intensities that ranged from 300 to 600 nT/min during this storm. Yet both recent and historical data indicate that storms with disturbance levels that range from 2000 nT/min to as much ~5000 nT/min may be possible over extensive regions at latitudes of concern for large continental power grids across North America and Europe. Large GIC have also been

  8. Electrical stimulation systems for cardiac tissue engineering.

    Science.gov (United States)

    Tandon, Nina; Cannizzaro, Christopher; Chao, Pen-Hsiu Grace; Maidhof, Robert; Marsano, Anna; Au, Hoi Ting Heidi; Radisic, Milica; Vunjak-Novakovic, Gordana

    2009-01-01

    We describe a protocol for tissue engineering of synchronously contractile cardiac constructs by culturing cardiac cells with the application of pulsatile electrical fields designed to mimic those present in the native heart. Tissue culture is conducted in a customized chamber built to allow for cultivation of (i) engineered three-dimensional (3D) cardiac tissue constructs, (ii) cell monolayers on flat substrates or (iii) cells on patterned substrates. This also allows for analysis of the individual and interactive effects of pulsatile electrical field stimulation and substrate topography on cell differentiation and assembly. The protocol is designed to allow for delivery of predictable electrical field stimuli to cells, monitoring environmental parameters, and assessment of cell and tissue responses. The duration of the protocol is 5 d for two-dimensional cultures and 10 d for 3D cultures.

  9. Surface electric fields for North America during historical geomagnetic storms

    Science.gov (United States)

    Wei, Lisa H.; Homeier, Nichole; Gannon, Jennifer L.

    2013-01-01

    To better understand the impact of geomagnetic disturbances on the electric grid, we recreate surface electric fields from two historical geomagnetic storms—the 1989 “Quebec” storm and the 2003 “Halloween” storms. Using the Spherical Elementary Current Systems method, we interpolate sparsely distributed magnetometer data across North America. We find good agreement between the measured and interpolated data, with larger RMS deviations at higher latitudes corresponding to larger magnetic field variations. The interpolated magnetic field data are combined with surface impedances for 25 unique physiographic regions from the United States Geological Survey and literature to estimate the horizontal, orthogonal surface electric fields in 1 min time steps. The induced horizontal electric field strongly depends on the local surface impedance, resulting in surprisingly strong electric field amplitudes along the Atlantic and Gulf Coast. The relative peak electric field amplitude of each physiographic region, normalized to the value in the Interior Plains region, varies by a factor of 2 for different input magnetic field time series. The order of peak electric field amplitudes (largest to smallest), however, does not depend much on the input. These results suggest that regions at lower magnetic latitudes with high ground resistivities are also at risk from the effect of geomagnetically induced currents. The historical electric field time series are useful for estimating the flow of the induced currents through long transmission lines to study power flow and grid stability during geomagnetic disturbances.

  10. Finite Element Model of Cardiac Electrical Conduction.

    Science.gov (United States)

    Yin, John Zhihao

    1994-01-01

    In this thesis, we develop mathematical models to study electrical conduction of the heart. One important pattern of wave propagation of electrical excitation in the heart is reentry which is believed to be the underlying mechanism of some dangerous cardiac arhythmias such as ventricular tachycardia and ventricular fibrillation. We present in this thesis a new ionic channel model of the ventricular cardiac cell membrane to study the microscopic electrical properties of myocardium. We base our model on recent single channel experiment data and a simple physical diffusion model of the calcium channel. Our ionic channel model of myocardium has simpler differential equations and fewer parameters than previous models. Further more, our ionic channel model achieves better results in simulating the strength-interval curve when we connect the membrane patch model to form a one dimensional cardiac muscle strand. We go on to study a finite element model which uses multiple states and non-nearest neighbor interactions to include curvature and dispersion effects. We create a generalized lattice randomization to overcome the artifacts generated by the interaction between the local dynamics and the regularities of the square lattice. We show that the homogeneous model does not display spontaneous wavefront breakup in a reentrant wave propagation once the lattice artifacts have been smoothed out by lattice randomization with a randomization scale larger than the characteristic length of the interaction. We further develop a finite 3-D 3-state heart model which employs a probability interaction rule. This model is applied to the simulation of Body Surface Laplacian Mapping (BSLM) using a cylindrical volume conductor as the torso model. We show that BSLM has a higher spatial resolution than conventional mapping methods in revealing the underlying electrical activities of the heart. The results of these studies demonstrate that mathematical modeling and computer simulation are very

  11. Atmospheric Electricity Effects of Eastern Mediterranean Dust Storms

    Science.gov (United States)

    Katz, Shai; Yair, Yoav; Yaniv, Roy; Price, Colin

    2016-04-01

    We present atmospheric electrical measurements conducted at the Wise Observatory (WO) in Mizpe-Ramon (30035'N, 34045'E) and Mt. Hermon (30024'N, 35051'E), Israel, during two massive and unique dust storms that occurred over the Eastern Mediterranean region on February 10-11 and September 08-12, 2015. The first event transported Saharan dust from Egypt and the Sinai Peninsula in advance of a warm front of a Cyprus low pressure system. In the second event, dust particles were transported from the Syrian desert, which dominates the north-east border with Iraq, through flow associated with a shallow Persian trough system. In both events the concentrations of PM10 particles measured by the air-quality monitoring network of the Israeli Ministry of the Environment in Beer-Sheba reached values > 2200 μg m-3. Aerosol Optical Thickness (AOT) obtained from the AERONET station in Sde-Boker reached values up to 4.0. The gradual intensification of the first event reached peak values on the February 11th > 1200 μg m-3 and an AOT ~ 1.8, while the second dust storm commenced on September 8th with a sharp increase reaching peak values of 2225 μg m-3 and AOT of 4.0. Measurements of the fair weather vertical electric field (Ez) and of the vertical current density (Jz) were conducted continuously with a 1 minute temporal resolution. During the February event, very large fluctuations in the electrical parameters were measured at the WO. The Ez values changed between +1000 and +8000 V m-1 while the Jz fluctuated between -10 and +20 pA m-2 (this is an order of magnitude larger compared to the fair weather current density of ~2 pA m-2. In contrast, during the September event, Ez values registered at WO were between -430 and +10 V m-1 while the Jz fluctuated between -6 and +3 pA m2. For the September event the Hermon site showed Ez and Jz values fluctuating between -460 and +570 V m-1 and -14.5 and +18 pA m-2 respectively. The electric field and current variability, amplitude and the

  12. Optimization of electrical stimulation parameters for cardiac tissue engineering.

    Science.gov (United States)

    Tandon, Nina; Marsano, Anna; Maidhof, Robert; Wan, Leo; Park, Hyoungshin; Vunjak-Novakovic, Gordana

    2011-06-01

    In vitro application of pulsatile electrical stimulation to neonatal rat cardiomyocytes cultured on polymer scaffolds has been shown to improve the functional assembly of cells into contractile engineered cardiac tissues. However, to date, the conditions of electrical stimulation have not been optimized. We have systematically varied the electrode material, amplitude and frequency of stimulation to determine the conditions that are optimal for cardiac tissue engineering. Carbon electrodes, exhibiting the highest charge-injection capacity and producing cardiac tissues with the best structural and contractile properties, were thus used in tissue engineering studies. Engineered cardiac tissues stimulated at 3 V/cm amplitude and 3 Hz frequency had the highest tissue density, the highest concentrations of cardiac troponin-I and connexin-43 and the best-developed contractile behaviour. These findings contribute to defining bioreactor design specifications and electrical stimulation regime for cardiac tissue engineering.

  13. Massive Electrical Storm at Disease Onset in a Patient with Brugada Syndrome

    DEFF Research Database (Denmark)

    Pallisgaard, Jannik L; Gang, Uffe; Kanters, Jørgen K.;

    2014-01-01

    and fibrillation. Case Report A 49-year-old previously healthy man was admitted with electrical storm. The patient received direct current (DC) cardioversion shocks and only after intravenous lidocaine did the electrical storm slowly subside with a total of 255 DC shocks administered during the first 24 h after......Background Brugada syndrome (BrS) is a genetic arrhythmogenic disease characterized by ST-segment elevations in the right precordial leads of the electrocardiogram (ECG). These ECG changes may be concealed and BrS may present with electrical storm characterized by recurrent ventricular tachycardia...... admission. He fully recovered and received an implantable cardioverter-defibrillator. Subsequent drug challenge with flecainide revealed type 1 BrS. Conclusions Massive electrical storm can be the first symptom of BrS and the diagnostic ECG changes may be concealed at presentation. Although hundreds of DC...

  14. Combined Aircraft and Satellite-Derived Storm Electric Current and Lightning Rates Measurements and Implications for the Global Electric Circuit

    Science.gov (United States)

    Mach, Douglas M.; Blakeslee, Richard J.; Bateman, Monte G.

    2010-01-01

    Using rotating vane electric field mills and Gerdien capacitors, we measured the electric field profile and conductivity during 850 overflights of electrified shower clouds and thunderstorms spanning regions including the Southeastern United States, the Western Atlantic Ocean, the Gulf of Mexico, Central America and adjacent oceans, Central Brazil, and the South Pacific. The overflights include storms over land and ocean, with and without lightning, and with positive and negative fields above the storms. The measurements were made with the NASA ER-2 and the Altus-II high altitude aircrafts. Peak electric fields, with lightning transients removed, ranged from -1.0 kV/m to 16 kV/m, with a mean value of 0.9 kV/m. The median peak field was 0.29 kV/m. Integrating our electric field and conductivity data, we determined total conduction currents and flash rates for each overpass. With knowledge of the storm location (land or ocean) and type (with or without lightning), we determine the mean currents by location and type. The mean current for ocean storms with lightning is 1.6 A while the mean current for land storms with lightning is 1.0 A. The mean current for oceanic storms without lightning (i.e., electrified shower clouds) is 0.39 A and the mean current for land storms without lightning is 0.13 A. Thus, on average, land storms with or without lightning have about half the mean current as their corresponding oceanic storm counterparts. Over three-quarters (78%) of the land storms had detectable lightning, while less than half (43%) of the oceanic storms had lightning. We did not find any significant regional or latitudinal based patterns in our total conduction currents. By combining the aircraft derived storm currents and flash rates with diurnal lightning statistics derived from the Lightning Imaging Sensor (LIS) and Optical Transient Detector (OTD) low Earth orbiting satellites, we reproduce the diurnal variation in the global electric circuit (i.e., the Carnegie

  15. Electrical Storm Simulation to Improve the Learning Physics Process

    Science.gov (United States)

    Martínez Muñoz, Miriam; Jiménez Rodríguez, María Lourdes; Gutiérrez de Mesa, José Antonio

    2013-01-01

    This work is part of a research project whose main objective is to understand the impact that the use of Information and Communication Technology (ICT) has on the teaching and learning process on the subject of Physics. We will show that, with the use of a storm simulator, physics students improve their learning process on one hand they understand…

  16. The Cause and Mechanism of Cardiac Electrical Instability. Defibrillation Mechanism

    Directory of Open Access Journals (Sweden)

    Rustam G. Habchabov

    2012-06-01

    Full Text Available The reason for the ominous arrhythmias pathway, causing sudden somatic death from cardiovascular diseases is still not clear, cardiological examinations of this phenomenon are conducted throughout the world. Laceration of connective insulating tissue membrane of heart pathway with ectopic nodes oxidation may cause ominous arrhythmias; nobody has considered this cause as a cardiac electrical instability before. Defibrillator electric discharges cannot penetrate into myocardium due to the connective insulating tissue membrane, nobody has considered nervous system, transmitting electricity.

  17. Evaluation of the electrical properties of dust storms by multi-parameter observations and theoretical calculations

    Science.gov (United States)

    Zhang, Huan; Bo, Tian-Li; Zheng, Xiaojing

    2017-03-01

    Dusty phenomena, such as wind-blown sand, dust devils, and dust storms, play key roles in Earth's climate and geological processes. Dust electrification considerably affects the lifting and transport of dust particles. However, the electrical properties of dust storms remain poorly understood. Here, we conducted multi-parameter measurements and theoretical calculations to investigate the electrical properties of dust storms and their application to dust storm prediction. The results show that the vertical electric field (E-field) decreases first, then increases, and finally decreases with the height above the ground, reversing its direction at two heights, ∼ 8- 12 and ∼ 24 m. This suggests that the charge polarity of dust particles changes from negative to positive and back to negative again as the height increases. By carefully analyzing the E-field and dust concentration data, we further found that there is a significant positive linear relationship between the measured E-field intensity and dust concentration at the given ambient conditions. In addition, measurements and calculations demonstrate that a substantial enhancement in the vertical E-field can be observed several hours before the arrival of the external-source dust storms, indicating that the E-field can be used to provide an early warning of external-source dust storms.

  18. Automated Identification of Initial Storm Electrification and End-of-Storm Electrification Using Electric Field Mill Sensors

    Science.gov (United States)

    Maier, Launa M.; Huddleston, Lisa L.

    2017-01-01

    Kennedy Space Center (KSC) operations are located in a region which experiences one of the highest lightning densities across the United States. As a result, on average, KSC loses almost 30 minutes of operational availability each day for lightning sensitive activities. KSC is investigating using existing instrumentation and automated algorithms to improve the timeliness and accuracy of lightning warnings. Additionally, the automation routines will be warning on a grid to minimize under-warnings associated with not being located in the center of the warning area and over-warnings associated with encompassing too large an area. This study discusses utilization of electric field mill data to provide improved warning times. Specifically, this paper will demonstrate improved performance of an enveloping algorithm of the electric field mill data as compared with the electric field zero crossing to identify initial storm electrification. End-of-Storm-Oscillation (EOSO) identification algorithms will also be analyzed to identify performance improvement, if any, when compared with 30 minutes after the last lightning flash.

  19. Design of electrical stimulation bioreactors for cardiac tissue engineering.

    Science.gov (United States)

    Tandon, N; Marsano, A; Cannizzaro, C; Voldman, J; Vunjak-Novakovic, G

    2008-01-01

    Electrical stimulation has been shown to improve functional assembly of cardiomyocytes in vitro for cardiac tissue engineering. Carbon electrodes were found in past studies to have the best current injection characteristics. The goal of this study was to develop rational experimental design principles for the electrodes and stimulation regime, in particular electrode configuration, electrode ageing, and stimulation amplitude. Carbon rod electrodes were compared via electrochemical impedance spectroscopy (EIS) and we identified a safety range of 0 to 8 V/cm by comparing excitation thresholds and maximum capture rates for neonatal rat cardiomyocytes cultured with electrical stimulation. We conclude with recommendations for studies involving carbon electrodes for cardiac tissue engineering.

  20. External cardiac compression may be harmful in some scenarios of pulseless electrical activity.

    LENUS (Irish Health Repository)

    Hogan, T S

    2012-10-01

    Pulseless electrical activity occurs when organised or semi-organised electrical activity of the heart persists but the product of systemic vascular resistance and the increase in systemic arterial flow generated by the ejection of the left venticular stroke volume is not sufficient to produce a clinically detectable pulse. Pulseless electrical activity encompasses a very heterogeneous variety of severe circulatory shock states ranging in severity from pseudo-cardiac arrest to effective cardiac arrest. Outcomes of cardiopulmonary resuscitation for pulseless electrical activity are generally poor. Impairment of cardiac filling is the limiting factor to cardiac output in many scenarios of pulseless electrical activity, including extreme vasodilatory shock states. There is no evidence that external cardiac compression can increase cardiac output when impaired cardiac filling is the limiting factor to cardiac output. If impaired cardiac filling is the limiting factor to cardiac output and the heart is effectively ejecting all the blood returning to it, then external cardiac compression can only increase cardiac output if it increases venous return and cardiac filling. Repeated cardiac compression asynchronous with the patient\\'s cardiac cycle and raised mean intrathoracic pressure due to chest compression can be expected to reduce rather than to increase cardiac filling and therefore to reduce rather than to increase cardiac output in such circumstances. The hypothesis is proposed that the performance of external cardiac compression will have zero or negative effect on cardiac output in pulseless electrical activity when impaired cardiac filling is the limiting factor to cardiac output. External cardiac compression may be both directly and indirectly harmful to significant sub-groups of patients with pulseless electrical activity. We have neither evidence nor theory to provide comfort that external cardiac compression is not harmful in many scenarios of pulseless

  1. External cardiac compression may be harmful in some scenarios of pulseless electrical activity.

    Science.gov (United States)

    Hogan, T S

    2012-10-01

    Pulseless electrical activity occurs when organised or semi-organised electrical activity of the heart persists but the product of systemic vascular resistance and the increase in systemic arterial flow generated by the ejection of the left venticular stroke volume is not sufficient to produce a clinically detectable pulse. Pulseless electrical activity encompasses a very heterogeneous variety of severe circulatory shock states ranging in severity from pseudo-cardiac arrest to effective cardiac arrest. Outcomes of cardiopulmonary resuscitation for pulseless electrical activity are generally poor. Impairment of cardiac filling is the limiting factor to cardiac output in many scenarios of pulseless electrical activity, including extreme vasodilatory shock states. There is no evidence that external cardiac compression can increase cardiac output when impaired cardiac filling is the limiting factor to cardiac output. If impaired cardiac filling is the limiting factor to cardiac output and the heart is effectively ejecting all the blood returning to it, then external cardiac compression can only increase cardiac output if it increases venous return and cardiac filling. Repeated cardiac compression asynchronous with the patient's cardiac cycle and raised mean intrathoracic pressure due to chest compression can be expected to reduce rather than to increase cardiac filling and therefore to reduce rather than to increase cardiac output in such circumstances. The hypothesis is proposed that the performance of external cardiac compression will have zero or negative effect on cardiac output in pulseless electrical activity when impaired cardiac filling is the limiting factor to cardiac output. External cardiac compression may be both directly and indirectly harmful to significant sub-groups of patients with pulseless electrical activity. We have neither evidence nor theory to provide comfort that external cardiac compression is not harmful in many scenarios of pulseless

  2. Characterization of electrical stimulation electrodes for cardiac tissue engineering.

    Science.gov (United States)

    Tandon, Nina; Cannizzaro, Chris; Figallo, Elisa; Voldman, Joel; Vunjak-Novakovic, Gordana

    2006-01-01

    Electrical stimulation has been shown to improve functional assembly of cardiomyocytes in vitro for cardiac tissue engineering. The goal of this study was to assess the conditions of electrical stimulation with respect to the electrode geometry, material properties and charge-transfer characteristics at the electrode-electrolyte interface. We compared various biocompatible materials, including nanoporous carbon, stainless steel, titanium and titanium nitride, for use in cardiac tissue engineering bioreactors. The faradaic and non-faradaic charge transfer mechanisms were assessed by electrochemical impedance spectroscopy (EIS), studying current injection characteristics, and examining surface properties of electrodes with scanning electron microscopy. Carbon electrodes were found to have the best current injection characteristics. However, these electrodes require careful handling because of their limited mechanical strength. The efficacy of various electrodes for use in 2-D and 3-D cardiac tissue engineering systems with neonatal rat cardiomyocytes is being determined by assessing cell viability, amplitude of contractions, excitation thresholds, maximum capture rate, and tissue morphology.

  3. Electro-Anatomical Characterization by Cardiac Electric Near-Fields

    Science.gov (United States)

    2007-11-02

    CHARACTERIZATION BY CARDIAC ELECTRIC NEAR-FIELDS E. Hofer1, G. Plank2, I. Schafferhofer1, D. Sanchez-Quintana3 1Institute of Medical Physics and...Project Number Task Number Work Unit Number Performing Organization Name(s) and Address(es) Institute of Medical Physics and Biophysics Karl-Frazens

  4. Role of substorm-associated impulsive electric fields in the ring current development during storms

    Directory of Open Access Journals (Sweden)

    N. Yu. Ganushkina

    2005-02-01

    Full Text Available Particles with different energies produce varying contributions to the total ring current energy density as the storm progresses. Ring current energy densities and total ring current energies were obtained using particle data from the Polar CAMMICE/MICS instrument during several storms observed during the years 1996-1998. Four different energy ranges for particles are considered: total (1-200keV, low (1-20keV, medium (20-80keV and high (80-200keV. Evolution of contributions from particles with different energy ranges to the total energy density of the ring current during all storm phases is followed. To model this evolution we trace protons with arbitrary pitch angles numerically in the drift approximation. Tracing is performed in the large-scale and small-scale stationary and time-dependent magnetic and electric field models. Small-scale time-dependent electric field is given by a Gaussian electric field pulse with an azimuthal field component propagating inward with a velocity dependent on radial distance. We model particle inward motion and energization by a series of electric field pulses representing substorm activations during storm events. We demonstrate that such fluctuating fields in the form of localized electromagnetic pulses can effectively energize the plasma sheet particles to higher energies (>80keV and transport them inward to closed drift shells. The contribution from these high energy particles dominates the total ring current energy during storm recovery phase. We analyse the model contributions from particles with different energy ranges to the total energy density of the ring current during all storm phases. By comparing these results with observations we show that the formation of the ring current is a combination of large-scale convection and pulsed inward shift and consequent energization of the ring current particles.

  5. Global Electric Circuit Diurnal Variation Derived from Storm Overflight and Satellite Optical Lightning Datasets

    Science.gov (United States)

    Mach, Douglas M.; Blakeslee, R. J.; Bateman, M. J.; Bailey, J. C.

    2011-01-01

    We have combined analyses of over 1000 high altitude aircraft observations of electrified clouds with diurnal lightning statistics from the Lightning Imaging Sensor (LIS) and Optical Transient Detector (OTD) to produce an estimate of the diurnal variation in the global electric circuit. Using basic assumptions about the mean storm currents as a function of flash rate and location, and the global electric circuit, our estimate of the current in the global electric circuit matches the Carnegie curve diurnal variation to within 4% for all but two short periods of time. The agreement with the Carnegie curve was obtained without any tuning or adjustment of the satellite or aircraft data. Mean contributions to the global electric circuit from land and ocean thunderstorms are 1.1 kA (land) and 0.7 kA (ocean). Contributions to the global electric circuit from ESCs are 0.22 kA for ocean storms and 0.04 kA for land storms. Using our analysis, the mean total conduction current for the global electric circuit is 2.0 kA.

  6. Global Electric Circuit Implications of Combined Aircraft Storm Electric Current Measurements and Satellite-Based Diurnal Lightning Statistics

    Science.gov (United States)

    Mach, Douglas M.; Blakeslee, Richard J.; Bateman, Monte G.

    2011-01-01

    Using rotating vane electric field mills and Gerdien capacitors, we measured the electric field profile and conductivity during 850 overflights of thunderstorms and electrified shower clouds (ESCs) spanning regions including the Southeastern United States, the Western Atlantic Ocean, the Gulf of Mexico, Central America and adjacent oceans, Central Brazil, and the South Pacific. The overflights include storms over land and ocean, and with positive and negative fields above the storms. Over three-quarters (78%) of the land storms had detectable lightning, while less than half (43%) of the oceanic storms had lightning. Integrating our electric field and conductivity data, we determined total conduction currents and flash rates for each overpass. With knowledge of the storm location (land or ocean) and type (with or without lightning), we determine the mean currents by location and type. The mean current for ocean thunderstorms is 1.7 A while the mean current for land thunderstorms is 1.0 A. The mean current for ocean ESCs 0.41 A and the mean current for land ESCs is 0.13 A. We did not find any significant regional or latitudinal based patterns in our total conduction currents. By combining the aircraft derived storm currents and flash rates with diurnal flash rate statistics derived from the Lightning Imaging Sensor (LIS) and Optical Transient Detector (OTD) low Earth orbiting satellites, we reproduce the diurnal variation in the global electric circuit (i.e., the Carnegie curve) to within 4% for all but two short periods of time. The agreement with the Carnegie curve was obtained without any tuning or adjustment of the satellite or aircraft data. Given our data and assumptions, mean contributions to the global electric circuit are 1.1 kA (land) and 0.7 kA (ocean) from thunderstorms, and 0.22 kA (ocean) and 0.04 (land) from ESCs, resulting in a mean total conduction current estimate for the global electric circuit of 2.0 kA. Mean storm counts are 1100 for land

  7. Electrically Induced Calcium Handling in Cardiac Progenitor Cells

    Science.gov (United States)

    Wagner, Mary B.

    2016-01-01

    For nearly a century, the heart was viewed as a terminally differentiated organ until the discovery of a resident population of cardiac stem cells known as cardiac progenitor cells (CPCs). It has been shown that the regenerative capacity of CPCs can be enhanced by ex vivo modification. Preconditioning CPCs could provide drastic improvements in cardiac structure and function; however, a systematic approach to determining a mechanistic basis for these modifications founded on the physiology of CPCs is lacking. We have identified a novel property of CPCs to respond to electrical stimulation by initiating intracellular Ca2+ oscillations. We used confocal microscopy and intracellular calcium imaging to determine the spatiotemporal properties of the Ca2+ signal and the key proteins involved in this process using pharmacological inhibition and confocal Ca2+ imaging. Our results provide valuable insights into mechanisms to enhance the therapeutic potential in stem cells and further our understanding of human CPC physiology.

  8. Thermospheric mass density variations during geomagnetic storms and a prediction model based on the merging electric field

    NARCIS (Netherlands)

    Liu, R.; Lühr, H.; Doornbos, E.; Ma, S.Y.

    2010-01-01

    With the help of four years (2002–2005) of CHAMP accelerometer data we have investigated the dependence of low and mid latitude thermospheric density on the merging electric field, Em, during major magnetic storms. Altogether 30 intensive storm events (Dstmin <−100 nT) are chosen for a statistical s

  9. [Geomagnetic storm decreases coherence of electric oscillations of human brain while working at the computer].

    Science.gov (United States)

    Novik, O B; Smirnov, F A

    2013-01-01

    The effect of geomagnetic storms at the latitude of Moscow on the electric oscillations of the human brain cerebral cortex was studied. In course of electroencephalogram measurements it was shown that when the voluntary persons at the age of 18-23 years old were performing tasks using a computer during moderate magnetic storm or no later than 24 hrs after it, the value of the coherence function of electric oscillations of the human brain in the frontal and occipital areas in a range of 4.0-7.9 Hz (so-called the theta rhythm oscillations of the human brain) decreased by a factor of two or more, sometimes reaching zero, although arterial blood pressure, respiratory rate and the electrocardiogram registered during electroencephalogram measurements remained within the standard values.

  10. Practical aspects of cardiac tissue engineering with electrical stimulation.

    Science.gov (United States)

    Cannizzaro, Christopher; Tandon, Nina; Figallo, Elisa; Park, Hyoungshin; Gerecht, Sharon; Radisic, Milica; Elvassore, Nicola; Vunjak-Novakovic, Gordana

    2007-01-01

    Heart disease is a leading cause of death in western society. Despite the success of heart transplantation, a chronic shortage of donor organs, along with the associated immunological complications of this approach, demands that alternative treatments be found. One such option is to repair, rather than replace, the heart with engineered cardiac tissue. Multiple studies have shown that to attain functional tissue, assembly signaling cues must be recapitulated in vitro. In their native environment, cardiomyocytes are directed to beat in synchrony by propagation of pacing current through the tissue. Recently, we have shown that electrical stimulation directs neonatal cardiomyocytes to assemble into native-like tissue in vitro. This chapter provides detailed methods we have employed in taking this "biomimetic" approach. After an initial discussion on how electric field stimulation can influence cell behavior, we examine the practical aspects of cardiac tissue engineering with electrical stimulation, such as electrode selection and cell seeding protocols, and conclude with what we feel are the remaining challenges to be overcome.

  11. Sudden cardiac arrest as a presentation of Brugada syndrome unmasked by thyroid storm

    NARCIS (Netherlands)

    Korte, Anna K M; Derde, Lennie; van Wijk, Jeroen; Tjan, David H

    2015-01-01

    An 18-year-old man suffered a sudden cardiac arrest with ventricular fibrillation and was successfully resuscitated. He had neither a medical nor family history of cardiac disease/sudden death, but was known to have Graves' disease, for which he was treated with radioactive iodine. Recently, block-a

  12. Post-Storm Middle and Low-Latitude Ionospheric Electric Fields Effects

    Science.gov (United States)

    Fejer, B. G.; Blanc, M.; Richmond, A. D.

    2016-12-01

    The Earth's upper atmosphere and ionosphere undergoes large and complex perturbations during and after geomagnetic storms. Thermospheric winds driven by enhanced energy and momentum due to geomagnetic activity generate large disturbance electric fields, plasma drifts and currents with a broad range of temporal and spatial scales from high to equatorial latitudes. This disturbance dynamo mechanism plays a fundamental role on the response of the middle and low-latitude ionosphere to geomagnetic activity. In this review, we initially describe the early evidence for the importance of this process and the first simulation study which already was able to explain its main effects on the electrodynamics of the middle and low-latitude ionosphere. We then describe the results of more recent simulations and the extensive experimental work that highlights the importance of this mechanism for ionospheric space weather studies extending to post-storms periods, and present some suggestions for future studies.

  13. Effects of disturbed electric fields in the low-latitude and equatorial ionosphere during the 2015 St. Patrick's Day storm

    Science.gov (United States)

    Kuai, Jiawei; Liu, Libo; Liu, Jing; Sripathi, S.; Zhao, Biqiang; Chen, Yiding; Le, Huijun; Hu, Lianhuan

    2016-09-01

    The 2015 St. Patrick's Day geomagnetic storm with SYM-H value of -233 nT is an extreme space weather event in the current 24th solar cycle. In this work, we investigated the main mechanisms of the profound ionospheric disturbances over equatorial and low latitudes in the Asian-Australian sector and the American sector during this super storm event. The results reveal that the disturbed electric fields, which comprise penetration electric fields (PEFs) and disturbance dynamo electric fields (DDEFs), play a decisive role in the ionospheric storm effects in low latitude and equatorial regions. PEFs occur on 17 March in both the American sector and the Asian-Australian sector. The effects of DDEFs are also remarkable in the two longitudinal sectors. Both the DDEFs and PEFs show the notable local time dependence, which causes the sector differences in the characteristics of the disturbed electric fields. This differences would further lead to the sector differences in the low-latitude ionospheric response during this storm. The negative storm effects caused by the long-duration DDEFs are intense over the Asian-Australian sector, while the repeated elevations of hmF2 and the equatorial ionization anomaly intensifications caused by the multiple strong PEFs are more distinctive over the American sector. Especially, the storm time F3 layer features are caught on 17 March in the American equatorial region, proving the effects of the multiple strong eastward PEFs.

  14. Electrical Pacing of Cardiac Tissue Including Potassium Inward Rectification.

    Science.gov (United States)

    Galappaththige, Suran; Roth, Bradley J

    2015-01-01

    In this study cardiac tissue is stimulated electrically through a small unipolar electrode. Numerical simulations predict that around an electrode are adjacent regions of depolarization and hyperpolarization. Experiments have shown that during pacing of resting cardiac tissue the hyperpolarization is often inhibited. Our goal is to determine if the inward rectifying potassium current (IK1) causes the inhibition of hyperpolarization. Numerical simulations were carried out using the bidomain model with potassium dynamics specified to be inward rectifying. In the simulations, adjacent regions of depolarization and hyperpolarization were observed surrounding the electrode. For cathodal currents the virtual anode produces a hyperpolarization that decreases over time. For long duration pulses the current-voltage curve is non-linear, with very small hyperpolarization compared to depolarization. For short pulses, the hyperpolarization is more prominent. Without the inward potassium rectification, the current voltage curve is linear and the hyperpolarization is evident for both long and short pulses. In conclusion, the inward rectification of the potassium current explains the inhibition of hyperpolarization for long duration stimulus pulses, but not for short duration pulses.

  15. Electrical Pacing of Cardiac Tissue Including Potassium Inward Rectification.

    Directory of Open Access Journals (Sweden)

    Suran Galappaththige

    Full Text Available In this study cardiac tissue is stimulated electrically through a small unipolar electrode. Numerical simulations predict that around an electrode are adjacent regions of depolarization and hyperpolarization. Experiments have shown that during pacing of resting cardiac tissue the hyperpolarization is often inhibited. Our goal is to determine if the inward rectifying potassium current (IK1 causes the inhibition of hyperpolarization. Numerical simulations were carried out using the bidomain model with potassium dynamics specified to be inward rectifying. In the simulations, adjacent regions of depolarization and hyperpolarization were observed surrounding the electrode. For cathodal currents the virtual anode produces a hyperpolarization that decreases over time. For long duration pulses the current-voltage curve is non-linear, with very small hyperpolarization compared to depolarization. For short pulses, the hyperpolarization is more prominent. Without the inward potassium rectification, the current voltage curve is linear and the hyperpolarization is evident for both long and short pulses. In conclusion, the inward rectification of the potassium current explains the inhibition of hyperpolarization for long duration stimulus pulses, but not for short duration pulses.

  16. Cardiac thrombus developing after an accidental high-voltage electric shock in a child.

    Science.gov (United States)

    Akın, Alper; Bilici, Meki; Demir, Fikri; Gözü Pirinççioğlu, Ayfer; Yavuz, Celal

    2015-01-01

    Electric shock is a condition that may affect various organ systems and potentially cause death. Cardiac findings vary from asymptomatic mild injury to fatal myocardial involvement. Herein we present a five-year-old boy with a cardiac thrombus developing after an accidental electrical shock. Cardiac arrhythmias and evidence of ischemia have been reported after electric shock; we were, however, unable to identify an earlier case report of intracardiac thrombosis related to electric shock. Findings such as elevated cardiac enzymes and systolic dysfunction, which indicate myocardial damage following electric shock, were present in our patient. We think that the cardiac thrombus might have resulted from the myocardial damage and the slowed intracardiac blood flow related to systolic dysfunction. As the thrombus was thought to have been formed through known mechanisms, it was treated traditionally. However, further data regarding the etiology and management of such thrombi is needed.

  17. Effect of transcutaneous electric stimulation on the cardiac electrical activity in New Zealand white rabbits

    Directory of Open Access Journals (Sweden)

    Wang ZHANG

    2015-10-01

    Full Text Available Objective To study the effect of transcutaneous electric stimulation on the cardiac electrical activity in New Zealand white rabbits, in order to search a safety threshold for clinical electrical stimulation therapy, as to provide the theoretical basis for the design of in vitro pacemaker. Methods New Zealand white rabbits were randomly assigned into 17 groups (6 each. Rabbits in 16 experimental groups were given 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75 and 80V electrical stimulation, respectively, with the stimulating site designated at epigastric region. BL -420F biological function experimental system was employed to supply the power and acquire the ECG, with the output pulse electrical stimulation frequency set at 270 times/minute, and the stimulating wave as square wave. A control group was set, in which the stimulating voltage was set to 35V, the stimulant anode was located in the anterior chest area, and the cathode was on the skin surface of back corresponding to the site of the heart, and the rest was the same as in experimental groups. Results No stimulation rhythm was observed in rabbits of those experimental groups with voltage ≤35V, but all stimulation rhythm was observed in rabbits of control group. No arrhythmia occurred in rabbits of those experimental groups with voltage ≤30V, while the heart rate was slowed down after stimulation in rabbits of the experimental groups with voltage ≥45V stimulation. In rabbits receiving stimulation with voltage ≤35V there was no dystropy or light dystropy, but with no visible injury to the local tissues. No visible injury was observed in the rabbits undergoing stimulation with voltage ≤40V. Conclusion Pulse electric stimulation with voltage ≤35V in the epigastric region would not affect the cardiac electrical activity in rabbits, while stimulation with 35V will lead to all pacing rhythm of the heart without affecting the cardiac electrical activity in rabbits

  18. Nanowires and Electrical Stimulation Synergistically Improve Functions of hiPSC Cardiac Spheroids.

    Science.gov (United States)

    Richards, Dylan J; Tan, Yu; Coyle, Robert; Li, Yang; Xu, Ruoyu; Yeung, Nelson; Parker, Arran; Menick, Donald R; Tian, Bozhi; Mei, Ying

    2016-07-13

    The advancement of human induced pluripotent stem-cell-derived cardiomyocyte (hiPSC-CM) technology has shown promising potential to provide a patient-specific, regenerative cell therapy strategy to treat cardiovascular disease. Despite the progress, the unspecific, underdeveloped phenotype of hiPSC-CMs has shown arrhythmogenic risk and limited functional improvements after transplantation. To address this, tissue engineering strategies have utilized both exogenous and endogenous stimuli to accelerate the development of hiPSC-CMs. Exogenous electrical stimulation provides a biomimetic pacemaker-like stimuli that has been shown to advance the electrical properties of tissue engineered cardiac constructs. Recently, we demonstrated that the incorporation of electrically conductive silicon nanowires to hiPSC cardiac spheroids led to advanced structural and functional development of hiPSC-CMs by improving the endogenous electrical microenvironment. Here, we reasoned that the enhanced endogenous electrical microenvironment of nanowired hiPSC cardiac spheroids would synergize with exogenous electrical stimulation to further advance the functional development of nanowired hiPSC cardiac spheroids. For the first time, we report that the combination of nanowires and electrical stimulation enhanced cell-cell junction formation, improved development of contractile machinery, and led to a significant decrease in the spontaneous beat rate of hiPSC cardiac spheroids. The advancements made here address critical challenges for the use of hiPSC-CMs in cardiac developmental and translational research and provide an advanced cell delivery vehicle for the next generation of cardiac repair.

  19. Electrical stimulation of cardiac adipose tissue-derived progenitor cells modulates cell phenotype and genetic machinery.

    Science.gov (United States)

    Llucià-Valldeperas, A; Sanchez, B; Soler-Botija, C; Gálvez-Montón, C; Prat-Vidal, C; Roura, S; Rosell-Ferrer, J; Bragos, R; Bayes-Genis, A

    2015-11-01

    A major challenge of cardiac tissue engineering is directing cells to establish the physiological structure and function of the myocardium being replaced. Our aim was to examine the effect of electrical stimulation on the cardiodifferentiation potential of cardiac adipose tissue-derived progenitor cells (cardiac ATDPCs). Three different electrical stimulation protocols were tested; the selected protocol consisted of 2 ms monophasic square-wave pulses of 50 mV/cm at 1 Hz over 14 days. Cardiac and subcutaneous ATDPCs were grown on biocompatible patterned surfaces. Cardiomyogenic differentiation was examined by real-time PCR and immunocytofluorescence. In cardiac ATDPCs, MEF2A and GATA-4 were significantly upregulated at day 14 after stimulation, while subcutaneous ATDPCs only exhibited increased Cx43 expression. In response to electrical stimulation, cardiac ATDPCs elongated, and both cardiac and subcutaneous ATDPCs became aligned following the linear surface pattern of the construct. Cardiac ATDPC length increased by 11.3%, while subcutaneous ATDPC length diminished by 11.2% (p = 0.013 and p = 0.030 vs unstimulated controls, respectively). Compared to controls, electrostimulated cells became aligned better to the patterned surfaces when the pattern was perpendicular to the electric field (89.71 ± 28.47º for cardiac ATDPCs and 92.15 ± 15.21º for subcutaneous ATDPCs). Electrical stimulation of cardiac ATDPCs caused changes in cell phenotype and genetic machinery, making them more suitable for cardiac regeneration approaches. Thus, it seems advisable to use electrical cell training before delivery as a cell suspension or within engineered tissue.

  20. Prophylactic left thoracic sympathectomy to prevent electrical storms in CPVT patients needing ICD placement.

    Science.gov (United States)

    Moray, Amol; Kirk, Edwin P; Grant, Peter; Camphausen, Christoph

    2011-11-01

    Catecholaminergic Polymorphic Ventricular Tachycardia (CPVT), a life threatening arrhythmia induced by sympathetic stimulation in susceptible individuals is often refractory to antiarrhythmic agents. First line of treatment, beta-blockers can be ineffective in up to 50% with implantable cardioverter-defibrillator (ICD) placement for refractory cases. Paradoxically ICD can be arryhthmogenic from shock-associated sympathetic stimulation, initiating more shocks and "electrical storms". This has led to the use of more effective beta blockade offered by left sympathectomy, now performed by minimally invasive video assisted thoracoscopic surgery (VATS). Sympathectomy has been traditionally performed long after ICD placement, after the patient has experienced multiple shocks, thus necessitating two procedures. We report simultaneous ICD insertion and thoracoscopic sympathectomy in a 10 year-old boy with CPVT, and suggest it as a better approach than sequential procedures. To our knowledge this is first such reported case.

  1. Sensing Cardiac Electrical Activity With a Cardiac Myocyte--Targeted Optogenetic Voltage Indicator

    NARCIS (Netherlands)

    Chang Liao, Mei-Ling; de Boer, Teun P; Mutoh, Hiroki; Raad, Nour; Richter, Claudia; Wagner, Eva; Downie, Bryan R; Unsöld, Bernhard; Arooj, Iqra; Streckfuss-Bömeke, Katrin; Döker, Stephan; Luther, Stefan; Guan, Kaomei; Wagner, Stefan; Lehnart, Stephan E; Maier, Lars S; Stühmer, Walter; Wettwer, Erich; van Veen, Toon; Morlock, Michael M; Knöpfel, Thomas; Zimmermann, Wolfram-Hubertus

    2015-01-01

    RATIONALE: Monitoring and controlling cardiac myocyte activity with optogenetic tools offer exciting possibilities for fundamental and translational cardiovascular research. Genetically encoded voltage indicators may be particularly attractive for minimal invasive and repeated assessments of cardiac

  2. Storm-time total electron content and its response to penetration electric fields over South America

    Directory of Open Access Journals (Sweden)

    P. M. de Siqueira

    2011-10-01

    Full Text Available In this work the response of the ionosphere due to the severe magnetic storm of 7–10 November 2004 is investigated by analyzing GPS Total Electron Content (TEC maps constructed for the South America sector. In order to verify the disturbed zonal electric fields in South America during the superstorm, ionospheric vertical drift data obtained from modeling results are used in the analysis. The vertical drifts were inferred from ΔH magnetometer data (Jicamarca-Piura following the methodology presented by Anderson et al. (2004. Also used were vertical drifts measured by the Jicamarca ISR. Data from a digisonde located at São Luís, Brazil (2.33° S, 44.2° W, dip latitude 0.25° are presented to complement the Jicamarca equatorial data. Penetration electric fields were observed by the comparison between the equatorial vertical drifts and the Interplanetary Electric Field (IEF. The TEC maps obtained from GPS data reflect the ionospheric response over the South America low-latitude and equatorial region. They reveal unexpected plasma distributions and TEC levels during the main phase of the superstorm on 7 November, which is coincident with the local post-sunset hours. At this time an increase in the pre-reversal enhancement was expected to develop the Equatorial Ionization Anomaly (EIA but we observed the absence of EIA. The results also reveal well known characteristics of the plasma distributions on 8, 9, and 10 November. The emphasized features are the expansion and intensification of EIA due to prompt penetration electric fields on 9 November and the inhibition of EIA during post-sunset hours on 7, 8, and 10 November. One important result is that the TEC maps provided a bi-dimensional view of the ionospheric changes offering a spatial description of the electrodynamics involved, which is an advantage over TEC measured by isolated GPS receivers.

  3. [Severe dysautonomy as a result of intra-cranial bleeding can cause an electrical storm with auricular fibrillation].

    Science.gov (United States)

    Lindelof, Mette; Jensen, Helene; Vilhjamsson, Asgier Snær; Kemppi, Kajsa; Høst, Ulla

    2015-12-14

    A 69-year-old woman with a medical history of stroke and an ICD device due to torsade de pointes was admitted with a right basal ganglia haemorrhage. In the hours after admission the patient's condition severely declined and she developed fever, hypertension and flushing consistent with autonomic dysfunction with sympathetic storming. ICD interrogation revealed electrical storm with 138 appropriate shocks delivered at the night of admission. We wish to draw attention to the close link between brain and heart, which in predisposed patients with a new stroke can cause malignant arrhythmias.

  4. Understanding cardiac electrical phenotypes in the genomic era

    NARCIS (Netherlands)

    A. Milano

    2015-01-01

    Sudden cardiac death (SCD) is defined as unexpected death due to a cardiac cause. It most often results from life-threatening ventricular fibrillation (VF) and ranks among the most common causes of death worldwide, with an incidence in the community varying between 0.6 and >1.4 per 1,000 individuals

  5. Three dimensional graphene scaffold for cardiac tissue engineering and in-situ electrical recording.

    Science.gov (United States)

    Ameri, S K; Singh, P K; D'Angelo, R; Stoppel, W; Black, L; Sonkusale, S R

    2016-08-01

    In this paper, we present a three-dimensional graphene foam made of few layers of CVD grown graphene as a scaffold for growing cardiac cells and recording their electrical activity. Our results show that graphene foam not only provides an excellent extra-cellular matrix (ECM) for the culture of such electrogenic cells but also enables recording of its extracellular electrical activity in-situ. Recording is possible due to graphene's excellent conductivity. In this paper, we present our results on the fabrication of the graphene scaffold and initial studies on the culture of cardiac cell lines such as HL-1 and recording of their real-time electrical activity.

  6. Role of neutral wind and storm time electric fields inferred from the storm time ionization distribution at low latitudes: in-situ measurements by Indian satellite SROSS-C2

    Directory of Open Access Journals (Sweden)

    P. Subrahmanyam

    2005-11-01

    Full Text Available Recently, there has been a renewal of interest in the study of the effects of solar weather events on the ionization redistribution and irregularity generation. The observed changes at low and equatorial latitudes are rather complex and are noted to be a function of location, the time of the storm onset and its intensity, and various other characteristics of the geomagnetic storms triggered by solar weather events. At these latitudes, the effects of geomagnetic storms are basically due to (a direct penetration of the magnetospheric electric fields to low latitudes, (b development of disturbance dynamo, (c changes in atmospheric neutral winds at ionospheric level and (d changes in neutral composition triggered by the storm time atmospheric heating.

    In the present study an attempt is made to further understand some of the observed storm time effects in terms of storm time changes in zonal electric fields and meridional neutral winds. For this purpose, observations made by the Retarding Potential Analyzer (RPA payload on board the Indian satellite SROSS-C2 are examined for four prominent geomagnetic storm events that occurred during the high solar activity period of 1997-2000. Available simultaneous observations, from the GPS satellite network, are also used. The daytime passes of SROSS-C2 have been selected to examine the redistribution of ionization in the equatorial ionization anomaly (EIA region. In general, EIA is observed to be weakened 12-24 h after the main phase onset (MPO of the storm. The storm time behaviour inferred by SROSS-C2 and the GPS satellite network during the geomagnetic storm of 13 November 1998, for which simultaneous observations are available, is found to be consistent. Storm time changes in the delay of received GPS signals are noted to be ~1-3 m, which is a significant component of the total delay observed on a quiet day.

    An attempt is made to identify and

  7. Effects of Potassium Currents upon Action Potential of Cardiac Cells Exposed to External Electric fields

    Institute of Scientific and Technical Information of China (English)

    An-Ying Zhang; Xiao-Feng Pang

    2008-01-01

    Previous studies show that exposure to high-voltage electric fields would influence the electro cardiogram both in experimental animate and human beings. The effects of the external electric fields upon action potential of cardiac cells are studied in this paper based on the dynamical model, LR91. Fourth order Runger-Kuta is used to analyze the change of potassium ion channels exposed to external electric fields in detail. Results indicate that external electric fields could influence the current of potassium ion by adding an induced component voltage on membrane. This phenomenon might be one of the reasons of heart rate anomaly under the high-voltage electric fields.

  8. An unusual case of cardiac tamponade following electrical cardioversion

    NARCIS (Netherlands)

    Jessurun, GAJ; Crijns, HJGM; vanWijngaarden, J

    1996-01-01

    The clinical presentation of cardiac tamponade may uncover underlying pericardial disease. We describe a patient who was being treated for lone atrial fibrillation, In this case, direct current cardioversion for recurrence of atrial fibrillation was complicated by a life-threatening hemopericardium.

  9. Biphasic Electrical Field Stimulation Aids in Tissue Engineering of Multicell-Type Cardiac Organoids

    Science.gov (United States)

    Chiu, Loraine L.Y.; Iyer, Rohin K.; King, John-Paul

    2011-01-01

    The main objectives of current work were (1) to compare the effects of monophasic or biphasic electrical field stimulation on structure and function of engineered cardiac organoids based on enriched cardiomyocytes (CM) and (2) to determine if electrical field stimulation will enhance electrical excitability of cardiac organoids based on multiple cell types. Organoids resembling cardiac myofibers were cultivated in Matrigel-coated microchannels fabricated of poly(ethylene glycol)-diacrylate. We found that field stimulation using symmetric biphasic square pulses at 2.5 V/cm, 1 Hz, 1 ms (per pulse phase) was an improved stimulation protocol, as compared to no stimulation and stimulation using monophasic square pulses of identical total amplitude and duration (5 V/cm, 1 Hz, 2 ms). This was supported by the highest success rate for synchronous contractions, low excitation threshold, the highest cell density, and the highest expression of Connexin-43 in the biphasic group. Subsequently, enriched CM were seeded on the networks of (1) cardiac fibroblasts (FB), (2) D4T endothelial cells (EC), or (3) a mixture of FB and EC that were precultured for 2 days prior to the addition of enriched CM. Biphasic field stimulation was also effective at improving electrical excitability of these cardiac organoids by improving the three-dimensional organization of the cells, increasing cellular elongation and enhancing Connexin-43 presence. PMID:18783322

  10. Biphasic electrical field stimulation aids in tissue engineering of multicell-type cardiac organoids.

    Science.gov (United States)

    Chiu, Loraine L Y; Iyer, Rohin K; King, John-Paul; Radisic, Milica

    2011-06-01

    The main objectives of current work were (1) to compare the effects of monophasic or biphasic electrical field stimulation on structure and function of engineered cardiac organoids based on enriched cardiomyocytes (CM) and (2) to determine if electrical field stimulation will enhance electrical excitability of cardiac organoids based on multiple cell types. Organoids resembling cardiac myofibers were cultivated in Matrigel-coated microchannels fabricated of poly(ethylene glycol)-diacrylate. We found that field stimulation using symmetric biphasic square pulses at 2.5 V/cm, 1 Hz, 1 ms (per pulse phase) was an improved stimulation protocol, as compared to no stimulation and stimulation using monophasic square pulses of identical total amplitude and duration (5 V/cm, 1 Hz, 2 ms). This was supported by the highest success rate for synchronous contractions, low excitation threshold, the highest cell density, and the highest expression of Connexin-43 in the biphasic group. Subsequently, enriched CM were seeded on the networks of (1) cardiac fibroblasts (FB), (2) D4T endothelial cells (EC), or (3) a mixture of FB and EC that were precultured for 2 days prior to the addition of enriched CM. Biphasic field stimulation was also effective at improving electrical excitability of these cardiac organoids by improving the three-dimensional organization of the cells, increasing cellular elongation and enhancing Connexin-43 presence.

  11. Wave trains induced by circularly polarized electric fields in cardiac tissues.

    Science.gov (United States)

    Feng, Xia; Gao, Xiang; Tang, Juan-Mei; Pan, Jun-Ting; Zhang, Hong

    2015-08-25

    Clinically, cardiac fibrillation caused by spiral and turbulent waves can be terminated by globally resetting electric activity in cardiac tissues with a single high-voltage electric shock, but it is usually associated with severe side effects. Presently, a promising alternative uses wave emission from heterogeneities induced by a sequence of low-voltage uniform electric field pulses. Nevertheless, this method can only emit waves locally near obstacles in turbulent waves and thereby requires multiple obstacles to globally synchronize myocardium and thus to terminate fibrillation. Here we propose a new approach using wave emission from heterogeneities induced by a low-voltage circularly polarized electric field (i.e., a rotating uniform electric field). We find that, this approach can generate circular wave trains near obstacles and they propagate outwardly. We study the characteristics of such circular wave trains and further find that, the higher-frequency circular wave trains can effectively suppress spiral turbulence.

  12. Thyroid storm

    Science.gov (United States)

    Thyrotoxic storm; Hyperthyroid storm; Accelerated hyperthyroidism; Thyroid crisis; Thyrotoxicosis - thyroid storm ... thyroid storm can be caused by treatment of hyperthyroidism with radioiodine therapy.

  13. A case study of storm commencement and recovery plasmaspheric electric fields near L=2.5 at equinox

    Directory of Open Access Journals (Sweden)

    H. F. Balmforth (*

    Full Text Available Data from the VLF Doppler experiment at Faraday, Antarctica (65° S, 64° W are used to study the penetration of the high-latitude convection electric field to lower latitudes during severely disturbed conditions. Alterations of the electric field at L-values within the range 2.0 - 2.7 are studied for two cases at equinox (10 - 12 September 1986 and 1 - 3 May 1986. The recovery of the electric field is found to be approximately an exponential function of time. Values for the equatorial meridional E×B drift velocity, inferred from the data, are used as inputs to a model of the plasmasphere and ionosphere. The model and experimental results are used to investigate the post-storm alteration of ionospheric coupling processes. The magnitude of the effect of ionosphere-plasmasphere coupling fluxes on NmF2 values and the O+-H+ transition height is dependent on the local time of storm commencement, and on the orientation of the electric field. The coupling fluxes appear to have a maximum influence on ionospheric content during the main phase of geomagnetic activity that produces outward motion of plasmaspheric whistler ducts.

  14. The 17 March 2013 storm: Synergy of observations related to electric field modes and their ionospheric and magnetospheric Effects

    Science.gov (United States)

    Lyons, L. R.; Gallardo-Lacourt, B.; Zou, S.; Weygand, J. M.; Nishimura, Y.; Li, W.; Gkioulidou, M.; Angelopoulos, V.; Donovan, E. F.; Ruohoniemi, J. M.; Anderson, B. J.; Shepherd, S. G.; Nishitani, N.

    2016-11-01

    The main phase of the 17 March 2013 storm had excellent coverage from ground-based instruments and from low- and high-altitude spacecraft, allowing for evaluation of the relations between major storm time phenomena that are often considered separately. The shock impact with its concurrent southward interplanetary magnetic field (IMF) immediately drove dramatic poleward expansion of the poleward boundary of the auroral oval (implying strong nightside reconnection), strong auroral activity, and strong penetrating midlatitude convection and ionospheric currents. This was followed by periods of southward IMF driving of electric fields that were at first relatively smooth as often employed in storm modeling but then became extremely bursty and structured associated with equatorward extending auroral streamers. The auroral oval did not expand much further poleward during these two latter periods, suggesting a lower overall nightside reconnection rate than that during the first period and approximate balance with dayside reconnection. Characteristics of these three modes of driving were reflected in horizontal and field-aligned currents. Equatorward expansion of the auroral oval occurred predominantly during the structured convection mode, when electric fields became extremely bursty. The period of this third mode also approximately corresponded to the time of largest equatorward motion of the ionospheric trough, of apparent transport of high total electron content (TEC) features into the auroral oval from the polar cap, and of largest earthward injection of ions and electrons into the ring current. The enhanced responses of the aurora, currents, TEC, and the ring current indicate a common driving of all these storm time features during the bursty convection mode period.

  15. Forward and inverse problem for cardiac magnetic field and electric potential using two boundary element methods

    Science.gov (United States)

    Tang, Fa-Kuan; Wang, Qian; Hua, Ning; Tang, Xue-Zheng; Lu, Hong; Ma, Ping

    2010-12-01

    This paper discusses the forward and inverse problem for cardiac magnetic fields and electric potentials. A torso-heart model established by boundary element method (BEM) is used for studying the distributions of cardiac magnetic fields and electric potentials. Because node-to-node and triangle-to-triangle BEM can lead to discrepant field distributions, their properties and influences are compared. Then based on constructed torso-heart model and supposed current source functional model—current dipole array, the magnetic and electric imaging by optimal constrained linear inverse method are applied at the same time. Through figure and reconstructing parameter comparison, though the magnetic current dipole array imaging possesses better reconstructing effect, however node-to-node BEM and triangle-to-triangle BEM make little difference to magnetic and electric imaging.

  16. Bcl10 mediates angiotensin II-induced cardiac damage and electrical remodeling.

    Science.gov (United States)

    Markó, Lajos; Henke, Norbert; Park, Joon-Keun; Spallek, Bastian; Qadri, Fatimunnisa; Balogh, András; Apel, Ingrid J; Oravecz-Wilson, Katherine I; Choi, Mira; Przybyl, Lukasz; Binger, Katrina J; Haase, Nadine; Wilck, Nicola; Heuser, Arnd; Fokuhl, Verena; Ruland, Jürgen; Lucas, Peter C; McAllister-Lucas, Linda M; Luft, Friedrich C; Dechend, Ralf; Müller, Dominik N

    2014-11-01

    Angiotensin (Ang) II is a potent mediator of both hypertension and cardiac damage; however, the mechanisms by which this occur remain unclear. B-cell lymphoma/leukemia 10 (Bcl10) is a member of the CBM signalosome, which links Ang II and nuclear factor-κB signaling. We hypothesized that Bcl10 is pivotal in the pathogenesis of Ang II-induced cardiac damage. Ang II infusion in mice lacking Bcl10 resulted in reduced cardiac fibrosis, less cellular infiltration, and improved arrhythmogenic electric remodeling, despite a similar degree of hypertension or cardiac hypertrophy. Adoptive transfer of bone marrow (BM), whereby Bcl10 knockout or wildtype BM was transferred to their opposite genotype recipients, revealed the dual importance of Bcl10 within both cardiac and immune cells. Loss of Bcl10 in cardiac cells resulted in reduced expression of genes important for the adhesion and recruitment of immune cells. In vitro experiments demonstrated that adhesion of monocytes to Ang II-treated endothelial cells also required Bcl10. Additionally, Bcl10 deficiency in macrophages reduced their intrinsic migratory ability. To address the role of BM-derived fibroblasts in the formation of cardiac fibrosis, we explored whether Bcl10 is also important for the infiltration of BM-derived (myo)fibroblasts into the heart. The transfer of green fluorescent protein positive wildtype BM into Bcl10 knockout recipient mice revealed a reduced number of noncardiac (myo)fibroblasts compared with those wildtype recipients. Our results demonstrate the significant role of Bcl10 in multiple cell types important for the generation of Ang II-induced cardiac damage and electric remodeling and may provide a new avenue for therapeutic intervention.

  17. [Despite medication, overdrive pacing is required to stabilize the electrical storm associated with acute coronary syndrome: a case report].

    Science.gov (United States)

    Umeda, Masanobu; Morimoto, Atsushi; Yokoyama, Kaori; Tateishi, Emi; Makino, Kanako; Yamamoto, Kazuo; Nakagawa, Yoko; Fukuhara, Shinya; Takase, Eiji

    2007-10-01

    A 75-year-old female complained of severe chest pain and was emergently admitted to our hospital because of anterior acute myocardial infarction. Emergent coronary angiography was performed and revealed occlusion in segment 7, so a stent was implanted. Lidocaine, carvedilol, amiodarone, magnesium, and nifekalant were administered successively because non-sustained ventricular tachycardia (NSVT) frequently appeared like an electrical storm. After nifekalant administration, QTc was significantly prolonged and torsades de pointes was induced. Overdrive pacing was performed and finally the NSVT was completely controlled. If fatal arrhythmias such as NSVT show resistance to medication, overdrive pacing should be considered to stabilize the arrhythmia associated with acute coronary syndrome.

  18. Hemodynamic Sensor in Cardiac Implantable Electric Devices: The Endocardial Accelaration Technology

    Directory of Open Access Journals (Sweden)

    Stefania Sacchi

    2013-01-01

    Full Text Available There have been substantial progresses in the technology of cardiac implantable electric devices (CIEDs during the past decades. One of the progresses is represented by the development of a hemodynamic sensor embedded at the tip of a pacing lead that measures myocardial contractility by the analysis of myocardial mechanical vibrations occurring during the cardiac cycle. This sensor, providing continuous hemodynamic monitoring, could play an important role in clinical practice because of several clinical applications in CIEDs recipients. The objectives of this work are to report how this sensor operates and to review the main findings about its clinical applications.

  19. Modeling cardiac mechano-electrical feedback using reaction-diffusion-mechanics systems

    Science.gov (United States)

    Keldermann, R. H.; Nash, M. P.; Panfilov, A. V.

    2009-06-01

    In many practically important cases, wave propagation described by the reaction-diffusion equation initiates deformation of the medium. Mathematically, such processes are described by coupled reaction-diffusion-mechanics (RDM) systems. RDM systems were recently used to study the effects of deformation on wave propagation in cardiac tissue, so called mechano-electrical feedback (MEF). In this article, we review the results of some of these studies, in particular those relating to the effects of deformation on pacemaker activity and spiral wave dynamics in the heart. We also provide brief descriptions of the numerical methods used, and the underlying cardiac physiology.

  20. Cardiac microstructure: implications for electrical propagation and defibrillation in the heart.

    Science.gov (United States)

    Hooks, Darren A; Tomlinson, Karl A; Marsden, Scott G; LeGrice, Ian J; Smaill, Bruce H; Pullan, Andrew J; Hunter, Peter J

    2002-08-23

    Our understanding of the electrophysiological properties of the heart is incomplete. We have investigated two issues that are fundamental to advancing that understanding. First, there has been widespread debate over the mechanisms by which an externally applied shock can influence a sufficient volume of heart tissue to terminate cardiac fibrillation. Second, it has been uncertain whether cardiac tissue should be viewed as an electrically orthotropic structure, or whether its electrical properties are, in fact, isotropic in the plane orthogonal to myofiber direction. In the present study, a computer model that incorporates a detailed three-dimensional representation of cardiac muscular architecture is used to investigate these issues. We describe a bidomain model of electrical propagation solved in a discontinuous domain that accurately represents the microstructure of a transmural block of rat left ventricle. From analysis of the model results, we conclude that (1) the laminar organization of myocytes determines unique electrical properties in three microstructurally defined directions at any point in the ventricular wall of the heart, and (2) interlaminar clefts between layers of cardiomyocytes provide a substrate for bulk activation of the ventricles during defibrillation.

  1. Electrical storm in the brain and in the heart: epilepsy and Brugada syndrome.

    Science.gov (United States)

    Sandorfi, Gabor; Clemens, Bela; Csanadi, Zoltan

    2013-10-01

    We describe a patient with the coincidence of 2 ion channel disorders with autosomal dominant inheritance: Brugada syndrome, a potentially fatal cardiac condition, and cryptogenic focal epilepsy, likely due to a neurologic channelopathy. Although Brugada syndrome was discovered incidentally, most of the clinical features of epilepsy in this patient shared the risk factor characteristics of sudden unexplained death in epilepsy syndrome. This case provides additional information on the potential interaction between ion channel abnormalities in the heart and in the brain. Furthermore, it may suggest that patients with epilepsy at increased risk for sudden unexplained death in epilepsy syndrome should undergo a careful cardiac evaluation.

  2. Unpinning of rotating spiral waves in cardiac tissues by circularly polarized electric fields

    Science.gov (United States)

    Feng, Xia; Gao, Xiang; Pan, De-Bei; Li, Bing-Wei; Zhang, Hong

    2014-04-01

    Spiral waves anchored to obstacles in cardiac tissues may cause lethal arrhythmia. To unpin these anchored spirals, comparing to high-voltage side-effect traditional therapies, wave emission from heterogeneities (WEH) induced by the uniform electric field (UEF) has provided a low-voltage alternative. Here we provide a new approach using WEH induced by the circularly polarized electric field (CPEF), which has higher success rate and larger application scope than UEF, even with a lower voltage. And we also study the distribution of the membrane potential near an obstacle induced by CPEF to analyze its mechanism of unpinning. We hope this promising approach may provide a better alternative to terminate arrhythmia.

  3. Rainfall yield characteristics of electrical storm observed in the Spanish Basque Country area during the period 1992 1996

    Science.gov (United States)

    Ezcurra, A.; Saenz, J.; Ibarra-Berastegi, G.; Areitio, J.

    2008-08-01

    This paper is focused on the study of rainfall yield characteristics of electrical storms observed over the Northern Iberian Peninsula during 1992-1996. To this aim Principal Components Analysis (PCA) and Self-Organizing Maps (SOM) method have been used. The SOM method is a group of artificial neural networks based on the topological properties of the human brain. Results clearly suggest that there exist three different meteorological patterns that are linked to the characteristics of electrical events found in the study area. In winter, most of the electrical events are formed under oceanic advection (NW air fluxes). On these cases, mean rainfall yield estimates reach values of 700 10 4 m 3 per cloud to ground lightning flash (CG flash). During summer most frequent electrical storms are associated to local instability shooting by surface heating with advection of humidity coming from the Iberian Peninsula. Under these meteorological situations, rain is scarcer if compared with oceanic events but lightning CG counts reach the maximum values found in the area (about 10 CG counts per 20 × 20 km 2 and day) giving this way the smallest rainfall yield with a mean value of 15 10 4 m 3 per CG flash. Iberian air fluxes associated with cold air in upper parts of the atmosphere represent the third meteorological pattern found. This pattern is most common in spring and autumn but is not unusual in the rest of the seasons. In those cases mean rainfall yield in the area is about 150 10 4 m 3 per CG flash. In all electrical episodes K instability index is greater than 15 °C but in the most lightning producing events, this index reaches in the area values greater than 24 °C. PCA results pointed out that there exists a relationship between rain and CG counts expressed by the first principal component computed from standardized data. However, we must notice that no event is solely linked to this axis, since a seasonal influence which decreases lightning production when rain

  4. Storm time equatorial plasma bubble zonal drift reversal due to disturbance Hall electric field over the Brazilian region

    Science.gov (United States)

    Santos, A. M.; Abdu, M. A.; Souza, J. R.; Sobral, J. H. A.; Batista, I. S.; Denardini, C. M.

    2016-06-01

    The dynamics of equatorial ionospheric plasma bubbles over Brazilian sector during two magnetic storm events are investigated in this work. The observations were made at varying phases of magnetic disturbances when the bubble zonal drift velocity was found to reverse westward from its normally eastward velocity. Calculation of the zonal drift based on a realistic low-latitude ionosphere modeled by the Sheffield University Plasmasphere-Ionosphere Model showed on a quantitative basis a clear competition between vertical Hall electric field and disturbance zonal winds on the variations observed in the zonal velocity of the plasma bubble. The Hall electric field arising from enhanced ratio of field line-integrated conductivities, ΣH/ΣP, is most often generated by an increase in the integrated Hall conductivity, arising from enhanced energetic particle precipitation in the South American Magnetic Anomaly region for which evidence is provided from observation of anomalous sporadic E layers over Cachoeira Paulista and Fortaleza. Such sporadic E layers are also by themselves evidence for the development of the Hall electric field that modifies the zonal drift.

  5. Comparison of Transcutaneous Electrical Nerve Stimulation and Parasternal Block for Postoperative Pain Management after Cardiac Surgery

    Directory of Open Access Journals (Sweden)

    Nilgun Kavrut Ozturk

    2016-01-01

    Full Text Available Background. Parasternal block and transcutaneous electrical nerve stimulation (TENS have been demonstrated to produce effective analgesia and reduce postoperative opioid requirements in patients undergoing cardiac surgery. Objectives. To compare the effectiveness of TENS and parasternal block on early postoperative pain after cardiac surgery. Methods. One hundred twenty patients undergoing cardiac surgery were enrolled in the present randomized, controlled prospective study. Patients were assigned to three treatment groups: parasternal block, intermittent TENS application, or a control group. Results. Pain scores recorded 4 h, 5 h, 6 h, 7 h, and 8 h postoperatively were lower in the parasternal block group than in the TENS and control groups. Total morphine consumption was also lower in the parasternal block group than in the TENS and control groups. It was also significantly lower in the TENS group than in the control group. There were no statistical differences among the groups regarding the extubation time, rescue analgesic medication, length of intensive care unit stay, or length of hospital stay. Conclusions. Parasternal block was more effective than TENS in the management of early postoperative pain and the reduction of opioid requirements in patients who underwent cardiac surgery through median sternotomy. This trial is registered with Clinicaltrials.gov number NCT02725229.

  6. Role of TGF-β on cardiac structural and electrical remodeling

    Directory of Open Access Journals (Sweden)

    Roberto Ramos-Mondragón

    2008-12-01

    Full Text Available Roberto Ramos-Mondragón, Carlos A Galindo, Guillermo AvilaDepartamento de Bioquímica, Cinvestav-IPN, MéxicoAbstract: The type β transforming growth factors (TGF-βs are involved in a number of human diseases, including heart failure and myocardial arrhythmias. In fact, during the last 20 years numerous studies have demonstrated that TGF-β affects the architecture of the heart under both normal and pathological conditions. Moreover, TGF-β signaling is currently under investigation, with the aim of discovering potential therapeutic roles in human disease. In contrast, only few studies have investigated whether TGF-β affects electrophysiological properties of the heart. This fact is surprising since electrical remodeling represents an important substrate for cardiac disease. This review discusses the potential role of TGF-β on cardiac excitation-contraction (EC coupling, action potentials, and ion channels. We also discuss the effects of TGF-β on cardiac development and disease from structural and electrophysiological points of view.Keywords: transforming growth factor, ion channel, cardiac electrophysiology

  7. Myocardial scaffold-based cardiac tissue engineering: application of coordinated mechanical and electrical stimulations.

    Science.gov (United States)

    Wang, Bo; Wang, Guangjun; To, Filip; Butler, J Ryan; Claude, Andrew; McLaughlin, Ronald M; Williams, Lakiesha N; de Jongh Curry, Amy L; Liao, Jun

    2013-09-03

    Recently, we developed an optimal decellularization protocol to generate 3D porcine myocardial scaffolds, which preserve the natural extracellular matrix structure, mechanical anisotropy, and vasculature templates and also show good cell recellularization and differentiation potential. In this study, a multistimulation bioreactor was built to provide coordinated mechanical and electrical stimulation for facilitating stem cell differentiation and cardiac construct development. The acellular myocardial scaffolds were seeded with mesenchymal stem cells (10(6) cells/mL) by needle injection and subjected to 5-azacytidine treatment (3 μmol/L, 24 h) and various bioreactor conditioning protocols. We found that after 2 days of culturing with mechanical (20% strain) and electrical stimulation (5 V, 1 Hz), high cell density and good cell viability were observed in the reseeded scaffold. Immunofluorescence staining demonstrated that the differentiated cells showed a cardiomyocyte-like phenotype by expressing sarcomeric α-actinin, myosin heavy chain, cardiac troponin T, connexin-43, and N-cadherin. Biaxial mechanical testing demonstrated that positive tissue remodeling took place after 2 days of bioreactor conditioning (20% strain + 5 V, 1 Hz); passive mechanical properties of the 2 day and 4 day tissue constructs were comparable to those of the tissue constructs produced by stirring reseeding followed by 2 weeks of static culturing, implying the effectiveness and efficiency of the coordinated simulations in promoting tissue remodeling. In short, the synergistic stimulations might be beneficial not only for the quality of cardiac construct development but also for patients by reducing the waiting time in future clinical scenarios.

  8. Assessment of cardiac stroke volume in patients with implanted cardiac pacemaker using parametric electrical impedance tomography: a theoretical 2D study.

    Science.gov (United States)

    Mhajna, Muhammad; Abboud, Shimon

    2013-05-01

    The present theoretical study examines the ability to estimate cardiac stroke volume (CSV) in patients with implanted cardiac pacemaker using parametric electrical impedance tomography (pEIT) in a 2D computerized model of the thorax. CSV is a direct indicator of the cardiac pumping efficiency. The commonly used methods for measuring CSV require the invasive procedure of right heart catheterization or use expensive imaging techniques (i.e., MRI). Hence, experience with these techniques for diagnosis and monitoring has been limited to hospitalized patients. In the present study, pEIT scheme was applied in a computerized 2D model of the human thorax with implanted cardiac device to determine the left ventricular (LV) volume at different cardiac cycle phases. The LV was simulated as a prolate ellipse with its axes' lengths as the reconstruction parameters while all other geometries and conductivity values remained constant. An optimization was carried out in order to ensure that the ellipse is the appropriate model for the LV at each cardiac cycle phase. LV volumes calculated by both the pEIT algorithm and the ellipsoid model are consistent. A high correlation (ρ = 0.99) between the true and reconstructed volumes was found. The SV calculation error was ∼1%. The results suggest that the LV volume can be estimated using the pEIT method in a 2D computerized model, and that the method has the potential to be used for monitoring patients with implanted cardiac pacemaker.

  9. Mechanisms of electrical activation and conduction in the gastrointestinal system: lessons from cardiac electrophysiology

    Directory of Open Access Journals (Sweden)

    Gary eTse

    2016-05-01

    Full Text Available The gastrointestinal (GI tract is an electrically excitable organ system containing multiple cell types, which coordinate electrical activity propagating through this tract. Disruption in its normal electrophysiology is observed in a number of GI motility disorders. However, this is not well characterized and the field of GI electrophysiology is much less developed compared to the cardiac field. The aim of this article is to use the established knowledge of cardiac electrophysiology to shed light on the mechanisms of electrical activation and propagation along the GI tract, and how abnormalities in these processes lead to motility disorders and suggest better treatment options based on this improved understanding. In the first part of the article, the ionic contributions to the generation of GI slow wave and the cardiac action potential (AP are reviewed. Propagation of these electrical signals can be described by the core conductor theory in both systems. However, specifically for the GI tract, the following unique properties are observed: changes in slow wave frequency along its length, periods of quiescence, synchronization in short distances and desynchronization over long distances. These are best described by a coupled oscillator theory. Other differences include the diminished role of gap junctions in mediating this conduction in the GI tract compared to the heart. The electrophysiology of conditions such as gastroesophageal reflux disease and gastroparesis, and functional problems such as irritable bowel syndrome are discussed in detail, with reference to ion channel abnormalities and potential therapeutic targets. A deeper understanding of the molecular basis and physiological mechanisms underlying GI motility disorders will enable the development of better diagnostic and therapeutic tools and the advancement of this field.

  10. Study of Electrical Activity in Martian Dust Storms with the Deep Space Network antennas

    Science.gov (United States)

    Martinez, S.; Kuiper, T. B. H.; Majid, W. A.; Garcia-Miro, C.; Tamppari, L. K.; Renno, N. O.; Ruf, C.; Trinh, J. T.

    2012-09-01

    Evidence for non-thermal emission produced by electrostatic discharges in a deep Martian dust storm has been reported by Ruf et al. 2009 [1]. Such discharges had been detected with an innovative kurtosis detector installed in a 34m radio telescope of the Deep Space Network (DSN) in June of 2006. The kurtosis (the fourth central moment of the signal normalized by the square of the second central moment) is extremely sensitive to the presence of non-thermal radiation, but is insensitive to variations in the intensity of the thermal radiation and instrument gain. The non-thermal radiation was detected while a 35 Km deep Martian dust storm was within the field of view of the radio telescope and presented signatures of modulation by the Martian Schumann Resonance. Encouraged by this discovery, several attempts have been made within the DSN to confirm the detection using the R&D antenna (DSS-13) and other antennas in the Madrid and Goldstone complexes, but using a very limited receiver, in terms of recorded data rates, the Very Long Baseline Interferometry (VLBI) Science Receiver (VSR). We are planning to initiate an extensive monitoring of Mars emission in a noninterfering basis while our antennas are tracking various Mars probes, using the Wideband Very Long Baseline Interferometry (VLBI) Science Receiver (WVSR). The WVSR is a very flexible open-loop digital backend that is used for radio science and spacecraft navigation support in the DSN. This instrument allows us to sample a larger bandwidth than with previously used detectors. The processing to look for the kurtosis signature will be performed in software, limited only by the computer capacity. Additionally there are plans to develop an even more powerful custom-built detector based in CASPER technology and Graphic Processing Units for enhance computational power. This contribution will describe how we plan to select the target Mars tracking passes from the DSN schedule. An automated process will generate

  11. Optimisation of a Generic Ionic Model of Cardiac Myocyte Electrical Activity

    Directory of Open Access Journals (Sweden)

    Tianruo Guo

    2013-01-01

    Full Text Available A generic cardiomyocyte ionic model, whose complexity lies between a simple phenomenological formulation and a biophysically detailed ionic membrane current description, is presented. The model provides a user-defined number of ionic currents, employing two-gate Hodgkin-Huxley type kinetics. Its generic nature allows accurate reconstruction of action potential waveforms recorded experimentally from a range of cardiac myocytes. Using a multiobjective optimisation approach, the generic ionic model was optimised to accurately reproduce multiple action potential waveforms recorded from central and peripheral sinoatrial nodes and right atrial and left atrial myocytes from rabbit cardiac tissue preparations, under different electrical stimulus protocols and pharmacological conditions. When fitted simultaneously to multiple datasets, the time course of several physiologically realistic ionic currents could be reconstructed. Model behaviours tend to be well identified when extra experimental information is incorporated into the optimisation.

  12. Echocardiography integrated ACLS protocol versus conventional cardiopulmonary resuscitation in patients with pulseless electrical activity cardiac arrest

    Institute of Scientific and Technical Information of China (English)

    Mojtaba Chardoli; Farhad Heidari; Helaleh Rabiee; Mahdi Sharif-Alhoseini; Hamid Shokoohi; Vafa Rahimi-Movaghar

    2012-01-01

    Objective: To examine the utility of bedside echocardiography in detecting the reversible causes of pulseless electrical activity (PEA) cardiac arrest and predicting the resuscitation outcomes.Methods: In this prospective interventional study,patients presenting with PEA cardiac arrest were randomized into two groups.In Group A,ultrasound trained emergency physicians performed echocardiography evaluating cardiac activity,right ventricle dilation,left ventricle function,pericardial effusion/tamponade and ⅣC size along with the advanced cardiac life support (ACLS) protocol.Patients in Group B solely underwent ACLS protocol without applying echocardiography.The presence or absence of mechanical ventricular activity (MVA) and evidences of PEA reversible causes were recorded.The return of spontaneous circulation (ROSC) and death were evaluated in both groups.Results: One hundred patients with the mean age of (58±6.1) years were enrolled in this study.Fifty patients (Group A) had echocardiography detected in parallel with cardiopulmonary resuscitation (CPR).Among them,7 patients (14%) had pericardial effusion,11 (22%) had hypovolemia,and 39 (78%) were revealed the presence of MVA.In the pseudo PEA subgroup (presence of MVA),43% had ROSC (positive predictive value) and in the true PEA subgroup with cardiac standstill (absence of MVA),there was no recorded ROSC (negative predictive value).Among patients in Group B,no reversible etiology was detected.There was no significant difference in resuscitation results between Groups A and B observed (P=0.52).Conclusion: Bedside echocardiography can identify some reversible causes of PEA.However,there are no significant changes in survival outcome between the echo group and those with traditional CPR.

  13. Electrically conductive gold nanoparticle-chitosan thermosensitive hydrogels for cardiac tissue engineering

    Energy Technology Data Exchange (ETDEWEB)

    Baei, Payam [Department of Stem Cells and Developmental Biology, Cell Science Research Center, Royan Institute for Stem Cell Biology and Technology, ACECR, Tehran (Iran, Islamic Republic of); Cardiovascular Engineering Laboratory, Faculty of Biomedical Engineering, Amirkabir University of Technology (Tehran Polytechnic), Tehran (Iran, Islamic Republic of); Jalili-Firoozinezhad, Sasan [Department of Biomedicine and Surgery, University Hospital Basel, University of Basel, Hebelstrasse 20, CH-4031 Basel (Switzerland); Department of Bioengineeringand IBB - Institute for Bioengineering and Biosciences, Instituto Superior Técnico, Universidade de Lisboa, Lisboa (Portugal); Rajabi-Zeleti, Sareh [Department of Stem Cells and Developmental Biology, Cell Science Research Center, Royan Institute for Stem Cell Biology and Technology, ACECR, Tehran (Iran, Islamic Republic of); Tafazzoli-Shadpour, Mohammad [Cardiovascular Engineering Laboratory, Faculty of Biomedical Engineering, Amirkabir University of Technology (Tehran Polytechnic), Tehran (Iran, Islamic Republic of); Baharvand, Hossein, E-mail: Baharvand@royaninstitute.org [Department of Stem Cells and Developmental Biology, Cell Science Research Center, Royan Institute for Stem Cell Biology and Technology, ACECR, Tehran (Iran, Islamic Republic of); Department of Developmental Biology, University of Science and Culture, ACECR, Tehran (Iran, Islamic Republic of); Aghdami, Nasser, E-mail: Nasser.Aghdami@royaninstitute.org [Department of Stem Cells and Developmental Biology, Cell Science Research Center, Royan Institute for Stem Cell Biology and Technology, ACECR, Tehran (Iran, Islamic Republic of)

    2016-06-01

    Injectable hydrogels that resemble electromechanical properties of the myocardium are crucial for cardiac tissue engineering prospects. We have developed a facile approach that uses chitosan (CS) to generate a thermosensitive conductive hydrogel with a highly porous network of interconnected pores. Gold nanoparticles (GNPs) were evenly dispersed throughout the CS matrix in order to provide electrical cues. The gelation response and electrical conductivity of the hydrogel were controlled by different concentrations of GNPs. The CS-GNP hydrogels were seeded with mesenchymal stem cells (MSCs) and cultivated for up to 14 days in the absence of electrical stimulations. CS-GNP scaffolds supported viability, metabolism, migration and proliferation of MSCs along with the development of uniform cellular constructs. Immunohistochemistry for early and mature cardiac markers showed enhanced cardiomyogenic differentiation of MSCs within the CS-GNP compared to the CS matrix alone. The results of this study demonstrate that incorporation of nanoscale electro-conductive GNPs into CS hydrogels enhances the properties of myocardial constructs. These constructs could find utilization for regeneration of other electroactive tissues. - Highlights: • Thermosensitive electro-conductive hydrogels were prepared from CS and GNPs. • Gelation time and conductivity were tuned by varying concentration of GNPs. • CS-2GNP with gelation time of 25.7 min and conductivity of 0.13 S·m{sup −1} was selected for in vitro studies. • CS-2GNP supported active metabolism, migration and proliferation of MSCs. • Expression of cardiac markers increased about two-fold in CS-2GNP compared to CS.

  14. Observation of enhanced ozone in an electrically active storm over Socorro, NM: Implications for ozone production from corona discharges

    Science.gov (United States)

    Minschwaner, K.; Kalnajs, L. E.; Dubey, M. K.; Avallone, L. M.; Sawaengphokai, P. C.; Edens, H. E.; Winn, W. P.

    2008-09-01

    Enhancements in ozone were observed between about 3 and 10 km altitude within an electrically active storm in central New Mexico. Measurements from satellite sensors and ground-based radar show cloud top pressures between 300 and 150 mb in the vicinity of an ozonesonde launched from Socorro, NM, and heavy precipitation with radar reflectivities exceeding 50 dBZ. Data from a lightning mapping array and a surface electric field mill show a large amount of electrical activity within this thunderstorm. The observed ozone enhancements are large (50% above the mean) and could have resulted from a number of possible processes, including the advection of polluted air from the urban environments of El Paso and Juarez, photochemical production by lightning-generated NOx from aged thunderstorm outflow, downward mixing of stratospheric air, or local production from within the thunderstorm. We find that a large fraction of the ozone enhancement is consistent with local production from corona discharges, either from cloud particles or by corona associated with lightning. The implied global source of ozone from thunderstorm corona discharge is estimated to be 110 Tg O3 a-1 with a range between 40 and 180 Tg O3 a-1. This value is about 21% as large as the estimated ozone production rate from lightning NOx, and about 3% as large as the total chemical production rate of tropospheric ozone. Thus while the estimated corona-induced production of ozone may be significant on local scales, it is unlikely to be as important to the global ozone budget as other sources.

  15. [Effects and the mechanisms of cardiac short-term memory on cellular electrical excitability].

    Science.gov (United States)

    Wang, Juan; Zhang, Hong; Yang, Lin; Wu, Ruijuan; Zhang, Zhenxi

    2012-08-01

    Electrical instability easily induces a unidirectional conduction block, resulting in ventricular tachycardia (VT) or even fibrillation (VF). Cardiac memory affects dynamic electrical characteristics through previous pacing so that it makes the memory important in arrhythmia study. This paper investigates the impact of the rapid pacing duration on cellular excitability and its mechanism. Based on the canine endocardial single cell, a one-dimensional tissue model was developed. Simulations were realized with OpenMP parallel programming method. The results showed that with repetitive pacing, the cellular excitability became low while the conduction velocity decreased. Accumulation of intracellular [Ca2+]i and [Na+]i and depletion of [K+]i led to the shift of membrane current-voltage curves, changing the membrane resistance. Excitability determined by the resistance at the large width of stimulus pulse, therefore, it suggested that [Ca2+]i and [K+]i-induced memory formed the ionic substrates for the alteration of excitability.

  16. Convection and overshielding electric fields in the global ionosphere as observed with magnetometers and SuperDARN during the geomagnetic storm on 14-15 December 2006

    Science.gov (United States)

    Kikuchi, T.; Ebihara, Y.; Hashimoto, K. K.; Kataoka, R.; Hori, T.; Watari, S.; Nishitani, N.

    2008-12-01

    The convection electric field penetrates to the equatorial ionosphere with no significant shielding effects during the DP2 fluctuation event of period of 30 - 60 min (Nishida, 1968) and during the storm main phase continuing over several hours (Huang et al., 2007). On the other hand, shielding becomes effective during the substorm growth phase (Somajajulu et al., 1987; Kikuchi et al., 2000) and even during storm main phase (Kikuchi et al., 2008). The well-developed shielding electric field results in an overshielding at the beginning of the recovery phase of storm/substorms (Kikuchi et al., 2003, 2008). Thus, the electric field manifests complex features at mid-equatorial latitudes, which is not determined only by the solar wind electric field but strongly controlled by magnetospheric processes such as the ring current. To reveal comparative roles of the convection and overshielding electric fields and in what condition the overshielding occurs at mid-equatorial latitudes, we analyzed the geomagnetic storm on 14-15 December, 2006, characterized by the quasi-periodic DP2 fluctuation of 30 min period at the beginning of the storm. We used magnetometer data from mid- equatorial latitudes to detect magnetic signatures due to the electric field originating in the magnetosphere, and used the SuperDARN data to identify electric fields associated with the solar wind dynamo (Region-1 FAC) and the ring current (R2 FAC). We further calculated an electric potential pattern caused by the R1 and R2 FACs with the comprehensive ring current model (CRCM) to better understand the SuperDARN convection pattern. First we show that the DP2 fluctuation was caused by alternating eastward (e-EJ) and westward currents (w-EJ) in the equatorial ionosphere, which were caused by the southward and northward IMF, respectively. We further show that the e-EJ was associated with the large-scale two-cell convection vortices, while the w-EJ accompanied a reverse flow equatorward of the two

  17. Cardiac tissue structure. Electric field interactions in polarizing the heart: 3D computer models and applications

    Science.gov (United States)

    Entcheva, Emilia

    1998-11-01

    The goal of this research is to investigate the interactions between the cardiac tissue structure and applied electric fields in producing complex polarization patterns. It is hypothesized that the response of the heart in the conditions of strong electric shocks, as those applied in defibrillation, is dominated by mechanisms involving the cardiac muscle structure perceived as a continuum. Analysis is carried out in three-dimensional models of the heart with detailed fiber architecture. Shock-induced transmembrane potentials are calculated using the bidomain model in its finite element implementation. The major new findings of this study can be summarized as follows: (1) The mechanisms of polarization due to cardiac fiber curvature and fiber rotation are elucidated in three-dimensional ellipsoidal hearts of variable geometry; (2) Results are presented showing that the axis of stimulation and the polarization axis on a whole heart level might differ significantly due to geometric and anisotropic factors; (3) Virtual electrode patterns are demonstrated numerically inside the ventricular wall in internal defibrillation conditions. The role of the tissue-bath interface in shaping the shock-induced polarization is revealed; (4) The generation of 3D phase singularity scrolls by shock-induced intramural virtual electrode patterns is proposed as evidence for a possible new mechanism for the failure to defibrillate. The results of this study emphasize the role of unequal anisotropy in the intra- and extracellular domains, as well as the salient fiber architecture characteristics, such as curvature and transmural rotation, in polarizing the myocardium. Experimental support of the above findings was actively sought and found in recent optical mapping studies using voltage-sensitive dyes. If validated in vivo, these findings would significantly enrich the prevailing concepts about the mechanisms of stimulation and defibrillation of the heart.

  18. Modeling storm-time electrodynamics of the low-latitude ionosphere thermosphere system: Can long lasting disturbance electric fields be accounted for?

    Science.gov (United States)

    Maruyama, Naomi; Sazykin, Stanislav; Spiro, Robert W.; Anderson, David; Anghel, Adela; Wolf, Richard A.; Toffoletto, Frank R.; Fuller-Rowell, Timothy J.; Codrescu, Mihail V.; Richmond, Arthur D.; Millward, George H.

    2007-07-01

    Storm-time ionospheric disturbance electric fields are studied for two large geomagnetic storms, March 31, 2001 and April 17 18, 2002, by comparing low-latitude observations of ionospheric plasma drifts with results from numerical simulations based on a combination of first-principles models. The simulation machinery combines the Rice convection model (RCM), used to calculate inner magnetospheric electric fields, and the coupled thermosphere ionosphere plasmasphere electrodynamics (CTIPe) model, driven, in part, by RCM-computed electric fields. Comparison of model results with measured or estimated low-latitude vertical drift velocities (zonal electric fields) shows that the coupled model is capable of reproducing measurements under a variety of conditions. In particular, our model results suggest, from theoretical grounds, a possibility of long-lasting penetration of magnetospheric electric fields to low latitudes during prolonged periods of enhanced convection associated with southward-directed interplanetary magnetic field, although the model probably overestimates the magnitude and duration of such penetration during extremely disturbed conditions. During periods of moderate disturbance, we found surprisingly good overall agreement between model predictions and data, with penetration electric fields accounting for early main phase changes and oscillations in low-latitude vertical drift, while the disturbance dynamo mechanism becomes increasingly important later in the modeled events. Discrepancies between the model results and the observations indicate some of the difficulties in validating these combined numerical models, and the limitations of the available experimental data.

  19. Effects of Electric Stimulations Applied during Absolute Refractory Period on Cardiac Function of Rabbits with Heart Failure

    Institute of Scientific and Technical Information of China (English)

    张海柱; 崔长琮; 胡大一

    2010-01-01

    The effects of electric currents applied during absolute refractory period(ARP) on the cardiac function of rabbits with heart failure due to myocardial infarction(MI),and the safety of this method were investigated.Thirty rabbits were randomly assigned equally to 3 groups:sham-operated group,LV-anterior wall cardiac contractility modulation(LV-CCM) group,and septum-CCM(S-CCM) group.A thoracotomy was performed on all the rabbits.Electric pulses were delivered during the ARP on the anterior wall of left ventr...

  20. Effect of Twisted Fiber Anisotropy in Cardiac Tissue on Ablation with Pulsed Electric Fields

    Science.gov (United States)

    Xie, Fei; Zemlin, Christian W.

    2016-01-01

    Background Ablation of cardiac tissue with pulsed electric fields is a promising alternative to current thermal ablation methods, and it critically depends on the electric field distribution in the heart. Methods We developed a model that incorporates the twisted anisotropy of cardiac tissue and computed the electric field distribution in the tissue. We also performed experiments in rabbit ventricles to validate our model. We find that the model agrees well with the experimentally determined ablation volume if we assume that all tissue that is exposed to a field greater than 3 kV/cm is ablated. In our numerical analysis, we considered how tissue thickness, degree of anisotropy, and electrode configuration affect the geometry of the ablated volume. We considered two electrode configurations: two parallel needles inserted into the myocardium (“penetrating needles” configuration) and one circular electrode each on epi- and endocardium, opposing each other (“epi-endo” configuration). Results For thick tissues (10 mm) and moderate anisotropy ratio (a = 2), we find that the geometry of the ablated volume is almost unaffected by twisted anisotropy, i.e. it is approximately translationally symmetric from epi- to endocardium, for both electrode configurations. Higher anisotropy ratio (a = 10) leads to substantial variation in ablation width across the wall; these variations were more pronounced for the penetrating needle configuration than for the epi-endo configuration. For thinner tissues (4 mm, typical for human atria) and higher anisotropy ratio (a = 10), the epi-endo configuration yielded approximately translationally symmetric ablation volumes, while the penetrating electrodes configuration was much more sensitive to fiber twist. Conclusions These results suggest that the epi-endo configuration will be reliable for ablation of atrial fibrillation, independently of fiber orientation, while the penetrating electrode configuration may experience problems when the

  1. Cardiac Mean Electrical Axis in Thoroughbreds—Standardization by the Dubois Lead Positioning System

    Science.gov (United States)

    da Costa, Cássia Fré; Samesima, Nelson; Pastore, Carlos Alberto

    2017-01-01

    Background Different methodologies for electrocardiographic acquisition in horses have been used since the first ECG recordings in equines were reported early in the last century. This study aimed to determine the best ECG electrodes positioning method and the most reliable calculation of mean cardiac axis (MEA) in equines. Materials and Methods We evaluated the electrocardiographic profile of 53 clinically healthy Thoroughbreds, 38 males and 15 females, with ages ranging 2–7 years old, all reared at the São Paulo Jockey Club, in Brazil. Two ECG tracings were recorded from each animal, one using the Dubois lead positioning system, the second using the base-apex method. QRS complex amplitudes were analyzed to obtain MEA values in the frontal plane for each of the two electrode positioning methods mentioned above, using two calculation approaches, the first by Tilley tables and the second by trigonometric calculation. Results were compared between the two methods. Results There was significant difference in cardiac axis values: MEA obtained by the Tilley tables was +135.1° ± 90.9° vs. -81.1° ± 3.6° (p<0.0001), and by trigonometric calculation it was -15.0° ± 11.3° vs. -79.9° ± 7.4° (p<0.0001), base-apex and Dubois, respectively. Furthermore, Dubois method presented small range of variation without statistical or clinical difference by either calculation mode, while there was a wide variation in the base-apex method. Conclusion Dubois improved centralization of the Thoroughbreds' hearts, engendering what seems to be the real frontal plane. By either calculation mode, it was the most reliable methodology to obtain cardiac mean electrical axis in equines. PMID:28095442

  2. The Storm in The Storm

    Institute of Scientific and Technical Information of China (English)

    王颖

    2015-01-01

    The Storm tells a story about sexual issues that two former lovers met in a stormy day and spent a short period of happy time together. In this story, the storm plays an important part,which is just like the thread that joins the plots together, both in natural storm and in feeling storm. It is the driving force behind the story and the affair. As the storm begins climaxes and ends so do the affair and the story. From the appearance, the storm has no harm. Actually, the storm in feeling is bad for the marriage, even in current times, so the story make people speculate the loyalty to the marriage.

  3. Effects of muscle electrical stimulation on peak VO2 in cardiac transplant patients.

    Science.gov (United States)

    Vaquero, A F; Chicharro, J L; Gil, L; Ruiz, M P; Sánchez, V; Lucía, A; Urrea, S; Gómez, M A

    1998-07-01

    Peak oxygen consumption (peak VO2) has become a critical component in the evaluation of heart transplant recipients (HTR). In these patients, peak VO2 remains low after cardiac transplantation mainly because of persisting peripheral limitations in the working muscles. Muscular electrical stimulation, on the other hand, has been shown to enhance the oxidative capacity of healthy muscle. It was the purpose of our investigation to study the effects of ES on the peak VO2 of HTR. Fourteen (11 males and 3 females) HTR (age: 57+/-7yr, mean +/- SD; height: 163+/-7 cm, weight: 70.5+/-8.6 kg) were selected as subjects and each of them was randomly assigned to one of two groups: (a) group EXP (n = 7), receiving electrical stimulation on both quadriceps muscles during a period of 8 weeks, and (b) group CONT (n = 7), not receiving electrical stimulation. Before (PRE) and after (POST) the aforementioned 8-week period, respectively, all the subjects performed a cardiopulmonary exercise test (ramp protocol) on a cycle ergometer for peak VO2 determination. PRE values of peak VO2 were similar in both groups (17.1+/-2.0 vs 16.9+/-3.8ml x kg(-1) x min(-1) in EXP and CONT, respectively). However, peak values of VO2 significantly increased in EXP (p < 0.05) after the period of electrical stimulation (POST peak VO2: 18.7+/-2.0ml x kg(-1)), whereas no change was observed in CONT (POST peak VO2: 16.2+/-3.2 ml x kg(-1) x min(-1)). In conclusion, electrical stimulation could therefore be used to improve the functional capacity of HTR, and might be included in the rehabilitation programs of this population group.

  4. Simulation method for cardiac stroke volume estimation by intracardiac electrical impedance measurement.

    Science.gov (United States)

    Barak, C; Leviatan, Y; Inbar, G F; Hoekstein, K N

    1992-09-01

    Using the electrical impedance measurement technique to investigate stroke volume estimation, three models of the ventricle were simulated. A four-electrode impedance catheter was used; two electrodes to set up an electric field in the model and the other two to measure the potential difference. A new approach, itself an application of the quasi-static case of a method used to solve electromagnetic field problems, was used to solve the electric field in the model. The behaviour of the estimation is examined with respect to the electrode configuration on the catheter and to catheter location with respect to the ventricle walls. Cardiac stroke volume estimation was found to be robust to catheter location generating a 10 per cent error for an offset of 40 per cent of the catheter from the chamber axis and rotation of 20 degrees with respect to the axis. The electrode configuration has a dominant effect on the sensitivity and accuracy of the estimation. Certain configurations gave high accuracy, whereas in others high sensitivity was found with lower accuracy. This led to the conclusion that the electrode configuration should be carefully chosen according to the desired criteria.

  5. THE EFFICACY OF MELDONIUM IN REDUCTION OF CARDIAC ELECTRICAL INSTABILITY IN PATIENTS WITH ISCHEMIC STROKE

    Directory of Open Access Journals (Sweden)

    A. A. Abdullaev

    2015-09-01

    Full Text Available Aim. To study meldonium effect in the combination therapy for ventricular repolarization disorders and cardiac electrical instability in patients with ischemic stroke.Material and methods. Patients (n=46 with acute phase of ischemic stroke were included in a randomized, open-label, uncontrolled study. Patients were randomized into two groups. Group 1 patients (n=25 had been receiving meldonium (Mildronate;Grindex,Latvia;Pharmstandard,Russia, 1.0 g/day intravenously once daily, as a part of standard therapy for 10 days since admission to the hospital. Group 2 patients (n=21 had standard therapy alone. A standart 12-lead ECG, ventricular late potentials (VLP, 24-hour Holter monitoring, troponin test were performed at the baseline and after 10 days.Results. Patients of the group 1 as compared to the group 2 demonstrated more significant positive effect on the clinical condition of patients with ischemic stroke, ventricular repolarization, reduction of frequency (from 3.7±0.5 to 2.1±0.4; p<0.05 and duration (from 6.6±1, 3 to 4.0±1.1 min; p<0.05 of painless myocardial ischemia episodes and VLP (from 48 to 32%.Conclusion. Adding meldonium to standard therapy in patients with acute phase of ischemic stroke can have a positive effect on the clinical condition, repolarization disorders on ECG, frequency of VLP and episodes of painless myocardial ischemia detection. This may have a positive effect on the electrical stability and prevention of cardiac arrhythmias. 

  6. THE EFFICACY OF MELDONIUM IN REDUCTION OF CARDIAC ELECTRICAL INSTABILITY IN PATIENTS WITH ISCHEMIC STROKE

    Directory of Open Access Journals (Sweden)

    A. A. Abdullaev

    2014-01-01

    Full Text Available Aim. To study meldonium effect in the combination therapy for ventricular repolarization disorders and cardiac electrical instability in patients with ischemic stroke.Material and methods. Patients (n=46 with acute phase of ischemic stroke were included in a randomized, open-label, uncontrolled study. Patients were randomized into two groups. Group 1 patients (n=25 had been receiving meldonium (Mildronate;Grindex,Latvia;Pharmstandard,Russia, 1.0 g/day intravenously once daily, as a part of standard therapy for 10 days since admission to the hospital. Group 2 patients (n=21 had standard therapy alone. A standart 12-lead ECG, ventricular late potentials (VLP, 24-hour Holter monitoring, troponin test were performed at the baseline and after 10 days.Results. Patients of the group 1 as compared to the group 2 demonstrated more significant positive effect on the clinical condition of patients with ischemic stroke, ventricular repolarization, reduction of frequency (from 3.7±0.5 to 2.1±0.4; p<0.05 and duration (from 6.6±1, 3 to 4.0±1.1 min; p<0.05 of painless myocardial ischemia episodes and VLP (from 48 to 32%.Conclusion. Adding meldonium to standard therapy in patients with acute phase of ischemic stroke can have a positive effect on the clinical condition, repolarization disorders on ECG, frequency of VLP and episodes of painless myocardial ischemia detection. This may have a positive effect on the electrical stability and prevention of cardiac arrhythmias. 

  7. Acute and long term outcomes of catheter ablation using remote magnetic navigation for the treatment of electrical storm in patients with severe ischemic heart failure

    DEFF Research Database (Denmark)

    Jin, Qi; Jacobsen, Peter Karl; Pehrson, Steen;

    2015-01-01

    BACKGROUND: Catheter ablation with remote magnetic navigation (RMN) can offer some advantages compared to manual techniques. However, the relevant clinical evidence for how RMN-guided ablation affects electrical storm (ES) due to ventricular tachycardia (VT) in patients with severe ischemic heart......-guided catheter ablation can prevent VT recurrence and significantly reduce ICD shocks, suggesting that this strategy can be used as an alternative therapy for VT storm in SIHF patients with ICDs.......BACKGROUND: Catheter ablation with remote magnetic navigation (RMN) can offer some advantages compared to manual techniques. However, the relevant clinical evidence for how RMN-guided ablation affects electrical storm (ES) due to ventricular tachycardia (VT) in patients with severe ischemic heart...... was defined as noninducibility of any sustained monophasic VT at the end of the procedure. Long-term analysis addressed VT recurrence, ICD therapies and all-cause death. ES was acutely suppressed by ablation in all patients. RESULTS: Acute ablation success was obtained in 32 of 40 (80%) patients...

  8. Electrical stimulation directs engineered cardiac tissue to an age-matched native phenotype

    Directory of Open Access Journals (Sweden)

    Richard A Lasher

    2012-12-01

    Full Text Available Quantifying structural features of native myocardium in engineered tissue is essential for creating functional tissue that can serve as a surrogate for in vitro testing or the eventual replacement of diseased or injured myocardium. We applied three-dimensional confocal imaging and image analysis to quantitatively describe the features of native and engineered cardiac tissue. Quantitative analysis methods were developed and applied to test the hypothesis that environmental cues direct engineered tissue toward a phenotype resembling that of age-matched native myocardium. The analytical approach was applied to engineered cardiac tissue with and without the application of electrical stimulation as well as to age-matched and adult native tissue. Individual myocytes were segmented from confocal image stacks and assigned a coordinate system from which measures of cell geometry and connexin-43 spatial distribution were calculated. The data were collected from 9 nonstimulated and 12 electrically stimulated engineered tissue constructs and 5 postnatal day 12 and 7 adult hearts. The myocyte volume fraction was nearly double in stimulated engineered tissue compared to nonstimulated engineered tissue (0.34 ± 0.14 vs 0.18 ± 0.06 but less than half of the native postnatal day 12 (0.90 ± 0.06 and adult (0.91 ± 0.04 myocardium. The myocytes under electrical stimulation were more elongated compared to nonstimulated myocytes and exhibited similar lengths, widths, and heights as in age-matched myocardium. Furthermore, the percentage of connexin-43-positive membrane staining was similar in the electrically stimulated, postnatal day 12, and adult myocytes, whereas it was significantly lower in the nonstimulated myocytes. Connexin-43 was found to be primarily located at cell ends for adult myocytes and irregularly but densely clustered over the membranes of nonstimulated, stimulated, and postnatal day 12 myocytes. These findings support our hypothesis and reveal

  9. Role of the basement membrane in regulation of cardiac electrical properties.

    Science.gov (United States)

    Yang, Huaxiao; Borg, Thomas K; Wang, Zhonghai; Ma, Zhen; Gao, Bruce Z

    2014-06-01

    In the heart muscle, each adult cardiomyocyte is enclosed by a basement membrane (BM). This innermost extracellular matrix is a layered assembly of laminin, collagen IV, glycoproteins, and proteoglycans. In this study, the role of the BM network in regulation of the electrical properties of neonatal cardiomyocytes (NCMs) cultured on an aligned collagen I gel was investigated using a multielectrode array (MEA). A laminin antibody was added to the culture medium for 48-120 h to conjugate newly secreted laminin. Then, morphology of the NCMs on an MEA was monitored using a phase contrast microscope, and the BM network that was immunocytostained for laminin was imaged using a fluorescence microscope. When the BM laminin was absent in this culture model, dramatic changes in NCM morphology were observed. Simultaneously, the MEA-recorded cardiac field potential showed changes compared to that from the control groups: The period of contraction shortened to 1/2 of that from the control groups, and the waveform of the calcium influx shifted from a flat plateau to a peak-like waveform, indicating that the electrical properties of the NCMs were closely related to the components and distribution of the BM network.

  10. A generalized finite difference method for modeling cardiac electrical activation on arbitrary, irregular computational meshes.

    Science.gov (United States)

    Trew, Mark L; Smaill, Bruce H; Bullivant, David P; Hunter, Peter J; Pullan, Andrew J

    2005-12-01

    A generalized finite difference (GFD) method is presented that can be used to solve the bi-domain equations modeling cardiac electrical activity. Classical finite difference methods have been applied by many researchers to the bi-domain equations. However, these methods suffer from the limitation of requiring computational meshes that are structured and orthogonal. Finite element or finite volume methods enable the bi-domain equations to be solved on unstructured meshes, although implementations of such methods do not always cater for meshes with varying element topology. The GFD method solves the bi-domain equations on arbitrary and irregular computational meshes without any need to specify element basis functions. The method is useful as it can be easily applied to activation problems using existing meshes that have originally been created for use by finite element or finite difference methods. In addition, the GFD method employs an innovative approach to enforcing nodal and non-nodal boundary conditions. The GFD method performs effectively for a range of two and three-dimensional test problems and when computing bi-domain electrical activation moving through a fully anisotropic three-dimensional model of canine ventricles.

  11. Learning Storm

    CERN Document Server

    Jain, Ankit

    2014-01-01

    If you are a Java developer who wants to enter into the world of real-time stream processing applications using Apache Storm, then this book is for you. No previous experience in Storm is required as this book starts from the basics. After finishing this book, you will be able to develop not-so-complex Storm applications.

  12. Modeling the response of normal and ischemic cardiac tissue to electrical stimulation

    Science.gov (United States)

    Kandel, Sunil Mani

    Heart disease, the leading cause of death worldwide, is often caused by ventricular fibrillation. A common treatment for this lethal arrhythmia is defibrillation: a strong electrical shock that resets the heart to its normal rhythm. To design better defibrillators, we need a better understanding of both fibrillation and defibrillation. Fundamental mysteries remain regarding the mechanism of how the heart responds to a shock, particularly anodal shocks and the resultant hyperpolarization. Virtual anodes play critical roles in defibrillation, and one cannot build better defibrillators until these mechanisms are understood. We are using mathematical modeling to numerically simulate observed phenomena, and are exploring fundamental mechanisms responsible for the heart's electrical behavior. Such simulations clarify mechanisms and identify key parameters. We investigate how systolic tissue responds to an anodal shock and how refractory tissue reacts to hyperpolarization by studying the dip in the anodal strength-interval curve. This dip is due to electrotonic interaction between regions of depolarization and hyperpolarization following a shock. The dominance of the electrotonic mechanism over calcium interactions implies the importance of the spatial distribution of virtual electrodes. We also investigate the response of localized ischemic tissue to an anodal shock by modeling a regional elevation of extracellular potassium concentration. This heterogeneity leads to action potential instability, 2:1 conduction block (alternans), and reflection-like reentry at the boarder of the normal and ischemic regions. This kind of reflection (reentry) occurs due to the delay between proximal and distal segments to re-excite the proximal segment. Our numerical simulations are based on the bidomain model, the state-of-the-art mathematical description of how cardiac tissue responds to shocks. The dynamic LuoRudy model describes the active properties of the membrane. To model ischemia

  13. Abnormal sodium current properties contribute to cardiac electrical and contractile dysfunction in a mouse model of myotonic dystrophy type 1.

    Science.gov (United States)

    Algalarrondo, Vincent; Wahbi, Karim; Sebag, Frédéric; Gourdon, Geneviève; Beldjord, Chérif; Azibi, Kamel; Balse, Elise; Coulombe, Alain; Fischmeister, Rodolphe; Eymard, Bruno; Duboc, Denis; Hatem, Stéphane N

    2015-04-01

    Myotonic dystrophy type 1 (DM1) is the most common neuromuscular disorder and is associated with cardiac conduction defects. However, the mechanisms of cardiac arrhythmias in DM1 are unknown. We tested the hypothesis that abnormalities in the cardiac sodium current (INa) are involved, and used a transgenic mouse model reproducing the expression of triplet expansion observed in DM1 (DMSXL mouse). The injection of the class-I antiarrhythmic agent flecainide induced prominent conduction abnormalities and significantly lowered the radial tissular velocities and strain rate in DMSXL mice compared to WT. These abnormalities were more pronounced in 8-month-old mice than in 3-month-old mice. Ventricular action potentials recorded by standard glass microelectrode technique exhibited a lower maximum upstroke velocity [dV/dt](max) in DMSXL. This decreased [dV/dt](max) was associated with a 1.7 fold faster inactivation of INa in DMSXL myocytes measured by the whole-cell patch-clamp technique. Finally in the DMSXL mouse, no mutation in the Scn5a gene was detected and neither cardiac fibrosis nor abnormalities of expression of the sodium channel protein were observed. Therefore, alterations in the sodium current markedly contributed to electrical conduction block in DM1. This result should guide pharmaceutical and clinical research toward better therapy for the cardiac arrhythmias associated with DM1.

  14. Development of Electrically Conductive Double-Network Hydrogels via One-Step Facile Strategy for Cardiac Tissue Engineering.

    Science.gov (United States)

    Yang, Boguang; Yao, Fanglian; Hao, Tong; Fang, Wancai; Ye, Lei; Zhang, Yabin; Wang, Yan; Li, Junjie; Wang, Changyong

    2016-02-18

    Cardiac tissue engineering is an effective method to treat the myocardial infarction. However, the lack of electrical conductivity of biomaterials limits their applications. In this work, a homogeneous electronically conductive double network (HEDN) hydrogel via one-step facile strategy is developed, consisting of a rigid/hydrophobic/conductive network of chemical crosslinked poly(thiophene-3-acetic acid) (PTAA) and a flexible/hydrophilic/biocompatible network of photo-crosslinking methacrylated aminated gelatin (MAAG). Results suggest that the swelling, mechanical, and conductive properties of HEDN hydrogel can be modulated via adjusting the ratio of PTAA network to MAAG network. HEDN hydrogel has Young's moduli ranging from 22.7 to 493.1 kPa, and its conductivity (≈10(-4) S cm(-1)) falls in the range of reported conductivities for native myocardium tissue. To assess their biological activity, the brown adipose-derived stem cells (BADSCs) are seeded on the surface of HEDN hydrogel with or without electrical stimulation. Our data show that the HEDN hydrogel can support the survival and proliferation of BADSCs, and that it can improve the cardiac differentiation efficiency of BADSCs and upregulate the expression of connexin 43. Moreover, electrical stimulation can further improve this effect. Overall, it is concluded that the HEDN hydrogel may represent an ideal scaffold for cardiac tissue engineering.

  15. [Electrical cardioversion in the treatment of cardiac arrhythmias during pregnancy--case report and review of literature].

    Science.gov (United States)

    Gałczyński, Krzysztof; Marciniak, Beata; Kudlicki, Janusz; Kimber-Trojnar, Zaneta; Leszczyńska-Gorzelak, Bozena; Oleszczukz, Jan

    2013-10-01

    The incidence of cardiac arrhythmias is estimated et 1.2 per 1000 pregnancies, usually in the third trimester and 50% of them are asymptomatic. They may appear for the first time in pregnancy or have a recurring character An important risk factor related to their appearance is the presence of structural heart disease, which complicates arrhythmias may require urgent, life-saving procedures. External electrical cardioversion is associated with the application of certain amount of energy via two electrodes placed on the thorax. It is used to treat hemodynamically unstable supraventricular tachycardias, including atrial fibrillation and atrial flutter Also in hemodynamically stable patients in whom drug therapy was ineffective elective electrical cardioversion can be use to convert cardiac arrhythmia to sinus rhythm. We present a case of a 33 years old patient with congenital heart disease surgically corrected in childhood who had first incident of atrial flutter in pregnancy. Arrhytmia occured in 26th week of gestation. The patient was hemodynamically stable and did not approve electrical cardioversion as a method of treatment therefore pharmacotherapy was started. Heart rate was controled with metoprolol and digoxin, warfarin was used to anticoagulation. Calcium and potassium were also given. Described therapy did not convert atrial flutter to sinus rhythm therefore in 33rd week of gestation after patient's approval electrical cardioversion was performed. Before cardioversion transesophageal echocardiogram was made to exclude the presence of thrombus inside atria. Energy of 50J was applied and sinus rhythm was restored. Cardiotocography during and after cardioversion did not show any significant fetal heart rate changes. Further pregnancy and puerperium were uneventful. Case report and review of the literature about cardiac arrhytmias and methods of its treatment especially in pregnant women. Analysis of medical documentation of the patient treated in the Department

  16. Groundwater discharge to wetlands driven by storm and flood events: Quantification using continuous Radon-222 and electrical conductivity measurements and dynamic mass-balance modelling

    Science.gov (United States)

    Gilfedder, B. S.; Frei, S.; Hofmann, H.; Cartwright, I.

    2015-09-01

    The dynamic response of groundwater discharge to external influences such as rainfall is an often neglected part of water and solute balances in wetlands. Here we develop a new field platform for long-term continuous 222Rn and electrical conductivity (EC) measurements at Sale Wetland, Australia to study the response of groundwater discharge to storm and flood events. The field measurements, combined with dynamic mass-balance modelling, demonstrate that the groundwater flux can increase from 3 to ∼20 mm d-1 following storms and up to 5 mm d-1 on the receding limb of floods. The groundwater pulses are likely produced by activation of local groundwater flow paths by water ponding on the surrounding flood plains. While 222Rn is a sensitive tracer for quantifying transient groundwater discharge, the mass-balance used to estimate fluxes is sensitive to parameterisation of gas exchange (k) with the atmosphere. Comparison of six equations for calculating k showed that, based on parameterisation of k alone, the groundwater flux estimate could vary by 58%. This work shows that neglecting transient processes will lead to errors in water and solute flux estimates based on infrequent point measurements. This could be particularly important for surface waters connected to contaminated or saline groundwater systems.

  17. Security of the French electric systems after the 1999 storms; La securisation du systeme electrique francais apres les tempetes de 1999

    Energy Technology Data Exchange (ETDEWEB)

    Piketty, G. [Ecole Nationale Superieure des Mines, 75 - Paris (France)

    2002-08-01

    Given the costs of damages to the power grid during the storms of 26 and 28 December 1999, and for reasons related to EdF's image as a 'public service, it was necessary to carefully reexamine the level of security of various parts of the system in coping with events of an unprecedented violence and scope. The state has the responsibility of setting penalties (rate rebates) in the case of a prolonged blackout and the procedures for applying them. But it must also specify the order of magnitude and length of time for the program that it wants implemented to deal with such emergencies. It can do this by laying down general guidelines for investments in each major part of the electricity grid. (author)

  18. [Parameters of cardiac muscle repolarization on the electrocardiogram when changing anatomical and electric position of the heart].

    Science.gov (United States)

    Chaĭkovskiĭ, I A; Baum, O V; Popov, L A; Voloshin, V I; Budnik, N N; Frolov, Iu A; Kovalenko, A S

    2014-01-01

    While discussing the diagnostic value of the single channel electrocardiogram a set of theoretical considerations emerges inevitably, one of the most important among them is the question about dependence of the electrocardiogram parameters from the direction of electrical axis of heart. In other words, changes in what of electrocardiogram parameters are in fact liable to reflect pathological processes in myocardium, and what ones are determined by extracardiac factors, primarily by anatomic characteristics of patients. It is arguable that while analyzing electrocardiogram it is necessary to orient to such physiologically based informative indexes as ST segment displacement. Also, symmetry of the T wave shape is an important parameter which is independent of patients anatomic features. The results obtained are of interest for theoretical and applied aspects of the biophysics of the cardiac electric field.

  19. Turbulent electrical activity at sharp-edged inexcitable obstacles in a model for human cardiac tissue.

    Science.gov (United States)

    Majumder, Rupamanjari; Pandit, Rahul; Panfilov, A V

    2014-10-01

    Wave propagation around various geometric expansions, structures, and obstacles in cardiac tissue may result in the formation of unidirectional block of wave propagation and the onset of reentrant arrhythmias in the heart. Therefore, we investigated the conditions under which reentrant spiral waves can be generated by high-frequency stimulation at sharp-edged obstacles in the ten Tusscher-Noble-Noble-Panfilov (TNNP) ionic model for human cardiac tissue. We show that, in a large range of parameters that account for the conductance of major inward and outward ionic currents of the model [fast inward Na(+) current (INa), L-type slow inward Ca(2+) current (ICaL), slow delayed-rectifier current (IKs), rapid delayed-rectifier current (IKr), inward rectifier K(+) current (IK1)], the critical period necessary for spiral formation is close to the period of a spiral wave rotating in the same tissue. We also show that there is a minimal size of the obstacle for which formation of spirals is possible; this size is ∼2.5 cm and decreases with a decrease in the excitability of cardiac tissue. We show that other factors, such as the obstacle thickness and direction of wave propagation in relation to the obstacle, are of secondary importance and affect the conditions for spiral wave initiation only slightly. We also perform studies for obstacle shapes derived from experimental measurements of infarction scars and show that the formation of spiral waves there is facilitated by tissue remodeling around it. Overall, we demonstrate that the formation of reentrant sources around inexcitable obstacles is a potential mechanism for the onset of cardiac arrhythmias in the presence of a fast heart rate.

  20. Evaluation of cerebral electrical activity and cardiac output after patent ductus arteriosus ligation in preterm infants.

    LENUS (Irish Health Repository)

    Leslie, A T F S

    2013-11-01

    To characterize and investigate the relationship between systemic blood flow and pre- and postoperative cerebral electrical activity in preterm neonates undergoing patent ductus arteriosus (PDA) ligation.

  1. Geomagnetic storms: historical perspective to modern view

    Science.gov (United States)

    Lakhina, Gurbax S.; Tsurutani, Bruce T.

    2016-12-01

    The history of geomagnetism is more than 400 years old. Geomagnetic storms as we know them were discovered about 210 years ago. There has been keen interest in understanding Sun-Earth connection events, such as solar flares, CMEs, and concomitant magnetic storms in recent times. Magnetic storms are the most important component of space weather effects on Earth. We give an overview of the historical aspects of geomagnetic storms and the progress made during the past two centuries. Super magnetic storms can cause life-threatening power outages and satellite damage, communication failures and navigational problems. The data for such super magnetic storms that occurred in the last 50 years during the space era is sparce. Research on historical geomagnetic storms can help to create a database for intense and super magnetic storms. New knowledge of interplanetary and solar causes of magnetic storms gained from spaceage observations will be used to review the super magnetic storm of September 1-2, 1859. We discuss the occurrence probability of such super magnetic storms, and the maximum possible intensity for the effects of a perfect ICME: extreme super magnetic storm, extreme magnetospheric compression, and extreme magnetospheric electric fields.

  2. Nanosecond pulsed platelet-rich plasma (nsPRP) improves mechanical and electrical cardiac function following myocardial reperfusion injury.

    Science.gov (United States)

    Hargrave, Barbara; Varghese, Frency; Barabutis, Nektarios; Catravas, John; Zemlin, Christian

    2016-02-01

    Ischemia and reperfusion (I/R) of the heart is associated with biochemical and ionic changes that result in cardiac contractile and electrical dysfunction. In rabbits, platelet-rich plasma activated using nanosecond pulsed electric fields (nsPRP) has been shown to improve left ventricular pumping. Here, we demonstrate that nsPRP causes a similar improvement in mouse left ventricular function. We also show that nsPRP injection recovers electrical activity even before reperfusion begins. To uncover the mechanism of nsPRP action, we studied whether the enhanced left ventricular function in nsPRP rabbit and mouse hearts was associated with increased expression of heat-shock proteins and altered mitochondrial function under conditions of oxidative stress. Mouse hearts underwent 30 min of global ischemia and 1 h of reperfusion in situ. Rabbit hearts underwent 30 min of ischemia in vivo and were reperfused for 14 days. Hearts treated with nsPRP expressed significantly higher levels of Hsp27 and Hsp70 compared to hearts treated with vehicle. Also, pretreatment of cultured H9c2 cells with nsPRP significantly enhanced the "spare respiratory capacity (SRC)" also referred to as "respiratory reserve capacity" and ATP production in response to the uncoupler FCCP. These results suggest a cardioprotective effect of nsPRP on the ischemic heart during reperfusion.

  3. Why QRS Duration Should Be Replaced by Better Measures of Electrical Activation to Improve Patient Selection for Cardiac Resynchronization Therapy.

    Science.gov (United States)

    Engels, Elien B; Mafi-Rad, Masih; van Stipdonk, Antonius M W; Vernooy, Kevin; Prinzen, Frits W

    2016-08-01

    Cardiac resynchronization therapy (CRT) is a well-known treatment modality for patients with a reduced left ventricular ejection fraction accompanied by a ventricular conduction delay. However, a large proportion of patients does not benefit from this therapy. Better patient selection may importantly reduce the number of non-responders. Here, we review the strengths and weaknesses of the electrocardiogram (ECG) markers currently being used in guidelines for patient selection, e.g., QRS duration and morphology. We shed light on the current knowledge on the underlying electrical substrate and the mechanism of action of CRT. Finally, we discuss potentially better ECG-based biomarkers for CRT candidate selection, of which the vectorcardiogram may have high potential.

  4. Imaging cardiac activity by the D-bar method for electrical impedance tomography

    OpenAIRE

    Isaacson, D; Mueller, J L; Newell, J C; Siltanen, S

    2006-01-01

    A practical D-bar algorithm for reconstructing conductivity changes from EIT data taken on electrodes in a 2D geometry is described. The algorithm is based on the global uniqueness proof of Nachman (1996 Ann. Math. 143 71–96) for the 2D inverse conductivity problem. Results are shown for reconstructions from data collected on electrodes placed around the circumference of a human chest to reconstruct a 2D cross-section of the torso. The images show changes in conductivity during a cardiac cycl...

  5. Quantifying Power Grid Risk from Geomagnetic Storms

    Science.gov (United States)

    Homeier, N.; Wei, L. H.; Gannon, J. L.

    2012-12-01

    We are creating a statistical model of the geophysical environment that can be used to quantify the geomagnetic storm hazard to power grid infrastructure. Our model is developed using a database of surface electric fields for the continental United States during a set of historical geomagnetic storms. These electric fields are derived from the SUPERMAG compilation of worldwide magnetometer data and surface impedances from the United States Geological Survey. This electric field data can be combined with a power grid model to determine GICs per node and reactive MVARs at each minute during a storm. Using publicly available substation locations, we derive relative risk maps by location by combining magnetic latitude and ground conductivity. We also estimate the surface electric fields during the August 1972 geomagnetic storm that caused a telephone cable outage across the middle of the United States. This event produced the largest surface electric fields in the continental U.S. in at least the past 40 years.

  6. Cardiac sodium channelopathies

    NARCIS (Netherlands)

    Amin, A.S.; Asghari-Roodsari, A.; Tan, H.L.

    2010-01-01

    Cardiac sodium channel are protein complexes that are expressed in the sarcolemma of cardiomyocytes to carry a large inward depolarizing current (I-Na) during phase 0 of the cardiac action potential. The importance of I-Na for normal cardiac electrical activity is reflected by the high incidence of

  7. Vagal control of cardiac electrical activity and wall motion during ventricular fibrillation in large animals.

    Science.gov (United States)

    Naggar, Isaac; Nakase, Ko; Lazar, Jason; Salciccioli, Louis; Selesnick, Ivan; Stewart, Mark

    2014-07-01

    Vagal inputs control pacemaking and conduction systems in the heart. Anatomical evidence suggests a direct ventricular action, but functional evidence that separates direct and indirect (via the conduction system) vagal actions is less well established. We studied vagus nerve stimulation (VNS) during sinus rhythm and ventricular fibrillation (VF) in pigs and sheep to determine: 1) the range of unilateral and bilateral actions (inotropic and chronotropic) and 2) whether VNS alters left ventricular motion and/or electrical activity during VF, a model of abnormal electrical conduction of the left ventricle that excludes sinus and atrioventricular nodal function. Adult pigs (N=8) and sheep (N=10) were anesthetized with urethane and mechanically ventilated. VNS was performed in animals at 1, 2, 5, 10, 20, 50, and 100Hz for 20s. VF was induced with direct current to the ventricles or occlusion of the left anterior descending coronary artery. In 4 pigs and 3 sheep, left ventricular wall motion was assessed from endocardial excursion in epicardial echocardiography. In sheep and pigs, the best frequency among those tested for VNS during sinus rhythm to produce sustained electrical and mechanical ventricular standstill was 50Hz for unilateral or bilateral stimulation. When applied during VF, bilateral VNS increased the variability of the dominant VF frequency, indicating a direct impact on the excitability of ventricular myocytes, and decreased endocardial excursion by more than 50% during VF. We conclude that the vagus nerve directly modulates left ventricular function independently from its effects on the conduction system.

  8. Regional electroporation of single cardiac myocytes in a focused electric field.

    Science.gov (United States)

    Klauke, Norbert; Smith, Godfrey; Cooper, Jonathan M

    2010-01-15

    There is now a significant interest in being able to locate single cells within geometrically defined regions of a microfluidic chip and to gain intracellular access through the local electroporation of the cell membrane. This paper describes the microfabrication of electroporation devices which can enable the regional electroporation of adult ventricular myocytes, in order to lower the local electrical resistance of the cell membrane. Initially three different devices, designed to suit the characteristic geometry of the cardiomyocyte, were investigated (all three designs serve to focus the electric field to selected regions of the cell). We demonstrate that one of these three devices revealed the sequence of cellular responses to field strengths of increasing magnitudes, namely, cell contraction, hypercontraction, and lysis. This same device required a reduced threshold voltage for each of these events, including in particular membrane breakdown. We were not only able to show the gradual regional increase in the electric conductivity of the cell membrane but were also able to avoid changes in the local intra- and extracellular pH (by preventing the local generation of protons at the electrode surface, as a consequence of the reduced threshold voltage). The paper provides evidence for new strategies for achieving robust and reproducible regional electroporation, a technique which, in future, may be used for the insertion of large molecular weight molecules (including genes) as well as for on-chip voltage clamping of the primary adult cardiomyocyte.

  9. Geomagnetic Storm Sudden Commencements

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Storm Sudden Commencements (ssc) 1868 to present: STORM1 and STORM2 Lists: (Some text here is taken from the International Association of Geomagnetism and Aeronomy...

  10. 直接冠状动脉介入治疗发生电风暴的危险因素及护理%Risk factors and nursing of electrical storm in percutaneous coronary intervention

    Institute of Scientific and Technical Information of China (English)

    李晓彤; 马勇波; 徐日新; 徐冰

    2011-01-01

    目的 分析急性ST段抬高型心肌梗死(STEMI)患者直接冠状动脉介入治疗(PCI)发生电风暴的危险因素,为预见性护理提供依据.方法 总结2008年1月至2010年12月114例STEMI患者直接PCI的临床资料,将24h内自发室性心动过速(VT)或心室颤动(VF) ≥2次,需紧急治疗者归入电风暴组,其余纳入对照组.结果 电风暴发生9例,发生率7.9%.电风暴组患者入院时肌酸激酶同工酶(CK-MB)值(105.8±16.3)U/L、高于对照组(90.4±17.5)U/L,差异有统计学意义(=2.545,P<0.05);肌钙蛋白Ⅰ(TNI)值及梗死相关动脉(IRA)为右冠状动脉、TIMI0级血流、心动过缓、持续性低血压发生率均显著高于对照组,差异有统计学意义(P<0.05).结论 CK-MB值、TNI值、IRA为右冠状动脉、无血流、心动过缓、持续性低血压是发生电风暴的主要危险因素,应在护理过程中重视这些高危风险,配合临床治疗,改善预后.%Objective To investigate the risk factors for occurrence of electrical storm in the patients with acute ST segment elevation myocardial infarction (STEMI) when giving treatment of percutaneous coronary intervention (PCI) and to provide evidence for prospective nursing.Methods Collected the clinical data of 114 patients with STEMI and treated by PCI from January 2008 to December 2010,patients with no less than twice spontaneous ventricular tachycardia (VT) or ventricular fibrillation (VF) were classified to the electrical storm group and others were classified to control group.Results The number of patients with electrical storm is nine and the incidence rate is 7.9%.The electrical storm group:The value of creatine kinase isoenzyme MB (CK-MB) in the electrical storm group was higher than in control group,( 105.8 ± 16.3 ) U/L vs (90.4 ± 17.5) U/L,there was statistically significant difference(t =2.545,P <0.05).The value of troponin I (TNI),right coronary artery being the infarction related artery (IRA),T1MI 0 level blood

  11. Storm-Time Ionospheric Disturbances Monitored by GPS Beacon Measurements

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The Total Electron Content (TEC) during three great storms, from April to August 2000, was collected by means of a GPS receiver located in Jingzhou (30. 4° N, 112. 2° E). The time-latitude-dependent features of ionospheric storms are identified using TEC difference images based on the deviations of TEC during storm relative to quiet time. The responses of ionospheric TEC to magnetic storms were analyzed. The results show that: 1) In middle and low latitude, ionospheric storms effects are more apparent in local day time than at night; 2) Ionospheric storm effects are more dominant near the hump of the equatorial anomaly region than in other regions of TEC measurements; 3) The positive effects during the main phase of iono spheric storm may be caused by electric fields in low latitude; 4) During the recovery period of ionospheric storm, the negative phase of storm may be due to the perturbation of the neutral gas composition.

  12. A coupled 3D-1D numerical monodomain solver for cardiac electrical activation in the myocardium with detailed Purkinje network

    Science.gov (United States)

    Vergara, Christian; Lange, Matthias; Palamara, Simone; Lassila, Toni; Frangi, Alejandro F.; Quarteroni, Alfio

    2016-03-01

    We present a model for the electrophysiology in the heart to handle the electrical propagation through the Purkinje system and in the myocardium, with two-way coupling at the Purkinje-muscle junctions. In both the subproblems the monodomain model is considered, whereas at the junctions a resistor element is included that induces an orthodromic propagation delay from the Purkinje network towards the heart muscle. We prove a sufficient condition for convergence of a fixed-point iterative algorithm to the numerical solution of the coupled problem. Numerical comparison of activation patterns is made with two different combinations of models for the coupled Purkinje network/myocardium system, the eikonal/eikonal and the monodomain/monodomain models. Test cases are investigated for both physiological and pathological activation of a model left ventricle. Finally, we prove the reliability of the monodomain/monodomain coupling on a realistic scenario. Our results underlie the importance of using physiologically realistic Purkinje-trees with propagation solved using the monodomain model for simulating cardiac activation.

  13. Angiotensin II Type 1 Receptor-Mediated Electrical Remodeling in Mouse Cardiac Myocytes.

    Directory of Open Access Journals (Sweden)

    Jeremy Kim

    Full Text Available We recently characterized an autocrine renin angiotensin system (RAS in canine heart. Activation of Angiotensin II Type 1 Receptors (AT1Rs induced electrical remodeling, including inhibition of the transient outward potassium current Ito, prolongation of the action potential (AP, increased calcium entry and increased contractility. Electrical properties of the mouse heart are very different from those of dog heart, but if a similar system existed in mouse, it could be uniquely studied through genetic manipulations. To investigate the presence of a RAS in mouse, we measured APs and Ito in isolated myocytes. Application of angiotensin II (A2 for 2 or more hours reduced Ito magnitude, without affecting voltage dependence, and prolonged APs in a dose-dependent manner. Based on dose-inhibition curves, the fast and slow components of Ito (Ito,fast and IK,slow appeared to be coherently regulated by [A2], with 50% inhibition at an A2 concentration of about 400 nM. This very high K0.5 is inconsistent with systemic A2 effects, but is consistent with an autocrine RAS in mouse heart. Pre-application of the microtubule destabilizing agent colchicine eliminated A2 effects on Ito and AP duration, suggesting these effects depend on intracellular trafficking. Application of the biased agonist SII ([Sar1-Ile4-Ile8]A2, which stimulates receptor internalization without G protein activation, caused Ito reduction and AP prolongation similar to A2-induced changes. These data demonstrate AT1R mediated regulation of Ito in mouse heart. Moreover, all measured properties parallel those measured in dog heart, suggesting an autocrine RAS may be a fundamental feedback system that is present across species.

  14. Space storms as natural hazards

    Directory of Open Access Journals (Sweden)

    L. I. Dorman

    2008-04-01

    Full Text Available Eruptive activity of the Sun produces a chain of extreme geophysical events: high-speed solar wind, magnetic field disturbances in the interplanetary space and in the geomagnetic field and also intense fluxes of energetic particles. Space storms can potentially destroy spacecrafts, adversely affect astronauts and airline crew and human health on the Earth, lead to pipeline breaking, melt electricity transformers, and discontinue transmission. In this paper we deal with two consequences of space storms: (i rise in failures in the operation of railway devices and (ii rise in myocardial infarction and stroke incidences.

  15. Iron deposition following chronic myocardial infarction as a substrate for cardiac electrical anomalies: initial findings in a canine model.

    Directory of Open Access Journals (Sweden)

    Ivan Cokic

    Full Text Available PURPOSE: Iron deposition has been shown to occur following myocardial infarction (MI. We investigated whether such focal iron deposition within chronic MI lead to electrical anomalies. METHODS: Two groups of dogs (ex-vivo (n = 12 and in-vivo (n = 10 were studied at 16 weeks post MI. Hearts of animals from ex-vivo group were explanted and sectioned into infarcted and non-infarcted segments. Impedance spectroscopy was used to derive electrical permittivity ([Formula: see text] and conductivity ([Formula: see text]. Mass spectrometry was used to classify and characterize tissue sections with (IRON+ and without (IRON- iron. Animals from in-vivo group underwent cardiac magnetic resonance imaging (CMR for estimation of scar volume (late-gadolinium enhancement, LGE and iron deposition (T2* relative to left-ventricular volume. 24-hour electrocardiogram recordings were obtained and used to examine Heart Rate (HR, QT interval (QT, QT corrected for HR (QTc and QTc dispersion (QTcd. In a fraction of these animals (n = 5, ultra-high resolution electroanatomical mapping (EAM was performed, co-registered with LGE and T2* CMR and were used to characterize the spatial locations of isolated late potentials (ILPs. RESULTS: Compared to IRON- sections, IRON+ sections had higher[Formula: see text], but no difference in[Formula: see text]. A linear relationship was found between iron content and [Formula: see text] (p1.5% with similar scar volumes (7.28% ± 1.02% (Iron (1.5%, p = 0.51 but markedly different iron volumes (1.12% ± 0.64% (Iron (1.5%, p = 0.02, QT and QTc were elevated and QTcd was decreased in the group with the higher iron volume during the day, night and 24-hour period (p<0.05. EAMs co-registered with CMR images showed a greater tendency for ILPs to emerge from scar regions with iron versus without iron. CONCLUSION: The electrical behavior of infarcted hearts with iron appears to be different from those without iron. Iron within infarcted zones may

  16. CyberStorm III

    NARCIS (Netherlands)

    Luiijf, H.A.M.; et al

    2010-01-01

    Projectteam Cyber Storm III - De Verenigde Staten organiseerden de afgelopen jaren een reeks grootschalige ICT-crisisoefeningen met de naam Cyber Storm. Cyber Storm III is de derde oefening in de reeks. Het scenario van Cyber Storm III staat in het teken van grootschalige ICT-verstoringen, waarbij n

  17. Magnetic Imaging of Applied and Propagating Action Currents in Cardiac Tissue Slices: Determination of Anisotropic Electrical Conductivities in a Two-Dimensional Bidomain.

    Science.gov (United States)

    Staton, Daniel Joseph

    We describe the first, high-resolution magnetic images of applied currents and propagating action currents in slices of canine cardiac tissue. This tissue was maintained in vitro at 37^circC. Our main conclusions are summarized as follows: the action currents produce magnetic fields which are measurable; during the initial stages of the propagating action potential, small, expanding, quatrefoil loops of current develop; the magnetic fields produced by repolarization currents are larger than previously anticipated. Most of the current associated with the propagating action potential is confined within the wavefront and should be magnetically silent; however, differences in the intracellular and extracellular electrical conductivities, in both the longitudinal and transverse fiber directions, are great enough that expanding quatrefoil current densities are associated with the wavefront and produce measurable magnetic fields. Since action currents are affected by the electrical conductivities, it is of interest to determine their values, which depend not only upon the tissue characteristics, but also on the mathematical model used to interpret the measured data. In our analysis of current injection, we use the anisotropic bidomain model which incorporates a passive, linear membrane. We introduce theoretical techniques to calculate the anisotropic conductivities of a two-dimensional bidomain. To apply these techniques to magnetic fields resulting from current injection into cardiac tissue slices, we need to improve the higher spatial frequency content of our present measurements. This may be done by measuring the magnetic field closer to the cardiac slice (presently 2.5 mm), decreasing the sampling interval of the measurement, and increasing the sampling area of the field. Magnetic fields are produced by propagating action currents, which are in turn the result of the propagating action potential. From the magnetic field, we directly image isochronal transmembrane

  18. Solar noise storms

    CERN Document Server

    Elgaroy, E O

    2013-01-01

    Solar Noise Storms examines the properties and features of solar noise storm phenomenon. The book also presents some theories that can be used to gain a better understanding of the phenomenon. The coverage of the text includes topics that cover the features and behavior of noise storms, such as the observable features of noise storms; the relationship between noise storms and the observable features on the sun; and ordered behavior of storm bursts in the time-frequency plane. The book also covers the spectrum, polarization, and directivity of noise storms. The text will be of great use to astr

  19. Crib death: further support for the concept of fatal cardiac electrical instability as the final common pathway.

    Science.gov (United States)

    Ottaviani, Giulia; Matturri, Luigi; Rossi, Lino; James, Thomas N

    2003-11-01

    This work intends to be a review of the current status of knowledge on the cardiac conduction system in the crib death as well as remaining challenges, including reflections upon authors' personal works as well as many studies by others. The cardiac conduction system findings of resorptive degeneration, His bundle dispersion, Mahaim fibers, cartilaginous meta-hyperplasia, persistent fetal dispersion, left sided His bundle, hemorrhage of the atrio-ventricular junction, septation of the bifurcation, atrio-ventricular node dispersion, sinus node hypoplasia, Zahn node, His bundle hypoplasia, atrio-ventricular node and His bundle dualism are hereby discussed by the authors. The cardiac hypotheses postulating that crib death could be due to lethal cardiac arrhythmias or heart block were considered of great interest in the 1970s. After a general abandon of the conduction studies in crib death, the cardiac concept of crib death is gathering a renewed interest, as well as the occurrence of infantile junctional tachycardia. Both the morphological and functional derangement underlying crib death remain poorly understood, assuring that it remains to be a major medical and social problem. Despite the non-specificity of most of the cardiac conduction findings in crib death, we believe that they, in association with altered neurovegetative stimuli, could underlie potentially malignant arrhythmias, providing a morphologic support for the cardiac concept of crib death.

  20. The risk factors of perioperative electrical storm in direct percutaneous coronary Intervention%直接经皮冠状动脉介入治疗围手术期发生电风暴的危险因素

    Institute of Scientific and Technical Information of China (English)

    徐建然; 胡海雷; 黄鸿博; 俞静芬; 史习宝; 陈岳维; 岑镇波; 胡于健

    2012-01-01

    Objective To investigate the risk factors of electrical storm(ES) in patients with acute myocardial infarction (AMI) during perioperative period of direct percutaneous coronary intervention(PCI).Methods Forty-one AMI patients had been treated with direct PCI.The patients with perioperative ES were included in ES group and those without perioperative ES were included in conntrol group.ES was defined as the occurrence of spontaneous ventricular tachycardia or venicular fibrillation was twice or more within 24 h and unable to stop by itself and emergency treatment was needed.The difference of the clinical data between two groups were compared.Results There were 7 in 41 patients with direct PCI who had ES,the incidence was 17.07%,and 34 cases didn't have ES.Systolic pressure,diastolic pressure,white cell count,blood glucose,international normalized ratio and time duration from chest pain onset to direct PCI between two groups had no significant differences (P >0.05).Age,CK-MB,cardiac troponin I,the diameter of infarctrelated arleries(IRA ),incidence of reperfusion arrhythmia and mortality of ES group were all obviously higher than those of control group (P < 0.05 or < 0.01 ).The incidence of ES in patients whose IRA was left main artery or occlusion of middle section of two main coronary arteries,right coronary artery,left anterior descending branch and left circumflex artery was 66.67%(2/3),18.75%(3/16),11.76%(2/17) and O, respectively.Conclusions Perioperative ES during direct PCI most commonly occurrs in AMI patients with left main artery or occlusion of middle section of two main coronary artery.The diameter of IRA,TIMI flow classification after the patency of IRA and recanalization arrhythmia are the main risk factors of the occurrence of perioperative ES.%目的 探讨急性心肌梗死(AMI)患者直接经皮冠状动脉介入治疗(PCI)围手术期发生电风暴的危险因素.方法 对41例AMI患者行直接PCI,将围手术期发生电风暴的

  1. The Study of Risk Factors and Clinical Safety of Esmolol in the Treatment of Sympathetic Electrical Storm%交感电风暴危险因素的研究及艾司洛尔治疗的安全性观察

    Institute of Scientific and Technical Information of China (English)

    马俊秀; 李振伟; 樊凌华

    2014-01-01

    目的:评价超敏C反应蛋白、脑钠肽前体、肌钙蛋白等生化指标对交感电风暴的预测作用及评价艾司洛尔对交感电风暴的治疗安全性。方法:选取2010年3月-2013年5月间我院IC U收治的反复发作恶性心律失常29例,其中急性冠脉综合征21例,重症心肌炎7例,长Q T综合征1例,对照组30例,为随机挑选心血管内科普通住院患者,住院期间无心律失常发作且均无其他系统严重疾病。两组进行回顾性分析。结果:交感电风暴组患者的超敏C反应蛋白、脑钠肽前体及肌钙蛋白均较对照组高,差异有统计学意义。29例患者应用艾司洛尔治疗,最终抢救成功27例,死亡2例。结论:超敏C反应蛋白、脑钠肽前体、肌钙蛋白对交感电风暴的发生有一定的预测作用。合理使用艾司洛尔能有效控制恶性心律失常的发作,降低死亡率,安全性高。%To evaluate the hs-CRP ,brain natriuretic peptide precursor ,troponin and other biochemical inde-xes for predicting the sympathetic electrical storm and the clinical safety of esmolol in the treatment of it .Methods :We picked 29 patients who were treated in our ICU from March 2010 to May 2013 .Including 21 acute coronary syndrome , 7 myocarditis ,1 long QT sydrome .It is a retrospective analysis .Results:hs-CRP ,brain natriuretic peptide and cardiac troponin in patients with sympathetic electrical storm is higher than the control group ,there was a significant differ-ence .Conclusion:hs-CRP ,brain natriuretic peptide precursor ,troponin is predictive to sympathetic electrical storm . The rational use of esmolol can effectively control the malignant ventricular arrhythmia ,reduce the mortality rate ,and it is high safety .

  2. NCDC Storm Events Database

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Storm Data is provided by the National Weather Service (NWS) and contain statistics on personal injuries and damage estimates. Storm Data covers the United States of...

  3. Comparison of transthoracic electrical bioimpedance cardiac output measurement with thermodilution method in post coronary artery bypass graft patients.

    Science.gov (United States)

    Sharma, Vikas; Singh, Ajmer; Kansara, Bhuvnesh; Karlekar, Anil

    2011-01-01

    Transthoracic electrical bioimpedance (TEB) has been proposed as a non-invasive, continuous, and cost-effective method of cardiac output (CO) measurement. In this prospective, non-randomized, clinical study, we measured CO with NICOMON (Larsen and Toubro Ltd., Mysore, India) and compared it with thermodilution (TD) method in patients after off-pump coronary artery bypass (OPCAB) graft surgery. We also evaluated the effect of ventilation (mechanical and spontaneous) on the measurement of CO by the two methods. Forty-six post-OPCAB patients were studied at five predefined time points during controlled ventilation and at five time points when breathing spontaneously. A total of 230 data pairs of CO were obtained. During controlled ventilation, TD CO values ranged from 2.29 to 6.74 L/min (mean 4.45 ± 0.85 L/min), while TEB CO values ranged from 1.70 to 6.90 L/min (mean 4.43 ± 0.94 L/min). The average correlation (r) was 0.548 (P = 0.0002), accompanied by a bias of 0.015 L/min and precision of 0.859 L/min. In spontaneously breathing patients, TD CO values ranged from 2.66 to 6.92 L/min (mean 4.66 ± 0.76 L/min), while TEB CO values ranged from 3.08 to 6.90 L/min (mean 4.72 ± 0.82 L/min). Their average correlation was relatively poor (r = 0.469, P= 0.002), accompanied by a bias of -0.059 L/min and precision of 0.818 L/min. The overall percent errors between TD CO and TEB CO were 19.3% (during controlled ventilation) and 17.4% (during spontaneous breathing), respectively. To conclude, a fair correlation was found between TD CO and TEB CO measurements among post-OPCAB patients during controlled ventilation. However, the correlation was weak in spontaneously breathing patients.

  4. Comparison of transthoracic electrical bioimpedance cardiac output measurement with thermodilution method in post coronary artery bypass graft patients

    Directory of Open Access Journals (Sweden)

    Sharma Vikas

    2011-01-01

    Full Text Available Transthoracic electrical bioimpedance (TEB has been proposed as a non-invasive, continuous, and cost-effective method of cardiac output (CO measurement. In this prospective, non-randomized, clinical study, we measured CO with NICOMON (Larsen and Toubro Ltd., Mysore, India and compared it with thermodilution (TD method in patients after off-pump coronary artery bypass (OPCAB graft surgery. We also evaluated the effect of ventilation (mechanical and spontaneous on the measurement of CO by the two methods. Forty-six post-OPCAB patients were studied at five predefined time points during controlled ventilation and at five time points when breathing spontaneously. A total of 230 data pairs of CO were obtained. During controlled ventilation, TD CO values ranged from 2.29 to 6.74 L/min (mean 4.45 ± 0.85 L/min, while TEB CO values ranged from 1.70 to 6.90 L/min (mean 4.43 ± 0.94 L/min. The average correlation (r was 0.548 (P = 0.0002, accompanied by a bias of 0.015 L/min and precision of 0.859 L/min. In spontaneously breathing patients, TD CO values ranged from 2.66 to 6.92 L/min (mean 4.66 ± 0.76 L/min, while TEB CO values ranged from 3.08 to 6.90 L/min (mean 4.72 ± 0.82 L/min. Their average correlation was relatively poor (r = 0.469, P= 0.002, accompanied by a bias of −0.059 L/min and precision of 0.818 L/min. The overall percent errors between TD CO and TEB CO were 19.3% (during controlled ventilation and 17.4% (during spontaneous breathing, respectively. To conclude, a fair correlation was found between TD CO and TEB CO measurements among post-OPCAB patients during controlled ventilation. However, the correlation was weak in spontaneously breathing patients.

  5. Cardiac output measured by electrical velocimetry in the CT suite correlates with coronary artery enhancement: a feasibility study

    Energy Technology Data Exchange (ETDEWEB)

    Flinck, Marianne; Graden, Aasa; Milde, Helen; Flinck, Agneta; Hellstroem, Mikael (Dept. of Radiology, Sahlgrenska Univ. Hospital and Sahlgrenska Academy at Goetenborg Univ., Goeteborg (Sweden)); Bjoerk, Jonas (Competence Centre for Clinical Research, Lund Univ. Hospital, Lund (Sweden)); Nyman, Ulf (Dept. of Radiology, Lasarettet Trelleborg, Univ. of Lund, Trelleborg (Sweden)), e-mail: ulf.nyman@skane.se

    2010-10-15

    Background: Cardiac output (CO) is inversely related to vascular contrast medium (CM) enhancement during computed tomography (CT). Impedance cardiography with a new technique, electrical velocimetry (EV), may create opportunities to measure CO pre-examination for adaptation of CM injection parameters. Purpose: To relate COEV measured by radiology staff to aortic attenuation as a measure of coronary artery attenuation during CT coronary angiography (CTCA), and to formulate a tentative statistical model to adapt CM injection parameters to CO. Material and Methods: COEV was measured immediately before 100 kVp CTCA (64-multirow detector) in 27 patients with presumed coronary artery disease. For CTCA, 260 mg I/kg (maximum dosage weight: 80/90 kg for women/men) was injected intravenously during 12 s. Simple linear regression analysis was performed to explore the correlation between aortic attenuation (Hounsfield units, HU) and body weight, the influence of COEV on aortic attenuation adjusted to injected CM dose rate (HU per mg I/kg/s), and to establish a tentative formula on how to adapt CM injection parameters to COEV and desired aortic attenuation. Results: The correlation between aortic attenuation and body weight was weak and non-significant (r=-0.14 after outlier exclusion). A significant negative correlation (r=-0.63) was found between aortic attenuation adjusted to injected CM dose rate (HU per mg I/kg/s) and COEV. The resulting formula, CM dose rate=COEVx(aortic attenuation-240)/55, made it possible to calculate CM volumes and injection rates at various COs and, for example, the present mean aortic attenuation (438 HU), injection time (12 s), CM concentration (320 mg I/ml), and a certain body weight. Conclusion: EV makes it possible to measure CO in the CT suite before vascular examinations. Hence, CM doses may be decreased in low CO states to reduce the risk of CM-induced nephropathy without jeopardizing diagnostic quality and may be increased in high CO states

  6. Multilinear approach to the precipitation–lightning relationship: a case study of summer local electrical storms in the northern part of Spain during 2002–2009 period

    Directory of Open Access Journals (Sweden)

    I. Herrero

    2013-11-01

    Full Text Available Storms developed under local instability conditions are studied in the Spanish Basque region with the aim of establishing precipitation–lightning relationships. Those situations may produce, in some cases, flash flood. Data used correspond to daily rain depth (mm and the number of CG flashes in the area. Rain and lightning are found to be weakly correlated on a daily basis, a fact that seems related to the existence of opposite gradients in their geographical distribution. Rain anomalies, defined as the difference between observed and estimated rain depth based on CG flashes, are analysed by PCA method. Results show a first EOF explaining 50% of the variability that linearly relates the rain anomalies observed each day and that confirms their spatial structure. Based on those results, a multilinear expression has been developed to estimate the rain accumulated daily in the network based on the CG flashes registered in the area. Moreover, accumulates and maximum values of rain are found to be strongly correlated, therefore making the multilinear expression a useful tool to estimate maximum precipitation during those kind of storms.

  7. Do mathematical model studies settle the controversy on the origin of cardiac synchronous trans-thoracic electrical impedance variations? A systematic review.

    Science.gov (United States)

    de Sitter, A; Verdaasdonk, R M; Faes, T J C

    2016-09-01

    Impedance cardiography (ICG) is a method to evaluate cardiac-stroke volume and cardiac-output by measuring the cardiac-synchronous changes in the dynamic trans-thoracic electrical impedance (ΔZ). Clinical evaluations on the accuracy of ICG showed varying results. Consequently, the classic assumption in ICG-the aorta as a main source of ΔZ-is questioned and subsequently investigated in simulation studies using mathematical models of the electrical resistivity of the human body. The aim is to review the consensus in mathematical modelling studies that investigate the origin of the ΔZ as measured in ICG. In a systematic literature search, studies were identified and surveyed with reference to characteristics, such as included organs and their resistivity and geometries, electrode positions and calculation of ΔZ, to review the consensus between mathematical modelling studies that investigate the origin of the ΔZ as measured in ICG. Thirteen papers showed considerable variation in the model's characteristics with varying or contradicting outcomes for the ΔZ 's origin. For instance, 11 studies excluded perfused muscle tissue, implying implicitly their insignificance, while 3 other studies included muscle tissue and indicated it as the most important origin of ΔZ. In conclusion, the reviewed papers show a lack of consensus with respect to both the modelled characteristics as well as the model outcomes and, as a result, these studies failed to settle the controversy on ΔZ 's origin. Recommendations have been added to improve future mathematical model studies.

  8. Pacific Northwest Storms Situation Report # 1

    Energy Technology Data Exchange (ETDEWEB)

    None

    2006-12-15

    Severe wind and snow storms hit the Pacific Northwest region on December 14 – 15, 2006, following severe flooding during the past few days. The severe weather resulted in major power outages through the region. At peak there were 1.8 million customers without power which included BC Hydro in Canada. Currently, there are over 1.5 million outages in the region as a result of the Pacific Northwest Storms. This represents about 42 percent of customers in affected utility service areas in Oregon and Washington. See table below. Because the current wind and snow storms are coming on the heels of extensive flooding in the region, electric utilities are experiencing damage. Wind gusts reached close to 100 mph in some areas of the region. The storm is expected to bring its strong winds and heavy snow into Idaho, Montana and Wyoming Friday and into the weekend. There are currently no reported major impacts to the petroleum and natural gas infrastructure.

  9. Subtropical Storm Andrea

    Science.gov (United States)

    2007-01-01

    The circling clouds of an intense low-pressure system sat off the southeast coast of the United States on May 8, 2007, when the Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA's Terra satellite captured this image. By the following morning, the storm developed enough to be classified as a subtropical storm, a storm that forms outside of the tropics, but has many of the characteristics--hurricane-force winds, driving rains, low pressure, and sometimes an eye--of a tropical storm. Although it arrived several weeks shy of the official start of the hurricane season (June 1), Subtropical Storm Andrea became the first named storm of the 2007 Atlantic hurricane season. The storm has the circular shape of a tropical cyclone in this image, but lacks the tight organization seen in more powerful storms. By May 9, the storm's winds reached 75 kilometers per hour (45 miles per hour), and the storm was not predicted to get any stronger, said the National Hurricane Center. Though Subtropical Storm Andrea was expected to remain offshore, its strong winds and high waves pummeled coastal states, prompting a tropical storm watch. The winds fueled wild fires (marked with red boxes) in Georgia and Florida. The wind-driven flames generated thick plumes of smoke that concentrated in a gray-brown mass over Tampa Bay, Florida. Unfortunately for Georgia and Florida, which are experiencing moderate to severe drought, Subtropical Storm Andrea was not predicted to bring significant rain to the region right away, according to reports on the Washington Post Website.

  10. Renal sympathetic denervation as an adjunct to catheter ablation for the treatment of ventricular electrical storm in the setting of acute myocardial infarction.

    Science.gov (United States)

    Hoffmann, Boris A; Steven, Daniel; Willems, Stephan; Sydow, Karsten

    2013-10-01

    We present a case of ventricular storm (VS) in a patient with acute ST-elevation myocardial infarction (STEMI). After initial successful thrombus extraction and percutaneous coronary intervention (PCI) of the proximal left anterior descending (LAD) coronary artery, a 63-year-old male patient showed recurrent monomorphic ventricular tachycardia (VT) and fibrillation (VF) episodes refractory to antiarrhythmic drug therapy. After initial successful VT ablation, fast VT and VF episodes remained an evident problem despite maximum antiarrhythmic drug therapy. Due to an increasing instability, renal sympathetic denervation (RDN) was performed. ICD interrogation and 24-hour Holter monitoring excluded recurrent episodes of VT or VF at a 6-month follow-up (FU) after discharge. This case highlights that RDN was effective and safely performed in a hemodynamically unstable patient with VS after STEMI and adjunct catheter ablation. RDN may open a new avenue for an adjunctive interventional bailout treatment of such highly challenging patients.

  11. Characterizing Extreme Ionospheric Storms

    Science.gov (United States)

    Sparks, L.; Komjathy, A.; Altshuler, E.

    2011-12-01

    Ionospheric storms consist of disturbances of the upper atmosphere that generate regions of enhanced electron density typically lasting several hours. Depending upon the storm magnitude, gradients in electron density can sometimes become large and highly localized. The existence of such localized, dense irregularities is a major source of positioning error for users of the Global Positioning System (GPS). Consequently, satellite-based augmentation systems have been implemented to improve the accuracy and to ensure the integrity of user position estimates derived from GPS measurements. Large-scale irregularities generally do not pose a serious threat to estimate integrity as they can be readily detected by such systems. Of greater concern, however, are highly localized irregularities that interfere with the propagation of a signal detected by a user measurement but are poorly sampled by the receivers in the system network. The most challenging conditions have been found to arise following disturbances of large magnitude that occur only rarely over the course of a solar cycle. These extremely disturbed conditions exhibit behavior distinct from moderately disturbed conditions and, hence, have been designated "extreme storms". In this paper we examine and compare the behavior of the extreme ionospheric storms of solar cycle 23 (or, more precisely, extreme storms occurring between January 1, 2000, and December 31, 2008), as represented in maps of vertical total electron content. To identify these storms, we present a robust means of quantifying the regional magnitude of an ionospheric storm. Ionospheric storms are observed frequently to occur in conjunction with magnetic storms, i.e., periods of geophysical activity as measured by magnetometers. While various geomagnetic indices, such as the disturbance storm time (Dst) and the planetary Kp index, have long been used to rank the magnitudes of distinct magnetic storms, no comparable, generally recognized index exists for

  12. Cardiac electrical defects in progeroid mice and Hutchinson–Gilford progeria syndrome patients with nuclear lamina alterations

    Science.gov (United States)

    Rivera-Torres, José; Calvo, Conrado J.; Llach, Anna; Guzmán-Martínez, Gabriela; Caballero, Ricardo; González-Gómez, Cristina; Jiménez-Borreguero, Luis J.; Guadix, Juan A.; Osorio, Fernando G.; López-Otín, Carlos; Herraiz-Martínez, Adela; Cabello, Nuria; Vallmitjana, Alex; Benítez, Raul; Gordon, Leslie B.; Pérez-Pomares, José M.; Tamargo, Juan; Delpón, Eva; Hove-Madsen, Leif; Filgueiras-Rama, David; Andrés, Vicente

    2016-01-01

    Hutchinson–Gilford progeria syndrome (HGPS) is a rare genetic disease caused by defective prelamin A processing, leading to nuclear lamina alterations, severe cardiovascular pathology, and premature death. Prelamin A alterations also occur in physiological aging. It remains unknown how defective prelamin A processing affects the cardiac rhythm. We show age-dependent cardiac repolarization abnormalities in HGPS patients that are also present in the Zmpste24−/− mouse model of HGPS. Challenge of Zmpste24−/− mice with the β-adrenergic agonist isoproterenol did not trigger ventricular arrhythmia but caused bradycardia-related premature ventricular complexes and slow-rate polymorphic ventricular rhythms during recovery. Patch-clamping in Zmpste24−/− cardiomyocytes revealed prolonged calcium-transient duration and reduced sarcoplasmic reticulum calcium loading and release, consistent with the absence of isoproterenol-induced ventricular arrhythmia. Zmpste24−/− progeroid mice also developed severe fibrosis-unrelated bradycardia and PQ interval and QRS complex prolongation. These conduction defects were accompanied by overt mislocalization of the gap junction protein connexin43 (Cx43). Remarkably, Cx43 mislocalization was also evident in autopsied left ventricle tissue from HGPS patients, suggesting intercellular connectivity alterations at late stages of the disease. The similarities between HGPS patients and progeroid mice reported here strongly suggest that defective cardiac repolarization and cardiomyocyte connectivity are important abnormalities in the HGPS pathogenesis that increase the risk of arrhythmia and premature death. PMID:27799555

  13. Ionospheric data assimilation and forecasting during storms

    Science.gov (United States)

    Chartier, Alex T.; Matsuo, Tomoko; Anderson, Jeffrey L.; Collins, Nancy; Hoar, Timothy J.; Lu, Gang; Mitchell, Cathryn N.; Coster, Anthea J.; Paxton, Larry J.; Bust, Gary S.

    2016-01-01

    Ionospheric storms can have important effects on radio communications and navigation systems. Storm time ionospheric predictions have the potential to form part of effective mitigation strategies to these problems. Ionospheric storms are caused by strong forcing from the solar wind. Electron density enhancements are driven by penetration electric fields, as well as by thermosphere-ionosphere behavior including Traveling Atmospheric Disturbances and Traveling Ionospheric Disturbances and changes to the neutral composition. This study assesses the effect on 1 h predictions of specifying initial ionospheric and thermospheric conditions using total electron content (TEC) observations under a fixed set of solar and high-latitude drivers. Prediction performance is assessed against TEC observations, incoherent scatter radar, and in situ electron density observations. Corotated TEC data provide a benchmark of forecast accuracy. The primary case study is the storm of 10 September 2005, while the anomalous storm of 21 January 2005 provides a secondary comparison. The study uses an ensemble Kalman filter constructed with the Data Assimilation Research Testbed and the Thermosphere Ionosphere Electrodynamics General Circulation Model. Maps of preprocessed, verticalized GPS TEC are assimilated, while high-latitude specifications from the Assimilative Mapping of Ionospheric Electrodynamics and solar flux observations from the Solar Extreme Ultraviolet Experiment are used to drive the model. The filter adjusts ionospheric and thermospheric parameters, making use of time-evolving covariance estimates. The approach is effective in correcting model biases but does not capture all the behavior of the storms. In particular, a ridge-like enhancement over the continental USA is not predicted, indicating the importance of predicting storm time electric field behavior to the problem of ionospheric forecasting.

  14. Data analysis in cardiac arrhythmias.

    Science.gov (United States)

    Rodrigo, Miguel; Pedrón-Torecilla, Jorge; Hernández, Ismael; Liberos, Alejandro; Climent, Andreu M; Guillem, María S

    2015-01-01

    Cardiac arrhythmias are an increasingly present in developed countries and represent a major health and economic burden. The occurrence of cardiac arrhythmias is closely linked to the electrical function of the heart. Consequently, the analysis of the electrical signal generated by the heart tissue, either recorded invasively or noninvasively, provides valuable information for the study of cardiac arrhythmias. In this chapter, novel cardiac signal analysis techniques that allow the study and diagnosis of cardiac arrhythmias are described, with emphasis on cardiac mapping which allows for spatiotemporal analysis of cardiac signals.Cardiac mapping can serve as a diagnostic tool by recording cardiac signals either in close contact to the heart tissue or noninvasively from the body surface, and allows the identification of cardiac sites responsible of the development or maintenance of arrhythmias. Cardiac mapping can also be used for research in cardiac arrhythmias in order to understand their mechanisms. For this purpose, both synthetic signals generated by computer simulations and animal experimental models allow for more controlled physiological conditions and complete access to the organ.

  15. Effects of Electrical Spinal Cord Stimulation on Cardiac Ischemic Rat%脊髓电刺激对心肌缺血再灌注损伤大鼠的作用

    Institute of Scientific and Technical Information of China (English)

    苏秋香; 丁晓慧; 姚敏; 解辉; 郭丽; 祁荣; 唐青松; 王璐奇

    2012-01-01

    目的 检测脊髓电刺激对心肌缺血的治疗作用.方法 36只健康成年雄性SD大鼠随机分为对照组、心肌缺血组和脊髓电刺激+心肌缺血组.检测各组P物质在中枢神经系统的表达及心肌缺血组和脊髓电刺激+心肌缺血组心肌缺血面积的大小.结果 与对照组比较,心肌缺血组P物质在中枢神经系统的表达明显增高(P<0.05);脊髓电刺激+心肌缺血组与心肌缺血组比较,脊髓电刺激可减低P物质在心肌缺血时表达的增加(P<0.05).心肌缺血组和脊髓电刺激+心肌缺血组心肌缺血面积占左心室面积的百分比平均值分别为(46.51±2.19)%和(35.33±3.34)%,脊髓电刺激+心肌缺血组与心肌缺血组相比降低30.0%(P< 0.01).结论 脊髓电刺激使心肌缺血时传导痛觉的神经递质P物质在中枢神经系统的表达减少,且降低了心肌缺血损伤面积,对心肌缺血具有治疗作用.%Objective To investigate the effects of electrical spinal cord stimulation on cardiac ischemia area induced by cardiac ischemia reperfusion injury. Methods A total of 36 healthy male adult SD rats were randomly divided into 3 groups (control group, cardiac ischemia group and cardiac ischemia + spinal cord stimulation group). The expression of substance P in central nervous system and the cardiac ischemic area of the latter two groups were observed and compared statistically. Results Compared with the control group, the expression of substance P in central nervous system was increased in cardiac ischemia group (P < 0.05). Comparing cardiac ischemia + spinal cord stimulation group with cardiac ischemia group, (lie spinal cord stimulation could reduce the expression of substance P during cardiac ischemia (P < 0.05). In cardiac ischemia group,the mean ratio of cardiac ischemic area to the left ventricle was about 46.51%±2.19%. In cardiac ischemia + spinal cord stimulation group,the mean ratio of cardiac ischemia area to the left ventricle

  16. Storm Data Publication

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — 'Storm Data and Unusual Weather Phenomena' is a monthly publication containing a chronological listing, by state, of hurricanes, tornadoes, thunderstorms, hail,...

  17. Coastal storm monitoring in Virginia

    Science.gov (United States)

    Wicklein, Shaun M.; Bennett, Mark

    2014-01-01

    Coastal communities in Virginia are prone to flooding, particularly during hurricanes, nor’easters, and other coastal low-pressure systems. These weather systems affect public safety, personal and public property, and valuable infrastructure, such as transportation, water and sewer, and electric-supply networks. Local emergency managers, utility operators, and the public are tasked with making difficult decisions regarding evacuations, road closures, and post-storm recovery efforts as a result of coastal flooding. In coastal Virginia these decisions often are made on the basis of anecdotal knowledge from past events or predictions based on data from monitoring sites located far away from the affected area that may not reflect local conditions. Preventing flood hazards, such as hurricane-induced storm surge, from becoming human disasters requires an understanding of the relative risks that flooding poses to specific communities. The risk to life and property can be very high if decisions about evacuations and road closures are made too late or not at all.

  18. Protection of structures and buildings against the effect of electrical storms: basic concepts, evolution and application in Mexico; Proteccion contra el efecto de las tormentas electricas de estructuras y edificios: conceptos basicos, evolucion y aplicacion en Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Galvan Diego, Arturo; Velazquez Sanchez, Raul [Instituto de Investigaciones Electricas, Cuernavaca, Morelos (Mexico)

    2001-07-01

    The applied technology, supported by the analysis, the experimentation and the scientific observation, has demonstrated its effectiveness in the modernization of hundreds of industrial and commercial processes, of communication and services, as well as of the materials and methodologies used for the protection of diverse equipment and processes; from the protection in systems and equipment in high tension to systems that handle very low energy, among them are included electronic and digital devices. Nevertheless, fundamental laws like the Ohm's Law, the gravity law or the universal gas law exist that, although they were discovered many years ago, still are effective and their validity provides invaluable elements for the development of new methods, technological processes and developments. One of the most relevant cases than amalgamates the application of fundamental criteria and the development of new technologies and its application in the so-called no conventional protective devices, constitute the protection against the effect of electrical storms in buildings and structures. The worldwide application of these devices has generated skepticism of a great part of the scientific community, diverse reactions among the users and a firm position on the part of the manufacturers so that these technologies are included in international standards. The objective of this article is to offer the reader the basic information on the beginnings of the protection, the evolution that the protection methods against electrical storms have had since the XVIII century, the application of the fundamental criteria of protection in structures or modern buildings and their content, as well as the situation that prevails at the moment in the committees of the diverse national and international normative organizations with respect to the inclusion of the new technologies in the design guides. [Spanish] La tecnologia aplicada, apoyada en el analisis, la experimentacion y la

  19. Letter to the Editor: Geomagnetic storm effects at low latitudes

    Directory of Open Access Journals (Sweden)

    R. G. Rastogi

    Full Text Available The geomagnetic horizontal (H field from the chain of nine observatories in India are used to study the storm-time and disturbance daily variations. The peak decrease in storm-time variation in H showed significant enhancements at the equatorial electrojet stations over and above the normally expected decrease due to the ring current effects corrected for geomagnetic latitudes. The disturbance daily variation of H at equatorial stations showed a large decrease around midday hours over and above the usual dawn-maximum and dusk-minimum seen at any mid-latitude stations around the world. These slow and persistent additional decreases of H of disturbance daily variation at equatorial latitudes could be the effect of a westward electric field due to the Disturbance Ionospheric dynamo coupled with abnormally large electrical conductivities in the E region over the equator.Key words. Ionosphere (electric fields and currents · Magnetospheric physics (electric fields; storms and substorms

  20. Storms and Moons

    Science.gov (United States)

    2007-01-01

    The New Horizons Long Range Reconnaissance Imager (LORRI) took this 2-millisecond exposure of Jupiter at 04:41:04 UTC on January 24, 2007. The spacecraft was 57 million kilometers (35.3 million miles) from Jupiter, closing in on the giant planet at 41,500 miles (66,790 kilometers) per hour. At right are the moons Io (bottom) and Ganymede; Ganymede's shadow creeps toward the top of Jupiter's northern hemisphere. Two of Jupiter's largest storms are visible; the Great Red Spot on the western (left) limb of the planet, trailing the Little Red Spot on the eastern limb, at slightly lower latitude. The Great Red Spot is a 300-year old storm more than twice the size of Earth. The Little Red Spot, which formed over the past decade from the merging of three smaller storms, is about half the size of its older and 'greater' counterpart.

  1. Cardiac arrest

    Science.gov (United States)

    ... Article.jsp. Accessed June 16, 2014. Myerburg RJ, Castellanos A. Approach to cardiac arrest and life-threatening ... PA: Elsevier Saunders; 2011:chap 63. Myerburg RJ, Castellanos A. Cardiac arrest and audden aardiac death. In: ...

  2. Storm and cloud dynamics

    CERN Document Server

    Cotton, William R

    1992-01-01

    This book focuses on the dynamics of clouds and of precipitating mesoscale meteorological systems. Clouds and precipitating mesoscale systems represent some of the most important and scientifically exciting weather systems in the world. These are the systems that produce torrential rains, severe winds including downburst and tornadoes, hail, thunder and lightning, and major snow storms. Forecasting such storms represents a major challenge since they are too small to be adequately resolved by conventional observing networks and numerical prediction models.Key Features* Key Highlight

  3. Tropical storm Flossie and the Ark Royal storm

    Science.gov (United States)

    Peteherych, S.; Cunningham, G. F.; Davies, A. F.; Muttitt, G.

    1986-01-01

    The development of the tropical storm Flossie north of Scotland on September 16-17, 1978 from the Ark Royal storm is described. Land, marine, upper air data, satellite imagery, Seasat scatterometer (SASS) wind data, and SMMR moisture data were utilized to analyze the storms' development. The factors which contributed to the formation of the Ark Royal storm are discussed. Isobaric surface charts, isotachs and streamlines of the SASS winds, and SMMR water vapor contours are provided.

  4. A Case of Thyroid Storm Associated with Cardiomyopathy and Poststreptococcal Glomerulonephritis

    Directory of Open Access Journals (Sweden)

    Lisa J. Underland

    2016-01-01

    Full Text Available Thyroid storm has a high mortality rate and is often associated with a precipitating factor such as intercurrent illness or infection. It is rare in pediatric patients. Cardiac disease in hyperthyroidism mostly manifests itself as tachycardia but more serious cardiac findings have also been described. A 5-year-old male with recent strep throat infection presented with dilated cardiomyopathy, hematuria, and symptoms and lab findings consistent with severe hyperthyroidism. He was diagnosed with thyroid storm secondary to concurrent Graves’ disease and poststreptococcal glomerulonephritis (PSGN. After starting the treatment with methimazole and a beta-blocker, his cardiac disease gradually improved and the PSGN resolved over time. There are no specific pediatric criteria for thyroid storm. Adult criteria can be difficult to apply to pediatric cases. Criteria for diagnosis of thyroid storm are less clear for pediatric patients. Dilated cardiomyopathy is a rare cardiac manifestation of hyperthyroidism. PSGN is due to glomerular immune complexes and can complicate group A strep infection. Providers should be aware of cardiac disease as a complication of hyperthyroidism. PSGN should not mechanistically be related to hyperthyroidism but can precipitate the signs of thyroid storm such as hypertension. This association has not been previously reported in the literature.

  5. Electrical admittance for filling of the heart during lower body negative pressure in humans

    DEFF Research Database (Denmark)

    Cai, Yan; Holm, Søren; Jenstrup, Morten;

    2000-01-01

    cardiac output, electrical impedance, heart rate, positron emission tomography, technetium-labeled erythrocytes......cardiac output, electrical impedance, heart rate, positron emission tomography, technetium-labeled erythrocytes...

  6. Interview with Gert Storm

    NARCIS (Netherlands)

    Storm, Gert

    2013-01-01

    Gert Storm studied biology at the Utrecht University, The Netherlands, and obtained his PhD degree in 1987 at the Department of Pharmaceutics of the same university. He is now Professor of targeted drug delivery at the University of Utrecht, as well as Professor of targeted therapeutics at the MIRA

  7. Dave Storm esitleb singlit

    Index Scriptorium Estoniae

    2002-01-01

    7. märtsil klubis Spirit ja 8. märtsil klubis Terminal presenteerib tallinlane DJ Dave Storm oma uut singlit "Ride", millel teeb laulmisega kaasa ameeriklane Charlie C. Singelplaadi annab peadselt välja Inglise plaadifirma Refunkt

  8. Storms Across the Nation

    Institute of Scientific and Technical Information of China (English)

    HU YUE

    2010-01-01

    @@ Summer rainstorms have been sweeping through much of the country,causing immeasurable damage to affected provinces and people.By August 4,some 28 provinces,municipalities and autonomous regions have been hit by storms,victimizing a population of 140 million,said the State Flood Control and Drought Relief Headquarters.

  9. Cardiac Electrophysiology: Normal and Ischemic Ionic Currents and the ECG

    Science.gov (United States)

    Klabunde, Richard E.

    2017-01-01

    Basic cardiac electrophysiology is foundational to understanding normal cardiac function in terms of rate and rhythm and initiation of cardiac muscle contraction. The primary clinical tool for assessing cardiac electrical events is the electrocardiogram (ECG), which provides global and regional information on rate, rhythm, and electrical…

  10. Cardiac applications of optogenetics.

    Science.gov (United States)

    Ambrosi, Christina M; Klimas, Aleksandra; Yu, Jinzhu; Entcheva, Emilia

    2014-08-01

    In complex multicellular systems, such as the brain or the heart, the ability to selectively perturb and observe the response of individual components at the cellular level and with millisecond resolution in time, is essential for mechanistic understanding of function. Optogenetics uses genetic encoding of light sensitivity (by the expression of microbial opsins) to provide such capabilities for manipulation, recording, and control by light with cell specificity and high spatiotemporal resolution. As an optical approach, it is inherently scalable for remote and parallel interrogation of biological function at the tissue level; with implantable miniaturized devices, the technique is uniquely suitable for in vivo tracking of function, as illustrated by numerous applications in the brain. Its expansion into the cardiac area has been slow. Here, using examples from published research and original data, we focus on optogenetics applications to cardiac electrophysiology, specifically dealing with the ability to manipulate membrane voltage by light with implications for cardiac pacing, cardioversion, cell communication, and arrhythmia research, in general. We discuss gene and cell delivery methods of inscribing light sensitivity in cardiac tissue, functionality of the light-sensitive ion channels within different types of cardiac cells, utility in probing electrical coupling between different cell types, approaches and design solutions to all-optical electrophysiology by the combination of optogenetic sensors and actuators, and specific challenges in moving towards in vivo cardiac optogenetics.

  11. Thyroid Storm Provoked by Interleukin-2 Therapy for Metastatic Melanoma

    Directory of Open Access Journals (Sweden)

    Yao-Chung Liu

    2014-06-01

    Full Text Available With the growing use of immunotherapy in the treatment of cancer and autoimmune disease, severe autoimmune thyroid dysfunction may be provoked at an increasing rate. We herein report a 49-year-old male patient experiencing a life- threatening thyroid storm provoked by interleukin-2 (IL-2. This was a case of pulmonary metastasis of melanoma without a previous history of thyroid dysfunction. For the metastatic melanoma, he underwent combined immunochemotherapy including dacarbazine and IL-2. The 3rd course of immunochemotherapy was complicated with a thyroid storm manifested by high fever, tachycardia and even transient cardiac arrest. Fortunately, he recovered eventually from this crisis by immediate resuscitation followed by antithyroid dugs. Our case highlights the rare complication of a thyroid storm provoked by IL-2 treatment. Precaution against autoimmune thyroid dysfunction is required during treatment with IL-2 and probably also other kinds of newly-developed immunotherapy to avoid life-threatening complications.

  12. Extreme Geomagnetic Storms - 1868 - 2010

    Science.gov (United States)

    Vennerstrom, S.; Lefevre, L.; Dumbović, M.; Crosby, N.; Malandraki, O.; Patsou, I.; Clette, F.; Veronig, A.; Vršnak, B.; Leer, K.; Moretto, T.

    2016-05-01

    We present the first large statistical study of extreme geomagnetic storms based on historical data from the time period 1868 - 2010. This article is the first of two companion papers. Here we describe how the storms were selected and focus on their near-Earth characteristics. The second article presents our investigation of the corresponding solar events and their characteristics. The storms were selected based on their intensity in the aa index, which constitutes the longest existing continuous series of geomagnetic activity. They are analyzed statistically in the context of more well-known geomagnetic indices, such as the Kp and Dcx/Dst index. This reveals that neither Kp nor Dcx/Dst provide a comprehensive geomagnetic measure of the extreme storms. We rank the storms by including long series of single magnetic observatory data. The top storms on the rank list are the New York Railroad storm occurring in May 1921 and the Quebec storm from March 1989. We identify key characteristics of the storms by combining several different available data sources, lists of storm sudden commencements (SSCs) signifying occurrence of interplanetary shocks, solar wind in-situ measurements, neutron monitor data, and associated identifications of Forbush decreases as well as satellite measurements of energetic proton fluxes in the near-Earth space environment. From this we find, among other results, that the extreme storms are very strongly correlated with the occurrence of interplanetary shocks (91 - 100 %), Forbush decreases (100 %), and energetic solar proton events (70 %). A quantitative comparison of these associations relative to less intense storms is also presented. Most notably, we find that most often the extreme storms are characterized by a complexity that is associated with multiple, often interacting, solar wind disturbances and that they frequently occur when the geomagnetic activity is already elevated. We also investigate the semiannual variation in storm occurrence

  13. Leonid storm research

    CERN Document Server

    Rietmeijer, Frans; Brosch, Noah; Fonda, Mark

    2000-01-01

    This book will appeal to all researchers that have an interest in the current Leonid showers It contains over forty research papers that present some of the first observational results of the November 1999 Leonid meteor storm, the first storm observed by modern observing techniques The book is a first glimpse of the large amount of information obtained during NASA's Leonid Multi-Instrument Aircraft Campaign and groundbased campaigns throughout the world It provides an excellent overview on the state of meteor shower research for any professional researcher or amateur meteor observer interested in studies of meteors and meteoroids and their relation to comets, the origin of life on Earth, the satellite impact hazard issue, and upper atmosphere studies of neutral atom chemistry, the formation of meteoric debris, persistent trains, airglow, noctilucent clouds, sprites and elves

  14. Development in the STORM

    OpenAIRE

    Kamiyama, Daichi; Huang, Bo

    2012-01-01

    The recent invention of super-resolution microscopy has brought up much excitement in the biological research community. Here, we will focus on Stochastic Optical Reconstruction Microscopy/Photoactivated Localization Microscopy (STORM/PALM) to discuss the challenges in applying super-resolution microscopy to the study of developmental biology, including tissue imaging, sample preparation artifacts, and image interpretation. We will also summarize new opportunities that super-resolution micros...

  15. Solar storms; Tormentas solares

    Energy Technology Data Exchange (ETDEWEB)

    Collaboration: Pereira Cuesta, S.; Pereira Pagan, B.

    2016-08-01

    Solar storms begin with an explosion, or solar flare, on the surface of the sun. The X-rays and extreme ultraviolet radiation from the flare reach the Earths orbit minutes later-travelling at light speed. The ionization of upper layers of our atmosphere could cause radio blackouts and satellite navigation errors (GPS). Soon after, a wave of energetic particles, electrons and protons accelerated by the explosion crosses the orbit of the Earth, and can cause real and significant damage. (Author)

  16. LibrarySTORM

    DEFF Research Database (Denmark)

    Breüner, Niels; Bech, Tine

    2013-01-01

    Når flere uddannelser samles i en nybygning til Campus C på Ceres grunden i Aarhus, skal der også indrettes et fælles bibliotek. Når der samtidig er midler til at arbejde med brugerdreven innovation, lå det lige for at inddrage de studerende og få deres visioner for fremtidens bibliotek. Der blev...... arrangeret en udviklingsdag, hvor der skulle brainstormes – og projektet blev kaldt LibrarySTORM....

  17. Influence of magnetospheric inputs definition on modeling of ionospheric storms

    Science.gov (United States)

    Tashchilin, A. V.; Romanova, E. B.; Kurkin, V. I.

    Usually for numerical modeling of ionospheric storms corresponding empirical models specify parameters of neutral atmosphere and magnetosphere. Statistical kind of these models renders them impractical for simulation of the individual storm. Therefore one has to correct the empirical models using various additional speculations. The influence of magnetospheric inputs such as distributions of electric potential, number and energy fluxes of the precipitating electrons on the results of the ionospheric storm simulations has been investigated in this work. With this aim for the strong geomagnetic storm on September 25, 1998 hour global distributions of those magnetospheric inputs from 20 to 27 September were calculated by the magnetogram inversion technique (MIT). Then with the help of 3-D ionospheric model two variants of ionospheric response to this magnetic storm were simulated using MIT data and empirical models of the electric fields (Sojka et al., 1986) and electron precipitations (Hardy et al., 1985). The comparison of the received results showed that for high-latitude and subauroral stations the daily variations of electron density calculated with MIT data are more close to observations than those of empirical models. In addition using of the MIT data allows revealing some peculiarities in the daily variations of electron density during strong geomagnetic storm. References Sojka J.J., Rasmussen C.E., Schunk R.W. J.Geophys.Res., 1986, N10, p.11281. Hardy D.A., Gussenhoven M.S., Holeman E.A. J.Geophys.Res., 1985, N5, p.4229.

  18. Cardiac Sarcoidosis.

    Science.gov (United States)

    Birnie, David; Ha, Andrew C T; Gula, Lorne J; Chakrabarti, Santabhanu; Beanlands, Rob S B; Nery, Pablo

    2015-12-01

    Studies suggest clinically manifest cardiac involvement occurs in 5% of patients with pulmonary/systemic sarcoidosis. The principal manifestations of cardiac sarcoidosis (CS) are conduction abnormalities, ventricular arrhythmias, and heart failure. Data indicate that an 20% to 25% of patients with pulmonary/systemic sarcoidosis have asymptomatic (clinically silent) cardiac involvement. An international guideline for the diagnosis and management of CS recommends that patients be screened for cardiac involvement. Most studies suggest a benign prognosis for patients with clinically silent CS. Immunosuppression therapy is advocated for clinically manifest CS. Device therapy, with implantable cardioverter defibrillators, is recommended for some patients.

  19. Cardiac tissue engineering

    Directory of Open Access Journals (Sweden)

    MILICA RADISIC

    2005-03-01

    Full Text Available We hypothesized that clinically sized (1-5 mm thick,compact cardiac constructs containing physiologically high density of viable cells (~108 cells/cm3 can be engineered in vitro by using biomimetic culture systems capable of providing oxygen transport and electrical stimulation, designed to mimic those in native heart. This hypothesis was tested by culturing rat heart cells on polymer scaffolds, either with perfusion of culture medium (physiologic interstitial velocity, supplementation of perfluorocarbons, or with electrical stimulation (continuous application of biphasic pulses, 2 ms, 5 V, 1 Hz. Tissue constructs cultured without perfusion or electrical stimulation served as controls. Medium perfusion and addition of perfluorocarbons resulted in compact, thick constructs containing physiologic density of viable, electromechanically coupled cells, in contrast to control constructs which had only a ~100 mm thick peripheral region with functionally connected cells. Electrical stimulation of cultured constructs resulted in markedly improved contractile properties, increased amounts of cardiac proteins, and remarkably well developed ultrastructure (similar to that of native heart as compared to non-stimulated controls. We discuss here the state of the art of cardiac tissue engineering, in light of the biomimetic approach that reproduces in vitro some of the conditions present during normal tissue development.

  20. Cardiac Malpositions

    Energy Technology Data Exchange (ETDEWEB)

    Yoo, Shi Joon; Im, Chung Gie; Yeon, Kyung Mo; Hasn, Man Chung [Seoul National University College of Medicine, Seoul (Korea, Republic of)

    1979-06-15

    Cardiac Malposition refers to any position of the heart other than a left-sided heart in a situs solitus individual. Associated cardiac malformations are so complex that even angiocardiographic and autopsy studies may not afford an accurate information. Although the terms and classifications used to describe the internal cardiac anatomy and their arterial connections in cardiac malpositions differ and tend to be confusing, common agreement exists on the need for a segmental approach to diagnosis. Authors present 18 cases of cardiac malpositions in which cardiac catheterization and angiocardiography were done at the Department of Radiology, Seoul National University Hospital between 1971 and 1979. Authors analyzed the clinical, radiographic, operative and autopsy findings with the emphasis on the angiocardiographic findings. The results are as follows: 1. Among 18 cases with cardiac malpositions, 6 cases had dextrocardia with situs inversus, 9 cases had dextrocardia with situs solitus and 3 cases had levocardia with situs inversus. 2. There was no genuine exception to visceroatrial concordance rule. 3. Associated cardiac malpositions were variable and complex with a tendency of high association of transposition and double outlet varieties with dextrocardia in situs solitus and levocardia in situs inversus. Only one in 6 cases of dextrocardia with situs inversus had pure transposition. 4. In two cases associated pulmonary atresia was found at surgery which was not predicted by angiocardiography. 5. Because many of the associated complex lesions can be corrected surgically provided the diagnosis is accurate, the selective biplane angiocardiography with or without cineradiography is essential.

  1. Tropical Storm Erin

    Science.gov (United States)

    2007-01-01

    Location: The Atlantic Ocean 210 miles south of Galveston, Texas Categorization: Tropical Storm Sustained Winds: 40 mph (60 km/hr) [figure removed for brevity, see original site] [figure removed for brevity, see original site] Infrared ImageMicrowave Image Infrared Images Because infrared radiation does not penetrate through clouds, AIRS infrared images show either the temperature of the cloud tops or the surface of the Earth in cloud-free regions. The lowest temperatures (in purple) are associated with high, cold cloud tops that make up the top of the storm. In cloud-free areas the AIRS instrument will receive the infrared radiation from the surface of the Earth, resulting in the warmest temperatures (orange/red). Microwave Images In the AIRS microwave imagery, deep blue areas in storms show where the most precipitation occurs, or where ice crystals are present in the convective cloud tops. Outside of these storm regions, deep blue areas may also occur over the sea surface due to its low radiation emissivity. On the other hand, land appears much warmer due to its high radiation emissivity. Microwave radiation from Earth's surface and lower atmosphere penetrates most clouds to a greater or lesser extent depending upon their water vapor, liquid water and ice content. Precipitation, and ice crystals found at the cloud tops where strong convection is taking place, act as barriers to microwave radiation. Because of this barrier effect, the AIRS microwave sensor detects only the radiation arising at or above their location in the atmospheric column. Where these barriers are not present, the microwave sensor detects radiation arising throughout the air column and down to the surface. Liquid surfaces (oceans, lakes and rivers) have 'low emissivity' (the signal isn't as strong) and their radiation brightness temperature is therefore low. Thus the ocean also appears 'low temperature' in the AIRS microwave images and is assigned the color blue. Therefore deep blue areas in

  2. Storm surge variational assimilation model

    Directory of Open Access Journals (Sweden)

    Shi-li HUANG

    2010-06-01

    Full Text Available To eliminate errors caused by uncertainty of parameters and further improve capability of storm surge forecasting, the variational data assimilation method is applied to the storm surge model based on unstructured grid with high spatial resolution. The method can effectively improve the forecasting accuracy of storm surge induced by typhoon through controlling wind drag force coefficient parameter. The model is first theoretically validated with synthetic data. Then, the real storm surge process induced by the TC 0515 typhoon is forecasted by the variational data assimilation model, and results show the feasibility of practical application.

  3. Analysis on the risk factors for occurrence of electrical storm in percutaneous coronary intervention and its treatment%急性心肌梗死急诊PCI发生室性心律失常风暴危险因素及早期干预的效果

    Institute of Scientific and Technical Information of China (English)

    何胜虎; 袁彬; 纪军; 徐日新; 陈述; 刘晓东; 谢勇; 汪华玲; 廖清池

    2014-01-01

    Objective To investigate the risk factors for occurrence of electrical storm in the patients with acute ST segment elevation myocardial infarction (STEMI) when treat them by percutaneous coronary intervention (PCI) and provide evidence for prospective treatment.Methods Collected the clinical data of 280 patients with STEMI and treated by PCI from January 2008 to December 2011,the patients with no less than twice spontaneous ventricular tachycardia (VT) or ventricular fibrillation (VF) were classified to the electrical storm group and others were classified to control group.Results The number of patients with electrical storm is nineteen and the incidence rate is 6.8%.In early group (from January 2008 to December 2009),the number of patients with electrical storm is sixteen.In late group (from January 2010 to December 2011),the number of patients with electrical storm is three.The electrical storm group:The value of creatine kinase isoenzyme MB (CK-MB),the value of troponin I (TNI),right coronary artery being the infarction related artery (IRA),TIMI level,bradycardia and sustained hypotension in the electrical group are significantly higher than those of control group (P < 0.05).Multiple logistic regression analysis showed that the independent predictors of VAS were the value of troponin I (TNI),TIMI level and sustained hypotension.Conclusions The value of creatine kinase isoenzyme MB (CK-MB),the value of troponin I (TNI),right coronary artery being the infarction related artery (IRA),TIMI level,bradycardia and sustained hypotension are the risk factors for occurrence of electrical storm.the value of troponin I (TNI),TIMI level and sustained hypotension were stronger predictors of electrical storm.Early treatment to the risk factors can reduce the incidence of VAS,and improve the prognosis.%目的 探索急性ST段抬高型心肌梗死(STEMI)患者直接冠状动脉介入治疗(PCI)发生室性心律失常风暴(VAS)的危险因素

  4. Occurrence of Equatorial Plasma Bubbles during Intense Magnetic Storms

    Directory of Open Access Journals (Sweden)

    Chao-Song Huang

    2011-01-01

    Full Text Available An important issue in low-latitude ionospheric space weather is how magnetic storms affect the generation of equatorial plasma bubbles. In this study, we present the measurements of the ion density and velocity in the evening equatorial ionosphere by the Defense Meteorological Satellite Program (DMSP satellites during 22 intense magnetic storms. The DMSP measurements show that deep ion density depletions (plasma bubbles are generated after the interplanetary magnetic field (IMF turns southward. The time delay between the IMF southward turning and the first DMSP detection of plasma depletions decreases with the minimum value of the IMF Bz, the maximum value of the interplanetary electric field (IEF Ey, and the magnitude of the Dst index. The results of this study provide strong evidence that penetration electric field associated with southward IMF during the main phase of magnetic storms increases the generation of equatorial plasma bubbles in the evening sector.

  5. Molecular Aspects of Exercise-induced Cardiac Remodeling.

    Science.gov (United States)

    Bernardo, Bianca C; McMullen, Julie R

    2016-11-01

    Exercise-induced cardiac remodeling is typically an adaptive response associated with cardiac myocyte hypertrophy and renewal, increased cardiac myocyte contractility, sarcomeric remodeling, cell survival, metabolic and mitochondrial adaptations, electrical remodeling, and angiogenesis. Initiating stimuli/triggers of cardiac remodeling include increased hemodynamic load, increased sympathetic activity, and the release of hormones and growth factors. Prolonged and strenuous exercise may lead to maladaptive exercise-induced cardiac remodeling including cardiac dysfunction and arrhythmia. In addition, this article describes novel therapeutic approaches for the treatment of heart failure that target mechanisms responsible for adaptive exercise-induced cardiac remodeling, which are being developed and tested in preclinical models.

  6. Assessment of storm forecast

    DEFF Research Database (Denmark)

    Cutululis, Nicolaos Antonio; Hahmann, Andrea N.; Huus Bjerge, Martin

    storms was analysed based on historical meteorological data available at Risø DTU and dynamically down-scaled to the Horns Rev 2 wind farm level. This solution was chosen due to the lack of measurements. Moreover, since the project started, there were four events during which Horns Rev 2 wind farm...... at analysing the ability of existing forecast tools to predict storms at the Horns Rev 2 wind farm. The focus will be on predicting the time where the wind turbine will need to shut down to protect itself, e.g. the time where wind speed exceeds 25 m/s. At the same time, the planned shut-down should cost...... stopped, completely or partially, producing due to extreme wind speeds. Wind speed and power measurements from those events are presented and compared to the forecast available at Energinet.dk. The analysis looked at wind speed and wind power forecast. The main conclusion of the analysis is that the wind...

  7. Clouds and Dust Storms

    Science.gov (United States)

    2004-01-01

    [figure removed for brevity, see original site] Released 2 July 2004 The atmosphere of Mars is a dynamic system. Water-ice clouds, fog, and hazes can make imaging the surface from space difficult. Dust storms can grow from local disturbances to global sizes, through which imaging is impossible. Seasonal temperature changes are the usual drivers in cloud and dust storm development and growth. Eons of atmospheric dust storm activity has left its mark on the surface of Mars. Dust carried aloft by the wind has settled out on every available surface; sand dunes have been created and moved by centuries of wind; and the effect of continual sand-blasting has modified many regions of Mars, creating yardangs and other unusual surface forms. This image was acquired during mid-spring near the North Pole. The linear water-ice clouds are now regional in extent and often interact with neighboring cloud system, as seen in this image. The bottom of the image shows how the interaction can destroy the linear nature. While the surface is still visible through most of the clouds, there is evidence that dust is also starting to enter the atmosphere. Image information: VIS instrument. Latitude 68.4, Longitude 180 East (180 West). 38 meter/pixel resolution. Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time. NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The Thermal Emission Imaging System (THEMIS) was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote

  8. Cardiac cameras.

    Science.gov (United States)

    Travin, Mark I

    2011-05-01

    Cardiac imaging with radiotracers plays an important role in patient evaluation, and the development of suitable imaging instruments has been crucial. While initially performed with the rectilinear scanner that slowly transmitted, in a row-by-row fashion, cardiac count distributions onto various printing media, the Anger scintillation camera allowed electronic determination of tracer energies and of the distribution of radioactive counts in 2D space. Increased sophistication of cardiac cameras and development of powerful computers to analyze, display, and quantify data has been essential to making radionuclide cardiac imaging a key component of the cardiac work-up. Newer processing algorithms and solid state cameras, fundamentally different from the Anger camera, show promise to provide higher counting efficiency and resolution, leading to better image quality, more patient comfort and potentially lower radiation exposure. While the focus has been on myocardial perfusion imaging with single-photon emission computed tomography, increased use of positron emission tomography is broadening the field to include molecular imaging of the myocardium and of the coronary vasculature. Further advances may require integrating cardiac nuclear cameras with other imaging devices, ie, hybrid imaging cameras. The goal is to image the heart and its physiological processes as accurately as possible, to prevent and cure disease processes.

  9. Dust Storms: Why Are Dust Storms a Concern?

    Science.gov (United States)

    ... Radon Solvents Styrene Sulfur Dioxide Toluene Uranium Volatile Organic Compounds (VOCs) For Educators Introduction Tox Town-Based Curriculum Units / Science Club Careers in Environmental Health, Chemistry, and Toxicology More Resources Dust Storms en español ...

  10. Formation of the storm-time ring current

    Institute of Scientific and Technical Information of China (English)

    XIE Lun; PU Zuyin; ZHOU Xuzhi; FU Suiyan; ZONG Qiugang

    2004-01-01

    An extensive study of ring current injection and intensification of the storm-time symmetric ring current is conducted with three-dimensional (3-D) test particle trajectory calculations (TPTCs) in this paper. TPTCs reveal more accurately the process of ring current injection. The main results are the following: (1) an intense convection electric field can effectively energize and inject plasma sheet particles into ring current region within 1-3 h. (2) Injection ions often follow chaotic trajectories in non-adiabatic regions,which may have implications in storm and ring current physics. (3) The shielding electric field, which arises as a consequence of enhanced convection and co-exists with injection and convection electric field, leads the original open trajectories to change into closed ones, thus may play an important role in the formation of the symmetric ring current.

  11. Cardiac echinococcosis

    Directory of Open Access Journals (Sweden)

    Ivanović-Krstić Branislava A.

    2002-01-01

    Full Text Available Cardiac hydatid disease is rare. We report on an uncommon hydatid cyst localized in the right ventricular wall, right atrial wall tricuspid valve left atrium and pericard. A 33-year-old woman was treated for cough, fever and chest pain. Cardiac echocardiograpic examination revealed a round tumor (5.8 x 4 cm in the right ventricular free wall and two smaller cysts behind that tumor. There were cysts in right atrial wall and tricuspidal valve as well. Serologic tests for hydatidosis were positive. Computed tomography finding was consistent with diagnosis of hydatid cyst in lungs and right hylar part. Surgical treatment was rejected due to great risk of cardiac perforation. Medical treatment with albendazole was unsuccessful and the patient died due to systemic hydatid involvement of the lungs, liver and central nervous system.

  12. Storm Water Management Model (SWMM)

    Science.gov (United States)

    EPA's Storm Water Management Model (SWMM) is used throughout the world for planning, analysis and design related to stormwater runoff, combined and sanitary sewers, and other drainage systems in urban areas.

  13. US Weather Bureau Storm Reports

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Weather Bureau and US Army Corps and other reports of storms from 1886-1955. Hourly precipitation from recording rain gauges captured during heavy rain, snow,...

  14. Weathering the financial storm

    DEFF Research Database (Denmark)

    Ólafsson, Tjörvi; Pétursson, Thórarinn G.

    2011-01-01

    The recent global financial tsunami has had economic consequences that have not been witnessed since the Great Depression. But while some countries suffered a particularly large contraction in economic activity on top of a system-wide banking collapse, others came off relatively lightly. In this ......The recent global financial tsunami has had economic consequences that have not been witnessed since the Great Depression. But while some countries suffered a particularly large contraction in economic activity on top of a system-wide banking collapse, others came off relatively lightly...... and severity of the crisis. In particular, we find that the pre-crisis rate of inflation is important in explaining the post-crisis experience. Our results also suggest an important role for financial factors. In particular, we find that large banking systems tended to be associated with a deeper and more...... of the crisis and, in particular, that countries with sound fundamentals and flexible economic frameworks were better able to weather the financial storm....

  15. Impact of famous CEDAR, GEM and ISTP geomagnetic Storms on HF Radio Propagation

    Science.gov (United States)

    Blagoveshchensky, D.; Sergeeva, M.

    The mighty geomagnetic storms due to the extraordinary Sun s activity cause as a rule some impacts in these areas radiation effects on human and satellites commercial airlines outages electric power and other geomagnetic effects navigation and communication GPS effects ionospheric disturbances HF communication effects Therefore our scientific understanding of this activity is very important Joint efforts for example within the framework of the CAWSES enable progress in our ability to i identify critical inputs to specify the geospace environment at a level needed to minimize impacts on technology human society and life and ii support the development of robust models that predict conditions in geospace based on understanding of the Sun-Earth system and all of its interacting components In this study influence of 14 geomagnetic storms from a list of CEDAR GEM and ISTP storms within 1997-99 on radio propagation conditions have been investigated These conditions were estimated through variations of the MOF and LOF the maximum and lowest operation frequencies on each path from three high-latitude HF radio paths of North-west Russia before during and after a storm It was shown that the storm impact on the ionosphere and radio propagation for each storm has an individual character Nevertheless the common character of the certain manifestations during storm-time was revealed For example the frequency range MOF - LOF is getting wider several hours before a storm then it is sharply narrow during a storm-time and further it is expanded again several

  16. Positive and negative ionospheric responses to the March 2015 geomagnetic storm from BDS observations

    Science.gov (United States)

    Jin, Shuanggen; Jin, Rui; Kutoglu, H.

    2017-01-01

    The most intense geomagnetic storm in solar cycle 24 occurred on March 17, 2015, and the detailed ionospheric storm morphologies are difficultly obtained from traditional observations. In this paper, the Geostationary Earth Orbit (GEO) observations of BeiDou Navigation Satellite System (BDS) are for the first time used to investigate the ionospheric responses to the geomagnetic storm. Using BDS GEO and GIMs TEC series, negative and positive responses to the March 2015 storm are found at local and global scales. During the main phase, positive ionospheric storm is the main response to the geomagnetic storm, while in the recovery phase, negative phases are pronounced at all latitudes. Maximum amplitudes of negative and positive phases appear in the afternoon and post-dusk sectors during both main and recovery phases. Furthermore, dual-peak positive phases in main phase and repeated negative phase during the recovery are found from BDS GEO observations. The geomagnetic latitudes corresponding to the maximum disturbances during the main and recovery phases show large differences, but they are quasi-symmetrical between southern and northern hemispheres. No clear zonal propagation of traveling ionospheric disturbances is detected in the GNSS TEC disturbances at high and low latitudes. The thermospheric composition variations could be the dominant source of the observed ionospheric storm effect from GUVI [O]/[N2] ratio data as well as storm-time electric fields. Our study demonstrates that the BDS (especially the GEO) observations are an important data source to observe ionospheric responses to the geomagnetic storm.

  17. Cardiac Rehabilitation

    Science.gov (United States)

    ... your risk of future heart problems, and to improve your health and quality of life. Cardiac rehabilitation programs increase ... exercise routine at home or at a local gym. You may also continue to ... health concerns. Education about nutrition, lifestyle and weight loss ...

  18. Riding out the storm: sympathetic storming after traumatic brain injury.

    Science.gov (United States)

    Lemke, Denise M

    2004-02-01

    Following acute multiple trauma, hypothalamic stimulation of the sympathetic nervous system and adrenal glands causes an increase in circulating corticoids and catecholamines, or a stress response. In individuals with severe traumatic brain injury or a Glasgow Coma Scale score of 3-8, this response can be exaggerated and episodic. A term commonly used by nurses caring for these individuals to describe this phenomenon is storming. Symptoms can include alterations in level of consciousness, increased posturing, dystonia, hypertension, hyperthermia, tachycardia, tachypnea, diaphoresis, and agitation. These individuals generally are at a low level of neurological activity with minimal alertness, minimal awareness, and reflexive motor response to stimulation, and the storming can take a seemingly peaceful individual into a state of chaos. Diagnosis is commonly made solely on clinical assessment, and treatment is aimed at controlling the duration and severity of the symptoms and preventing additional brain injury. Storming can pose a challenge for the nurse, from providing daily care for the individual in the height of the storming episode and treating the symptoms, to educating the family. Careful assessment of the individual leads the nurse to the diagnosis and places the nurse in the role of moderator of the storming episode, including providing treatment and evaluating outcomes.

  19. Research on Historical Records of Geomagnetic Storms

    Science.gov (United States)

    Lakhina, G. S.; Alex, S.; Tsurutani, B. T.; Gonzalez, W. D.

    In recent times, there has been keen interest in understanding Sun-Earth connection events, such as solar flares, CMEs and concomitant magnetic storms. Magnetic storms are the most dramatic and perhaps important component of space weather effects on Earth. Super-intense magnetic storms (defined here as those with Dst cause life-threatening power outages, satellite damage, communication failures and navigational problems. However, the data for such magnetic storms is rather scarce. For example, only one super-intense magnetic storm has been recorded (Dst=-640 nT, March 13, 1989) during the space-age (since 1958), although such storms may have occurred many times in the last 160 years or so when the regular observatory network came into existence. Thus, research on historical geomagnetic storms can help to create a good data base for intense and super-intense magnetic storms. From the application of knowledge of interplanetary and solar causes of storms gained from the spaceage observations applied to the super-intense storm of September 1-2, 1859, it has been possible to deduce that an exceptionally fast (and intense) magnetic cloud was the interplanetary cause of this geomagnetic storm with a Dst -1760 nT, nearly 3 times as large as that of March 13, 1989 super-intense storm. The talk will focus on super-intense storms of September 1-2, 1859, and also discuss the results in the context of some recent intense storms.

  20. Cardiac Calcification

    Directory of Open Access Journals (Sweden)

    Morteza Joorabian

    2011-05-01

    Full Text Available There is a spectrum of different types of cardiac"ncalcifications with the importance and significance"nof each type of cardiac calcification, especially"ncoronary artery calcification. Radiologic detection of"ncalcifications within the heart is quite common. The"namount of coronary artery calcification correlates"nwith the severity of coronary artery disease (CAD."nCalcification of the aortic or mitral valve may indicate"nhemodynamically significant valvular stenosis."nMyocardial calcification is a sign of prior infarction,"nwhile pericardial calcification is strongly associated"nwith constrictive pericarditis. A spectrum of different"ntypes of cardiac calcifications (linear, annular,"ncurvilinear,... could be seen in chest radiography and"nother imaging modalities. So a carful inspection for"ndetection and reorganization of these calcifications"nshould be necessary. Numerous modalities exist for"nidentifying coronary calcification, including plain"nradiography, fluoroscopy, intravascular ultrasound,"nMRI, echocardiography, and conventional, helical and"nelectron-beam CT (EBCT. Coronary calcifications"ndetected on EBCT or helical CT can be quantifie,"nand a total calcification score (Cardiac Calcification"nScoring may be calculated. In an asymptomatic"npopulation and/or patients with concomitant risk"nfactors like diabetes mellitus, determination of the"npresence of coronary calcifications identifies the"npatients at risk for future myocardial infarction and"ncoronary artery disease. In patients without coronary"ncalcifications, future cardiovascular events could"nbe excluded. Therefore, detecting and recognizing"ncalcification related to the heart on chest radiography"nand other imaging modalities such as fluoroscopy, CT"nand echocardiography may have important clinical"nimplications.

  1. Physics of Cardiac Arrhythmogenesis

    Science.gov (United States)

    Karma, Alain

    2013-04-01

    A normal heartbeat is orchestrated by the stable propagation of an excitation wave that produces an orderly contraction. In contrast, wave turbulence in the ventricles, clinically known as ventricular fibrillation (VF), stops the heart from pumping and is lethal without prompt defibrillation. I review experimental, computational, and theoretical studies that have shed light on complex dynamical phenomena linked to the initiation, maintenance, and control of wave turbulence. I first discuss advances made to understand the precursor state to a reentrant arrhythmia where the refractory period of cardiac tissue becomes spatiotemporally disordered; this is known as an arrhythmogenic tissue substrate. I describe observed patterns of transmembrane voltage and intracellular calcium signaling that can contribute to this substrate, and symmetry breaking instabilities to explain their formation. I then survey mechanisms of wave turbulence and discuss novel methods that exploit electrical pacing stimuli to control precursor patterns and low-energy pulsed electric fields to control turbulence.

  2. The need to immobilise the cervical spine during cardiopulmonary resuscitation and electric shock administration in out-of-hospital cardiac arrest.

    Science.gov (United States)

    Desroziers, Milene; Mole, Sophie; Jost, Daniel; Tourtier, Jean-Pierre

    2016-06-13

    In cases of out-of hospital cardiac arrest (OHCA), falling to the ground can cause brain and neck trauma to the patient. We present a case of a man in his mid-60s who suffered from an OHCA resulting in a violent collapse. The patient received immediate cardiopulmonary resuscitation, but his spine was immobilised only after a large frontal haematoma was found. The resuscitation efforts resulted in return of spontaneous circulation and discharge from hospital. After this, doctors performed angioplasty, followed by a cardiopulmonary bypass. Later, CT scan examination reported a displaced and unstable fracture of the 6th vertebra without bone marrow involvement. The patient underwent a second operation. 40 days later, he was able to return home without sequela. This case shows the importance of analysing the circumstances of a fall, considering the possibility of two concomitant diagnoses and prioritising investigations and treatment.

  3. Radiation Belt Storm Probe (RBSP) Mission

    Science.gov (United States)

    Sibeck, D. G.; Fox, N.; Grebowsky, J. M.; Mauk, B. H.

    2009-01-01

    Scheduled to launch in May 2012, NASA's dual spacecraft Living With a Star Radiation Belt Storm Probe mission carries the field and particle instrumentation needed to determine the processes that produce enhancements in radiation belt ion and electron fluxes, the dominant mechanisms that cause the loss of relativistic electrons, and the manner by which the ring current and other geomagnetic phenomena affect radiation belt behavior. The two spacecraft will operate in low-inclination elliptical lapping orbits around the Earth, within and immediately exterior to the Van Allen radiation belts. During course of their two year primary mission, they will cover the full range of local times, measuring both AC and DC electric and magnetic fields to 10kHz, as well as ions from 50 eV to 1 GeV and electrons with energies ranging from 50 eV to 10 MeV.

  4. Ionospheric response to great geomagnetic storms during solar cycle 23

    Science.gov (United States)

    Merline Matamba, Tshimangadzo; Bosco Habarulema, John

    2016-07-01

    The analyses of ionospheric responses due to great geomagnetic storms i.e. Dst index Total Electron Content (TEC) and ionosonde data over Southern and Northern Hemisphere mid-latitudes were used to study the ionospheric responses. A geomagnetic latitude region of ±30° to ±46° within a longitude sector of 15° to 40° was considered. Using a criteria of Dst Physical mechanisms related to (but not limited to) composition changes and electric fields will be discussed.

  5. Electrophysiological Cardiac Modeling: A Review.

    Science.gov (United States)

    Beheshti, Mohammadali; Umapathy, Karthikeyan; Krishnan, Sridhar

    2016-01-01

    Cardiac electrophysiological modeling in conjunction with experimental and clinical findings has contributed to better understanding of electrophysiological phenomena in various species. As our knowledge on underlying electrical, mechanical, and chemical processes has improved over time, mathematical models of the cardiac electrophysiology have become more realistic and detailed. These models have provided a testbed for various hypotheses and conditions that may not be easy to implement experimentally. In addition to the limitations in experimentally validating various scenarios implemented by the models, one of the major obstacles for these models is computational complexity. However, the ever-increasing computational power of supercomputers facilitates the clinical application of cardiac electrophysiological models. The potential clinical applications include testing and predicting effects of pharmaceutical agents and performing patient-specific ablation and defibrillation. A review of studies involving these models and their major findings are provided.

  6. Dune erosion during storm surges

    NARCIS (Netherlands)

    Van Thiel de Vries, J.S.M.

    2009-01-01

    Large parts of The Netherlands are protected from flooding by a narrow strip of sandy beaches and dunes. The aim of this thesis is to extend the existing knowledge of dune erosion during storm surges as it occurs along the Dutch coast. The thesis discusses: • A large scale dune erosion experiment to

  7. Storm Water Management Model (SWMM)

    Science.gov (United States)

    Stormwater discharges continue to cause impairment of our Nation’s waterbodies. Regulations that require the retention and/or treatment of frequent, small storms that dominate runoff volumes and pollutant loads are becoming more common. The U.S. Environmental Protection Agency (E...

  8. Interactive modeling of storm impact

    Science.gov (United States)

    van Rooijen, A.; Baart, F.; Roelvink, J. A.; Donchyts, G.; Scheel, F.; de Boer, W.

    2014-12-01

    In the past decades the impact of storms on the coastal zone has increasingly drawn the attention of policy makers and coastal planners, engineers and researchers. The mean reason for this interest is the high density of the world's population living near the ocean, in combination with climate change. Due to sea level rise and extremer weather conditions, many of the world's coastlines are becoming more vulnerable to the potential of flooding. Currently it is common practice to predict storm impact using physics-based numerical models. The numerical model utilizes several inputs (e.g. bathymetry, waves, surge) to calculate the impact on the coastline. Traditionally, the numerical modeller takes the following three steps: schematization/model setup, running and post-processing. This process generally has a total feedback time in the order of hours to days, and is suitable for so-called confirmatory modelling.However, often models are applied as an exploratory tool, in which the effect of e.g. different hydraulic conditions, or measures is investigated. The above described traditional work flow is not the most efficient method for exploratory modelling. Interactive modelling lets users adjust a simulation while running. For models typically used for storm impact studies (e.g. XBeach, Delft3D, D-Flow FM), the user can for instance change the storm surge level, wave conditions, or add a measure such as a nourishment or a seawall. The model will take the adjustments into account immediately, and will directly compute the effect. Using this method, tools can be developed in which stakeholders (e.g. coastal planners, policy makers) are in control and together evaluate ideas by interacting with the model. Here we will show initial results for interactive modelling with a storm impact model.

  9. Computational approaches to understand cardiac electrophysiology and arrhythmias

    Science.gov (United States)

    Roberts, Byron N.; Yang, Pei-Chi; Behrens, Steven B.; Moreno, Jonathan D.

    2012-01-01

    Cardiac rhythms arise from electrical activity generated by precisely timed opening and closing of ion channels in individual cardiac myocytes. These impulses spread throughout the cardiac muscle to manifest as electrical waves in the whole heart. Regularity of electrical waves is critically important since they signal the heart muscle to contract, driving the primary function of the heart to act as a pump and deliver blood to the brain and vital organs. When electrical activity goes awry during a cardiac arrhythmia, the pump does not function, the brain does not receive oxygenated blood, and death ensues. For more than 50 years, mathematically based models of cardiac electrical activity have been used to improve understanding of basic mechanisms of normal and abnormal cardiac electrical function. Computer-based modeling approaches to understand cardiac activity are uniquely helpful because they allow for distillation of complex emergent behaviors into the key contributing components underlying them. Here we review the latest advances and novel concepts in the field as they relate to understanding the complex interplay between electrical, mechanical, structural, and genetic mechanisms during arrhythmia development at the level of ion channels, cells, and tissues. We also discuss the latest computational approaches to guiding arrhythmia therapy. PMID:22886409

  10. Impact of storm risk on Faustmann rotation

    CERN Document Server

    Loisel, Patrice

    2014-01-01

    Global warming may induce in Western Europe an increase in storms. Hence the forest managers will have to take into account the risk increase. We study the impact of storm risk at the stand level. From the analytical expressions of the Faustmann criterion and the Expected Long-Run Average Yield, we deduce in presence of storm risk the influence of criteria and of discount rate in terms of optimal thinnings and cutting age. We discuss the validity of using a risk adjusted discount rate (a rate of storm risk added to the discount rate) without risk to mimic the storm risk case in terms of optimal thinnings.

  11. Magnetic Storms at Mars and Earth

    DEFF Research Database (Denmark)

    Vennerstrøm, Susanne; Falkenberg, Thea Vilstrup

    In analogy with magnetic storms at the Earth, periods of significantly enhanced global magnetic activity also exist at Mars. The extensive database of magnetic measurements from Mars Global Surveyor (MGS), covering almost an entire solar cycle, is used in combination with geomagnetic activity...... indices at Earth to compare the occurrence of magnetic storms at Mars and Earth. Based on superposed epochs analysis the time-development of typical magnetic storms at Mars and Earth is described. In contradiction to storms at Earth, most magnetic storms at Mars are found to be associated...... with heliospheric current sheet crossings, where the IMF changes polarity. While most storms at the Earth occur due to significant southward excursions of the IMF associated with CMEs, at Mars most storms seem to be associated with the density enhancement of the heliospheric current sheet. Density enhancements...

  12. Thyroid Storm Precipitated by Duodenal Ulcer Perforation

    Directory of Open Access Journals (Sweden)

    Shoko Natsuda

    2015-01-01

    Full Text Available Thyroid storm is a rare and life-threatening complication of thyrotoxicosis that requires prompt treatment. Thyroid storm is also known to be associated with precipitating events. The simultaneous treatment of thyroid storm and its precipitant, when they are recognized, in a patient is recommended; otherwise such disorders, including thyroid storm, can exacerbate each other. Here we report the case of a thyroid storm patient (a 55-year-old Japanese male complicated with a perforated duodenal ulcer. The patient was successfully treated with intensive treatment for thyroid storm and a prompt operation. Although it is believed that peptic ulcer rarely coexists with hyperthyroidism, among patients with thyroid storm, perforation of a peptic ulcer has been reported as one of the causes of fatal outcome. We determined that surgical intervention was required in this patient, reported despite ongoing severe thyrotoxicosis, and reported herein a successful outcome.

  13. Improving cardiac myocytes performance by CNTs platforms

    Directory of Open Access Journals (Sweden)

    Valentina eMartinelli

    2013-09-01

    Full Text Available The application of nanotechnology to the cardiovascular system has increasingly caught scientists’ attention as a potentially powerful tool for the development of new generation devices able to interface, repair or boost the performance of cardiac tissue. Carbon nanotubes (CNTs are considered as promising materials for nanomedicine applications in general and have been recently tested towards excitable cell growth. CNTs are cylindrically shaped structures made up of rolled-up graphene sheets, with unique electrical, thermal and mechanical properties, able to effectively conducting electrical current in electrochemical interfaces. CNTs-based scaffolds have been recently found to support the in vitro growth of cardiac cells: in particular, their ability to improve cardiomyocytes proliferation, maturation and electrical behavior are making CNTs extremely attractive for the development and exploitation of interfaces able to impact on cardiac cells physiology and function.

  14. Cardiac MRI in Athletes

    NARCIS (Netherlands)

    Luijkx, T.

    2012-01-01

    Cardiac magnetic resonance imaging (CMR) is often used in athletes to image cardiac anatomy and function and is increasingly requested in the context of screening for pathology that can cause sudden cardiac death (SCD). In this thesis, patterns of cardiac adaptation to sports are investigated with C

  15. Storm Warnings on Lake Balaton,

    Science.gov (United States)

    1982-04-06

    magnitude of this effect. Consequently, the employees of the Storm Warning Service decided in the course of the summer 1962, to set up a cup -type... anemometer on a passenger ship regularly passing between Si6fok and Balatonfired, and to take wind measurements along this route across the Lake in a...along this route. During the measurements, the reading of the anemometer was taken at intervals and noted together with the time of reading. Since the

  16. Cardiac arrhythmias

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    2010315 Effects on electrical restitution of given esanolol during cardiopulmonary resuscitation in a swine ventricular fibrillation model. WEI Jie(魏捷),et al. Dept Emerg Med,Renmin Hosp,Wuhan Univ,Wuhan 430060.Chin J Emerg Med 2010;19(3):257-263. Objective To

  17. Effects of geomagnetic storm on low latitude ionospheric total electron content: A case study from Indian sector

    Indian Academy of Sciences (India)

    Monti Chakraborty; Sanjay Kumar; Barin Kumar De; Anirban Guha

    2015-07-01

    The effect of geomagnetic storms on low latitude ionosphere has been investigated with the help of Global Positioning System Total Electron Content (GPS-TEC) data. The investigation has been done with the aid of TEC data from the Indian equatorial region, Port Blair (PBR) and equatorial ionization anomaly region, Agartala (AGR). During the geomagnetic storms on 24th April and 15th July 2012, significant enhancement up to 150% and depression up to 72% in VTEC is observed in comparison to the normal day variation. The variations in VTEC observed from equatorial to EIA latitudes during the storm period have been explained with the help of electro-dynamic effects (prompt penetration electric field (PPEF) and disturbance dynamo electric field (DDEF)) as well as mechanical effects (storm-induced equatorward neutral wind effect and thermospheric composition changes). The current study points to the fact that the electro-dynamic effect of geomagnetic storms around EIA region is more effective than at the lower latitude region. Drastic difference has been observed over equatorial region (positive storm impact) and EIA region (negative storm impact) around same longitude sector, during storm period on 24th April. This drastic change as observed in GPS-TEC on 24th April has been further confirmed by using the O/N2 ratio data from GUVI (Global Ultraviolet Imager) as well as VTEC map constructed from IGS data. The results presented in the paper are important for the application of satellite-based communication and navigational system.

  18. Investigation of Ionospheric Response to Geomagnetic Storms over a Low Latitude Station, Ile-Ife, Nigeria

    Science.gov (United States)

    Jimoh, Oluwaseyi E.; Yesufu, Thomas K.; Ariyibi, Emmanuel A.

    2016-06-01

    Due to several complexities associated with the equatorial ionosphere, and the significant role which the total electron content (TEC) variability plays in GPS signal transmission, there is the need to monitor irregularities in TEC during storm events. The GPS SCINDA receiver data at Ile-Ife, Nigeria, was analysed with a view to characterizing the ionospheric response to geomagnetic storms on 9 March and 1 October 2012. Presently, positive storm effects, peaks in TEC which were associated with prompt penetration of electric fields and changes in neutral gas composition were observed for the storms. The maximum percentage deviation in TEC of about 120 and 45% were observed for 9 March and 1 October 2012, respectively. An obvious negative percentage TEC deviation subsequent to sudden storm commencement (SSC) was observed and besides a geomagnetic storm does not necessarily suggest a high scintillation intensity (S4) index. The present results show that magnetic storm events at low latitude regions may have an adverse effect on navigation and communication systems.

  19. Simulation and 'TWINS Observations of the 22 July 2009 Storm

    Science.gov (United States)

    Fok, Mei-Ching; Buzulukova, Natalia Y.; Chen, Sheng-Hsien; Valek, Phil; Goldstein, Jerry; McComas, David

    2010-01-01

    TWINS is the first mission to perform stereo imaging of the Earth's ring current. The magnetic storm on 22 July 2009 is the largest storm observed since TWINS began routine stereo imaging in June 2008. On 22 July 2009, the Dst dropped to nearly -80nT at 7:00 and 10:00 UT. During the main phase and at the peak of the storm, TWINS 1 and 2 were near apogee and moving from pre-dawn to post-dawn local time. The energetic neutral atom (ENA) imagers on the 2 spacecraft captured the storm intensification and the formation of the partial ring current. The peak of the ENA emissions was seen in the midnight-to-dawn local-time sector. The development of this storm has been simulated using the Comprehensive Ring Current Model (CRCM) to understand and interpret the observed signatures. We perform CRCM runs with constant and time-varying magnetic field. The model calculations are validated by comparing the simulated ENA and ion flux intensities with TWINS ENA images and in-situ ion data from THEMIS satellites. Simulation with static magnetic field produces a strong shielding electric field that skews the ion drift trajectories toward dawn. The model's corresponding peak ENA emissions are always eastward than those in the observed TWINS images. On the other hand, simulation with a dynamic magnetic field gives better spatial agreements with both ENA and insitu particle data, suggesting that temporal variations of the geomagnetic field exert a significant influence upon global ring current ion dynamics.

  20. Simulation and Twins Observations of the 22 July 2009 Storm

    Science.gov (United States)

    Fok, M.-C.; Buzulukova, N.; Chen, S.-H.; Valek, P. W.; Goldstein, J.; McComas, D. J.

    2011-01-01

    TWINS is the first mission to perform stereo imaging of the Earth's ring current. The magnetic storm on 22 July 2009 was at the time the largest storm observed since TWINS began routine stereo imaging in June 2008. On 22 July 2009, the Dst dropped to nearly .80 nT at 0700 and 1000 UT. During the main phase, and at the peak of the storm, TWINS 1 and 2 were near apogee and moving between predawn and postdawn local time. The energetic neutral atom (ENA) imagers on the two spacecraft captured the storm intensification and the formation of the partial ring current. The peak of the high-altitude ENA emissions was seen in the midnight-to-dawn local time sector. The development of this storm has been simulated using the comprehensive ring current model (CRCM) to understand and interpret the observed signatures. We perform CRCM runs with constant and time-varying magnetic field. The model calculations are validated by comparing the simulated ENA and ion flux intensities with TWINS ENA images and in situ ion data from a THEMIS satellite. Simulation with a static magnetic field produces a strong shielding electric field that skews the ion drift trajectories toward dawn. The model's corresponding peak ENA emissions are always more eastward than those in the observed TWINS images. On the other hand, the simulation with a dynamic magnetic field gives better spatial agreement with both ENA and in situ particle data, suggesting that temporal variations of the geomagnetic field exert a significant influence upon global ring current ion dynamics.

  1. Responses in the polar and equatorial ionosphere to the March 2015 St. Patrick Day storm

    Science.gov (United States)

    Hairston, Marc; Coley, W. R.; Stoneback, Russell

    2016-11-01

    The St. Patrick Day storm of 2015 (17 March 2015) occurred at a unique time when there were multiple spacecraft observing the Earth's ionosphere between 350 and 885 km. Observations of the plasma flows and densities from the five operational polar-orbiting DMSP spacecraft combined with those from the equatorial-orbiting C/NOFS spacecraft provided a comprehensive global record of the both the polar and equatorial ionosphere regions' responses to the storm. This paper presents an overview of the data from this suite of spacecraft focusing on the following aspects: (1) the polar cap ionosphere's reaction to the storm, (2) the change in the penetration electric field in the midlatitude region as a function of time and the solar local time during the storm, (3) the equatorial ionosphere's response of the meridional (vertical) flows to the penetration electric field and the disturbance dynamo during the storm, and (4) the creation of a predawn ionospheric bubble system near the equator during the storm's main phase that was observed at low altitudes by C/NOFS and later at high altitudes by several DMSP. Examining these phenomenon enable us to trace the dynamic flow of energy from the solar wind input in the polar ionosphere all the way to the equatorial ionosphere.

  2. The responses of the thermosphere due to a geomagnetic storm: A MHD model

    Science.gov (United States)

    Wu, S. T.; Chang, S.

    1972-01-01

    A magnetohydrodynamics theory was used to study the dynamic response of the neutral atmosphere to a geomagnetic storm. A full set of magnetohydrodynamic equations appropriate for the present problem is derived and their various orders of approximation are discussed in some detail. In order to demonstrate the usefulness of this theoretical model, the May 1967 geomagnetic storm data were used in the resulting set of nonlinear, time dependent, partial differential magnetohydrodynamic equations to calculate variations of the thermosphere due to the storm. The numerical results are presented for wind speeds, electric field strength, and amount of joule heating at a constant altitude for the data recorded. Data show that the strongest thermospheric responses are at the polar region becoming weaker in the equatorial region. This may lead to the speculation that a thermospheric wave is generated in the polar region due to the geomagnetic storm which propagates towards the equator.

  3. Toward microendoscopy-inspired cardiac optogenetics in vivo: technical overview and perspective

    Science.gov (United States)

    Klimas, Aleksandra; Entcheva, Emilia

    2014-08-01

    The ability to perform precise, spatially localized actuation and measurements of electrical activity in the heart is crucial in understanding cardiac electrophysiology and devising new therapeutic solutions for control of cardiac arrhythmias. Current cardiac imaging techniques (i.e. optical mapping) employ voltage- or calcium-sensitive fluorescent dyes to visualize the electrical signal propagation through cardiac syncytium in vitro or in situ with very high-spatiotemporal resolution. The extension of optogenetics into the cardiac field, where cardiac tissue is genetically altered to express light-sensitive ion channels allowing electrical activity to be elicited or suppressed in a precise cell-specific way, has opened the possibility for all-optical interrogation of cardiac electrophysiology. In vivo application of cardiac optogenetics faces multiple challenges and necessitates suitable optical systems employing fiber optics to actuate and sense electrical signals. In this technical perspective, we present a compendium of clinically relevant access routes to different parts of the cardiac electrical conduction system based on currently employed catheter imaging systems and determine the quantitative size constraints for endoscopic cardiac optogenetics. We discuss the relevant technical advancements in microendoscopy, cardiac imaging, and optogenetics and outline the strategies for combining them to create a portable, miniaturized fiber-based system for all-optical interrogation of cardiac electrophysiology in vivo.

  4. 78 FR 1162 - Cardiovascular Devices; Reclassification of External Cardiac Compressor

    Science.gov (United States)

    2013-01-08

    ... improper energy transmission by the device. Cardiac arrhythmias or electrical shock. Excessive electrical... and continuous therapy; or prolonged CPR--to avoid/replace rescuer fatigue) and CPR Aid devices should... that incorporate electrical components, appropriate analysis and testing must validate...

  5. Electric utility industry experience with geomagnetic disturbances

    Energy Technology Data Exchange (ETDEWEB)

    Barnes, P.R.; Rizy, D.T.; McConnell, B.W. [Oak Ridge National Lab., TN (United States); Taylor, E.R. Jr. [ABB Power Systems, Inc., Pittsburgh, PA (United States); Tesche, F.M.

    1991-09-01

    A geomagnetic disturbance (GMD) by its nature occurs globally and almost simultaneously. Severe geomagnetic storms cause problems for electric power systems. The vulnerability of electric power systems to such events has apparently increased during the last 10 to 20 years because power system transmission lines have become more interconnected and have increased in length and because power systems are now operated closer to their limits than in the past. In this report, the experience of electric utilities during geomagnetic storms is examined and analyzed. Measured data, effects on power system components, and power system impacts are considered. It has been found that electric power systems are susceptible to geomagnetically induced earth-surface potential gradients as small as few (2 to 3) volts per kilometer, corresponding to a storm of K-6 intensity over an area of high earth resistivity. The causes and effects are reasonably well understood, but additional research is needed to develop a better understanding of solar-induced geomagnetic storms and the responses of power systems to these types of storms. A better understanding of geomagnetic storms and the power systems` responses to GMDs is needed so that mitigation measures can be implemented that will make power systems less susceptible to severe geomagnetic disturbances. A GMD caused by a large high-altitude nuclear detonation is similar in many ways to that of solar-induced geomagnetic storms except that a nuclear-caused disturbance would be much more intense with a far shorter duration. 49 refs.

  6. Electric utility industry experience with geomagnetic disturbances

    Energy Technology Data Exchange (ETDEWEB)

    Barnes, P.R.; Rizy, D.T.; McConnell, B.W. (Oak Ridge National Lab., TN (United States)); Taylor, E.R. Jr. (ABB Power Systems, Inc., Pittsburgh, PA (United States)); Tesche, F.M.

    1991-09-01

    A geomagnetic disturbance (GMD) by its nature occurs globally and almost simultaneously. Severe geomagnetic storms cause problems for electric power systems. The vulnerability of electric power systems to such events has apparently increased during the last 10 to 20 years because power system transmission lines have become more interconnected and have increased in length and because power systems are now operated closer to their limits than in the past. In this report, the experience of electric utilities during geomagnetic storms is examined and analyzed. Measured data, effects on power system components, and power system impacts are considered. It has been found that electric power systems are susceptible to geomagnetically induced earth-surface potential gradients as small as few (2 to 3) volts per kilometer, corresponding to a storm of K-6 intensity over an area of high earth resistivity. The causes and effects are reasonably well understood, but additional research is needed to develop a better understanding of solar-induced geomagnetic storms and the responses of power systems to these types of storms. A better understanding of geomagnetic storms and the power systems' responses to GMDs is needed so that mitigation measures can be implemented that will make power systems less susceptible to severe geomagnetic disturbances. A GMD caused by a large high-altitude nuclear detonation is similar in many ways to that of solar-induced geomagnetic storms except that a nuclear-caused disturbance would be much more intense with a far shorter duration. 49 refs.

  7. Electric Utility Industry Experience with Geomagnetic Disturbances

    Energy Technology Data Exchange (ETDEWEB)

    Barnes, P.R.

    1991-01-01

    A geomagnetic disturbance (GMD) by its nature occurs globally and almost simultaneously. Severe geomagnetic storms cause problems for electric power systems. The vulnerability of electric power systems to such events has apparently increased during the last 10 to 20 years because power system transmission lines have become more interconnected and have increased in length and because power systems are now operated closer to their limits than in the past. In this report, the experience of electric utilities during geomagnetic storms is examined and analyzed. Measured data, effects on power system components, and power system impacts are considered. It has been found that electric power systems are susceptible to geomagnetically induced earth-surface potential gradients as small as a few (2 to 3) volts per kilometer, corresponding to a storm of K-6 intensity over an area of high earth resistivity. The causes and effects are reasonably well understood, but additional research is needed to develop a better understanding of solar-induced geomagnetic storms and the responses of power systems to these types of storms. A better understanding of geomagnetic storms and the power systems' responses to GMDs is needed so that mitigation measures can be implemented that will make power systems less susceptible to severe geomagnetic disturbances. A GMD caused by a large high-altitude nuclear detonation is similar in many ways to that of solar-induced geomagnetic storms except that a nuclear-caused disturbance would be much more intense with a far shorter duration.

  8. Occurrence rate of extreme magnetic storms

    CERN Document Server

    Yermolaev, Yu I; Nikolaeva, N S; Yermolaev, M Yu

    2013-01-01

    Statistical analysis of occurrence rate of magnetic storms induced by different types of interplanetary drivers is made on the basis of OMNI data for period 1976-2000. Using our catalog of large scale types of solar wind streams we study storms induced by interplanetary coronal mass ejections (ICME) (separately magnetic clouds (MC) and Ejecta) and both types of compressed regions: corotating interaction regions (CIR) and Sheaths. For these types of drivers we calculate integral probabilities of storms with minimum Dst < -50, -70, -100, -150, and -200 nT. The highest probability in this interval of Dst is observed for MC, probabilities for other drivers are 3-10 times lower than for MC. Extrapolation of obtained results to extreme storms shows that such a magnetic storm as Carrington storm in 1859 with Dst = -1760 nT is observed on the Earth with frequency 1 event during ~500 year.

  9. The storm-time ring current: a statistical analysis at two widely separated low-latitude stations

    Directory of Open Access Journals (Sweden)

    P. Francia

    2004-11-01

    Full Text Available We conducted a statistical analysis of the geomagnetic field variations during the storm main phase at two low-latitude stations, separated by several hours in magnetic local time, in order to investigate the asymmetry and longitudinal extent of the storm-time ring current. The results show evidence for an asymmetric current which typically extends from evening to noon and, during moderate solar wind electric field conditions, up to the early morning, confirming the important role of the magnetospheric convection in the ring current energization. We also analyzed a possible relationship between the local current intensity during the storm main phase and the substorm activity observed at different time delays τ with respect to the storm onset. The results show a significant anticorrelation for τ =-1h, indicating that if the substorm activity is high just before the storm, a weaker ring current develops.

  10. Mechanical modulation of cardiac microtubules.

    Science.gov (United States)

    White, Ed

    2011-07-01

    Microtubules are a major component of the cardiac myocyte cytoskeleton. Interventions that alter it may influence cardiac mechanical and electrical activity by disrupting the trafficking of proteins to and from the surface membrane by molecular motors such as dynein, which use microtubules as tracks to step along. Free tubulin dimers may transfer GTP to the α-subunits of G-proteins, thus an increase in free tubulin could increase the activity of G-proteins; evidence for and against such a role exists. There is more general agreement that microtubules act as compression-resisting structures within myocytes, influencing visco-elasticity of myocytes and increasing resistance to shortening when proliferated and resisting deformation from longitudinal shear stress. In response to pressure overload, there can be post-translational modifications resulting in more stable microtubules and an increase in microtubule density. This is accompanied by contractile dysfunction of myocytes which can be reversed by microtubule disruption. There are reports of mechanically induced changes in electrical activity that are dependent upon microtubules, but at present, a consensus is lacking on whether disruption or proliferation would be beneficial in the prevention of arrhythmias. Microtubules certainly play a role in the response of cardiac myocytes to mechanical stimulation, the exact nature and significance of this role is still to be fully determined.

  11. Sudden cardiac death risk stratification.

    Science.gov (United States)

    Deyell, Marc W; Krahn, Andrew D; Goldberger, Jeffrey J

    2015-06-01

    Arrhythmic sudden cardiac death (SCD) may be caused by ventricular tachycardia/fibrillation or pulseless electric activity/asystole. Effective risk stratification to identify patients at risk of arrhythmic SCD is essential for targeting our healthcare and research resources to tackle this important public health issue. Although our understanding of SCD because of pulseless electric activity/asystole is growing, the overwhelming majority of research in risk stratification has focused on SCD-ventricular tachycardia/ventricular fibrillation. This review focuses on existing and novel risk stratification tools for SCD-ventricular tachycardia/ventricular fibrillation. For patients with left ventricular dysfunction or myocardial infarction, advances in imaging, measures of cardiac autonomic function, and measures of repolarization have shown considerable promise in refining risk. Yet the majority of SCD-ventricular tachycardia/ventricular fibrillation occurs in patients without known cardiac disease. Biomarkers and novel imaging techniques may provide further risk stratification in the general population beyond traditional risk stratification for coronary artery disease alone. Despite these advances, significant challenges in risk stratification remain that must be overcome before a meaningful impact on SCD can be realized.

  12. Ice storm 1998 : lessons learned

    Energy Technology Data Exchange (ETDEWEB)

    McCready, J. [Eastern Ontario Model Forest, Kemptville, ON (Canada)

    2006-07-01

    This paper presented details of a partnership formed in response to the ice storm of 1998, which caused extensive damage to trees in woodlots and urban settings in eastern Ontario and western Quebec. The aim of the Ice Storm Forest Recovery Group was to assist in the recovery of eastern forests, collect information on the extent of the damage to trees as well as contribute to the development of assistance programs for woodlot owners and municipalities. In response to the group's request, an initial aerial survey was conducted by the Ontario Ministry of Natural Resources to map the extent of the damage in eastern Ontario, which was followed by a more scientific survey with the Canadian Forest Service through the development of a flying grid pattern to observe the status of trees, followed by extensive ground checks. Damage was variable, depending on tree species, stand age and composition, management practices, wind direction, topography and ice deposition patterns. A summary of the severity of damage indicated that conifers suffered less than hardwoods. Consultants were hired to prepare news releases and extension notes to the public in order to provide information for the caring of trees. Various educational workshops were held which attracted large numbers of landowners and homeowners. A literature review was undertaken to produce a summary of current published knowledge covering the effects of storms and ice damage to trees and forests. Science efforts were published in a series of papers, and financial assistance programs were then organized by governmental agencies. It was concluded that cooperation between all agencies, groups and levels of government is needed in order to coordinate effective emergency strategies. 7 refs., 1 tab., 1 fig.

  13. Observing storm surges from satellite altimetry

    Science.gov (United States)

    Han, Guoqi

    2016-07-01

    Storm surges can cause catastrophic damage to properties and loss of life in coastal communities. Thus it is important to enhance our capabilities of observing and forecasting storm surges for mitigating damage and loss. In this presentation we show examples of observing storm surges around the world using nadir satellite altimetry, during Hurricane Sandy, Igor, and Isaac, as well as other cyclone events. The satellite observations are evaluated against tide-gauge observations and discussed for dynamic mechanisms. We also show the potential of a new wide-swath altimetry mission, the Surface Water and Ocean Topography (SWOT), for observing storm surges.

  14. Analysis of the positive ionospheric response to a moderate geomagnetic storm using a global numerical model

    Directory of Open Access Journals (Sweden)

    A. A. Namgaladze

    Full Text Available Current theories of F-layer storms are discussed using numerical simulations with the Upper Atmosphere Model, a global self-consistent, time dependent numerical model of the thermosphere-ionosphere-plasmasphere-magnetosphere system including electrodynamical coupling effects. A case study of a moderate geomagnetic storm at low solar activity during the northern winter solstice exemplifies the complex storm phenomena. The study focuses on positive ionospheric storm effects in relation to thermospheric disturbances in general and thermospheric composition changes in particular. It investigates the dynamical effects of both neutral meridional winds and electric fields caused by the disturbance dynamo effect. The penetration of short-time electric fields of magnetospheric origin during storm intensification phases is shown for the first time in this model study. Comparisons of the calculated thermospheric composition changes with satellite observations of AE-C and ESRO-4 during storm time show a good agreement. The empirical MSISE90 model, however, is less consistent with the simulations. It does not show the equatorward propagation of the disturbances and predicts that they have a gentler latitudinal gradient. Both theoretical and experimental data reveal that although the ratio of [O]/[N2] at high latitudes decreases significantly during the magnetic storm compared with the quiet time level, at mid to low latitudes it does not increase (at fixed altitudes above the quiet reference level. Meanwhile, the ionospheric storm is positive there. We conclude that the positive phase of the ionospheric storm is mainly due to uplifting of ionospheric F2-region plasma at mid latitudes and its equatorward movement at low latitudes along geomagnetic field lines caused by large-scale neutral wind circulation and the passage of travelling atmospheric disturbances (TADs. The calculated zonal electric field disturbances also help

  15. Cardiac ryanodine receptor gene (hRyR2) mutation underlying catecholaminergic polymorphic ventricular tachycardia in a Chinese adolescent presenting with sudden cardiac arrest and cardiac syncope

    Institute of Scientific and Technical Information of China (English)

    Ngai-Shing Mok; Ching-Wan Lam; Nai-Chung Fong; Yim-Wo Hui; Yuen-Choi Choi; Kwok-Yin Chan

    2006-01-01

    @@ Sudden cardiac death (SCD) in children and adolescents is uncommon and yet it is devastating for both victim's family and the society.Recently, it was increasingly recognized that SCD in young patients with structurally normal heart may be caused by inheritable primary electrical diseases due to the malfunction of cardiac ion channels, a disease entity known as the ion channelopathies.Catecholaminergic polymorphic ventricular tachycardia (CPVT) is a specific form of ion channelopathy which can cause cardiac syncope or SCD in young patients by producing catecholamine-induced bi-directional ventricular tachycardia (BiVT), polymorphic VT and ventricular fibrillation (VF) during physical exertion or emotion.1-7 We reported here an index case of CPVT caused by cardiac ryanodine receptor gene (hRyR2)mutation which presented as cardiac syncope and sudden cardiac arrest in a Chinese adolescent female.

  16. 体表脉冲电刺激对昆明小鼠心电活动的影响%Effect of surface electric-impulse stimulation on cardiac electrical activity of Kunming mice

    Institute of Scientific and Technical Information of China (English)

    李永林; 张辉; 史若飞; 汤小曼; 解力; 黄吕; 张晓刚

    2014-01-01

    BACKGROUND: Electrical stimulation at different intensity, frequency and time on the human body may produce a variety of pathophysiological reactions. OBJECTIVE: To observe the effects of surface electric-impulse stimulation on heart rhythm and heart rate in mice. METHODS: Thirty Kunming mice were randomly divided into three groups, each group contained 10 mice. Electrical stimulation at different voltage, time and frequency was respectively applied to the three groups. The stimulus power was supplied by BL-420F Data Acquisition & Analysis System. The II lead electrocardiogram was recorded. The systemic reactions and local body changes of mice were observed.%背景:使用不同强度、频率及时间的电刺激作用于人体,可能产生各种不同的病理生理反应。  目的:观察体表脉冲电刺激对小鼠心律及心率的影响。  方法:将30只昆明小鼠随机分为3组,每组10只,用BL-420F型生物机能实验系统提供刺激电源,对3组昆明小鼠分别予以不同电压、不同时间、不同频率的体表电刺激,然后观察Ⅱ导联心电图、小鼠得全身反应与局部变化。  结果与结论:≤10 V的电刺激对小鼠心率无明显影响,并且未出现心律失常;电压≥15 V时,电刺激可使小鼠心率减慢,停止30 min后心率恢复正常;电压≥35 V时,小鼠出现心率减慢和心律失常,并且停止刺激后心率不能恢复正常;电压>75 V后,小鼠出现室颤。电压为10 V时,脉冲电刺激时间和频率变化对小鼠心电活动影响不显著。说明脉冲电刺激对小鼠心电活动的影响主要由所用电压高低不同引起,电压≤10 V 时对小鼠心电活动无影响;脉冲电刺激时间与电场频率对小鼠心电活动影响不明显。

  17. Severe Local Storms Cultural Heritage

    Science.gov (United States)

    Gladich, I.; Gallai, I.; Giaiotti, D. B.; Morgan, G. M.; Stel, F.

    2009-09-01

    Local storms always had a deep impact on people communities, mainly because of the severe damage caused, because of their unpredictability and, up to a few years ago, even because of the lack of knowledge and awareness on their physical origin. Because of this large impact on real life and on imagination, people needed and wanted to describe and report the occurrence of these events, giving them suited names. Often, these nouns are related to the myth developed to explain the cause of the events. In this work, a short presentation and description of the popular nouns used to describe severe local storm events in different areas of the World is given. Countries taken into account span from Italy, moving toward Africa and reaching a few communities of Native Americans. The etymology of the names gives interesting information, useful even under the anthropological point of view, on the Culture and Believes of the peoples who adopted them. This research work is the result of an underground activity carried out in the last ten years by the authors, during their contacts with students and researchers coming from different Countries and mainly met at the International Center for Theoretical Physics in Trieste.

  18. Calculation of Earthing System at Bangladesh Storm Water Pumping Station

    Institute of Scientific and Technical Information of China (English)

    ZHAO Xiaolei; QIAN Zhongyang; LIANG Wei; WANG Qin

    2015-01-01

    A Storm Water Pumping Station funded by the World Bank is under construction and commissioning, of which the earthing system design is a crucial part for the electrical design. Based on IEEE and BS standards, this article fully introduces the analysis methodology and calculation of the system within the framework of the World Bank supported project. A solution of this practical case satisfied with the requirements of international standards is shown in order to bring experience and convenience for engineers who are dedicated to projects abroad.

  19. Cardiac tamponade (image)

    Science.gov (United States)

    Cardiac tamponade is a condition involving compression of the heart caused by blood or fluid accumulation in the space ... they cannot adequately fill or pump blood. Cardiac tamponade is an emergency condition that requires hospitalization.

  20. What Is Cardiac Rehabilitation?

    Science.gov (United States)

    ANSWERS by heart Treatments + Tests What Is Cardiac Rehabilitation? A cardiac rehabilitation (rehab) program takes place in a hospital or ... special help in making lifestyle changes. During your rehabilitation program you’ll… • Have a medical evaluation to ...

  1. Using noise to determine cardiac restitution with memory

    Science.gov (United States)

    Dai, Shu; Keener, James P.

    2012-06-01

    Variation in cardiac pacing cycles, as seen, for example, in heart rate variability, has been observed for decades. Contemporarily, various mathematical models have been constructed to investigate the electrical activity of paced cardiac cells. Yet there has not been a study of these cardiac models when there is variation in the pacing cycles such as noise. We present a method that uses the stochasticity of pacing cycles to determine approximate models of the dynamics of cardiac cells, and use these models to detect bifurcations to alternans.

  2. Changes in ECG features and clinical prognosis of ventricular electrical storm in patients with left ventricular hypertrophy and acute myocardial infarction%左心室肥厚并急性心肌梗死室性电风暴心电图对预后的影响

    Institute of Scientific and Technical Information of China (English)

    于文江; 王为民

    2009-01-01

    目的 探讨沿海居民高血压性左室肥厚(left ventricular hypertrophy,LNH)并急性心肌梗死(acute myocardial infarction,AMI)后心电图特征性改变,评估室性电风暴与临床预后危险分层.方法 选择急诊住院有高皿压性LVH并AMI室性电风暴(室速或室颤)317例(Ⅱ组),另选无高血压性LVH室性电风暴AMI 109例(Ⅰ组)进行心电图检查和持续心电监护,分析心电图特征与临床高危特点.结果 室性电风暴组以高血压LVH并AMI患者心电图指标心房终末电势异常、∑ST段抬高振幅、ST段抬高导联数、QTc间期延长、对应导联ST段振幅下移等特征,梗死部位以前壁或复合前壁,并以左前降支合并回旋支或/和右冠脉完全闭塞多支病变为主,与Ⅰ组比较差异有统计学意义(P<0.05或P<0.01),临床并发泵衰竭、AMI扩展、住院病死率、室性电风暴AMI发病后6 h内发生率明显增多(P<0.01).结论 高血压性LVH并AMI室性电风暴患者,心电图多项指标异常对临床预后有预测作用.%Objective To investigate changes in ECG feature and clinical prognosis of ventricular electrical storm (VES) in patients with left ventricular hypertrophy (LVH) and acute myocardial infarction (AMI). Methods Three hundred and seventeen cases of left ventricular hypertrophy induced by hypertension and combined with AMI (Group Ⅱ) from emergency inpatients, and another 109 patients without LVH induced by hypertension and accompanied with AMI (Group Ⅰ) were chosen to have sustained ECG monitoring, analyze ECG features and clinical high risks. Results Clinical features, such as abnormality in PTFvl,ΣST segment elevation amplitude, ST segment elevation leads, ST segment reduction amplitude leads, QTc interval prolongation could be noted in the VES group. Infarction could be seen at sites of anterior and complex anterior walls, and dominant clinical signs were mainly at left descending branches accompanied by circumflex arteries and

  3. Luminescence dating of storm-surge sediment

    NARCIS (Netherlands)

    Cunningham, A.C.

    2011-01-01

    Geological evidence of storm surges has the potential to provide vital information on storm-surge risk. Sediment from the coastal dunes of the Netherlands contains evidence of extreme floods that occurred before reliable measurements of water level began. For these sediments to be useful in flood-ri

  4. Desert Shield and Desert Storm Emerging Observations

    Science.gov (United States)

    1991-10-07

    by identifying activo component an civilian maintenance instructors to replace active component instructors receiving orders for war or other PCS sites...STORM Desert scenarios in UCOFT 81619 /61WY (00687) DESERT STORM Activo Tank Table 911 816sy 90990 (006m) DESERT STloM Degraded Mode Guoery WS1W 4042iA

  5. Extreme Geomagnetic Storms – 1868–2010

    DEFF Research Database (Denmark)

    Vennerstrøm, Susanne; Lefèvre, L.; Dumbović, M.;

    2016-01-01

    We present the first large statistical study of extreme geomagnetic storms basedon historical data from the time period 1868 – 2010. This article is the first of two companionpapers. Here we describe how the storms were selected and focus on their near-Earth characteristics.The second article pre...

  6. Storm real-time processing cookbook

    CERN Document Server

    Anderson, Quinton

    2013-01-01

    A Cookbook with plenty of practical recipes for different uses of Storm.If you are a Java developer with basic knowledge of real-time processing and would like to learn Storm to process unbounded streams of data in real time, then this book is for you.

  7. Magnetic Storm Effects in the Auroral Ionosphere Observed with EISCAT Radar -Two Case Studies

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Storm-time changes of main plasma parameters in the auroral ionosphere are analyzed for two intense storms occurring on May 15, 1997 and Sept. 25, 1998, with emphasis on their relationship to the solar wind dynamic pressure and the IMF Bz component. Strong hard particle precipitation occurred in the initial phase for both storma,associated with high solar wind dynamical pressure. During the recovery phase of the storms, some strong particle precipitation was neither concerned with high solar wind pressure nor southward IMF Bz. Severe negative storm effects depicted by electron density depletion appeared in theF-region during the main and recovery phase of both storms, caused by intensive electric field-related strong Joule/frictional heating when IMF was largely southward. The ion temperature behaved similarly in E- and F-region, but the electron temperature did quite different, with a strong increase in the lower E-region relating to plasma instability excited by strong electric field and a slight decrease in the F-region probably concerning with a cooling process. The field-aligned ion velocity was high and apparently anticorrelated with the northward component of the ion convection velocity.

  8. Middle- and low-latitude ionosphere response to 2015 St. Patrick's Day geomagnetic storm

    Science.gov (United States)

    Nava, B.; Rodríguez-Zuluaga, J.; Alazo-Cuartas, K.; Kashcheyev, A.; Migoya-Orué, Y.; Radicella, S. M.; Amory-Mazaudier, C.; Fleury, R.

    2016-04-01

    This paper presents a study of the St Patrick's Day storm of 2015, with its ionospheric response at middle and low latitudes. The effects of the storm in each longitudinal sector (Asian, African, American, and Pacific) are characterized using global and regional electron content. At the beginning of the storm, one or two ionospheric positive storm effects are observed depending on the longitudinal zones. After the main phase of the storm, a strong decrease in ionization is observed at all longitudes, lasting several days. The American region exhibits the most remarkable increase in vertical total electron content (vTEC), while in the Asian sector, the largest decrease in vTEC is observed. At low latitudes, using spectral analysis, we were able to separate the effects of the prompt penetration of the magnetospheric convection electric field (PPEF) and of the disturbance dynamo electric field (DDEF) on the basis of ground magnetic data. Concerning the PPEF, Earth's magnetic field oscillations occur simultaneously in the Asian, African, and American sectors, during southward magnetization of the Bz component of the interplanetary magnetic field. Concerning the DDEF, diurnal magnetic oscillations in the horizontal component H of the Earth's magnetic field exhibit a behavior that is opposed to the regular one. These diurnal oscillations are recognized to last several days in all longitudinal sectors. The observational data obtained by all sensors used in the present paper can be interpreted on the basis of existing theoretical models.

  9. Global differences between moderate and large storms

    Science.gov (United States)

    Valek, P. W.; Buzulukova, N.; Fok, M. C. H.; Goldstein, J.; Keesee, A. M.; McComas, D. J.; Perez, J. D.

    2015-12-01

    The current solar maximum has been relatively quiet compared to previous solar cycles. Whereas numerous moderate storms (Dst ENA cameras flown aboard two separate spacecraft in Molniya orbits. TWINS images the ENA emissions from the inner magnetosphere across a broad range of energies (1 to 100 keV for H, 16 to 256 keV for O). This allows TWINS to observe the evolution in space and time of the trapped and precipitating particles most relevant for storm time dynamics on very high time scales (i.e., minutes). Here we will present the differences seen between moderate storms and the two large storms of 17 March 2015 (Dst ENA observations of the inner magnetosphere covering the both the medium (1 to 30 keV) and high (30 to > 100 keV) energy ranges, and describe how the inner magnetosphere evolves during storm time.

  10. Ionospheric storm effects and equatorial plasma irregularities during the 17-18 March 2015 event

    Science.gov (United States)

    Zhou, Yun-Liang; Lühr, Hermann; Xiong, Chao; Pfaff, Robert F.

    2016-09-01

    The intense magnetic storm on 17-18 March 2015 caused large disturbances of the ionosphere. Based on the plasma density (Ni) observations performed by the Swarm fleet of satellites, the Gravity Recovery and Climate Experiment mission, and the Communications/Navigation Outage Forecasting System satellite, we characterize the storm-related perturbations at low latitudes. All these satellites sampled the ionosphere in morning and evening time sectors where large modifications occurred. Modifications of plasma density are closely related to changes of the solar wind merging electric field (Em). We consider two mechanisms, prompt penetration electric field (PPEF) and disturbance dynamo electric field (DDEF), as the main cause for the Ni redistribution, but effects of meridional wind are also taken into account. At the start of the storm main phase, the PPEF is enhancing plasma density on the dayside and reducing it on the nightside. Later, DDEF takes over and causes the opposite reaction. Unexpectedly, there appears during the recovery phase a strong density enhancement in the morning/prenoon sector and a severe Ni reduction in the afternoon/evening sector, and we suggest a combined effect of vertical plasma drift, and meridional wind is responsible for these ionospheric storm effects. Different from earlier studies about this storm, we also investigate the influence of storm dynamics on the initiation of equatorial plasma irregularities (EPIs). Shortly after the start of the storm main phase, EPIs appear in the postsunset sector. As a response to a short-lived decline of Em, EPI activity appears in the early morning sector. Following the second start of the main phase, EPIs are generated for a few hours in the late evening sector. However, for the rest of the storm main phase, no more EPIs are initiated for more than 12 h. Only after the onset of recovery phase does EPI activity start again in the postmidnight sector, lasting more than 7 h. This comprehensive view of

  11. 10.2.Cardiac arrhythmias

    Institute of Scientific and Technical Information of China (English)

    1993-01-01

    930257 Electrophysiologic study of reperfu-sion arrhythmias.YIN Hong (尹红),et al.Af-fil Hosp,Shandong Med Univ,Jinan.Chin CirJ 1993;8(1):37—39.Twenty dogs of experimental ischemic reper-fusion were studied with a three-dimensionalmapping system of cardiac electric activity andmultiple—level myocardial recordings by bipolarplunge—needle electrodes.27% of the nonsus-tained ventricular tachycardia (NSVT) of intra-mural reentry occurred in the ischemic subendo-

  12. Mechanisms of cardiac pain.

    Science.gov (United States)

    Foreman, Robert D; Garrett, Kennon M; Blair, Robert W

    2015-04-01

    Angina pectoris is cardiac pain that typically is manifested as referred pain to the chest and upper left arm. Atypical pain to describe localization of the perception, generally experienced more by women, is referred to the back, neck, and/or jaw. This article summarizes the neurophysiological and pharmacological mechanisms for referred cardiac pain. Spinal cardiac afferent fibers mediate typical anginal pain via pathways from the spinal cord to the thalamus and ultimately cerebral cortex. Spinal neurotransmission involves substance P, glutamate, and transient receptor potential vanilloid-1 (TRPV1) receptors; release of neurokinins such as nuclear factor kappa b (NF-kb) in the spinal cord can modulate neurotransmission. Vagal cardiac afferent fibers likely mediate atypical anginal pain and contribute to cardiac ischemia without accompanying pain via relays through the nucleus of the solitary tract and the C1-C2 spinal segments. The psychological state of an individual can modulate cardiac nociception via pathways involving the amygdala. Descending pathways originating from nucleus raphe magnus and the pons also can modulate cardiac nociception. Sensory input from other visceral organs can mimic cardiac pain due to convergence of this input with cardiac input onto spinothalamic tract neurons. Reduction of converging nociceptive input from the gallbladder and gastrointestinal tract can diminish cardiac pain. Much work remains to be performed to discern the interactions among complex neural pathways that ultimately produce or do not produce the sensations associated with cardiac pain.

  13. An Evaluation of Lightning Flash Rate Parameterizations Based on Observations of Colorado Storms during DC3

    Science.gov (United States)

    Basarab, B.; Fuchs, B.; Rutledge, S. A.

    2013-12-01

    Predicting lightning activity in thunderstorms is important in order to accurately quantify the production of nitrogen oxides (NOx = NO + NO2) by lightning (LNOx). Lightning is an important global source of NOx, and since NOx is a chemical precursor to ozone, the climatological impacts of LNOx could be significant. Many cloud-resolving models rely on parameterizations to predict lightning and LNOx since the processes leading to charge separation and lightning discharge are not yet fully understood. This study evaluates predicted flash rates based on existing lightning parameterizations against flash rates observed for Colorado storms during the Deep Convective Clouds and Chemistry Experiment (DC3). Evaluating lightning parameterizations against storm observations is a useful way to possibly improve the prediction of flash rates and LNOx in models. Additionally, since convective storms that form in the eastern plains of Colorado can be different thermodynamically and electrically from storms in other regions, it is useful to test existing parameterizations against observations from these storms. We present an analysis of the dynamics, microphysics, and lightning characteristics of two case studies, severe storms that developed on 6 and 7 June 2012. This analysis includes dual-Doppler derived horizontal and vertical velocities, a hydrometeor identification based on polarimetric radar variables using the CSU-CHILL radar, and insight into the charge structure using observations from the northern Colorado Lightning Mapping Array (LMA). Flash rates were inferred from the LMA data using a flash counting algorithm. We have calculated various microphysical and dynamical parameters for these storms that have been used in empirical flash rate parameterizations. In particular, maximum vertical velocity has been used to predict flash rates in some cloud-resolving chemistry simulations. We diagnose flash rates for the 6 and 7 June storms using this parameterization and compare

  14. Cardiac conductive system excitation maps using intracardiac tissue Doppler imaging

    Institute of Scientific and Technical Information of China (English)

    尹立雪; 郑昌琼; 蔡力; 郑翊; 李春梅; 邓燕; 罗芸; 李德玉; 赵树魁

    2003-01-01

    Objective To precisely visualize cardiac anatomic structures and simultaneously depict ele ctro-mechanical events for the purpose of precise underblood intervention. Methods Intracardiac high-resolution tissue Doppler imaging was used to map realt imemyocardial contractions in response to electrical activation within the anat omic structure of the cardiac conductive system using a canine open-chest model . Results The detailed inner anatomic structure of the cardiac conductive system at differ entsites (i.e., sino-atrial, atrial wall, atrial-ventricular node and ventr icular wall) with the inside onset and propagation of myocardial velocity and ac celeration induced by electrical activation was clearly visualized and quan titatively evaluated.Conclusion The simultaneous single modality visualization of the anatomy, function and electrical events of the cardiac conductive system will foster target pacing and pre cision ablation.

  15. A new parameter of geomagnetic storms for the severity of space weather

    Science.gov (United States)

    Balan, N.; Batista, I. S.; Tulasi Ram, S.; Rajesh, P. K.

    2016-12-01

    Using the continuous Dst data available since 1957 and H component data for the Carrington space weather event of 1859, the paper shows that the mean value of Dst during the main phase of geomagnetic storms, called mean DstMP, is a unique parameter that can indicate the severity of space weather. All storms having high mean DstMP (≤-250 nT), which corresponds to high amount of energy input in the magnetosphere-ionosphere system in short duration, are found associated with severe space weather events that caused all known electric power outages and telegraph system failures.

  16. Biomimetic material strategies for cardiac tissue engineering

    Energy Technology Data Exchange (ETDEWEB)

    Prabhakaran, Molamma P., E-mail: nnimpp@nus.edu.sg [Health Care and Energy Materials Laboratory, Nanoscience and Nanotechnology Initiative, Faculty of Engineering, National University of Singapore, 2 Engineering Drive 3, Singapore 117576 (Singapore); Venugopal, J. [Health Care and Energy Materials Laboratory, Nanoscience and Nanotechnology Initiative, Faculty of Engineering, National University of Singapore, 2 Engineering Drive 3, Singapore 117576 (Singapore); Kai, Dan [NUS Graduate School for Integrative Sciences and Engineering, National University of Singapore (Singapore); Ramakrishna, Seeram [Health Care and Energy Materials Laboratory, Nanoscience and Nanotechnology Initiative, Faculty of Engineering, National University of Singapore, 2 Engineering Drive 3, Singapore 117576 (Singapore)

    2011-04-08

    Cardiovascular disease precedes many serious complications including myocardial infarction (MI) and it remains a major problem for the global community. Adult mammalian heart has limited ability to regenerate and compensate for the loss of cardiomyocytes. Restoration of cardiac function by replacement of diseased myocardium with functional cardiomyocytes is an intriguing strategy because it offers a potential cure for MI. Biomaterials are fabricated in nanometer scale dimensions by combining the chemical, biological, mechanical and electrical aspects of material for potential tissue engineering (TE) applications. Synthetic polymers offer advantageous in their ability to tailor the mechanical properties, and natural polymers offer cell recognition sites necessary for cell, adhesion and proliferation. Cardiac tissue engineering (TE) aim for the development of a bioengineered construct that can provide physical support to the damaged cardiac tissue by replacing certain functions of the damaged extracellular matrix and prevent adverse cardiac remodeling and dysfunction after MI. Electrospun nanofibers are applied as heart muscle patches, while hydrogels serve as a platform for controlled delivery of growth factors, prevent mechanical complications and assist in cell recruitment. This article reviews the applications of different natural and synthetic polymeric materials utilized as cardiac patches, injectables or 3D constructs for cardiac TE. Smart organization of nanoscale assemblies with synergistic approaches of utilizing nanofibers and hydrogels could further advance the field of cardiac tissue engineering. Rapid innovations in biomedical engineering and cell biology will bring about new insights in the development of optimal scaffolds and methods to create tissue constructs with relevant contractile properties and electrical integration to replace or substitute the diseased myocardium.

  17. Biomimetic materials design for cardiac tissue regeneration.

    Science.gov (United States)

    Dunn, David A; Hodge, Alexander J; Lipke, Elizabeth A

    2014-01-01

    Cardiovascular disease is the leading cause of death worldwide. In the absence of sufficient numbers of organs for heart transplant, alternate approaches for healing or replacing diseased heart tissue are under investigation. Designing biomimetic materials to support these approaches will be essential to their overall success. Strategies for cardiac tissue engineering include injection of cells, implantation of three-dimensional tissue constructs or patches, injection of acellular materials, and replacement of valves. To replicate physiological function and facilitate engraftment into native tissue, materials used in these approaches should have properties that mimic those of the natural cardiac environment. Multiple aspects of the cardiac microenvironment have been emulated using biomimetic materials including delivery of bioactive factors, presentation of cell-specific adhesion sites, design of surface topography to guide tissue alignment and dictate cell shape, modulation of mechanical stiffness and electrical conductivity, and fabrication of three-dimensional structures to guide tissue formation and function. Biomaterials can be engineered to assist in stem cell expansion and differentiation, to protect cells during injection and facilitate their retention and survival in vivo, and to provide mechanical support and guidance for engineered tissue formation. Numerous studies have investigated the use of biomimetic materials for cardiac regeneration. Biomimetic material design will continue to exploit advances in nanotechnology to better recreate the cellular environment and advance cardiac regeneration. Overall, biomimetic materials are moving the field of cardiac regenerative medicine forward and promise to deliver new therapies in combating heart disease.

  18. Reduced Baroclinicity During Martian Global Dust Storms

    Science.gov (United States)

    Battalio, Joseph; Szunyogh, Istvan; Lemmon, Mark

    2015-11-01

    The eddy kinetic energy equation is applied to the Mars Analysis Correction Data Assimilation (MACDA) dataset during the pre-winter solstice period for the northern hemisphere of Mars. Traveling waves are triggered by geopotential flux convergence, grow baroclinically, and decay barotropically. Higher optical depth increases the static stability, which reduces vertical and meridional heat fluxes. Traveling waves during a global dust storm year develop a mixed baroclinic/barotropic growth phase before decaying barotropically. Baroclinic energy conversion is reduced during the global dust storm, but eddy intensity is undiminished. Instead, the frequency of storms is reduced due to a stabilized vertical profile.

  19. Stimulating endogenous cardiac regeneration

    Directory of Open Access Journals (Sweden)

    Amanda eFinan

    2015-09-01

    Full Text Available The healthy adult heart has a low turnover of cardiac myocytes. The renewal capacity, however, is augmented after cardiac injury. Participants in cardiac regeneration include cardiac myocytes themselves, cardiac progenitor cells, and peripheral stem cells, particularly from the bone marrow compartment. Cardiac progenitor cells and bone marrow stem cells are augmented after cardiac injury, migrate to the myocardium, and support regeneration. Depletion studies of these populations have demonstrated their necessary role in cardiac repair. However, the potential of these cells to completely regenerate the heart is limited. Efforts are now being focused on ways to augment these natural pathways to improve cardiac healing, primarily after ischemic injury but in other cardiac pathologies as well. Cell and gene therapy or pharmacological interventions are proposed mechanisms. Cell therapy has demonstrated modest results and has passed into clinical trials. However, the beneficial effects of cell therapy have primarily been their ability to produce paracrine effects on the cardiac tissue and recruit endogenous stem cell populations as opposed to direct cardiac regeneration. Gene therapy efforts have focused on prolonging or reactivating natural signaling pathways. Positive results have been demonstrated to activate the endogenous stem cell populations and are currently being tested in clinical trials. A potential new avenue may be to refine pharmacological treatments that are currently in place in the clinic. Evidence is mounting that drugs such as statins or beta blockers may alter endogenous stem cell activity. Understanding the effects of these drugs on stem cell repair while keeping in mind their primary function may strike a balance in myocardial healing. To maximize endogenous cardiac regeneration,a combination of these approaches couldameliorate the overall repair process to incorporate the participation ofmultiple cell players.

  20. Direct and reflex cardiac bradydysrhythmias from small vagal nerve stiumaltions.

    Science.gov (United States)

    Hageman, G R; Randall, W C; Armour, J A

    1975-03-01

    Alterations in cardiac pacemaker location, its rate of discharge, and A-V conduction patterns were induced in anesthetized adult dogs by electrical stimulation of the thoracic vagi and their small cardiac branches before and after cervical vagotomy. Electrical activity from small, contiguous bipolar silver electrodes was amplified and recorded by an optical oscillograph. The electrodes were located over the SA node, the three internodal pathways, the left atrium, and ventricular epicardium. A hoffman-type plaque electrode was placed over the A-V node to record a His bundle electrogram simultaneously with a Lead II electrocardiogram. Electrical stimulation of the intact left recurrent laryngeal nerve and its cardiac branches before and after vagotomy induced both direct and reflex effects on SA nodal cycle length. Efferent dromotropic effects on the A-V node varied from first- to third-degree heart block during stimulation of individual left recurrent cardiac branches. Stimulation of the right recurrent cardiac nerve induced atrial bradycardia with heart block above the His bundle. Stimulation of individual right vagal branches near the heart induced bradycardia, cardiac asystole, shifts in atrial pacemaker location, or activation of His pacemakers. Establishment of the His rhythm probably indicates selective inhibition of supraventricular but not of the His bundle. Asystole and His rhythms induced during stimulation of the more caudal branches of the right cardiac vagal nerves were generally reflexly mediated and were abolished by cervical vagotomy.

  1. Criteria of interplanetary parameters causing intense magnetic storms (Dst of less than -100 nT)

    Science.gov (United States)

    Gonzalez, Walter D.; Tsurutani, Bruce T.

    1987-01-01

    An analysis of ISEE-3 field and plasma data shows that 10 intense magnetic storms that occurred in 1979 were caused by long-duration, large-amplitude (13-30 nT) and negative (less than -10 nT) IMF Bz events associated with interplanetary duskward-electric fields of greater than 5 mV/m. The results suggest that these criteria may be used as predictors of intense storms. A study of opposite polarity (northward) Bz events with the same criteria shows that their occurrence is similar both in number and in their relationship to interplanetary disturbances. The amplitudes of the storms were not found to vary with shock strengths.

  2. Clofibrate, calcium and cardiac muscle.

    Science.gov (United States)

    Fairhurst, A S; Wickie, G; Peabody, T

    1982-03-01

    The anti-hyperlipidemic drug clofibrate produces negative inotropic effects and arrythmias in isolated perfused rabbit heart Langendorff preparations. In electrically stimulated rat left atria, clofibrate produces negative inotropic effects, the speed of onset and extent of which are decreased by raising the Ca concentration of the bathing medium. Sensitivity of isolated rat atria to clofibrate is not increased when the tissues are stimulated under slow Ca channel conditions, in which the tissues are activated by either isoproterenol or dibutyryl cyclic AMP, although sensitivity to clofibrate is decreased when atria are exposed to increasing concentrations of norepinephrine. Increasing the stimulation frequency of isolated guinea-pig atria to produce a positive treppe also decreases the inhibitory effect of clofibrate, while in rat atria the typical negative treppe is altered towards a positive treppe in presence of clofibrate. The effects of paired electrical stimulation are not diminished by the drug, suggesting that Ca release from the sarcoplasmic reticulum is not affected by clofibrate, although the drug inhibits the rate of Ca uptake by isolated cardiac sarcoplasmic reticulum and mitochondria. These results suggest that clofibrate has multiple effects on Ca functions in cardiac muscle.

  3. Joint Typhoon Warning Center (JTWC) Storm Wallets

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Joint Typhoon Warning Center (JTWC) is responsible for typhoon forecasts and warnings for the Western Pacific and Indian Ocean basins. After each storm, the JTWC...

  4. Storm Water General Permit 2 for Construction

    Data.gov (United States)

    Iowa State University GIS Support and Research Facility — General permit #2 for storm water discharges associated with industrial activity for Construction Activities in Iowa for the National Pollutant Discharge Elimination...

  5. Solar storms, cycles and topology

    Directory of Open Access Journals (Sweden)

    Lundstedt H.

    2010-12-01

    Full Text Available Solar storms are produced due to plasma processes inside and between coronal loops. These loops are topologically examined using knot and braid theory. Solar cycles are topologically explored with a complex generalization of the three ordinary differential equations studied by Lorenz. By studying the Poincaré map we give numerical evidence that the flow has an attractor with fractal structure. The period is defined as the time needed for a point on a hyperplane to return to the hyperplane again. The periods are distributed in an interval. For large values of the Dynamo number there is a long tail toward long periods and other interesting comet-like features. We also found a relationship between the intensity of a cycle and the length for the previous cycle. Maunder like minima are also appearing. These general relations found for periods can further be physically interpreted with improved helioseismic estimates of the parameters used by the dynamical systems. Solar Dynamic Observatory is expected to offer such improved measurements.

  6. Storm sudden commencements and earthquakes

    Science.gov (United States)

    Lavrov, Ivan; Sobisevich, Aleksey; Guglielmi, Anatol

    2015-03-01

    We have investigated statistically the problem of possible impact of the geomagnetic storm sudden com-mencement (SSC) on the global seismic activity. SSC are used as reference points for comparative analysis of seismicity by the method of superposed epoch. We selected 405 earthquakes from 1973 to 2010 with M˜5 magnitudes from a representative part of USGS Catalog. The comparative analysis of seismicity was carried out at the intervals of ˜60 min relative to the reference point. With a high degree of reliability, it was found that before the reference point the number of earthquakes is noticeably greater than after it. In other words, the global seismicity is suppressed by SSC. We refer to some studies in which the chemical, thermal and force mechanisms of the electromagnetic field action on rocks are discussed. We emphasize the incompleteness of the study concerning the correlation between SSC and earthquakes because we still do not succeed in understanding and interpreting the relationship in terms of physics and mathematics. The study need to be continued to solve this problem of interest and importance.

  7. The effects of storms and storm-generated currents on sand beaches in Southern Maine, USA

    Science.gov (United States)

    Hill, H.W.; Kelley, J.T.; Belknap, D.F.; Dickson, S.M.

    2004-01-01

    Storms are one of the most important controls on the cycle of erosion and accretion on beaches. Current meters placed in shoreface locations of Saco Bay and Wells Embayment, ME, recorded bottom currents during the winter months of 2000 and 2001, while teams of volunteers profiled the topography of nearby beaches. Coupling offshore meteorological and beach profile data made it possible to determine the response of nine beaches in southern Maine to various oceanographic and meteorological conditions. The beaches selected for profiling ranged from pristine to completely developed and permitted further examination of the role of seawalls on the response of beaches to storms. Current meters documented three unique types of storms: frontal passages, southwest storms, and northeast storms. In general, the current meter results indicate that frontal passages and southwest storms were responsible for bringing sediment towards the shore, while northeast storms resulted in a net movement of sediment away from the beach. During the 1999-2000 winter, there were a greater percentage of frontal passages and southwest storms, while during the 2000-2001 winter, there were more northeast storms. The sediment that was transported landward during the 1999-2000 winter was reworked into the berm along moderately and highly developed beaches during the next summer. A northeast storm on March 5-6, 2001, resulted in currents in excess of 1 m s-1 and wave heights that reached six meters. The storm persisted over 10 high tides and caused coastal flooding and property damage. Topographic profiles made before and after the storm demonstrate that developed beaches experienced a loss of sediment volume during the storm, while sediment was redistributed along the profile on moderately developed and undeveloped beaches. Two months after the storm, the profiles along the developed beaches had not reached their pre-storm elevation. In comparison, the moderately developed and undeveloped beaches

  8. Two-Step Forecast of Geomagnetic Storm Using Coronal Mass Ejection and Solar Wind Condition

    Science.gov (United States)

    Kim, R.-S.; Moon, Y.-J.; Gopalswamy, N.; Park, Y.-D.; Kim, Y.-H.

    2014-01-01

    To forecast geomagnetic storms, we had examined initially observed parameters of coronal mass ejections (CMEs) and introduced an empirical storm forecast model in a previous study. Now we suggest a two-step forecast considering not only CME parameters observed in the solar vicinity but also solar wind conditions near Earth to improve the forecast capability. We consider the empirical solar wind criteria derived in this study (Bz = -5 nT or Ey = 3 mV/m for t = 2 h for moderate storms with minimum Dst less than -50 nT) (i.e. Magnetic Field Magnitude, B (sub z) less than or equal to -5 nanoTeslas or duskward Electrical Field, E (sub y) greater than or equal to 3 millivolts per meter for time greater than or equal to 2 hours for moderate storms with Minimum Disturbance Storm Time, Dst less than -50 nanoTeslas) and a Dst model developed by Temerin and Li (2002, 2006) (TL [i.e. Temerin Li] model). Using 55 CME-Dst pairs during 1997 to 2003, our solar wind criteria produce slightly better forecasts for 31 storm events (90 percent) than the forecasts based on the TL model (87 percent). However, the latter produces better forecasts for 24 nonstorm events (88 percent), while the former correctly forecasts only 71 percent of them. We then performed the two-step forecast. The results are as follows: (i) for 15 events that are incorrectly forecasted using CME parameters, 12 cases (80 percent) can be properly predicted based on solar wind conditions; (ii) if we forecast a storm when both CME and solar wind conditions are satisfied (n, i.e. cap operator - the intersection set that is comprised of all the elements that are common to both), the critical success index becomes higher than that from the forecast using CME parameters alone, however, only 25 storm events (81 percent) are correctly forecasted; and (iii) if we forecast a storm when either set of these conditions is satisfied (?, i.e. cup operator - the union set that is comprised of all the elements of either or both

  9. Marketing cardiac CT programs.

    Science.gov (United States)

    Scott, Jason

    2010-01-01

    There are two components of cardiac CT discussed in this article: coronary artery calcium scoring (CACS) and coronary computed tomography angiography (CCTA).The distinctive advantages of each CT examination are outlined. In order to ensure a successful cardiac CT program, it is imperative that imaging facilities market their cardiac CT practices effectively in order to gain a competitive advantage in this valuable market share. If patients receive quality care by competent individuals, they are more likely to recommend the facility's cardiac CT program. Satisfied patients will also be more willing to come back for any further testing.

  10. Mapping Hurricane Rita inland storm tide

    Science.gov (United States)

    Berenbrock, Charles; Mason, Jr., Robert R.; Blanchard, Stephen F.; Simonovic, Slobodan P.

    2009-01-01

    Flood-inundation data are most useful for decision makers when presented in the context of maps of effected communities and (or) areas. But because the data are scarce and rarely cover the full extent of the flooding, interpolation and extrapolation of the information are needed. Many geographic information systems (GIS) provide various interpolation tools, but these tools often ignore the effects of the topographic and hydraulic features that influence flooding. A barrier mapping method was developed to improve maps of storm tide produced by Hurricane Rita. Maps were developed for the maximum storm tide and at 3-hour intervals from midnight (0000 hour) through noon (1200 hour) on September 24, 2005. The improved maps depict storm-tide elevations and the extent of flooding. The extent of storm-tide inundation from the improved maximum storm-tide map was compared to the extent of flood-inundation from a map prepared by the Federal Emergency Management Agency (FEMA). The boundaries from these two maps generally compared quite well especially along the Calcasieu River. Also a cross-section profile that parallels the Louisiana coast was developed from the maximum storm-tide map and included FEMA high-water marks.

  11. Major Geomagnetic Storms (Dst less than or equal to -100 nT) Generated by Corotating Interaction Regions

    Science.gov (United States)

    Richardson, I. G.; Webb, D. F.; Zhang, J.; Berdichevsky, B. D.; Biesecker, D. A.; Kasper, J. C.; Kataoka, R.; Steinberg, J. T.; Thompson, B. J.; Wu, C.-C.; Zhukov, A. N.

    2006-01-01

    Seventy-nine major geomagnetic storms (minimum Dst less than or equal to -100 nT) observed in 1996 to 2004 were the focus of a Living with a Star Coordinated Data-Analysis Workshop (CDAW) in March, 2005. In 9 cases, the storm driver appears to have been purely a corotating interaction region (CIR) without any contribution from coronal mass ejection-related material (interplanetary coronal mass ejections, ICMEs). These storms were generated by structures within CIRs located both before and/or after the stream interface that included persistently southward magnetic fields for intervals of several hours. We compare their geomagnetic effects with those of 159 CIRs observed during 1996 - 2005. The major storms form the extreme tail of a continuous distribution of CIR geoeffectiveness which peaks at Dst approx. -40 nT but is subject to a prominent seasonal variation of - 40 nT which is ordered by the spring and fall equinoxes and the solar wind magnetic field direction towards or away from the Sun. The O'Brien and McPherron [2000] equations, which estimate Dst by integrating the incident solar wind electric field and incorporating a ring current loss term, largely account for the variation in storm size. They tend to underestimate the size of the larger CIR-associated storms by Dst approx. 20 nT. This suggests that injection into the ring current may be more efficient than expected in such storms. Four of the nine major storms in 1996 - 2004 occurred during a period of less than three solar rotations in September - November, 2002, also the time of maximum mean IMF and solar magnetic field intensity during the current solar cycle. The maximum CIR-storm strength found in our sample of events, plus additional 23 probable CIR-associated Dst less than or equal to -100 nT storms in 1972 - 1995, is (Dst = -161 nT). This is consistent with the maximum storm strength (Dst approx. -180 nT) expected from the O'Brien and McPherron equations for the typical range of solar wind

  12. Carnegie Institution Atmospheric-Electricity and Meteorological Data

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Department of Terrestrial Magnetism at the Carnegie Institute of Science conducted observations of atmospheric electricity and magnetic storms. In addition to...

  13. Criteria of interplanetary parameters causing intense magnetic storms (Dst less than -100nT)

    Science.gov (United States)

    Gonzalez, Walter D.; Tsurutani, Bruce T.

    1987-01-01

    Ten intense storms occurred during the 500 days of August 16, 1978 to December 28, 1979. From the analysis of ISEE-3 field and plasma data, it is found that the interplanetary cause of these storms are long-duration, large and negative IMF B sub Z events, associated with interplanetary duskward-electric fields greater than 5 mV/m. Because a one-to-one relationship was found between these interplanetary events and intense storms, it is suggested that these criteria can, in the future, be used as predictors of intense storms by an interplanetary monitor such as ISEE-3. These B sub Z events are found to occur in association with large amplitudes of the IMF magnitude within two days after the onset of either high-speed solar wind streams or of solar wind density enhancement events, giving important clues to their interplanetary origin. Some obvious possibilities will be discussed. The close proximity of B sub Z events and magnetic storms to the onset of high speed streams or density enhancement events is in sharp contrast to interplanetary Alfven waves and HILDCAA events previously reported, and thus the two interplanetary features corresponding geomagnetic responses can be thought of as being complementary in nature. An examination of opposite polarity B sub Z events with the same criteria show that their occurrence is similar both in number as well as in their relationship to interplanetary disturbances, and that they lead to low levels of geomagnetic activity.

  14. Criteria of interplanetary parameters causing intense magnetic storms (Dsub(st) < -100 nT)

    Energy Technology Data Exchange (ETDEWEB)

    Gonzalez, W.D.; Tsurutani, B.T.

    1987-09-01

    Ten intense magnetic storms (Dsub(st) < -100 nT) occurred during the 500 days from 16 August 1978 to 28 December 1979. From our analysis of ISEE-3 field and plasma data, it is found that the interplanetary causes of these storms are long-duration, large and negative (< - 10nT) IMF Bsub(z) events, associated with interplanetary duskward-electric fields > 5 mV m/sup -1/, that last for intervals > 3 h. Because we find a one-to-one relationship between these interplanetary events and intense storms, we suggest that these criteria can, in the future, be used as predictors of intense storms by an interplanetary monitor such as ISEE-3. The close proximity of the Bsub(z) events and magnetic storms to the onset of high speed streams or density enhancement events is in sharp contrast to interplanetary Alfven waves and HILDCAA events previously reported and thus the two interplanetary features and corresponding geomagnetic responses can be thought of as being complementary in nature. An examination of opposite polarity (northward) Bsub(z) events with the same criteria shows that their occurrence is similar both in number as well as in their relationship to interplanetary disturbances, and that they lead to low levels of geomagnetic activity.

  15. Ionospheric and Thermospheric Response to the 2015 St. Patrick's Day Storm: a Global Multi-Instrumental Overview

    Science.gov (United States)

    Astafyeva, E.; Zakharenkova, I.; Foerster, M.; Doornbos, E.; Encarnacao, J.; Siemes, C.

    2015-12-01

    We study the ionospheric response to the geomagnetic storm of 17-18 March 2015 (the St. Patrick's Day 2015 storm) that was up to now the strongest in the 24th solar cycle (minimum SYM-H value of -233 nT). For this purpose, we use data of ground-based GPS-receivers and ionosondes, along space-borne instruments onboard the following satellites: Jason-2, GRACE, Terra-SAR-X, the three Swarm satellites (A, B, and C), and GUVI/TIMED. The storm consisted of two successive moderate storms. In the response to the first short storm, a short-term positive effect in the ionospheric vertical electron content (VTEC) occurred at low- and mid-latitudes on the dayside. The second event lasted longer and caused significant and complex storm-time changes around the globe. At high-latitudes, negative storm signatures were recorded in all longitudinal regions. The negative storm phase was found to be strongest in the Asian sector, in particular in the northern hemisphere (NH), but developed globally on March 18 at the beginning of the recovery phase. At mid-latitudes, inverse hemispheric asymmetries occurred in different longitudinal regions: in the European-African sector, positive storm signatures were observed in the NH, whereas in the American sector, a large positive storm occurred in the southern hemisphere (SH), and the NH experienced a negative storm. These observations performed around the spring equinox signify the existence of other impact factors than seasonal dependence for hemispheric asymmetries to occur. At low-latitudes, data from multiple satellites revealed the strongest storm-time effects in the morning (~100-150% enhancement) and post-sunset (~80-100% enhancement) sectors in the topside ionosphere. These dramatic VTEC enhancements were observed at different UT, but around the same area of Eastern Pacific region. To further understand the storm development, we are planning to use thermospheric data from Swarm-C satellite, as well as the data from the electric field

  16. Is the storm time response of the inner magnetospheric hot ions universally similar or driver dependent?

    Science.gov (United States)

    Liemohn, Michael W.; Katus, Roxanne

    2012-04-01

    The Hot Electron and Ion Drift Integrator (HEIDI) model was used to simulate all of the intense storms (Dstmin total energy content, yielding error estimates on the correlation coefficients and root-mean-square error values for each run set. The accuracy of each run set depends on the method of comparison and classification of the driver. For the correlation coefficients, the simulations using a local-time-dependent outer boundary condition were consistently better than those using a local-time-averaged (but high-time-resolution) nightside boundary condition, with the simplistic electric field being better than the self-consistent field description. For the root-mean-square error, the results are less conclusive. For the CIR/HSS-driven storms, those with the high-time-resolution boundary condition were systematically better than those with the local-time-dependent (but lower-time-resolution) boundary condition. For the ICME-driven storms, those run sets employing the self-consistent electric field calculation were systematically better than those using the simplistic electric field. The implication, therefore, is that the inner magnetospheric physical response to strong driving is, at least to some degree, fundamentally different depending on the heliospheric structure impacting geospace. Specifically, for an accurate SYMH* comparison, it is found that CIR/HSS events respond strongly to transient spikes in the plasma outer boundary condition, while ICME passages exhibit a more highly structured electric field.

  17. Observatory geoelectric fields induced in a two-layer lithosphere during magnetic storms

    Science.gov (United States)

    Love, Jeffrey J.; Swidinsky, Andrei

    2015-01-01

    We report on the development and validation of an algorithm for estimating geoelectric fields induced in the lithosphere beneath an observatory during a magnetic storm. To accommodate induction in three-dimensional lithospheric electrical conductivity, we analyze a simple nine-parameter model: two horizontal layers, each with uniform electrical conductivity properties given by independent distortion tensors. With Laplace transformation of the induction equations into the complex frequency domain, we obtain a transfer function describing induction of observatory geoelectric fields having frequency-dependent polarization. Upon inverse transformation back to the time domain, the convolution of the corresponding impulse-response function with a geomagnetic time series yields an estimated geoelectric time series. We obtain an optimized set of conductivity parameters using 1-s resolution geomagnetic and geoelectric field data collected at the Kakioka, Japan, observatory for five different intense magnetic storms, including the October 2003 Halloween storm; our estimated geoelectric field accounts for 93% of that measured during the Halloween storm. This work demonstrates the need for detailed modeling of the Earth’s lithospheric conductivity structure and the utility of co-located geomagnetic and geoelectric monitoring.

  18. Storm:a Symbol of Desire-Analysis of The Storm by Kate Chopin

    Institute of Scientific and Technical Information of China (English)

    张恩秀

    2013-01-01

    Changes in natural environment are usually the reflection of human inner world. The Storm was a short story written by Kate Chopin, an America female writer. In the story storm not only creates the setting for her immoral behavior, but also sym⁃bolizes the female protagonist, Calixta’s desire for love.

  19. Cardiac Procedures and Surgeries

    Science.gov (United States)

    ... Peripheral Artery Disease Venous Thromboembolism Aortic Aneurysm More Cardiac Procedures and Surgeries Updated:Sep 16,2016 If you've had ... degree of coronary artery disease (CAD) you have. Cardiac Procedures and Surgeries Angioplasty Also known as Percutaneous Coronary Interventions [PCI], ...

  20. [Advances in cardiac pacing].

    Science.gov (United States)

    de Carranza, María-José Sancho-Tello; Fidalgo-Andrés, María Luisa; Ferrer, José Martínez; Mateas, Francisco Ruiz

    2012-01-01

    This article contains a review of the current status of remote monitoring and follow-up involving cardiac pacing devices and of the latest developments in cardiac resynchronization therapy. In addition, the most important articles published in the last year are discussed.

  1. Cardiac stem cell therapy and arrhythmogenicity: prometheus and the arrows of Apollo and Artemis.

    Science.gov (United States)

    Lyon, Alexander R; Harding, Sian E; Peters, Nicholas S

    2008-09-01

    Cardiac cell therapy is an expanding scientific field which is yielding new insights into the pathogenesis of cardiac disease and offers new therapeutic strategies. Inherent to both these areas of research are the electrical properties of individual cells, the electrical interplay between cardiomyocytes, and their roles in arrhythmogenesis. This review discusses the potential mechanisms by which various candidate cells for cardiac therapy may modulate the ventricular arrhythmic substrate and highlights the data and lessons learnt from the clinical cardiac cell therapy trials published to date. Pro- and antiarrhythmic mechanistic factors are discussed, and the importance of their consideration in the design of any future clinical cell therapy trials.

  2. Biomaterials for cardiac regeneration

    CERN Document Server

    Ruel, Marc

    2015-01-01

    This book offers readers a comprehensive biomaterials-based approach to achieving clinically successful, functionally integrated vasculogenesis and myogenesis in the heart. Coverage is multidisciplinary, including the role of extracellular matrices in cardiac development, whole-heart tissue engineering, imaging the mechanisms and effects of biomaterial-based cardiac regeneration, and autologous bioengineered heart valves. Bringing current knowledge together into a single volume, this book provides a compendium to students and new researchers in the field and constitutes a platform to allow for future developments and collaborative approaches in biomaterials-based regenerative medicine, even beyond cardiac applications. This book also: Provides a valuable overview of the engineering of biomaterials for cardiac regeneration, including coverage of combined biomaterials and stem cells, as well as extracellular matrices Presents readers with multidisciplinary coverage of biomaterials for cardiac repair, including ...

  3. Mathematical cardiac electrophysiology

    CERN Document Server

    Colli Franzone, Piero; Scacchi, Simone

    2014-01-01

    This book covers the main mathematical and numerical models in computational electrocardiology, ranging from microscopic membrane models of cardiac ionic channels to macroscopic bidomain, monodomain, eikonal models and cardiac source representations. These advanced multiscale and nonlinear models describe the cardiac bioelectrical activity from the cell level to the body surface and are employed in both the direct and inverse problems of electrocardiology. The book also covers advanced numerical techniques needed to efficiently carry out large-scale cardiac simulations, including time and space discretizations, decoupling and operator splitting techniques, parallel finite element solvers. These techniques are employed in 3D cardiac simulations illustrating the excitation mechanisms, the anisotropic effects on excitation and repolarization wavefronts, the morphology of electrograms in normal and pathological tissue and some reentry phenomena. The overall aim of the book is to present rigorously the mathematica...

  4. Interplay between cardiac function and heart development.

    Science.gov (United States)

    Andrés-Delgado, Laura; Mercader, Nadia

    2016-07-01

    Mechanotransduction refers to the conversion of mechanical forces into biochemical or electrical signals that initiate structural and functional remodeling in cells and tissues. The heart is a kinetic organ whose form changes considerably during development and disease. This requires cardiomyocytes to be mechanically durable and able to mount coordinated responses to a variety of environmental signals on different time scales, including cardiac pressure loading and electrical and hemodynamic forces. During physiological growth, myocytes, endocardial and epicardial cells have to adaptively remodel to these mechanical forces. Here we review some of the recent advances in the understanding of how mechanical forces influence cardiac development, with a focus on fluid flow forces. This article is part of a Special Issue entitled: Cardiomyocyte Biology: Integration of Developmental and Environmental Cues in the Heart edited by Marcus Schaub and Hughes Abriel.

  5. Non-invasive Mapping of Cardiac Arrhythmias.

    Science.gov (United States)

    Shah, Ashok; Hocini, Meleze; Haissaguerre, Michel; Jaïs, Pierre

    2015-08-01

    Since more than 100 years, 12-lead electrocardiography (ECG) is the standard-of-care tool, which involves measuring electrical potentials from limited sites on the body surface to diagnose cardiac disorder, its possible mechanism, and the likely site of origin. Several decades of research has led to the development of a 252-lead ECG and computed tomography (CT) scan-based three-dimensional electro-imaging modality to non-invasively map abnormal cardiac rhythms including fibrillation. These maps provide guidance towards ablative therapy and thereby help advance the management of complex heart rhythm disorders. Here, we describe the clinical experience obtained using non-invasive technique in mapping the electrical disorder and guide the catheter ablation of atrial arrhythmias (premature atrial beat, atrial tachycardia, atrial fibrillation), ventricular arrhythmias (premature ventricular beats), and ventricular pre-excitation (Wolff-Parkinson-White syndrome).

  6. Anion channelrhodopsins for inhibitory cardiac optogenetics

    Science.gov (United States)

    Govorunova, Elena G.; Cunha, Shane R.; Sineshchekov, Oleg A.; Spudich, John L.

    2016-01-01

    Optical control of the heart muscle is a promising strategy for cardiology because it is more specific than traditional electrical stimulation, and allows a higher temporal resolution than pharmacological interventions. Anion channelrhodopsins (ACRs) from cryptophyte algae expressed in cultured neonatal rat ventricular cardiomyocytes produced inhibitory currents at less than one-thousandth of the light intensity required by previously available optogenetic tools, such as the proton pump archaerhodopsin-3 (Arch). Because of their greater photocurrents, ACRs permitted complete inhibition of cardiomyocyte electrical activity under conditions in which Arch was inefficient. Most importantly, ACR expression allowed precisely controlled shortening of the action potential duration by switching on the light during its repolarization phase, which was not possible with previously used optogenetic tools. Optical shortening of cardiac action potentials may benefit pathophysiology research and the development of optogenetic treatments for cardiac disorders such as the long QT syndrome. PMID:27628215

  7. ARP Storm Detection and Prevention Measures

    Directory of Open Access Journals (Sweden)

    S Vidya

    2011-03-01

    Full Text Available The Address Resolution Protocol (ARP is used by computers to map network addresses (IP to physical addresses (MAC. The protocol has proved to work well under regular circumstances, but it was not designed to cope with malicious hosts. By performing ARP storming attacks, an intruder can create Denial of Service (DoS in another host and prevent it's functioning or just cause network slowdowns. Several methods to mitigate, detect and prevent these attacks do exist at the router level and through certain customized software tools. In this paper we propose an algorithm to detect the ARP storm at the local sub network level within the ARP boundary in real-time and in offline mode. In real-time, the software detects dynamically, the IPs from which the ARP storm emanates. The inexpensive and portable software developed can be implemented in SOHOs in each machine in the local network. The attempt was successful and also effective in terms of cost, portability and ease of use. The offline packet analysis software, detects all the possible malicious IPs that are responsible for the ARP storm from among the packets captured in real-time using Wireshark. The proposed method also suggests the means of preventing the ARP storm.

  8. Mathematical modeling of tornadoes and squall storms

    Directory of Open Access Journals (Sweden)

    Sergey A. Arsen’yev

    2011-04-01

    Full Text Available Recent advances in modeling of tornadoes and twisters consist of significant achievements in mathematical calculation of occurrence and evolution of a violent F5-class tornado on the Fujita scale, and four-dimensional mathematical modeling of a tornado with the fourth coordinate time multiplied by its characteristic velocity. Such a tornado can arise in a thunderstorm supercell filled with turbulent whirlwinds. A theory of the squall storms is proposed. The squall storm is modeled by running perturbation of the temperature inversion on the lower boundary of cloudiness. This perturbation is induced by the action of strong, hurricane winds in the upper and middle troposphere, and looks like a running solitary wave (soliton; which is developed also in a field of pressure and velocity of a wind. If a soliton of a squall storm gets into the thunderstorm supercell then this soliton is captured by supercell. It leads to additional pressure fall of air inside a storm supercell and stimulate amplification of wind velocity here. As a result, a cyclostrophic balance inside a storm supercell generates a tornado. Comparison of the radial distribution of wind velocity inside a tornado calculated by using the new formulas and equations with radar observations of the wind velocity inside Texas Tornado Dummit in 1995 and inside the 3 May 1999 Oklahoma City Tornado shows good correspondence.

  9. The Living with a Star Radiation Belt Storm Probes

    Science.gov (United States)

    Sibeck, D. G.; Mauk, B. H.; Grebowsky, J. M.; Fox, N. J.

    2007-01-01

    The goal of NASA's Living With a Star Radiation Belt Storm Probe mission is to understand, ideally to the point of predictability, how populations of relativistic electrons and ions in space form or change in response to the variable inputs of energy from the Sun. The investigations selected for this 2-spacecraft mission scheduled for launch in early 2012 address this task by making extensive observations of the plasma waves, thermal, ring current, and relativistic particle populations, and DC electric and magnetic fields within the Earth's inner and outer radiation belts. We first describe the current mission concept within the scope of NASA's strategic plan and the Vision for Exploration, and then consider how its observations will be used to define and quantify the processes that accelerate, transport, and remove particles in the Earth's radiation belts.

  10. Cardiac tumors: echo assessment.

    Science.gov (United States)

    Mankad, Rekha; Herrmann, Joerg

    2016-12-01

    Cardiac tumors are exceedingly rare (0.001-0.03% in most autopsy series). They can be present anywhere within the heart and can be attached to any surface or be embedded in the myocardium or pericardial space. Signs and symptoms are nonspecific and highly variable related to the localization, size and composition of the cardiac mass. Echocardiography, typically performed for another indication, may be the first imaging modality alerting the clinician to the presence of a cardiac mass. Although echocardiography cannot give the histopathology, certain imaging features and adjunctive tools such as contrast imaging may aid in the differential diagnosis as do the adjunctive clinical data and the following principles: (1) thrombus or vegetations are the most likely etiology, (2) cardiac tumors are mostly secondary and (3) primary cardiac tumors are mostly benign. Although the finding of a cardiac mass on echocardiography may generate confusion, a stepwise approach may serve well practically. Herein, we will review such an approach and the role of echocardiography in the assessment of cardiac masses.

  11. Modeling the ocean effect of geomagnetic storms

    DEFF Research Database (Denmark)

    Olsen, Nils; Kuvshinov, A.

    2004-01-01

    At coastal sites, geomagnetic variations for periods shorter than a few days are strongly distorted by the conductivity of the nearby sea-water. This phenomena, known as the ocean (or coast) effect, is strongest in the magnetic vertical component. We demonstrate the ability to predict the ocean...... effect of geomagnetic storms at geomagnetic observatories. The space-time structure of the storm is derived from the horizontal components at worldwide distributed observatories from which we predict the vertical component using a model of the Earth's conductivity that a) only depends on depth, and b......) includes the conductivity of the sea-water. The results for several strong geomagnetic storms (including the "Bastille Day" event of July 14-15, 2000) show much better agreement (improvement by up to a factor of 2.5) between the observed and the modeled magnetic vertical component at coastal sites...

  12. Pacific Northwest Storms Situation Report # 7

    Energy Technology Data Exchange (ETDEWEB)

    None

    2006-12-21

    Despite a small storm that came through the area last night with wind gusts peaking at 45 MPH, progress continues to be made in restoring power to customers who lost power during the December 14-15 storms which hit the Pacific Northwest region. Currently, 95,971 customers remain without power, down from 1.8 million customers. The wind storm which affected the area yesterday was not as bad as previously expected, with the majority of the customer outages in the BC Hydro region, and 3,000 additional customer outages in the Puget Sound Energy service area. The customers without power represent 5 percent of customers in the affected utility service areas of Washington. The majority of customers without power are served by Puget Sound Energy, BC Hydro, and Seattle City Light.

  13. Dust Storm Moving Near Phoenix Lander

    Science.gov (United States)

    2008-01-01

    This series of images show the movement of several dust storms near NASA's Phoenix Mars Lander. These images were taken by the lander's Surface Stereo Imager (SSI) on the 137th Martian day, or sol, of the mission (Oct. 13, 2008). These images were taken about 50 seconds apart, showing the formation and movement of dust storms for nearly an hour. Phoenix scientists are still figuring out the exact distances these dust storms occurred from the lander, but they estimate them to be about 1 to 2 kilometers (.6 or 1.2 miles) away. The Phoenix Mission is led by the University of Arizona, Tucson, on behalf of NASA. Project management of the mission is by NASA's Jet Propulsion Laboratory, Pasadena, Calif. Spacecraft development is by Lockheed Martin Space Systems, Denver.

  14. Adaptive mesh refinement for storm surge

    KAUST Repository

    Mandli, Kyle T.

    2014-03-01

    An approach to utilizing adaptive mesh refinement algorithms for storm surge modeling is proposed. Currently numerical models exist that can resolve the details of coastal regions but are often too costly to be run in an ensemble forecasting framework without significant computing resources. The application of adaptive mesh refinement algorithms substantially lowers the computational cost of a storm surge model run while retaining much of the desired coastal resolution. The approach presented is implemented in the GeoClaw framework and compared to ADCIRC for Hurricane Ike along with observed tide gauge data and the computational cost of each model run. © 2014 Elsevier Ltd.

  15. Weathering the storm: living with Parkinson's disease.

    Science.gov (United States)

    Hermanns, Melinda

    2011-01-01

    Parkinson's disease (PD), a movement disorder related to dopamine insufficiency in the brain, affects 7 to 10 million people worldwide. Research has focused on etiology and treatment, while research on how patients deal with PD is limited. This ehnographic study explored the illness experience of 14 participants living with PD. The metaphor, "Sailing the Seas in the Eye of the Storm" depicts their experience. Content themes "Daily Negotiations in the Midst of Uncertainty" (the storm) and "Reconstructin of the Self" (the travler's voyage) suggest aspects of holistic care for PD patients.

  16. Adaptive Mesh Refinement for Storm Surge

    CERN Document Server

    Mandli, Kyle T

    2014-01-01

    An approach to utilizing adaptive mesh refinement algorithms for storm surge modeling is proposed. Currently numerical models exist that can resolve the details of coastal regions but are often too costly to be run in an ensemble forecasting framework without significant computing resources. The application of adaptive mesh refinement algorithms substantially lowers the computational cost of a storm surge model run while retaining much of the desired coastal resolution. The approach presented is implemented in the \\geoclaw framework and compared to \\adcirc for Hurricane Ike along with observed tide gauge data and the computational cost of each model run.

  17. CloudSat Profiles Tropical Storm Andrea

    Science.gov (United States)

    2007-01-01

    CloudSat's Cloud Profiling Radar captured a profile across Tropical Storm Andrea on Wednesday, May 9, 2007, near the South Carolina/Georgia/Florida Atlantic coast. The upper image shows an infrared view of Tropical Storm Andrea from the Moderate Resolution Imaging Spectroradiometer instrument on NASA's Aqua satellite, with CloudSat's ground track shown as a red line. The lower image is the vertical cross section of radar reflectivity along this path, where the colors indicate the intensity of the reflected radar energy. CloudSat orbits approximately one minute behind Aqua in a satellite formation known as the A-Train.

  18. An ICD Programming Study for Patients with Electrical Storm after Implantation of Implantable Cardioverter Defib-rillator%除颤器植入患者发生心室电风暴慢室速时参数设置的研究

    Institute of Scientific and Technical Information of China (English)

    王召军; 郑蕾; 陈家亮; 曲秀芬; 李晶洁

    2014-01-01

    目的:探讨植入型心律转复除颤器( implantable cardioverter defibrillator, ICD)植入患者发生心室电风暴慢室性心动过速(慢室速,150~180/min)时合理的ICD工作模式的参数设置。方法对我院ICD植入以心室电风暴慢室速急诊入院的11例常规予抗室速药物治疗,慢室速的治疗工作模式均随机选择抗心动过速起搏( ATP)的短阵快速起搏(BURST)5次后不转复即予体内电击(SHOCK)治疗(B5方案)和BURST 1次后不转复即予低能量SHOCK治疗( S1方案)。 B5方案和S1方案,每种方案工作24 h,然后轮换,观察2周内慢室速总发作次数,B5方案和S1方案的总工作次数、复律成功率、室速治疗开始到成功的时间及患者耐受情况。结果本组共记录188 d,其中B5方案、S1方案各94 d。 ICD共检测到慢室速204次,其中室速监测未治疗(VT-monitored)82次(有3次事件在ATP治疗前自行终止),室速监测并治疗122次(治疗应用B5方案65次,S1方案57次)。住院期间无死亡患者,B5方案和S1方案的转复成功率和SHOCK发生率比较差异无统计学意义(P>0.05),但B5方案总ICD治疗时间较S1方案明显增加(P0. 05), but the treatment time was increased in B5 scheme than that in S1 scheme (P <0. 01). Conclusion Patients with ICD implantation during ventricular electrical storm should be pro-grammed individually. Excessive pursuit of ATP painless therapy may increase the risk of heart failure.

  19. Molecular Basis of Cardiac Myxomas

    Directory of Open Access Journals (Sweden)

    Pooja Singhal

    2014-01-01

    Full Text Available Cardiac tumors are rare, and of these, primary cardiac tumors are even rarer. Metastatic cardiac tumors are about 100 times more common than the primary tumors. About 90% of primary cardiac tumors are benign, and of these the most common are cardiac myxomas. Approximately 12% of primary cardiac tumors are completely asymptomatic while others present with one or more signs and symptoms of the classical triad of hemodynamic changes due to intracardiac obstruction, embolism and nonspecific constitutional symptoms. Echocardiography is highly sensitive and specific in detecting cardiac tumors. Other helpful investigations are chest X-rays, magnetic resonance imaging and computerized tomography scan. Surgical excision is the treatment of choice for primary cardiac tumors and is usually associated with a good prognosis. This review article will focus on the general features of benign cardiac tumors with an emphasis on cardiac myxomas and their molecular basis.

  20. Hybrid Adaptive Filter development for the minimisation of transient fluctuations superimposed on electrotelluric field recordings mainly by magnetic storms

    Directory of Open Access Journals (Sweden)

    A. Konstantaras

    2006-01-01

    Full Text Available The method of Hybrid Adaptive Filtering (HAF aims to recover the recorded electric field signals from anomalies of magnetotelluric origin induced mainly by magnetic storms. An adaptive filter incorporating neuro-fuzzy technology has been developed to remove any significant distortions from the equivalent magnetic field signal, as retrieved from the original electric field signal by reversing the magnetotelluric method. Testing with further unseen data verifies the reliability of the model and demonstrates the effectiveness of the HAF method.

  1. Cardiac Tumors; Tumeurs cardiaques

    Energy Technology Data Exchange (ETDEWEB)

    Laissy, J.P.; Fernandez, P. [Centre Hospitalier Universitaire Bichat Claude Bernard, Service d' Imagerie, 76 - Rouen (France); Mousseaux, E. [Hopital Europeen Georges Pompidou (HEGP), Service de Radiologie Cardio Vasculaire et Interventionnelle, 75 - Paris (France); Dacher, J.N. [Centre Hospitalier Universitaire Charles Nicolle, 75 - Rouen (France); Crochet, D. [Centre Hospitalier Universitaire, Hopital Laennec, Centre Hemodynamique, Radiologie Thoracique et Vasculaire, 44 - Nantes (France)

    2004-04-01

    Metastases are the most frequent tumors of the heart even though they seldom are recognized. Most primary cardiac tumors are benign. The main role of imaging is to differentiate a cardiac tumor from thrombus and rare pseudo-tumors: tuberculoma, hydatid cyst. Echocardiography is the fist line imaging technique to detect cardiac tumors, but CT and MRl arc useful for further characterization and differential diagnosis. Myxoma of the left atrium is the most frequent benign cardiac tumor. It usually is pedunculated and sometimes calcified. Sarcoma is the most frequent primary malignant tumor and usually presents as a sessile infiltrative tumor. Lymphoma and metastases are usually recognized by the presence of known tumor elsewhere of by characteristic direct contiguous involvement. Diagnosing primary and secondary pericardial tumors often is difficult. Imaging is valuable for diagnosis, characterization, pre-surgical evaluation and follow-up. (author)

  2. Socially differentiated cardiac rehabilitation

    DEFF Research Database (Denmark)

    Meillier, Lucette Kirsten; Nielsen, Kirsten Melgaard; Larsen, Finn Breinholt;

    2012-01-01

    to a standard rehabilitation programme (SRP). If patients were identified as socially vulnerable, they were offered an extended version of the rehabilitation programme (ERP). Excluded patients were offered home visits by a cardiac nurse. Concordance principles were used in the individualised programme elements......%. Patients were equally distributed to the SRP and the ERP. No inequality was found in attendance and adherence among referred patients. Conclusions: It seems possible to overcome unequal referral, attendance, and adherence in cardiac rehabilitation by organisation of systematic screening and social......Aim: The comprehensive cardiac rehabilitation (CR) programme after myocardial infarction (MI) improves quality of life and results in reduced cardiac mortality and recurrence of MI. Hospitals worldwide face problems with low participation rates in rehabilitation programmes. Inequality...

  3. A Novel Agent Based Approach for Controlling Network Storms

    CERN Document Server

    Nair, Dr T R Gopalakrishnan; M, Vaidehi

    2011-01-01

    One of the fundamental data transmission mechanisms in Ethernet LAN is broadcasting. Flooding is a direct broadcasting technique used in these networks. A significant drawback of this method is that it can lead to broadcast storms. This phenomenon is more common in multivendor switch environment. Broadcast storms usually results in dissension, collision and redundancy leading to degradation of the network performance. Most of the storms appear without much warning and it affects the efficiency of network even in situations when the network is expected to work most efficiently. There are several characteristic patterns by which storm can appear in a LAN, like rate monotonic repetition, transient appearances with different types of growth properties and decay profiles. In this paper we discuss the storm build up pattern in an industry and present various reasons for storm in LAN. We have identified a strategy for controlling network storms, using multiple static agents. These agents inhibit storm packet regener...

  4. Final Irondale Gulch storm water evaluation : Appendix E

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — Report on the Irondale Gulch Storm Water Evaluation and effects of routing off-site storm water flows through Rocky Mountain Arsenal. Retention facilities for...

  5. Cardiac arrest - cardiopulmonary resuscitation

    Institute of Scientific and Technical Information of China (English)

    Basri Lenjani; Besnik Elshani; Nehat Baftiu; Kelmend Pallaska; Kadir Hyseni; Njazi Gashi; Nexhbedin Karemani; Ilaz Bunjaku; Taxhidin Zaimi; Arianit Jakupi

    2014-01-01

    Objective:To investigate application of cardiopulmonary resuscitation(CPR) measures within the golden minutes inEurope.Methods:The material was taken from theUniversityClinical Center ofKosovo -EmergencyCentre inPristina, during the two(2) year period(2010-2011).The collected date belong to the patients with cardiac arrest have been recorded in the patients' log book protocol at the emergency clinic.Results:During the2010 to2011 in the emergency center of theCUCK inPristina have been treated a total of269 patients with cardiac arrest, of whom159 or59.1% have been treated in2010, and110 patients or40.9% in2011.Of the269 patients treated in the emergency centre,93 or34.6% have exited lethally in the emergency centre, and176 or 65.4% have been transferred to other clinics.In the total number of patients with cardiac arrest, males have dominated with186 cases, or69.1%.The average age of patients included in the survey was56.7 year oldSD±16.0 years.Of the269 patients with cardiac arrest, defibrillation has been applied for93 or34.6% of patients.In the outpatient settings defibrillation has been applied for3 or3.2% of patients.Patients were defibrillated with application of one to four shocks. Of27 cases with who have survived cardiac arrest, none of them have suffered cardiac arrest at home,3 or11.1% of them have suffered cardiac arrest on the street, and24 or88.9% of them have suffered cardiac arrest in the hospital.5 out of27 patients survived have ended with neurological impairment.Cardiac arrest cases were present during all days of the week, but frequently most reported cases have been onMonday with32.0% of cases, and onFriday with24.5% of cases. Conclusions:All survivors from cardiac arrest have received appropriate medical assistance within10 min from attack, which implies that if cardiac arrest occurs near an institution health care(with an opportunity to provide the emergent health care) the rate of survival is higher.

  6. Gold nanoparticle-decellularized matrix hybrids for cardiac tissue engineering.

    Science.gov (United States)

    Shevach, Michal; Fleischer, Sharon; Shapira, Assaf; Dvir, Tal

    2014-10-01

    Decellularized matrices are valuable scaffolds for engineering functional cardiac patches for treating myocardial infarction. However, the lack of quick and efficient electrical coupling between adjacent cells may jeopardize the success of the treatment. To address this issue, we have deposited gold nanoparticles on fibrous decellularized omental matrices and investigated their morphology, conductivity, and degradation. We have shown that cardiac cells engineered within the hybrid scaffolds exhibited elongated and aligned morphology, massive striation, and organized connexin 43 electrical coupling proteins. Finally, we have shown that the hybrid patches demonstrated superior function as compared to pristine patches, including a stronger contraction force, lower excitation threshold, and faster calcium transients.

  7. Cardiac imaging in adults

    Energy Technology Data Exchange (ETDEWEB)

    Jaffe, C.C.

    1987-01-01

    This book approaches adult cardiac disease from the correlative imaging perspective. It includes chest X-rays and angiographs, 2-dimensional echocardiograms with explanatory diagrams for clarity, plus details on digital radiology, nuclear medicine techniques, CT and MRI. It also covers the normal heart, valvular heart disease, myocardial disease, pericardial disease, bacterial endocarditis, aortic aneurysm, cardiac tumors, and congenital heart disease of the adult. It points out those aspects where one imaging technique has significant superiority.

  8. Port Access Cardiac Surgery.

    Science.gov (United States)

    Viganó, Mario; Minzioni, Gaetano; Spreafico, Patrizio; Rinaldi, Mauro; Pasquino, Stefano; Ceriana, Piero; Locatelli, Alessandro

    2000-10-01

    The port-access technique for cardiac surgery was recently developed at Stanford University in California as a less invasive method to perform some cardiac operations. The port-access system has been described in detail elsewhere. It is based on femoral arterial and venous access for cardiopulmonary bypass (CPB) and on the adoption of a specially designed triple-lumen catheter described originally by Peters, and subsequently modified and developed in the definitive configuration called the endoaortic clamp.

  9. Awareness in cardiac anesthesia.

    LENUS (Irish Health Repository)

    Serfontein, Leon

    2010-02-01

    Cardiac surgery represents a sub-group of patients at significantly increased risk of intraoperative awareness. Relatively few recent publications have targeted the topic of awareness in this group. The aim of this review is to identify areas of awareness research that may equally be extrapolated to cardiac anesthesia in the attempt to increase understanding of the nature and significance of this scenario and how to reduce it.

  10. Post cardiac injury syndrome

    DEFF Research Database (Denmark)

    Nielsen, S L; Nielsen, F E

    1991-01-01

    The post-pericardiotomy syndrome is a symptom complex which is similar in many respects to the post-myocardial infarction syndrome and these are summarized under the diagnosis of the Post Cardiac Injury Syndrome (PCIS). This condition, which is observed most frequently after open heart surgery, i...... on the coronary vessels, with cardiac tamponade and chronic pericardial exudate. In the lighter cases, PCIS may be treated with NSAID and, in the more severe cases, with systemic glucocorticoid which has a prompt effect....

  11. Autonomic cardiac innervation

    OpenAIRE

    Hasan, Wohaib

    2013-01-01

    Autonomic cardiac neurons have a common origin in the neural crest but undergo distinct developmental differentiation as they mature toward their adult phenotype. Progenitor cells respond to repulsive cues during migration, followed by differentiation cues from paracrine sources that promote neurochemistry and differentiation. When autonomic axons start to innervate cardiac tissue, neurotrophic factors from vascular tissue are essential for maintenance of neurons before they reach their targe...

  12. Infected cardiac hydatid cyst

    OpenAIRE

    Ceviz, M; Becit, N; Kocak, H.

    2001-01-01

    A 24 year old woman presented with chest pain and palpitation. The presence of a semisolid mass—an echinococcal cyst or tumour—in the left ventricular apex was diagnosed by echocardiography, computed tomography, and magnetic resonance imaging. The infected cyst was seen at surgery. The cyst was removed successfully by using cardiopulmonary bypass with cross clamp.


Keywords: cardiac hydatid cyst; infected cardiac hydatid cyst

  13. An electrified dust storm over the Negev desert, Israel

    Science.gov (United States)

    Yair, Yoav; Katz, Shai; Yaniv, Roy; Ziv, Baruch; Price, Colin

    2016-11-01

    We report on atmospheric electrical measurements conducted at the Wise Observatory in Mitzpe-Ramon, Israel (30°35‧N, 34°45‧E) during a large dust storm that occurred over the Eastern Mediterranean region on 10-11 February 2015. The dust was transported from the Sahara, Egypt and the Sinai Peninsula ahead of an approaching Cyprus low. Satellite images show the dust plume covering the Negev desert and Southern Israel and moving north. The concentrations of PM10 particles measured by the air-quality monitoring network of the Israeli Ministry of the Environment in Beer-Sheba reached values > 450 μg m- 3 and the AOT from the AERONET station in Sde-Boker was 1.5 on February 10th. The gradual intensification of the event reached peak concentrations on February 11th of over 1200 μg m- 3 and an AOT of 1.8. Continuous measurements of the fair weather vertical electric field (Ez) and vertical current density (Jz) were conducted at the Wise Observatory with 1 minute temporal resolution. Meteorological data was also recorded at the site. As the dust was advected over the observatory, very large fluctuations in the electrical parameters were registered. From the onset of the dust storm, the Ez values changed between + 1000 and + 8000 V m- 1 while the current density fluctuated between - 10 pA m2 and + 20 pA m2, both on time-scales of a few minutes. These values are significant departures from the average fair-weather values measured at the site, which are ~- 200 V m- 1 and ~ 2 pA m2. The disturbed episodes lasted for several hours on February 10th and the 11th and coincided with local meteorological conditions related to the wind speed and direction, which carried large amounts of dust particles over our observation station. We interpret the rapid changes as caused by the transport of electrically charged dust, carrying an excess of negative charge at lower altitudes.

  14. 3-D Storm Automatic Identification Based on Mathematical Morphology

    Institute of Scientific and Technical Information of China (English)

    HAN Lei; ZHENG Yongguang; WANG Hongqing; LIN Yinjing

    2009-01-01

    The strom identification, tracking, and forecasting method is one of the important nowcasting techniques. Accurate storm identification is a prerequisite for successful storm tracking and forecasting. Storm identi-fication faces two difficulties: one is false merger and the other is failure to isolate adjacent storms within a cluster of storms. The TITAN (Thunderstorm Identification, Tracking, Analysis, and Nowcasting) algo-rithm is apt to identify adjacent storm cells as one storm because it uses a single refiectivity threshold. The SCIT (Storm Cell Identification and Tracking) algorithm uses seven reflectivity thresholds and therefore is capable of isolating adjacent storm cells, but it discards the results identified by the lower threshold, leading to the loss of the internal structure information of storms. Both TITAN and SCIT have the problem of failing to satisfactorily identify false merger. To overcome these shortcomings, this paper proposes a novel approach based on mathematical morphology. The approach first applies the single threshold identification followed by implementing an erosion process to mitigate the false merger problem. During multi-threshold identification stages, dilation operation is performed against the storm cells which are just obtained by the higher threshold identification, until the storm edges touch each other or touch the edges of the previous storms identified by the lower threshold. The results of experiment show that by combining the strengths of the dilation and erosion operations, this approach is able to mitigate the false merger problem as well as maintain the internal structure of sub-storms when isolating storms within a cluster of storms.

  15. STORM WATER MANAGEMENT MODEL (SWMM) MODERNIZATION

    Science.gov (United States)

    The U.S. Environmental Protection Agency's Water Supply and Water Resources Division in partnership with the consulting firm of CDM to redevelop and modernize the Storm Water Management Model (SWMM). In the initial phase of this project EPA rewrote SWMM's computational engine usi...

  16. Storm impacts on small barrier islands

    DEFF Research Database (Denmark)

    Kroon, Aart; Fruergaard, Mikkel

    The shorelines of the Baltic Sea and the inner coastal waters in Denmark consist of many barrier islands. These sandy barrier islands were mainly formed in the Holocene and are still very dynamic. The present day changes in the morphology are dominantly governed by storm waves and associated high...

  17. The structure of solar radio noise storms

    CERN Document Server

    Mercier, Claude; Chambe, Gilbert; Janardhan, P

    2014-01-01

    The Nan\\c{c}ay Radioheliograph (NRH) routinely produces snapshot images of the full sun at frequencies between 150 and 450 MHz, with typical resolution 3 arcmin and time cadence 0.2 s. Combining visibilities from the NRH and from the Giant Meterwave Radio Telescope (GMRT) allows us to produce images of the sun at 236 or 327 MHz, with a large FOV, high resolution and time cadence. We seek to investigate the structure of noise storms (the most common non-thermal solar radio emission). We focus on the relation of position and altitude of noise storms with the observing frequency and on the lower limit of their sizes. We present results for noise storms on four days. The results consist of an extended halo and of one or several compact cores with relative intensity changing over a few seconds. We found that core sizes can be almost stable over one hour, with a minimum in the range 31-35 arcsec (less than previously reported) and can be stable over one hour. The heliocentric distances of noise storms are $\\sim 1.2...

  18. Storm disturbance in forest ecosystems in Estonia

    NARCIS (Netherlands)

    Ilisson, T.; Metslaid, M.; Vodde, F.; Jogiste, K.; Kurm, M.

    2005-01-01

    Several storms have damaged Estonian forests in recent years. Individual tree properties such as diameter at breast height (dbh) and tree height affect the type of damage (stem breakage or uprooting) and influence the formation of postdisturbance forest structure. The aim of this study was to analys

  19. Tornadic storm avoidance behavior in breeding songbirds.

    Science.gov (United States)

    Streby, Henry M; Kramer, Gunnar R; Peterson, Sean M; Lehman, Justin A; Buehler, David A; Andersen, David E

    2015-01-05

    Migration is a common behavior used by animals of many taxa to occupy different habitats during different periods. Migrant birds are categorized as either facultative (i.e., those that are forced to migrate by some proximal cue, often weather) or obligate (i.e., those that migrate on a regular cycle). During migration, obligate migrants can curtail or delay flights in response to inclement weather or until favorable winds prevail, and they can temporarily reorient or reverse direction when ecological or meteorological obstacles are encountered. However, it is not known whether obligate migrants undertake facultative migrations and make large-scale movements in response to proximal cues outside of their regular migration periods. Here, we present the first documentation of obligate long-distance migrant birds undertaking a facultative migration, wherein breeding golden-winged warblers (Vermivora chrysoptera) carrying light-level geolocators performed a >1,500 km 5-day circumvention of a severe tornadic storm. The birds evacuated their breeding territories >24 hr before the arrival of the storm and atmospheric variation associated with it. The probable cue, radiating >1,000 km from tornadic storms, perceived by birds and influencing bird behavior and movements, is infrasound (i.e., sound below the range of human hearing). With the predicted increase in severity and frequency of similar storms as anthropogenic climate change progresses, understanding large-scale behavioral responses of animals to such events will be an important objective of future research.

  20. A review of major storm impacts on coastal wetland elevations

    Science.gov (United States)

    Cahoon, D.R.

    2006-01-01

    Storms have long been recognized as agents of geomorphic change to coastal wetlands. A review of recent data on soil elevation dynamics before and after storms revealed that storms affected wetland elevations by storm surge, high winds, and freshwater flushing of the estuary (inferred). The data also indicate that measures of sediment deposition and erosion can often misrepresent the amount and even direction of elevation change because of storm influences on subsurface processes. Simultaneous influence on both surface and subsurface processes by storms means that soil elevation cannot always be accurately estimated from surface process data alone. Eight processes are identified as potentiatly influencing soil elevation: sediment deposition, sediment erosion, sediment compaction, soil shrinkage, root decomposition (following tree mortality from high winds), root growth (following flushing with freshwater, inferred), soil swelling, and lateral folding of the marsh root mat. Local wetland conditions (e.g., marsh health, tide height, groundwater level) and the physical characteristics of the storm (e.g., angle of approach, proximity, amount of rain, wind speed, and storm surge height) were apparently important factors determining the storm's effect on soil elevation. Storm effects on elevation were both permanent (on an ecological time scale) and short-lived, but even short-term changes have potentially important ecological consequences. Shallow soil subsidence or expansion caused by a storm must be considered when calculating local rates of relative sea level rise and evaluating storm effects on wetland stability.

  1. Storm-time Distortion of the Near Magnetosphere as Revealed by Data-Based Models

    Science.gov (United States)

    Sitnov, M. I.; Tsyganenko, N. A.

    2007-05-01

    electric current systems at different phases of a storm. During the main phase, the current distribution has an interesting, highly deformed `hook-like' shape, which has virtually nothing to do with a traditional notion of a closed ring current. In contrast, at the recovery phase the model reveals an almost completely axisymmetric smooth pattern, without any distinct boundary between the ring and tail currents. We will also discuss the use of the empirical dynamical models of the geomagnetic field for calculations of the inductive storm-time electric fields in the inner magnetosphere [Ukhorskiy et al., 2006].

  2. Evolution of the magnetospheric storm-ring current with a constant time delay

    Energy Technology Data Exchange (ETDEWEB)

    Cluadegonzalez, A.L.; Gonzalez, W.D.; Detman, T.R.; Joselyn, J.A. [National Oceanic and Atmospheric Administration, Boulder, CO (United States)

    1994-01-01

    Using the energy balance equation for the ring current during magnetic storms, a theoretical study of the response of this current is done, for the case of a constant time decay tau. The input energy function for the balance equation is assumed to be described by a simple time variation during the injection time, such that an analytical response can be obtained. The model is used for 5 of the 10 intense storms in the interval August 1978-December 1979, for which the ISEE-3 interplanetary data are available. The energy input function for these 5 events (those with less data gaps) is assumed to be one of both, the azimuthal interplanetary electric field or the Akasofu`s coupling function. These input functions are approximated by one of the simple mentioned input functions and the solution obtained from the energy balance equation, for different values of tau, is compared to the actual evolution of the ring current (derived from the geomagnetic index Dst). The sets of input functions and tau values that better reproduce the observed storm evolution are adopted as the best approximation. As a conclusion, it is found that the more appropriate values of tau are longer than those determined in previous studies, especially for the case of more intense storms.

  3. Modular assembly of thick multifunctional cardiac patches

    Science.gov (United States)

    Fleischer, Sharon; Shapira, Assaf; Feiner, Ron; Dvir, Tal

    2017-01-01

    In cardiac tissue engineering cells are seeded within porous biomaterial scaffolds to create functional cardiac patches. Here, we report on a bottom-up approach to assemble a modular tissue consisting of multiple layers with distinct structures and functions. Albumin electrospun fiber scaffolds were laser-patterned to create microgrooves for engineering aligned cardiac tissues exhibiting anisotropic electrical signal propagation. Microchannels were patterned within the scaffolds and seeded with endothelial cells to form closed lumens. Moreover, cage-like structures were patterned within the scaffolds and accommodated poly(lactic-co-glycolic acid) (PLGA) microparticulate systems that controlled the release of VEGF, which promotes vascularization, or dexamethasone, an anti-inflammatory agent. The structure, morphology, and function of each layer were characterized, and the tissue layers were grown separately in their optimal conditions. Before transplantation the tissue and microparticulate layers were integrated by an ECM-based biological glue to form thick 3D cardiac patches. Finally, the patches were transplanted in rats, and their vascularization was assessed. Because of the simple modularity of this approach, we believe that it could be used in the future to assemble other multicellular, thick, 3D, functional tissues. PMID:28167795

  4. [Psychosomatic aspects of cardiac arrhythmias].

    Science.gov (United States)

    Siepmann, Martin; Kirch, Wilhelm

    2010-07-01

    Emotional stress facilitates the occurrence of cardiac arrhythmias including sudden cardiac death. The prevalence of anxiety and depression is increased in cardiac patients as compared to the normal population. The risk of cardiovascular mortality is enhanced in patients suffering from depression. Comorbid anxiety disorders worsen the course of cardiac arrhythmias. Disturbance of neurocardiac regulation with predominance of the sympathetic tone is hypothesized to be causative for this. The emotional reaction to cardiac arrhythmias is differing to a large extent between individuals. Emotional stress may result from coping with treatment of cardiac arrhythmias. Emotional stress and cardiac arrhythmias may influence each other in the sense of a vicious circle. Somatoform cardiac arrhythmias are predominantly of psychogenic origin. Instrumental measures and frequent contacts between physicians and patients may facilitate disease chronification. The present review is dealing with the multifaceted relationships between cardiac arrhythmias and emotional stress. The underlying mechanisms and corresponding treatment modalities are discussed.

  5. Generation of cardiac pacemaker cells by programming and differentiation.

    Science.gov (United States)

    Husse, Britta; Franz, Wolfgang-Michael

    2016-07-01

    A number of diseases are caused by faulty function of the cardiac pacemaker and described as "sick sinus syndrome". The medical treatment of sick sinus syndrome with electrical pacemaker implants in the diseased heart includes risks. These problems may be overcome via "biological pacemaker" derived from different adult cardiac cells or pluripotent stem cells. The generation of cardiac pacemaker cells requires the understanding of the pacing automaticity. Two characteristic phenomena the "membrane-clock" and the "Ca(2+)-clock" are responsible for the modulation of the pacemaker activity. Processes in the "membrane-clock" generating the spontaneous pacemaker firing are based on the voltage-sensitive membrane ion channel activity starting with slow diastolic depolarization and discharging in the action potential. The influence of the intracellular Ca(2+) modulating the pacemaker activity is characterized by the "Ca(2+)-clock". The generation of pacemaker cells started with the reprogramming of adult cardiac cells by targeted induction of one pacemaker function like HCN1-4 overexpression and enclosed in an activation of single pacemaker specific transcription factors. Reprogramming of adult cardiac cells with the transcription factor Tbx18 created cardiac cells with characteristic features of cardiac pacemaker cells. Another key transcription factor is Tbx3 specifically expressed in the cardiac conduction system including the sinoatrial node and sufficient for the induction of the cardiac pacemaker gene program. For a successful cell therapeutic practice, the generated cells should have all regulating mechanisms of cardiac pacemaker cells. Otherwise, the generated pacemaker cells serve only as investigating model for the fundamental research or as drug testing model for new antiarrhythmics. This article is part of a Special Issue entitled: Cardiomyocyte Biology: Integration of Developmental and Environmental Cues in the Heart edited by Marcus Schaub and Hughes Abriel.

  6. Dependence of efficiency of magnetic storm generation on the types of interplanetary drivers.

    Science.gov (United States)

    Yermolaev, Yuri; Nikolaeva, Nadezhda; Lodkina, Irina

    2015-04-01

    To compare the coupling coefficients between the solar-wind electric field Ey and Dst (and corrected Dst*) index during the magnetic storms generated by different types of interplanetary drivers, we use the Kyoto Dst-index data, the OMNI data of solar wind plasma and magnetic field measurements, and our "Catalog of large scale phenomena during 1976-2000" (published in [1] and presented on websites: ftp://ftp.iki.rssi.ru/pub/omni/). Both indexes at the main phase of magnetic storms are approximated by the linear dependence on the following solar wind parameters: integrated electric field of solar wind (sumEy), solar wind dynamic pressure (Pd), and the level of magnetic field fluctuations (sB), and the fitting coefficients are determined by the technique of least squares. We present the results of the main phase modelling for magnetic storms with Dst<-50 nT induced by 4 types of the solar wind streams: MC (10 events), CIR (41), Sheath (26), Ejecta (45). Our analysis [2, 3] shows that the coefficients of coupling between Dst and Dst* indexes and integral electric field are significantly higher for Sheath (for Dst*and Dst they are -3.4 and -3.3 nT/V m-1 h, respectively) and CIR (-3.0 and -2.8) than for MC (-2.0 and -2.5) and Ejecta (-2.1 and -2.3). Thus we obtained additional confirmation of experimental fact that Sheath and CIR have higher efficiency in generation of magnetic storms than MC and Ejecta. This work was supported by the RFBR, project 13-02-00158a, and by the Program 9 of Presidium of Russian Academy of Sciences. References 1. Yu. I. Yermolaev, N. S. Nikolaeva, I. G. Lodkina, and M. Yu. Yermolaev, Catalog of Large-Scale Solar Wind Phenomena during 1976-2000, Cosmic Research, 2009, Vol. 47, No. 2, pp. 81-94. 2. N.S. Nikolaeva, Yu.I. Yermolaev, I.G. Lodkina, Modeling of Dst-index temporal profile on the main phase of the magnetic storms generated by different types of solar wind, Cosmic Research, 2013, Vol. 51, No. 6, pp. 401-412 3. Nikolaeva N.S., Yermolaev

  7. Overview of the ARkStorm scenario

    Science.gov (United States)

    Porter, Keith; Wein, Anne; Alpers, Charles; Baez, Allan; Barnard, Patrick L.; Carter, James; Corsi, Alessandra; Costner, James; Cox, Dale; Das, Tapash; Dettinger, Mike; Done, James; Eadie, Charles; Eymann, Marcia; Ferris, Justin; Gunturi, Prasad; Hughes, Mimi; Jarrett, Robert; Johnson, Laurie; Le-Griffin, Hanh Dam; Mitchell, David; Morman, Suzette; Neiman, Paul; Olsen, Anna; Perry, Suzanne; Plumlee, Geoffrey; Ralph, Martin; Reynolds, David; Rose, Adam; Schaefer, Kathleen; Serakos, Julie; Siembieda, William; Stock, Jonathan; Strong, David; Wing, Ian Sue; Tang, Alex; Thomas, Pete; Topping, Ken; Wills, Chris; Jones, Lucile

    2011-01-01

    The U.S. Geological Survey, Multi Hazards Demonstration Project (MHDP) uses hazards science to improve resiliency of communities to natural disasters including earthquakes, tsunamis, wildfires, landslides, floods and coastal erosion. The project engages emergency planners, businesses, universities, government agencies, and others in preparing for major natural disasters. The project also helps to set research goals and provides decision-making information for loss reduction and improved resiliency. The first public product of the MHDP was the ShakeOut Earthquake Scenario published in May 2008. This detailed depiction of a hypothetical magnitude 7.8 earthquake on the San Andreas Fault in southern California served as the centerpiece of the largest earthquake drill in United States history, involving over 5,000 emergency responders and the participation of over 5.5 million citizens. This document summarizes the next major public project for MHDP, a winter storm scenario called ARkStorm (for Atmospheric River 1,000). Experts have designed a large, scientifically realistic meteorological event followed by an examination of the secondary hazards (for example, landslides and flooding), physical damages to the built environment, and social and economic consequences. The hypothetical storm depicted here would strike the U.S. West Coast and be similar to the intense California winter storms of 1861 and 1862 that left the central valley of California impassible. The storm is estimated to produce precipitation that in many places exceeds levels only experienced on average once every 500 to 1,000 years. Extensive flooding results. In many cases flooding overwhelms the state's flood-protection system, which is typically designed to resist 100- to 200-year runoffs. The Central Valley experiences hypothetical flooding 300 miles long and 20 or more miles wide. Serious flooding also occurs in Orange County, Los Angeles County, San Diego, the San Francisco Bay area, and other

  8. Microwave Treatment for Cardiac Arrhythmias

    Science.gov (United States)

    Hernandez-Moya, Sonia

    2009-01-01

    NASA seeks to transfer the NASA developed microwave ablation technology, designed for the treatment of ventricular tachycardia (irregular heart beat), to industry. After a heart attack, many cells surrounding the resulting scar continue to live but are abnormal electrically; they may conduct impulses unusually slowly or fire when they would typically be silent. These diseased areas might disturb smooth signaling by forming a reentrant circuit in the muscle. The objective of microwave ablation is to heat and kill these diseased cells to restore appropriate electrical activity in the heart. This technology is a method and apparatus that provides for propagating microwave energy into heart tissues to produce a desired temperature profile therein at tissue depths sufficient for thermally ablating arrhythmogenic cardiac tissue while preventing excessive heating of surrounding tissues, organs, and blood. A wide bandwidth double-disk antenna is effective for this purpose over a bandwidth of about six gigahertz. A computer simulation provides initial screening capabilities for an antenna such as antenna, frequency, power level, and power application duration. The simulation also allows optimization of techniques for specific patients or conditions. In comparison with other methods that involve direct-current pulses or radio frequencies below 1 GHz, this method may prove more effective in treating ventricular tachycardia. This is because the present method provides for greater control of the location, cross-sectional area, and depth of a lesion via selection of the location and design of the antenna and the choice of microwave power and frequency.

  9. Cardiac radiology: centenary review.

    Science.gov (United States)

    de Roos, Albert; Higgins, Charles B

    2014-11-01

    During the past century, cardiac imaging technologies have revolutionized the diagnosis and treatment of acquired and congenital heart disease. Many important contributions to the field of cardiac imaging were initially reported in Radiology. The field developed from the early stages of cardiac imaging, including the use of coronary x-ray angiography and roentgen kymography, to nowadays the widely used echocardiographic, nuclear medicine, cardiac computed tomographic (CT), and magnetic resonance (MR) applications. It is surprising how many of these techniques were not recognized for their potential during their early inception. Some techniques were described in the literature but required many years to enter the clinical arena and presently continue to expand in terms of clinical application. The application of various CT and MR contrast agents for the diagnosis of myocardial ischemia is a case in point, as the utility of contrast agents continues to expand the noninvasive characterization of myocardium. The history of cardiac imaging has included a continuous process of advances in our understanding of the anatomy and physiology of the cardiovascular system, along with advances in imaging technology that continue to the present day.

  10. Driving Plasmaspheric Electron Density Simulations During Geomagnetic Storms

    Science.gov (United States)

    De Pascuale, S.; Kletzing, C.; Jordanova, V.; Goldstein, J.; Wygant, J. R.; Thaller, S. A.

    2015-12-01

    We test global convection electric field models driving plasmaspheric electron density simulations (RAM-CPL) during geomagnetic storms with in situ measurements provided by the Van Allen Probes (RBSP). RAM-CPL is the cold plasma component of the ring-current atmosphere interactions suite (RAM-SCB) and describes the evolution of plasma density in the magnetic equatorial plane near Earth. Geomagnetic events observed by the RBSP satellites in different magnetic local time (MLT) sectors enable a comparison of local asymmetries in the input electric field and output densities of these simulations. Using a fluid MHD approach, RAM-CPL reproduces core plasmaspheric densities (L<4) to less than 1 order of magnitude difference. Approximately 80% of plasmapause crossings, defined by a low-density threshold, are reproduced to within a mean radial difference of 0.6 L. RAM-CPL, in conjunction with a best-fit driver, can be used in other studies as an asset to predict density conditions in locations distant from RBSP orbits of interest.

  11. Earlier vegetation green-up has reduced spring dust storms.

    Science.gov (United States)

    Fan, Bihang; Guo, Li; Li, Ning; Chen, Jin; Lin, Henry; Zhang, Xiaoyang; Shen, Miaogen; Rao, Yuhan; Wang, Cong; Ma, Lei

    2014-01-01

    The observed decline of spring dust storms in Northeast Asia since the 1950s has been attributed to surface wind stilling. However, spring vegetation growth could also restrain dust storms through accumulating aboveground biomass and increasing surface roughness. To investigate the impacts of vegetation spring growth on dust storms, we examine the relationships between recorded spring dust storm outbreaks and satellite-derived vegetation green-up date in Inner Mongolia, Northern China from 1982 to 2008. We find a significant dampening effect of advanced vegetation growth on spring dust storms (r = 0.49, p = 0.01), with a one-day earlier green-up date corresponding to a decrease in annual spring dust storm outbreaks by 3%. Moreover, the higher correlation (r = 0.55, p green-up date and dust storm outbreak ratio (the ratio of dust storm outbreaks to times of strong wind events) indicates that such effect is independent of changes in surface wind. Spatially, a negative correlation is detected between areas with advanced green-up dates and regional annual spring dust storms (r = -0.49, p = 0.01). This new insight is valuable for understanding dust storms dynamics under the changing climate. Our findings suggest that dust storms in Inner Mongolia will be further mitigated by the projected earlier vegetation green-up in the warming world.

  12. Ionosphere data assimilation modeling of 2015 St. Patrick's Day geomagnetic storm

    Science.gov (United States)

    Chen, C. H.; Lin, C. H.; Matsuo, T.; Chen, W. H.

    2016-11-01

    The ionospheric plasma disturbances during a severe storm can affect human activities and systems, such as navigation and HF communication systems. Therefore, the forecast of ionospheric electron density is becoming an important topic recently. This study is conducted with the ionospheric assimilation model by assimilating the total electron content observations into the thermosphere-ionosphere coupling model with different high-latitude ionospheric convection models, Heelis and Weimer, and further to forecast the variations of ionospheric electron density during the 2015 St. Patrick's Day geomagnetic storm. The forecast capabilities of these two assimilation models are evaluated by the root-mean-square error values in different regions to discuss its latitudinal effects. Results show the better forecast in the electron density at the low-latitude region during the storm main phase and the recovery phase. The well reproduced eastward electric field at the low-latitude region by the assimilation model reveals that the electric fields may be an important factor to have the contributions on the accuracy of ionospheric forecast.

  13. Whether duration of the recovery phase of magnetic storm depends on the development rate of storm at its main phase?

    CERN Document Server

    Yermolaev, Yuri I

    2014-01-01

    We compare dependences between the storm development rate $|Dst_{min}|/\\Delta T$ ($\\Delta T$ is the durations of main phase) and the duration of recovery phase of magnetic storms generated by three various types of interplanetary drivers: (1, 2) compression regions CIR and Sheath, and (3) body of interplanetary CME (magnetic clouds and Ejecta). Our analyze shows that the duration of recovery phase correlates with the storm development rate for CIR- and Sheath-induced storms, and does not correlate for ICME- induced storms.

  14. Pediatric cardiac postoperative care

    Directory of Open Access Journals (Sweden)

    Auler Jr. José Otávio Costa

    2002-01-01

    Full Text Available The Heart Institute of the University of São Paulo, Medical School is a referral center for the treatment of congenital heart diseases of neonates and infants. In the recent years, the excellent surgical results obtained in our institution may be in part due to modern anesthetic care and to postoperative care based on well-structured protocols. The purpose of this article is to review unique aspects of neonate cardiovascular physiology, the impact of extracorporeal circulation on postoperative evolution, and the prescription for pharmacological support of acute cardiac dysfunction based on our cardiac unit protocols. The main causes of low cardiac output after surgical correction of heart congenital disease are reviewed, and methods of treatment and support are proposed as derived from the relevant literature and our protocols.

  15. Comprehensive cardiac rehabilitation

    DEFF Research Database (Denmark)

    Kruse, Marie; Hochstrasser, Stefan; Zwisler, Ann-Dorthe O;

    2006-01-01

    OBJECTIVES: The costs of comprehensive cardiac rehabilitation are established and compared to the corresponding costs of usual care. The effect on health-related quality of life is analyzed. METHODS: An unprecedented and very detailed cost assessment was carried out, as no guidelines existed...... for the situation at hand. Due to challenging circumstances, the cost assessment turned out to be ex-post and top-down. RESULTS: Cost per treatment sequence is estimated to be approximately euro 976, whereas the incremental cost (compared with usual care) is approximately euro 682. The cost estimate is uncertain...... and may be as high as euro 1.877. CONCLUSIONS: Comprehensive cardiac rehabilitation is more costly than usual care, and the higher costs are not outweighed by a quality of life gain. Comprehensive cardiac rehabilitation is, therefore, not cost-effective....

  16. Toothache of cardiac origin.

    Science.gov (United States)

    Kreiner, M; Okeson, J P

    1999-01-01

    Pain referred to the orofacial structures can sometimes be a diagnostic challenge for the clinician. In some instances, a patient may complain of tooth pain that is completely unrelated to any dental source. This poses a diagnostic and therapeutic problem for the dentist. Cardiac pain most commonly radiates to the left arm, shoulder, neck, and face. In rare instances, angina pectoris may present as dental pain. When this occurs, an improper diagnosis frequently leads to unnecessary dental treatment or, more significantly, a delay of proper treatment. This delay may result in the patient experiencing an acute myocardial infarction. It is the dentist's responsibility to establish a proper diagnosis so that the treatment will be directed toward the source of pain and not to the site of pain. This article reviews the literature concerning referred pain of cardiac origin and presents a case report of toothache of cardiac origin.

  17. Dynamics of wave fronts and filaments in anisotropic cardiac tissue

    CERN Document Server

    Dierckx, Hans J F M

    2015-01-01

    The heartbeat is mediated between cardiac cells by waves of electrical depolarisation. During cardiac arrhythmias, electrical activity was found to be organised in scroll waves which rotate around a dynamical filament curve. In this thesis, a curved-space approach is used to mathematically capture anisotropy of wave propagation. We derive for the first time the covariant laws of motion for traveling wave fronts and scroll wave filaments in anisotropic excitable media such as cardiac tissue. We show that locally varying anisotropy yields non-zero Riemann tensor components, which may alter the stability of scroll wave filaments. The instability of scroll wave filaments has been linked to transition from ventricular tachycardia to fibrillation.

  18. The cardiac anxiety questionnaire: cross-validation among cardiac inpatients

    NARCIS (Netherlands)

    Beek, M.H. van; Oude Voshaar, R.C.; Deelen, F.M. van; Balkom, A.J. van; Pop, G.A.; Speckens, A.E.

    2012-01-01

    OBJECTIVE: General anxiety symptoms are common in patients with cardiac disease and considered to have an adverse effect on cardiac prognosis. The role of specific cardiac anxiety, however, is still unknown. The aim of this study is to examine the factor structure, reliability, and validity of the D

  19. THE CARDIAC ANXIETY QUESTIONNAIRE : CROSS-VALIDATION AMONG CARDIAC INPATIENTS

    NARCIS (Netherlands)

    van Beek, M. H. C. T.; Voshaar, R. C. Oude; van Deelen, F. M.; van Balkom, A. J. L. M.; Pop, G.; Speckens, A. E. M.

    2012-01-01

    Objective: General anxiety symptoms are common in patients with cardiac disease and considered to have an adverse effect on cardiac prognosis. The role of specific cardiac anxiety, however, is still unknown. The aim of this study is to examine the factor structure, reliability, and validity of the D

  20. Mapping cardiac fiber orientations from high-resolution DTI to high-frequency 3D ultrasound

    Science.gov (United States)

    Qin, Xulei; Wang, Silun; Shen, Ming; Zhang, Xiaodong; Wagner, Mary B.; Fei, Baowei

    2014-03-01

    The orientation of cardiac fibers affects the anatomical, mechanical, and electrophysiological properties of the heart. Although echocardiography is the most common imaging modality in clinical cardiac examination, it can only provide the cardiac geometry or motion information without cardiac fiber orientations. If the patient's cardiac fiber orientations can be mapped to his/her echocardiography images in clinical examinations, it may provide quantitative measures for diagnosis, personalized modeling, and image-guided cardiac therapies. Therefore, this project addresses the feasibility of mapping personalized cardiac fiber orientations to three-dimensional (3D) ultrasound image volumes. First, the geometry of the heart extracted from the MRI is translated to 3D ultrasound by rigid and deformable registration. Deformation fields between both geometries from MRI and ultrasound are obtained after registration. Three different deformable registration methods were utilized for the MRI-ultrasound registration. Finally, the cardiac fiber orientations imaged by DTI are mapped to ultrasound volumes based on the extracted deformation fields. Moreover, this study also demonstrated the ability to simulate electricity activations during the cardiac resynchronization therapy (CRT) process. The proposed method has been validated in two rat hearts and three canine hearts. After MRI/ultrasound image registration, the Dice similarity scores were more than 90% and the corresponding target errors were less than 0.25 mm. This proposed approach can provide cardiac fiber orientations to ultrasound images and can have a variety of potential applications in cardiac imaging.

  1. Vagal cardiac efferent innervation in F344 rats: Effects of chronic intermittent hypoxia.

    Science.gov (United States)

    Cheng, Zixi Jack

    2017-03-01

    Chronic intermittent hypoxia (CIH), which is a physiological consequence of obstructive sleep apnea, reduces baroreflex control of heart rate (HR). Previously, we showed that the heart rate (HR) response to electrical stimulation of the vagal efferent nerve was significantly increased following CIH in F344 rats. Since vagal cardiac efferent from the nucleus ambiguus (NA) project to cardiac ganglia and regulate HR, we hypothesized that vagal cardiac efferent innervation of cardiac ganglia is reorganized. Young adult F344 rats were exposed either to room air (RA) or to intermittent hypoxia for 35-50days. Fluorescent tracer DiI was injected into the NA to label vagal efferent innervation of cardiac ganglia which had been counterstained by Fluoro-Gold (FG) injections (i.p). Confocal microscopy was used to examine vagal cardiac efferent axons and terminals in cardiac ganglia. NA axons entered cardiac ganglia and innervated principal neurons (PNs) with robust basket endings in both RA control and CIH animals. In addition, the percentage of PNs which were innervated by DiI-labeled fibers in ganglia was similar. In CIH rats, abnormally large swollen cardiac axon segments and disorganized terminals as well as leaky endings were observed. In general, vagal efferent terminal varicosities around PNs appeared larger and the number of varicosities was significantly increased. Interestingly, some cardiac axons had sprouting-like terminal structures in the cardiac ganglia as well as in cardiac muscle, which had not been found in RA control. Finally, CIH increased the size of PNs and reduced the ratio of nucleus to PN somata. Thus, CIH significantly remodeled the structure of vagal cardiac axons and terminals in cardiac ganglia as well as cardiac PNs.

  2. Storm surge and river interaction in etuaries

    Science.gov (United States)

    Maskell, J.

    2012-04-01

    In coastal areas, particularly in regions developed on estuaries, extreme river flow can combine with storm surges to present a combined hazard. This combined risk is likely to be more prominent in estuaries where fluvial fresh water input comes from catchments in hilly regions where the dependence of extreme river discharge and sea level elevation can be most statistically significant (Svensson and Jones, 2004). The risk associated with these combined coastal hazards could increase due to climate change if there were an increase in the frequency of extreme weather events. The global (IPCC, 2007) and local (Woodworth et al., 2009) rise in mean sea-level will increase the magnitude of extreme sea levels and surges will act on a higher coastal sea level and therefore increase the risk to coastal property and infrastructure. This may be associated with an increase in precipitation during extreme storm events which will have a large impact on river flooding. Therefore, the need for accurate operational forecasting of storm events will increase with the focus shifting to changes in the extreme 'tail end' of the distribution of storm events. Ideally an operational model that integrates storm surge, wave and fluvial forecasting with inundation and simulates their combined influence would be most effective for planning with respect to flood plain development, evacuation and flood defence. Current operational storm surge models are typically based on two-dimensional depth-averaged shallow water equations (Flather, 2000). Inundation models often use an approximation of the original shallow water equations which neglect the inertial terms (Prestininzi et al., 2011). These 2D flood plain inundation models are often coupled with a 1D model of the main channel of a river or estuary which permits the exchange of mass but assumes a limited exchange of momentum (Bates et al., 2005). A finite volume model (FVCOM) is used to investigate the combined influence of storm surge and river

  3. Storm: lightning-fast resource management

    Energy Technology Data Exchange (ETDEWEB)

    Frachtenberg, E. (Eitan); Petrini, F. (Fabrizio); Fernández, J. C. (Juan C.); Pakin, S. D. (Scott D.); Coll, S. (Salvador)

    2002-01-01

    Although workstation clusters are a common platform for high-performance computing (HPC), they remain more difficult to manage than sequential systems or even symmetric multiprocessors. Furthermore, as cluster sizes increase, the quality of the resource-management subsystem - essentially, all of the code that runs on a cluster other than the applications - increasingly impacts application efficiency. In this paper, we present STORM, a resource-management framework designed for scalability and performance. The key innovation behind STORMis a software architecture that enables resource management to exploit low-level network features. As a result of this HPC-application-like design, STORM is orders of magnitude faster than the best reported results in the literature on two sample resource-management functions: job launching and process scheduling.

  4. Weathering a Perfect Storm from Space

    Science.gov (United States)

    Love, Jeffrey J.

    2016-01-01

    Extreme space-weather events — intense solar and geomagnetic storms — have occurred in the past: most recently in 1859, 1921 and 1989. So scientists expect that, sooner or later, another extremely intense spaceweather event will strike Earth again. Such storms have the potential to cause widespread interference with and damage to technological systems. A National Academy of Sciences study projects that an extreme space-weather event could end up costing the American economy more than $1 trillion. The question now is whether or not we will take the actions needed to avoid such expensive consequences. Let’s assume that we do. Below is an imagined scenario of how, sometime in the future, an extreme space-weather event might play out.

  5. Complexity of cardiac signals for predicting changes in alpha-waves after stress in patients undergoing cardiac catheterization

    Science.gov (United States)

    Chiu, Hung-Chih; Lin, Yen-Hung; Lo, Men-Tzung; Tang, Sung-Chun; Wang, Tzung-Dau; Lu, Hung-Chun; Ho, Yi-Lwun; Ma, Hsi-Pin; Peng, Chung-Kang

    2015-08-01

    The hierarchical interaction between electrical signals of the brain and heart is not fully understood. We hypothesized that the complexity of cardiac electrical activity can be used to predict changes in encephalic electricity after stress. Most methods for analyzing the interaction between the heart rate variability (HRV) and electroencephalography (EEG) require a computation-intensive mathematical model. To overcome these limitations and increase the predictive accuracy of human relaxing states, we developed a method to test our hypothesis. In addition to routine linear analysis, multiscale entropy and detrended fluctuation analysis of the HRV were used to quantify nonstationary and nonlinear dynamic changes in the heart rate time series. Short-time Fourier transform was applied to quantify the power of EEG. The clinical, HRV, and EEG parameters of postcatheterization EEG alpha waves were analyzed using change-score analysis and generalized additive models. In conclusion, the complexity of cardiac electrical signals can be used to predict EEG changes after stress.

  6. Storm-water management through Infiltration trenches

    OpenAIRE

    Chahar, Bhagu Ram; Graillot, Didier; Gaur, Shishir

    2012-01-01

    International audience; With urbanization, the permeable soil surface area through which recharge by infiltration can occur is reducing. This is resulting in much less ground-water recharge and greatly increased surface run-off. Infiltration devices, which redirect run-off waters from the surface to the sub-surface environments, are commonly adopted to mitigate the negative hydrologic effects associated with urbanization. An infiltration trench alone or in combination with other storm water m...

  7. On storm weakening during substorm expansion phase

    Directory of Open Access Journals (Sweden)

    G. L. Siscoe

    Full Text Available Iyemori and Rao recently presented evidence that the strength of a magnetic storm, as measured by -Dst, weakens, or its rate of growth slows, during the substorm expansion phase. Yet the expansion phase is known to inject energetic particles into the ring current, which should strengthen the storm. We propose to reconcile these apparently contradictory results by combining the virial theorem and a principle of energy partitioning between energy storage elements in a system with dissipation. As applied to the unloading description of the substorm expansion phase, the virial theorem states that -Dst is proportional to the sum of the total magnetic energy and twice the total kinetic energy in the magnetosphere including the tail. Thus if expansion phase involves converting magnetic energy stored in the tail into kinetic energy stored in the ring current, a drop in -Dst during expansion phase requires that less than half the drop in magnetic energy goes into the ring current, the rest going into the ionosphere. Indeed Weiss et al., have estimated that the energy dissipated in the ionosphere during expansion phase is twice that injected into the ring current. This conclusion is also consistent with the mentioned energy partitioning principle, which requires that more energy be dissipated than transferred between storage elements. While Iyemori and Rao's observations seem to contradict the hypothesis that storms consist at least in part of a sum of substorms, this mode of description might nonetheless be preserved by including the substorm's growth-phase contribution. Then the change in storm strength measured from before the growth phase to after the expansion phase is positive, even though the expansion phase alone makes a negative contribution.

  8. Pacific Northwest Storms Situation Report # 4

    Energy Technology Data Exchange (ETDEWEB)

    None

    2006-12-18

    Significant progress has been made in restoring power to customers in the Pacific Northwest region. Currently, 237,030 customers remain without power. This is down from 1.8 million customers who lost power following severe wind and snow storms on December 14-15, 2006. The customers without power represent about 8 percent of customers in the affected utility service areas of Oregon and Washington.

  9. Pacific Northwest Storms Situation Report # 5

    Energy Technology Data Exchange (ETDEWEB)

    None

    2006-12-19

    Significant progress has been made in restoring power to customers in the Pacific Northwest region. Currently, 186,627 customers remain without power. The majority of customers without power are served by Puget Sound Energy. This is down from 1.8 million customers who lost power following severe wind and snow storms on December 14-15, 2006. The customers without power represent about 6 percent of customers in the affected utility service areas of Oregon and Washington. See table below.

  10. CRADE OF SAND AND DUST STORM WEATHER

    Institute of Scientific and Technical Information of China (English)

    Niu Ruoyun; Tian Cuiying; Bi Baogui; Yang Keming; Wang Youheng; Tuo Ya; Ding Haifang; Zhang Tairen

    2011-01-01

    Background Sand and dust storm,as one of the main disastrous weathers that affect northern China,not only affect the people health and normal life,but cause the short-term climatic changes due to the direct and indirect radiation of the earth-atmosphere system through the dust floating in the sky.The sand end dust weather and its potential harm on the national economy,ecological environment,social activities and other aspects have aroused worldwide concern.

  11. Gastric applications of electrical field stimulation.

    LENUS (Irish Health Repository)

    Hogan, Aisling M

    2012-02-01

    Advances in clinical applications of electricity have been vast since the launch of Hayman\\'s first cardiac pacemaker more than 70 years ago. Gastric electrical stimulation devices have been recently licensed for treatment of gastroparesis and preliminary studies examining their potential for use in refractory obesity yield promising results.

  12. A high resolution study of a hurricane storm surge and inundation in Veracruz, Mexico

    Science.gov (United States)

    Díaz García, Ovel; Zavala Hidalgo, Jorge; Douillet, Pascal

    2014-05-01

    Veracruz is the most populated city along the Mexican shoreline of the Gulf of Mexico and also is the country's largest commercial port. In recent years the city has been affected by hurricanes of medium intensity that have provoked human casualties, property damaged and economic loss. Two of the most recent events were hurricane Karl (2010), which caused a storm surge and severe flooding, and hurricane Ernesto (2012). The purpose of this work is to study, based on high-resolution numerical simulations, scenarios of storm surge flooding using state-of-the-art open source numerical models: the Weather, Research and Forecasting (WRF), and the coupled models ADvanced CIRCulation (ADCIRC) and Simulating WAves Nearshore (SWAN) for weather and storm surge hindcast, respectively. We also use topography high resolution data from LIDAR and bathymetry from GEBCO 30", the Mexican Navy and nautical charts from Electrical Federal Commission. We present the validation of the models evaluating several statistical parameters against measurements from Acoustic Data Current Profilers, pressure sensors, tide gauge and meteorological stations for these events. In the case of hurricane Karl, it made landfall 15 km north of Veracruz City, reducing the maximum surge along the city shoreline. The hurricane Ernesto made landfall 200 km southeast of the city, too far to have a significant impact. We did some numerical experiments slightly changing the trajectory, reported by the best track data, for these two hurricanes with the purpose of evaluating storm surge scenarios. The results shows that the worst storm surge cases were when the tracks of this hurricanes made landfall south of the city in the range of 30 to 60 km.

  13. Pacific Northwest Storms Situation Report # 2

    Energy Technology Data Exchange (ETDEWEB)

    None

    2006-12-16

    Severe wind and snow storms hit the Pacific Northwest region on December 14 – 15, 2006 resulting in major power outagesin the region. The storm is now moving off into southern Canada. A new weather disturbance nearing the Northwest coast may generate a few rain and snow showers across the Seattle and Portland areas today, but widespread active weather is not expected. There are roughly 950,000 customers in the region (including Canada) without power as a result of the Pacific Northweststorms, down from a peak of 1.8 million customers. This represents about 26 percent of customers in affected utility service areas in Oregon and Washington. See table below. As of 12:30 PM EST, the Renton Control Center for the Olympic Pipeline (petroleum products) had power restored. The pipeline, serviced by Puget Sound Energy, was shut down after it lost power during the storm. According to a pipeline official, the pipeline is expected to restart in approximately 2-3 hours with some reduced throughput later today. SeaTac International Airport receives jet fuel from the pipeline; however, it’s been reported that the airport has approximately eight days of jet fuel inventories on hand. There are no reports of problems regarding fuel production. There are some temporary and minor distribution at retail gas stations due to lack of power. Fuel delivery is also slowed in some areas due to delays on some roads. ESF #12 has not been deployed

  14. Geomagnetic storm effects on GPS based navigation

    Directory of Open Access Journals (Sweden)

    P. V. S. Rama Rao

    2009-05-01

    Full Text Available The energetic events on the sun, solar wind and subsequent effects on the Earth's geomagnetic field and upper atmosphere (ionosphere comprise space weather. Modern navigation systems that use radio-wave signals, reflecting from or propagating through the ionosphere as a means of determining range or distance, are vulnerable to a variety of effects that can degrade the performance of the navigational systems. In particular, the Global Positioning System (GPS that uses a constellation of earth orbiting satellites are affected due to the space weather phenomena.

    Studies made during two successive geomagnetic storms that occurred during the period from 8 to 12 November 2004, have clearly revealed the adverse affects on the GPS range delay as inferred from the Total Electron Content (TEC measurements made from a chain of seven dual frequency GPS receivers installed in the Indian sector. Significant increases in TEC at the Equatorial Ionization anomaly crest region are observed, resulting in increased range delay during the periods of the storm activity. Further, the storm time rapid changes occurring in TEC resulted in a number of phase slips in the GPS signal compared to those on quiet days. These phase slips often result in the loss of lock of the GPS receivers, similar to those that occur during strong(>10 dB L-band scintillation events, adversely affecting the GPS based navigation.

  15. Perioperative management of cardiac disease.

    Science.gov (United States)

    Aresti, N A; Malik, A A; Ihsan, K M; Aftab, S M E; Khan, W S

    2014-01-01

    Pre-existing cardiac disease contributes significantly to morbidity and mortality amongst patients undergoing non cardiac surgery. Patients with pre-existing cardiac disease or with risk factors for it, have as much as a 3.9% risk of suffering a major perioperative cardiac event (Lee et al 1999, Devereaux 2005). Furthermore, the incidence of perioperative myocardial infarction (MI) is increased 10 to 50 fold in patients with previous coronary events (Jassal 2008).

  16. Investigating storm-enhanced density and polar tongue of ionization development during the 22 October 1999 great storm

    Science.gov (United States)

    Horvath, Ildiko; Lovell, Brian C.

    2015-02-01

    We investigate large-scale plasma density increases occurring during the 22 October 1999 great storm and focus on storm-enhanced density (SED) and polar tongue of ionization (TOI) development. Observations include two-hourly Global Ionosphere Map series coupled with multi-instrument in situ, space-based, and ground-based data plots, with Super Dual Auroral Radar Network two-cell convection maps and with model-generated neutral wind vector maps. Results demonstrate the equatorial electrojet events occurring in the Australian and American sectors, the high-density plasma features, and their underlying plasma transportation processes. During the main phase, a series of four prompt penetration electric field (PPEF) events occurred with subauroral polarization stream E field development forming a plasmaspheric drainage plume. These E field events caused the repeated development of equatorial ionization anomaly (EIA), SED bulge, and SED plume during the local dusk-midnight hours in those sectors that covered these local times. Showing a westward movement in accordance with their local time dependence, the EIA-SED structure developed first in the American sector, later on over the Pacific, and finally in the Australian sector. The SED plume plasma found its way into the polar cap through the dayside cusp region, created in the north some large polar cap enhancements reaching up to seven times of the quiet time levels, and evolved in each hemisphere into a polar TOI. We speculate that the enhanced growth of EIA, transporting high-density solar-produced plasma to the SED bulge via strong net eastward E field effects, and the mechanical effects of equatorward neutral winds contributed to the polar TOI's increasingly better development.

  17. Midlatitude ionospheric changes to four great geomagnetic storms of solar cycle 23 in Southern and Northern Hemispheres

    Science.gov (United States)

    Merline Matamba, Tshimangadzo; Habarulema, John Bosco; Burešová, Dalia

    2016-12-01

    This paper presents an investigation of ionospheric response to great (Dst ≤-350 nT) geomagnetic storms that occurred during solar cycle 23. The storm periods analyzed are 29 March to 2 April 2001, 27-31 October 2003, 18-23 November 2003, and 6-11 November 2004. Global Navigation Satellite System, total electron content (TEC), and ionosonde critical frequency of F2 layer (foF2) data over Southern Hemisphere (African sector) and Northern Hemisphere (European sector) midlatitudes were used to study the ionospheric responses within 15°E-40°E longitude and ±31° to ±46° geomagnetic latitude. Midlatitude regions within the same longitude sector in both hemispheres were selected in order to assess the contribution of the low-latitude changes especially the expansion of equatorial ionization anomaly (EIA) also called the dayside ionospheric superfountain effect during these storms. In all storm periods, both negative and positive ionospheric responses were observed in both hemispheres. Negative ionospheric responses were mainly due to changes in neutral composition, while the expansion of the EIA led to pronounced positive storm effects at midlatitudes for some storm periods. In other cases (e.g., 29 October 2003), penetration electric fields, EIA expansion, and large-scale traveling ionospheric disturbances were found to be present during the positive storm effect at midlatitudes in both hemispheres. An increase in TEC on the 28 October 2003 was because of the large solar flare with previously determined intensity of X45 ±5.

  18. Biosynthesis of cardiac natriuretic peptides

    DEFF Research Database (Denmark)

    Goetze, Jens Peter

    2010-01-01

    Cardiac-derived peptide hormones were identified more than 25 years ago. An astonishing amount of clinical studies have established cardiac natriuretic peptides and their molecular precursors as useful markers of heart disease. In contrast to the clinical applications, the biogenesis of cardiac...

  19. Cardiac troponins and high-sensitivity cardiac troponin assays.

    Science.gov (United States)

    Conrad, Michael J; Jarolim, Petr

    2014-03-01

    Measurement of circulating cardiac troponins I and T has become integral to the diagnosis of myocardial infarction. This article discusses the structure and function of the troponin complex and the release of cardiac troponin molecules from the injured cardiomyocyte into the circulation. An overview of current cardiac troponin assays and their classification according to sensitivity is presented. The diagnostic criteria, role, and usefulness of cardiac troponin for myocardial infarction are discussed. In addition, several examples are given of the usefulness of high-sensitivity cardiac troponin assays for short-term and long-term prediction of adverse events.

  20. Low-E Storm Windows Gain Acceptance as a Home Weatherization Measure

    Energy Technology Data Exchange (ETDEWEB)

    Gilbride, Theresa L.; Cort, Katherine A.

    2016-05-16

    This article for Home Energy Magazine describes work by the U.S. Department of Energy to develop low-emissivity storm windows as an energy efficiency-retrofit option for existing homes. The article describes the low-emissivity invisible silver metal coatings on the glass, which reflect heat back into the home in winter or back outside in summer and the benefits of low-e storm windows including insulation, air sealing, noise blocking, protection of antique windows, etc. The article also describes Pacific Northwest National Laboratory's efforts on behalf of DOE to overcome market barriers to adoption of the technology, including performance validation studies in the PNNL Lab Homes, cost effectiveness analysis, production of reports, brochures, how-to guides on low-e storm window installation for the Building America Solution Center, and a video posted on YouTube. PNNL's efforts were reviewed by the Pacific Northwest Regional Technical Forum (RTF), which serves as the advisory board to the Pacific Northwest Electric Power Planning Council and Bonneville Power Administration. In late July 2015, the RTF approved the low-e storm window measure’s savings and specifications, a critical step in integrating low-e storm windows into energy-efficiency planning and utility weatherization and incentive programs. PNNL estimates that more than 90 million homes in the United States with single-pane or low-performing double-pane windows would benefit from the technology. Low-e storm windows are suitable not only for private residences but also for small commercial buildings, historic properties, and facilities that house residents, such as nursing homes, dormitories, and in-patient facilities. To further assist in the market transformation of low-e storm windows and other high-efficiency window attachments, DOE helped found the window Attachment Energy Rating Council (AERC) in 2015. AERC is an independent, public interest, non-profit organization whose mission is to rate

  1. Dynamics of the Solar Wind Electromagnetic Energy Transmission Into Magnetosphere during Large Geomagnetic Storms

    Science.gov (United States)

    Kuznetsova, Tamara; Laptukhov, Alexej; Petrov, Valery

    Causes of the geomagnetic activity (GA) in the report are divided into temporal changes of the solar wind parameters and the changes of the geomagnetic moment orientation relative directions of the solar wind electric and magnetic fields. Based on our previous study we concluded that a reconnection based on determining role of mutual orientation of the solar wind electric field and geomagnetic moment taking into account effects of the Earth's orbital and daily motions is the most effective compared with existing mechanisms. At present a reconnection as paradigma that has applications in broad fields of physics needs analysis of experimental facts to be developed. In terms of reconnection it is important not only mutual orientation of vectors describing physics of interaction region but and reconnection rate which depends from rate of energy flux to those regions where the reconnection is permitted. Applied to magnetosphere these regions first of all are dayside magnetopause and polar caps. Influence of rate of the energy flux to the lobe magnetopause (based on calculations of the Poyting electromagnetic flux component controlling the reconnection rate along the solar wind velocity Pv) on planetary GA (Dst, Kp indices) is investigated at different phases of geomagnetic storms. We study also the rate of energy flux to the polar caps during storms (based on calculations of the Poyting flux vector component along the geomagnetic moment Pm) and its influence on magnetic activity in the polar ionosphere: at the auroral zone (AU,AL indices). Results allow to evaluate contributions of high and low latitude sources of electromagnetic energy to the storm development and also to clear mechanism of the electromagnetic energy transmission from the solar wind to the magnetosphere. We evaluate too power of the solar wind electromagnetic energy during well-known large storms and compare result with power of the energy sources of other geophysical processes (atmosphere, ocean

  2. Cardiac potassium channel subtypes

    DEFF Research Database (Denmark)

    Schmitt, Nicole; Grunnet, Morten; Olesen, Søren-Peter

    2014-01-01

    About 10 distinct potassium channels in the heart are involved in shaping the action potential. Some of the K(+) channels are primarily responsible for early repolarization, whereas others drive late repolarization and still others are open throughout the cardiac cycle. Three main K(+) channels...

  3. Cardiac Risk Assessment

    Science.gov (United States)

    ... Risk Assessment Related tests: Lipid Profile , VLDL Cholesterol , hs-CRP , Lp(a) Overview | Common Questions | Related Pages What ... cardiac risk include: High-sensitivity C-reactive protein (hs-CRP) : Studies have shown that measuring CRP with a ...

  4. The cardiac malpositions.

    Science.gov (United States)

    Perloff, Joseph K

    2011-11-01

    Dextrocardia was known in the 17th century and was 1 of the first congenital malformations of the heart to be recognized. Fifty years elapsed before Matthew Baillie published his account of complete transposition in a human of the thoracic and abdominal viscera to the opposite side from what is natural. In 1858, Thomas Peacock stated that "the heart may be congenitally misplaced in various ways, occupying either an unusual position within the thorax, or being situated external to that cavity." In 1915, Maude Abbott described ectopia cordis, and Richard Paltauf's remarkable illustrations distinguished the various types of dextrocardia. In 1928, the first useful classification of the cardiac malpositions was proposed, and in 1966, Elliott et al's radiologic classification set the stage for clinical recognition. The first section of this review deals with the 3 basic cardiac malpositions in the presence of bilateral asymmetry. The second section deals with cardiac malpositions in the presence of bilateral left-sidedness or right-sidedness. Previous publications on cardiac malpositions are replete with an arcane vocabulary that confounds rather than clarifies. Even if the terms themselves are understood, inherent complexity weighs against clarity. This review was designed as a guided tour of an unfamiliar subject.

  5. Hepato-cardiac disorders

    Institute of Scientific and Technical Information of China (English)

    Yasser; Mahrous; Fouad; Reem; Yehia

    2014-01-01

    Understanding the mutual relationship between the liver and the heart is important for both hepatologists and cardiologists. Hepato-cardiac diseases can be classified into heart diseases affecting the liver, liver diseases affecting the heart, and conditions affecting the heart and the liver at the same time. Differential diagnoses of liver injury are extremely important in a cardiologist’s clinical practice calling for collaboration between cardiologists and hepatologists due to the many other diseases that can affect the liver and mimic haemodynamic injury. Acute and chronic heart failure may lead to acute ischemic hepatitis or chronic congestive hepatopathy. Treatment in these cases should be directed to the primary heart disease. In patients with advanced liver disease, cirrhotic cardiomyopathy may develop including hemodynamic changes, diastolic and systolic dysfunctions, reduced cardiac performance and electrophysiological abnormalities. Cardiac evaluation is important for patients with liver diseases especially before and after liver transplantation. Liver transplantation may lead to the improvement of all cardiac changes and the reversal of cirrhotic cardiomyopathy. There are systemic diseases that may affect both the liver and the heart concomitantly including congenital, metabolic and inflammatory diseases as well as alcoholism. This review highlights these hepatocardiac diseases

  6. Construction of cardiac atrioventricular electrical conduction pathway by rabbit bone marrow mesenchymal stem cells%兔骨髓间充质干细胞构建心脏电传导通路的潜能

    Institute of Scientific and Technical Information of China (English)

    周浩粤; 卢炯斌; 邱汉婴

    2014-01-01

    背景:自体干细胞移植到心脏是目前治疗心力衰竭的一个研究方向,但自体骨髓间充质干细胞移植针对心脏传导系统方面的研究相对较少。  目的:评价兔骨髓间充质干细胞是否具有治疗心脏传导阻滞方面疾病的潜能。  方法:获取兔骨髓间充质干细胞并利用5-氮胞苷诱导为心肌样细胞。14只新西兰大白兔开胸手术后,将左心耳左心室前壁进行缝合(实验组8只,对照组6只)。术后1个月将实验组兔经5-氮胞苷诱导4周的自体骨髓间充质干细胞采用 DAPI 标记后,开胸直视下注射入左心室前壁-左心耳左心室缝合瘢痕区-左心耳;对照组予以培养基替代细胞。细胞移植后1个月再次开胸暴露心脏,在左心耳、左室前壁分别插入电极,进行心脏房室旁道的电生理检测,观察骨髓间充质干细胞是否在左心房左心室缝合瘢痕区形成房室旁道。  结果与结论:细胞移植到兔左心耳左心室缝合区后,实验组有2只兔子在行电生理刺激时心电图提示有房室旁道形成。移植后心脏冰冻切片在荧光显镜下能观察到移植的细胞在左心室和缝合区存活,而对照组则未有上述表现。骨髓间充质干细胞表达 Cx43并与心肌细胞形成间隙连接的特点结合在细胞移植组中形成房室旁道的心脏电生理检测表现,提示骨髓间充质干细胞具备能够用于治疗心脏传导系统阻滞相关疾病的可能。%BACKGROUND:Autologous stem celltransplantation to the heart is a research direction of heart failure treatment, but there are relatively few of studies about autologous bone marrow mesenchymal stem celltransplantation targeting the cardiac conduction system. OBJECTIVE:To evaluate the potential of rabbit bone marrow mesenchymal stem cells for treatment of heart block. METHODS:Rabbit bone marrow mesenchymal stem cells were induced by 5-azacytidine to differentiate

  7. Cardiac fibrillation risk of Taser weapons.

    Science.gov (United States)

    Leitgeb, Norbert

    2014-06-01

    The debate on potential health hazards associated with delivering electric discharges to incapacitated subjects, in particular on whether electric discharge weapons are lethal, less lethal or non-lethal, is still controversial. The cardiac fibrillation risks of Taser weapons X26 and X3 have been investigated by measuring the delivered high-tension pulses in dependence on load impedance. Excitation thresholds and sinus-to-Taser conversion factors have been determined by numerical modeling of endocardial, myocardial, and epicardial cells. Detailed quantitative assessment of cardiac electric exposure has been performed by numerical simulation at the normal-weighted anatomical model NORMAN. The impact of anatomical variation has been quantified at an overweight model (Visible Man), both with a spatial resolution of 2 × 2 × 2 mm voxels. Spacing and location of dart electrodes were systematically varied and the worst-case position determined. Based on volume-weighted cardiac exposure assessment, the fibrillation probability of the worst-case hit was determined to 30% (Taser X26) and 9% (Taser X3). The overall risk assessment of Taser application accounting for realistic spatial hit distributions was derived from training sessions of police officers under realistic scenarios and by accounting for the influence of body (over-)weight as well as gender. The analysis of the results showed that the overall fibrillation risk of Taser use is not negligible. It is higher at Taser X26 than at Taser X3 and amounts to about 1% for Europeans with an about 20% higher risk for Asians. Results demonstrate that enhancement as well as further reduction of fibrillation risk depends on responsible use or abuse of Taser weapons.

  8. Cardiac health status implementation on mobile phone

    Directory of Open Access Journals (Sweden)

    Prasad Pomaji

    2012-11-01

    Full Text Available An ECG is a bio-medical signal which records the hearts electrical signal versus time. It is an important diagnosis tool for assessing hearts functions. The features extracted from the ECG signal play a significant role in diagnosing most of the cardiac diseases. Our focus is on developing an integrated electrocardiogram (ECG beat detector on mobile phone for health monitoring purpose. The feature extraction scheme determines the amplitude and intervals in the ECG signal for subsequent analysis. The amplitude and interval values of the P-QRS-T segment determines the functioning of heart of every human.

  9. Mid-septal hypertrophy and apical ballooning; potential mechanism of ventricular tachycardia storm in patients with hypertrophic cardiomyopathy.

    Science.gov (United States)

    Hwang, Eui-Seock; Pak, Hui-Nam

    2012-01-01

    Medically refractory ventricular tachycardia (VT) storm can be controlled with radiofrequency catheter ablation (RFCA), however, it may be difficult to control in some patients with hemodynamic overload. We experienced a patient with intractable VT storm controlled by hemodynamic unloading. The patient had mid-septal hypertrophic cardiomyopathy with an implantable cardioverter defibrillator (ICD) back-up. Because of the severe mid-septal hypertrophy, his left ventricle (LV) had an hourglass-like morphology and showed apical ballooning; the focus of VT was at the border of apical ballooning. Although we performed VT ablation because of electrical storm with multiple ICD shocks, VT recurred 1 hour after procedure. As the post-RFCA monomorphic VT was refractory to anti-tachycardia pacing or ICD shock, we reduced the hemodynamic overload of LV with β-blockade, hydration, and sedation. VT spontaneously stopped 1.5 hours later and the patient has remained free of VT for 24 months with β-blockade alone. In patients with VT storm refractory to antiarrhythmic drugs or RFCA, the mechanism of mechano-electrical feedback should be considered and hemodynamic unloading may be an essential component of treatment.

  10. Maps of the MY 25 Planet-encircling Dust Storm

    Science.gov (United States)

    Noble, J.; Cantor, B. A.; Wilson, R. J.; Haberle, R. M.; Bridger, A. F. C.; Barnes, J.; Hollingsworth, J. L.; Kahre, M. A.

    2015-12-01

    We have created 42 daily maps of the MY 25 planet-encircling dust storm (Ls=165-188) in order to better delimit the areal extent of storms observed by the Mars Orbiter Camera (MOC). These maps allow us to better compare storm evolution with eddies observed in Fast Fourier Synoptic Mapping (FFSM) of Thermal Emission Spectrometer (TES) temperatures. FFSM analysis of TES 3.7 hPa thermal data shows the presence of eastward traveling waves from 40 - 60° S with a period of about three sols. These maps use a new dust characterization scheme that categorizes dust storms and dust entrained in gravity waves by degree of (visual) structure. Preliminary analysis of these data indicate concurrent eastward migration of both storms and eddies. We hypothesize that these waves are transient baroclinic eddies that contributed to the initiation of precursor storms near Hellas.

  11. 电击死大鼠心脏超微结构及HSP70、HIF-1α表达变化%Cardiac Ultrastructure and Changes of HSP70 and HIF-1α Expression in Electric Shock Death Rats

    Institute of Scientific and Technical Information of China (English)

    张国忠; 李瑞利; 冯国伟; 毕海涛; 王松军; 丛斌; 左敏

    2015-01-01

    目的:观察电击死大鼠心脏超微结构及热休克蛋白70(heat shock protein 70,HSP70)、低氧诱导因子-1α(hypoxia inducible factor-1α,HIF-1α)的表达变化,探讨其是否能作为电击死法医学鉴定的依据。方法将72只SD大鼠随机分为电击死组、死后电击组和对照组。通过透射电镜观察电击死大鼠心肌超微结构的改变,并采用免疫组织化学技术观测心肌HSP70和HIF-1α的表达变化。结果电击大鼠心肌细胞肌原纤维断裂,线粒体嵴和膜溶解消失,Z线、M线排列紊乱。 HSP70和HIF-1α在电击死组呈强阳性表达,与死后电击组、对照组比较差异有统计学意义(P<0.05)。结论 HSP70和HIF-1α在电击死组表达明显上调,有望作为电击死的诊断参考指标。%Objective T o observe cardiac ultrastructure and the expression of heat shock protein 70 (H SP70) and hypoxia inducible factor-1α (H IF-1α) in electric shock death rats and to explore the application of these indexes as the basis of m edical identification in electric shock death. Methods Seventy-tw o SD rats w ere random ly divided into electric shock death group, postm ortem electric shock group and the control group. T he changes of m yocardial ultrastructure w ere observed by transm ission electron m icro-scope, and the expressions of m yocardial H SP70 and H IF-1α w ere observed by im m unohistochem ical technology. Results M yocardial m yofibril fracture, m itochondrial cristae and m em brane dissolution, and disordered arrangem ent of Z lines and M lines w ere observed in electric shock rats. H SP70 and H IF-1αw ere strong positive expressions in the electric shock death group, significantly com pared w ith the con-trol and postm ortem electric shock groups (P<0.05). Conclusion T he expressions of H SP70 and H IF-1αw ere obviously increased in electric shock death group, w hich m ay be used as the diagnostic indicator of electric shock

  12. Conditions for Two-Cell Structure in Severe Vortical Storms.

    Science.gov (United States)

    1984-02-01

    SEVERE VORTICAL STORMS by G. F. Carrier, F. E. Fendell , P. S. Feldman, and S. F. Fink TRW Space and Technology Group, Redondo Beach, CA 90278 Thi...Claification Conditions for Two-Call Structure in Severe Vortical Storms (U) 12. PERSONAL AUTHOR(S) Carrier. G. F. (Harvard U.): Fendell , F. E., Feldman...cell structure will occur. Very roughly, about half of all tropical storms ( Fendell 1974), and about one-quarter to one-half of meso- cyclones (Brooks

  13. Seismological Evidence for Increasing Oceanic Storm Intensity

    Science.gov (United States)

    McNamara, D. E.; Aster, R.; Bromirski, P.; Hutt, C.; Gee, L.

    2007-12-01

    Several major tropical cylones during the 2007 hurricane season have generated wave-induced seismic signals detectable by seismic instrumentation in the Global Seismographic Network (GSN) and Advanced National Seismic System (ANSS) (ex. Flossy, Dean, Felix, Henrietta). From these storms, seismic background energy "noise" between 6 and 25 s period is dominated by a persistent "microseism" arising from energy transferred from ocean gravity waves to elastic Rayleigh waves. Microseism power spectral density (PSD) is dominated by a primary peak (10-20s) that is generated by waves breaking on coastlines and by a (much stronger) secondary peak centered near (5-10s) that is generated by the half-period periodic variation of sea bottom pressure due to standing wave components generated from wave-wave interaction of the ocean gravity wave field. The microseism peaks can vary in amplitude by several orders of magnitude due to station proximity to coastlines and wave amplitudes, which have a strong seasonal dependence. Such observations demonstrate the utility of microseisms as an integrative proxy for assessing long-term and regional scale sea swell changes induced by changes in global storm activity. We examine changes in the microseism amplitude and use it as a proxy for decadal-scale changes in storm-wave amplitude, a topic of considerable interest in the debate about the impact of global climate change on oceanic storm frequency and intensity. High-quality continuous digital records from the GSN and its precursor networks now extend back over 30 years at the longest-operational sites. In this abstract, we demonstrate the development of an oceanic storm trigger algorithm by observing the current storm season using data from the ANSS and GSN and then apply the resulting methods to an investigation of oceanic wave climate changes over three decades. Limited spatial distribution and length of long-term seismic observational records causes some ambiguity for climate change

  14. Three-dimensional cardiac tissue fabrication based on cell sheet technology.

    Science.gov (United States)

    Masuda, Shinako; Shimizu, Tatsuya

    2016-01-15

    Cardiac tissue engineering is a promising therapeutic strategy for severe heart failure. However, conventional tissue engineering methods by seeding cells into biodegradable scaffolds have intrinsic limitations such as inflammatory responses and fibrosis arising from the degradation of scaffolds. On the other hand, we have developed cell sheet engineering as a scaffold-free approach for cardiac tissue engineering. Confluent cultured cells are harvested as an intact cell sheet using a temperature-responsive culture surface. By layering cardiac cell sheets, it is possible to form electrically communicative three-dimensional cardiac constructs. Cell sheet transplantation onto damaged hearts in several animal models has revealed improvements in heart functions. Because of the lack of vasculature, the thickness of viable cardiac cell sheet-layered tissues is limited to three layers. Pre-vascularized structure formation within cardiac tissue and multi-step transplantation methods has enabled the formation of thick vascularized tissues in vivo. Furthermore, development of original bioreactor systems with vascular beds has allowed reconstruction of three-dimensional cardiac tissues with a functional vascular structure in vitro. Large-scale culture systems to generate pluripotent stem cell-derived cardiac cells can create large numbers of cardiac cell sheets. Three-dimensional cardiac tissues fabricated by cell sheet engineering may be applied to treat heart disease and tissue model construction.

  15. Cardiac fusion and complex congenital cardiac defects in thoracopagus twins: diagnostic value of cardiac CT

    Energy Technology Data Exchange (ETDEWEB)

    Goo, Hyun Woo [University of Ulsan College of Medicine, Asan Medical Center, Department of Radiology and Research Institute of Radiology, Seoul (Korea, Republic of); Park, Jeong-Jun [University of Ulsan College of Medicine, Asan Medical Center, Department of Pediatric Cardiac Surgery, Seoul (Korea, Republic of); Kim, Ellen Ai-Rhan [University of Ulsan College of Medicine, Asan Medical Center, Division of Neonatology, Department of Pediatrics, Seoul (Korea, Republic of); Won, Hye-Sung [University of Ulsan College of Medicine, Asan Medical Center, Department of Obstetrics and Gynecology, Seoul (Korea, Republic of)

    2014-09-15

    Most thoracopagus twins present with cardiac fusion and associated congenital cardiac defects, and assessment of this anatomy is of critical importance in determining patient care and outcome. Cardiac CT with electrocardiographic triggering provides an accurate and quick morphological assessment of both intracardiac and extracardiac structures in newborns, making it the best imaging modality to assess thoracopagus twins during the neonatal period. In this case report, we highlight the diagnostic value of cardiac CT in thoracopagus twins with an interatrial channel and complex congenital cardiac defects. (orig.)

  16. Large enhancements in low latitude total electron content during 15 May 2005 geomagnetic storm in Indian zone

    Directory of Open Access Journals (Sweden)

    N. Dashora

    2009-05-01

    Full Text Available Results pertaining to the response of the equatorial and low latitude ionosphere to a major geomagnetic storm that occurred on 15 May 2005 are presented. These results are also the first from the Indian zone in terms of (i GPS derived total electron content (TEC variations following the storm (ii Local low latitude electrodynamics response to penetration of high latitude convection electric field (iii effect of storm induced traveling atmospheric disturbances (TAD's on GPS-TEC in equatorial ionization anomaly (EIA zone.

    Data set comprising of ionospheric TEC obtained from GPS measurements, ionograms from an EIA zone station, New Delhi (Geog. Lat. 28.42° N, Geog. Long. 77.21° E, ground based magnetometers in equatorial and low latitude stations and solar wind data obtained from Advanced Composition Explorer (ACE has been used in the present study. GPS receivers located at Udaipur (Geog. Lat. 24.73° N, Geog. Long. 73.73° E and Hyderabad (Geog. Lat. 17.33° N, Geog. Long. 78.47° E have been used for wider spatial coverage in the Indian zone. Storm induced features in vertical TEC (VTEC have been obtained comparing them with the mean VTEC of quiet days. Variations in solar wind parameters, as obtained from ACE and in the SYM-H index, indicate that the storm commenced on 15 May 2005 at 02:39 UT. The main phase of the storm commenced at 06:00 UT on 15 May with a sudden southward turning of the Z-component of interplanetary magnetic field (IMF-Bz and subsequent decrease in SYM-H index. The dawn-to-dusk convection electric field of high latitude origin penetrated to low and equatorial latitudes simultaneously as corroborated by the magnetometer data from the Indian zone. Subsequent northward turning of the IMF-Bz, and the penetration of the dusk-to-dawn electric field over the dip equator is also discernible. Response of the low latitude ionosphere to this storm may be characterized in terms of (i

  17. Probabilistic Storm Surge Hazard Assessment in Martinique

    Science.gov (United States)

    Krien, Yann; Dudon, Bernard; Sansorgne, Eliot; Roger, Jean; Zahibo, Narcisse; Roquelaure, Stevie

    2013-04-01

    Located at the center of the Lesser Antilles, Martinique is under the threat of hurricanes formed over the warm tropical waters of the Atlantic Ocean and Caribbean Sea. These events can be extremely costly in terms of human, property, and economic losses. Storm surge hazard studies are hence required to provide guidance to emergency managers and decision-makers. A few studies have been conducted so far in the French Lesser Antilles, but they mainly rely on scarce historical data of extreme sea levels or numerical models with coarse resolutions. Recent progress in statistical techniques for generating large number of synthetic hurricanes as well as availability of high-resolution topographic and bathymetric data (LIDAR) and improved numerical models enables us today to conduct storm surge hazard assessment studies with much more accuracy. Here we present a methodology to assess cyclonic surge hazard in Martinique both at regional and local scales. We first simulate the storm surges that would be induced by a large set of potential events generated by the statistical/deterministic models of Emanuel et al. [2006]. We use the ADCIRC-SWAN coupled models (Dietrich et al 2012) to simulate inundation inland with grid resolutions of up to 50-100m in the coastal area for the whole island.These models are validated against observations during past events such as hurricane Dean in 2007. The outputs can then be used in some specific sites to force higher resolution models for crisis management and local risk assessment studies. This work is supported by the INTERREG IV « Caribbean » program TSUNAHOULE.

  18. Mapping cardiac surface mechanics with structured light imaging.

    Science.gov (United States)

    Laughner, Jacob I; Zhang, Song; Li, Hao; Shao, Connie C; Efimov, Igor R

    2012-09-15

    Cardiovascular disease often manifests as a combination of pathological electrical and structural heart remodeling. The relationship between mechanics and electrophysiology is crucial to our understanding of mechanisms of cardiac arrhythmias and the treatment of cardiac disease. While several technologies exist for describing whole heart electrophysiology, studies of cardiac mechanics are often limited to rhythmic patterns or small sections of tissue. Here, we present a comprehensive system based on ultrafast three-dimensional (3-D) structured light imaging to map surface dynamics of whole heart cardiac motion. Additionally, we introduce a novel nonrigid motion-tracking algorithm based on an isometry-maximizing optimization framework that forms correspondences between consecutive 3-D frames without the use of any fiducial markers. By combining our 3-D imaging system with nonrigid surface registration, we are able to measure cardiac surface mechanics at unprecedented spatial and temporal resolution. In conclusion, we demonstrate accurate cardiac deformation at over 200,000 surface points of a rabbit heart recorded at 200 frames/s and validate our results on highly contrasting heart motions during normal sinus rhythm, ventricular pacing, and ventricular fibrillation.

  19. Genetic and physiologic dissection of the vertebrate cardiac conduction system.

    Directory of Open Access Journals (Sweden)

    Neil C Chi

    2008-05-01

    Full Text Available Vertebrate hearts depend on highly specialized cardiomyocytes that form the cardiac conduction system (CCS to coordinate chamber contraction and drive blood efficiently and unidirectionally throughout the organism. Defects in this specialized wiring system can lead to syncope and sudden cardiac death. Thus, a greater understanding of cardiac conduction development may help to prevent these devastating clinical outcomes. Utilizing a cardiac-specific fluorescent calcium indicator zebrafish transgenic line, Tg(cmlc2:gCaMP(s878, that allows for in vivo optical mapping analysis in intact animals, we identified and analyzed four distinct stages of cardiac conduction development that correspond to cellular and anatomical changes of the developing heart. Additionally, we observed that epigenetic factors, such as hemodynamic flow and contraction, regulate the fast conduction network of this specialized electrical system. To identify novel regulators of the CCS, we designed and performed a new, physiology-based, forward genetic screen and identified for the first time, to our knowledge, 17 conduction-specific mutations. Positional cloning of hobgoblin(s634 revealed that tcf2, a homeobox transcription factor gene involved in mature onset diabetes of the young and familial glomerulocystic kidney disease, also regulates conduction between the atrium and the ventricle. The combination of the Tg(cmlc2:gCaMP(s878 line/in vivo optical mapping technique and characterization of cardiac conduction mutants provides a novel multidisciplinary approach to further understand the molecular determinants of the vertebrate CCS.

  20. Space storms and radiation causes and effects

    CERN Document Server

    Schrijver, Carolus J

    2010-01-01

    Heliophysics is a fast-developing scientific discipline that integrates studies of the Sun's variability, the surrounding heliosphere, and the environment and climate of planets. The Sun is a magnetically variable star and for planets with intrinsic magnetic fields, planets with atmospheres, or planets like Earth with both, there are profound consequences. This 2010 volume, the second in this series of three heliophysics texts, integrates the many aspects of space storms and the energetic radiation associated with them - from causes on the Sun to effects in planetary environments. It reviews t

  1. USGS Multi-Hazards Winter Storm Scenario

    Science.gov (United States)

    Cox, D. A.; Jones, L. M.; Perry, S. C.

    2008-12-01

    The USGS began an inter-disciplinary effort, the Multi Hazards Demonstration Project (MHDP), in 2007 to demonstrate how hazards science can improve a community's resiliency to natural disasters including earthquakes, tsunamis, wildfires, landslides, floods and coastal erosion. The project engages the user community in setting research goals and directs efforts towards research products that can be applied to loss reduction and improved resiliency. The first public product of the MHDP was the ShakeOut Earthquake Scenario published in May 2008. It detailed the realistic outcomes of a hypothetical, but plausible, magnitude 7.8 earthquake on the San Andreas Fault in southern California. Over 300 scientist and experts contributed to designing the earthquake and understanding the impacts of such a disaster, including the geotechnical, engineering, social, cultural, environmental, and economic consequences. The scenario advanced scientific understanding and exposed numerous vulnerabilities related to emergency response and lifeline continuity management. The ShakeOut Scenario was the centerpiece of the Nation's largest-ever emergency response exercise in November 2008, dubbed "The Great Southern California ShakeOut" (www.shakeout.org). USGS Multi-Hazards is now preparing for its next major public project, a Winter Storm Scenario. Like the earthquake scenario, experts will be brought together to examine in detail the possibility, cost and consequences of a winter storm disaster including floods, landslides, coastal erosion and inundation; debris flows; biologic consequences like extirpation of endangered species; physical damages like bridge scour, road closures, dam failure, property loss, and water system collapse. Consideration will be given to the vulnerabilities associated with a catastrophic disruption to the water supply to southern California; the resulting impacts on ground water pumping, seawater intrusion, water supply degradation, and land subsidence; and a

  2. Pacific Northwest Storms Situation Report # 6

    Energy Technology Data Exchange (ETDEWEB)

    None

    2006-12-20

    Significant progress has been made in restoring power to customers in the Pacific Northwest region. Currently, 134,868 customers remain without power. The number of outages is down from 1.8 million customers who lost power following severe wind and snow storms on December 14-15, 2006. The customers without power represent less than 5 percent of customers in the affected utility service areas of Oregon and Washington. The majority of customers without power are served by Puget Sound Energy and Seattle City Light.

  3. Pacific Northwest Storms Situation Report # 3

    Energy Technology Data Exchange (ETDEWEB)

    None

    2006-12-17

    Significant progress has been made in restoring power to customers in the Pacific Northwest region. Currently, 468,200 customers, including Canada, remain without power. This is down from 1.8 million customers who lost power following severe wind and snow storms on December 14-15, 2006. The customers without power represent about 16 percent of customers in the affected utility service areas of Oregon and Washington. See table below. The Olympic pipeline reports that the pipeline is operational; however, pipeline throughput remains reduced since one substation along the line remains without power. Complete power restoration is expected later today. There are no reports of problems regarding fuel distribution and production.

  4. Investigations of Large Scale Storm Systems.

    Science.gov (United States)

    1982-06-08

    and data availability, Bull. Amer. Meteor. Soc. 58:1299-1301. 5. Bergeron, T. (1950) Uber der mechanssims der ausiebigen nederschlage, Berichte des...reference to the position of the surface storm difficult. The sampling area on 1 March was in New Mexico ; on 2 March it was in Arkansas; and on 3 March it...described by Cohen and Barnes (1980); 1 3 data were collected in northwestern New Mexico before (4 Apr) and after (5 Apr) the passage of a cold front

  5. Anticipating environmental and environmental-health implications of extreme storms: ARkStorm scenario

    Science.gov (United States)

    Plumlee, Geoffrey S.; Alpers, Charles N.; Morman, Suzette A.; San Juan, Carma A.

    2016-01-01

    The ARkStorm Scenario predicts that a prolonged winter storm event across California would cause extreme precipitation, flooding, winds, physical damages, and economic impacts. This study uses a literature review and geographic information system-based analysis of national and state databases to infer how and where ARkStorm could cause environmental damages, release contamination from diverse natural and anthropogenic sources, affect ecosystem and human health, and cause economic impacts from environmental-remediation, liability, and health-care costs. Examples of plausible ARkStorm environmental and health concerns include complex mixtures of contaminants such as petroleum, mercury, asbestos, persistent organic pollutants, molds, and pathogens; adverse physical and contamination impacts on riverine and coastal marine ecosystems; and increased incidences of mold-related health concerns, some vector-borne diseases, and valley fever. Coastal cities, the San Francisco Bay area, the Sacramento-San Joaquin River Delta, parts of the Central Valley, and some mountainous areas would likely be most affected. This type of screening analysis, coupled with follow-up local assessments, can help stakeholders in California and disaster-prone areas elsewhere better plan for, mitigate, and respond to future environmental disasters.

  6. Longitudinal variations of positive dayside ionospheric storms related to recurrent geomagnetic storms

    CERN Document Server

    Dmitriev, A V; Brahmanandam, P S; Chang, L C; Chen, K -T; Tsai, L -C

    2013-01-01

    We have performed an analysis of case events and statistics of positive ionospheric storms in the dayside region of the equatorial ionization anomaly during recurrent geomagnetic storms (RGSs), which dominate in geomagnetic and ionospheric conditions on the declining phase of solar activity in 2004 to 2008. It is shown that total electron content (TEC) has a tendency to minimize before the beginning of RGSs and to peak 3 to 4 days after, i.e. on the RGS recovery phase produced by high-intensity long-duration continuous auroral activity. The maximum of TEC coincides with the maximum of solar wind velocity within high-speed solar wind streams. An analysis of electron content vertical profiles, derived from two independent methods using ionosondes and COSMIC/FORMOSAT-3 radio occultation, showed that in the maximum of an ionospheric storm on 28 March 2008, the F2 layer thickens, NmF2 increases by ~50% and hmF2 elevates by a few tens of kilometers. The response of positive ionospheric storms to solar, heliospheric...

  7. Cardiac nuclear medicine

    Energy Technology Data Exchange (ETDEWEB)

    Gerson, M.C.

    1987-01-01

    The book begins with a review of the radionuclide methods available for evaluating cardiac perfusion and function. The authors discuss planar and tomographic thallium myocardial imaging, first-pass and equilibrium radionuclide angiography, and imaging with infarct-avid tracers. Several common but more specialized procedures are then reviewed: nonogemetric measurement of left ventricular volume, phase (Fourier) analysis, stroke volume ratio, right ventricular function, and diastolic function. A separate chapter is devoted to drug interventions and in particular the use of radionuclide ventriculography to monitor doxorubicin toxicity and therapy of congestive heart failure. The subsequent chapters provide a comprehensive guide to test selection, accuracy, and results in acute myocardial infarction, in postmyocardial infarction, in chronic coronary artery disease, before and after medical or surgical revascularization, in valvular heart disease, in cardiomyopathies, and in cardiac trauma.

  8. Sudden Cardiac Death

    Directory of Open Access Journals (Sweden)

    Yipsy María Gutiérrez Báez

    2015-09-01

    Full Text Available Since the second half of the twentieth century, dying suddenly due to heart-related problems has become the main health issue in all countries where infectious diseases are not prevalent. Sudden death from cardiac causes is an important global health problem. Major databases were searched for the leading causes of sudden cardiac death. It has been demonstrated that there is a group of hereditary diseases with structural alterations or without apparent organic cause that explains many cases of sudden death in young people, whether related or not to physical exertion. Certain population groups are at higher risk for this disease. They are relatively easy to identify and can be the target of primary prevention measures.

  9. Cardiac arrhythmias in pregnancy.

    Science.gov (United States)

    Knotts, Robert J; Garan, Hasan

    2014-08-01

    As more women with repaired congenital heart disease survive to their reproductive years and many other women are delaying pregnancy until later in life, a rising concern is the risk of cardiac arrhythmias during pregnancy. Naturally occurring cardiovascular changes during pregnancy increase the likelihood that a recurrence of a previously experienced cardiac arrhythmia or a de novo arrhythmia will occur. Arrhythmias should be thoroughly investigated to determine if there is a reversible etiology, and risks/benefits of treatment options should be fully explored. We discuss the approach to working up and treating various arrhythmias during pregnancy with attention to fetal and maternal risks as well as treatment of fetal arrhythmias. Acute management in stable patients includes close monitoring and intravenous pharmacologic therapy, while DC cardioversion should be used to terminate arrhythmias in hemodynamically unstable patients. Long-term management may require continued oral antiarrhythmic therapy, with particular attention to fetal safety, to prevent complications associated with arrhythmias.

  10. A model for the estimation of storm losses and the identification of severe winter storms in Germany

    Directory of Open Access Journals (Sweden)

    M. Klawa

    2003-01-01

    Full Text Available A storm loss model for Germany is presented. Input data to the model are the daily maximum gust wind speeds measured at stations distributed over the country. The individual daily peak gust values are scaled with the local climatological upper 2% quantile at each station. This scaling serves to take local conditions at the stations into account, and thus permits a simple spatial interpolation of the storm field. The next step is the computation of a loss index for each storm. It is based on the excess of (scaled wind speed over the upper 2% quantile, and on population numbers in the individual districts within Germany, with the latter serving as a proxy for the spatial distribution of values that could be affected by a storm. Using wind speeds in excess of the percentile value also serves to take spatial heterogeneity of vulnerability against storms into account. The aggregated storm index gives an estimate of the severity of an individual storm. Finally, the relation between actual loss produced by a storm and the index is estimated using published annual insurance loss due to windstorm in Germany. Index values are accumulated for each year, and the relation to actual loss is computed. The average ratio for the whole reference period is eventually used. It is shown that the interannual variability of storm-related losses can be reproduced with a correlation coefficient of r = 0.96, and even individual storm damages can be estimated. Based on these evaluations we found that only 50 storms account for about 80% of insured storm losses between 1970 and 1997.

  11. Graphene induces spontaneous cardiac differentiation in embryoid bodies

    Science.gov (United States)

    Ahadian, Samad; Zhou, Yuanshu; Yamada, Shukuyo; Estili, Mehdi; Liang, Xiaobin; Nakajima, Ken; Shiku, Hitoshi; Matsue, Tomokazu

    2016-03-01

    Graphene was embedded into the structure of mouse embryoid bodies (EBs) using the hanging drop technique. The inclusion of 0.2 mg per mL graphene in the EBs did not affect the viability of the stem cells. However, the graphene decreased the stem cell proliferation, probably by accelerating cell differentiation. The graphene also enhanced the mechanical properties and electrical conductivity of the EBs. Interestingly, the cardiac differentiation of the EB-graphene was significantly greater than that of the EBs at day 5 of culture, as confirmed by high-throughput gene analysis. Electrical stimulation (voltage, 4 V; frequency, 1 Hz; and duration, 10 ms for 2 continuous days) further enhanced the cardiac differentiation of the EBs, as demonstrated by analyses of the cardiac protein and gene expression and the beating activity of the EBs. Taken together, the results demonstrated that graphene played a major role in directing the cardiac differentiation of EBs, which has potential cell therapy and tissue regeneration applications.Graphene was embedded into the structure of mouse embryoid bodies (EBs) using the hanging drop technique. The inclusion of 0.2 mg per mL graphene in the EBs did not affect the viability of the stem cells. However, the graphene decreased the stem cell proliferation, probably by accelerating cell differentiation. The graphene also enhanced the mechanical properties and electrical conductivity of the EBs. Interestingly, the cardiac differentiation of the EB-graphene was significantly greater than that of the EBs at day 5 of culture, as confirmed by high-throughput gene analysis. Electrical stimulation (voltage, 4 V; frequency, 1 Hz; and duration, 10 ms for 2 continuous days) further enhanced the cardiac differentiation of the EBs, as demonstrated by analyses of the cardiac protein and gene expression and the beating activity of the EBs. Taken together, the results demonstrated that graphene played a major role in directing the cardiac

  12. System for the diagnosis and monitoring of coronary artery disease, acute coronary syndromes, cardiomyopathy and other cardiac conditions

    Science.gov (United States)

    Schlegel, Todd T. (Inventor); Arenare, Brian (Inventor)

    2008-01-01

    Cardiac electrical data are received from a patient, manipulated to determine various useful aspects of the ECG signal, and displayed and stored in a useful form using a computer. The computer monitor displays various useful information, and in particular graphically displays various permutations of reduced amplitude zones and kurtosis that increase the rapidity and accuracy of cardiac diagnoses. New criteria for reduced amplitude zones are defined that enhance the sensitivity and specificity for detecting cardiac abnormalities.

  13. Cardiac surgery 2015 reviewed.

    Science.gov (United States)

    Doenst, Torsten; Strüning, Constanze; Moschovas, Alexandros; Gonzalez-Lopez, David; Essa, Yasin; Kirov, Hristo; Diab, Mahmoud; Faerber, Gloria

    2016-10-01

    For the year 2015, almost 19,000 published references can be found in PubMed when entering the search term "cardiac surgery". The last year has been again characterized by lively discussions in the fields where classic cardiac surgery and modern interventional techniques overlap. Lacking evidence in the field of coronary revascularization with either percutaneous coronary intervention or bypass surgery has been added. As in the years before, CABG remains the gold standard for the revascularization of complex stable triple-vessel disease. Plenty of new information has been presented comparing the conventional to transcatheter aortic valve implantation (TAVI) demonstrating similar short- and mid-term outcomes at high and low risk, but even a survival advantage with transfemoral TAVI at intermediate risk. In addition, there were many relevant and interesting other contributions from the purely operative arena. This review article will summarize the most pertinent publications in the fields of coronary revascularization, surgical treatment of valve disease, heart failure (i.e., transplantation and ventricular assist devices), and aortic surgery. While the article does not have the expectation of being complete and cannot be free of individual interpretation, it provides a condensed summary that is intended to give the reader "solid ground" for up-to-date decision-making in cardiac surgery.

  14. Cardiac hybrid imaging

    Energy Technology Data Exchange (ETDEWEB)

    Gaemperli, Oliver [University Hospital Zurich, Cardiac Imaging, Zurich (Switzerland); University Hospital Zurich, Nuclear Cardiology, Cardiovascular Center, Zurich (Switzerland); Kaufmann, Philipp A. [University Hospital Zurich, Cardiac Imaging, Zurich (Switzerland); Alkadhi, Hatem [University Hospital Zurich, Institute of Diagnostic and Interventional Radiology, Zurich (Switzerland)

    2014-05-15

    Hybrid cardiac single photon emission computed tomography (SPECT)/CT imaging allows combined assessment of anatomical and functional aspects of cardiac disease. In coronary artery disease (CAD), hybrid SPECT/CT imaging allows detection of coronary artery stenosis and myocardial perfusion abnormalities. The clinical value of hybrid imaging has been documented in several subsets of patients. In selected groups of patients, hybrid imaging improves the diagnostic accuracy to detect CAD compared to the single imaging techniques. Additionally, this approach facilitates functional interrogation of coronary stenoses and guidance with regard to revascularization procedures. Moreover, the anatomical information obtained from CT coronary angiography or coronary artery calcium scores (CACS) adds prognostic information over perfusion data from SPECT. The use of cardiac hybrid imaging has been favoured by the dissemination of dedicated hybrid systems and the release of dedicated image fusion software, which allow simple patient throughput for hybrid SPECT/CT studies. Further technological improvements such as more efficient detector technology to allow for low-radiation protocols, ultra-fast image acquisition and improved low-noise image reconstruction algorithms will be instrumental to further promote hybrid SPECT/CT in research and clinical practice. (orig.)

  15. Radiation Belt Storm Probes—Observatory and Environments

    Science.gov (United States)

    Kirby, Karen; Artis, David; Bushman, Stewart; Butler, Michael; Conde, Rich; Cooper, Stan; Fretz, Kristen; Herrmann, Carl; Hill, Adrian; Kelley, Jeff; Maurer, Richard; Nichols, Richard; Ottman, Geffrey; Reid, Mark; Rogers, Gabe; Srinivasan, Dipak; Troll, John; Williams, Bruce

    2013-11-01

    The National Aeronautics and Space Administration's (NASA's) Radiation Belt Storm Probe (RBSP) is an Earth-orbiting mission that launched August 30, 2012, and is the latest science mission in NASA's Living with a Star Program. The RBSP mission will investigate, characterize and understand the physical dynamics of the radiation belts, as well as the influence of the Sun on the Earth's environment, by measuring particles, electric and magnetic fields and waves that comprise geospace. The mission is composed of two identically instrumented spinning observatories in an elliptical orbit around earth with 600 km perigee, 30,000 km apogee and 10∘ inclination to provide full sampling of the Van Allen radiation belts. The twin RBSP observatories (recently renamed the Van Allen Probes) will follow slightly different orbits and will lap each other four times per year, offering simultaneous measurements over a range of observatory separation distances. A description of the observatory environment is provided along with protection for sensitive electronics to support operations in the harsh radiation belt environment. Spacecraft and subsystem key characteristics and instrument accommodations are included that allow the RBSP science objectives to be met.

  16. The Meteorology of Storms that Produce Narrow Bipolar Events

    Science.gov (United States)

    Lang, Timothy J.; McCaul, Eugene W.; Cummer, Steven A.

    2013-01-01

    Narrow Bipolar Events (NBEs) are compact intracloud discharges that produce the most powerful lightning-related radio frequency signals that have been observed. However, their luminosity is below the threshold for detectability from current and past spaceborne optical sensors. NBEs have been loosely associated with convective intensity, but their occurrence tends to be highly localized in time and space within a thunderstorm, and there remain many questions about whether and to what extent they are significantly related to meteorological processes within thunderstorms. Using the North Alabama Lightning Mapping Array (NALMA), the National Lightning Detection Network, and available Doppler and polarimetric radar data, case studies will be presented for storm events that produced large numbers of NBEs (10s-100s) during their lifetimes. NBEs are documented via a method that identifies high peak power (>40-50 dBW) initial VHF sources within a specific altitude band in the upper levels of thunderstorms. The production of NBEs, including spatial and temporal variability, will be compared to the radar-inferred kinematic and microphysical structure and evolution of thunderstorms, as well as their NALMA- and NLDN-inferred electrical characteristics. The results should provide new insights into the relationships between NBEs and thunderstorm processes.

  17. Barotropic local instability and severe storm process

    Institute of Scientific and Technical Information of China (English)

    杨大升; 孙岚

    1997-01-01

    By means of barotropic model, the characteristic and initial value problems are investigated to reveal the local two-dimensional barotropic instability of the nonuniform current to the dynamic mechanism of the formation of the Yangtze-Huaihe River severe storm in July 1991. Analytical theory and numerical experiment show that (i) the unstable developing modes are chiefly the two periods of about 44d and 10 d, which are fundamentally consistent with that of the precipitation change of the Yangtze-Huaihe River, (ii) The growth rate of the local perturbation is dominated by the meridional wave number n = 1-5 and zonal wave number k = 1-12, i.e. the severe storm over the Yangtze-Huaihe River results from the interaction of the systems at different latitudes and waves of different scales, (iii) The perturbation over the Yangtze-Huaihe River possesses the property of local intensification, which slowly migrates westward over the lower and middle reaches of the Yangtze-Huaihe River, (iv) The growth rate of the

  18. Determination of design floods using storm data

    Science.gov (United States)

    Stallings, Eugene A.

    1987-12-01

    A brief historical perspective of hydrologic analyses used in the determination of spillway sizing is presented. The paper describes the procedures for determining a reasonable upper limit of flood potential for a given drainage basin. A previous paper by the National Weather Service detailed the development of probable maximum precipitation estimates. These estimates form the basis for the determination of spillway design floods which are used to size spillways of major reservoirs for the U.S. Army Corps of Engineers. Nationwide, the Corps has constructed hundreds of reservoirs which are operated for flood control, navigation, hydroelectric power and other purposes. These reservoirs are sized based on storm data and must withstand the most severe flood likely to occur. The paper also describes the design data including antecedent storms, infiltration, unit hydrographs and other hydrologic data used to convert probable maximum precipitation estimates into spillway design floods. Emphasis is given on designing safe reservoirs versus design flood selection based on economical considerations. Finally, a brief discussion of the similarities of design floods used by the other Federal construction agencies is presented.

  19. Simplified Storm Surge Simulations Using Bernstein Polynomials

    Science.gov (United States)

    Beisiegel, Nicole; Behrens, Jörn

    2016-04-01

    Storm surge simulations are vital for forecasting, hazard assessment and eventually improving our understanding of Earth system processes. Discontinuous Galerkin (DG) methods have recently been explored in that context, because they are locally mass-conservative and in combination with suitable robust nodal filtering techniques (slope limiters) positivity-preserving and well-balanced for the still water state at rest. These filters manipulate interpolation point values in every time step in order to retain the desirable properties of the scheme. In particular, DG methods are able to represent prognostic variables such as the fluid height at high-order accuracy inside each element (triangle). For simulations that include wetting and drying, however, the high-order accuracy will destabilize the numerical model because point values on quadrature points may become negative during the computation if they do not coincide with interpolation points. This is why the model that we are presenting utilizes Bernstein polynomials as basis functions to model the wetting and drying. This has the advantage that negative pointvalues away from interpolation points are prevented, the model is stabilized and no additional time step restriction is introduced. Numerical tests show that the model is capable of simulating simplified storm surges. Furthermore, a comparison of model results with third-order Bernstein polynomials with results using traditional nodal Lagrange polynomials reveals an improvement in numerical convergence.

  20. Levee Scour Protection for Storm Waves

    Science.gov (United States)

    Johnson, E.; Sustainable; Resiliency in Levee Scour Protection

    2011-12-01

    Earnest Johnson, Firat Y. Testik *, Nadarajah Ravichandran Civil Engineering, Clemson University, Clemson, SC, USA * Contact author ftestik@clemson.edu Levee failure due to scouring has been a prominent occurrence among intense storm surges and waves, giving rise to the implementation of various scour protection measures over the years. This study is to investigate the levee scour and to compare different scour protection measures on a model-levee system in a laboratory wave tank. The protection measures that are tested and compared for their effectiveness in this study include turf reinforcement mats, woven geotextiles, and core-locs. This is an ongoing research effort and experiments are currently being conducted with model levees constructed based upon the United States Army Corps of Engineers' levee design and construction guidelines under various simulated storm conditions. Parameters such as wave elevations, deformation time history of the floodwall, and the scour depth are measured in each test. The finding of this research will be translated to provide effective scour protection measures for robust levee designs.

  1. Solar Wind Charge Exchange During Geomagnetic Storms

    Science.gov (United States)

    Robertson, Ina P.; Cravens, Thomas E.; Sibeck, David G.; Collier, Michael R.; Kuntz, K. D.

    2012-01-01

    On March 31st. 2001, a coronal mass ejection pushed the subsolar magnetopause to the vicinity of geosynchronous orbit at 6.6 RE. The NASA/GSFC Community Coordinated Modeling Center (CCMe) employed a global magnetohydrodynamic (MHD) model to simulate the solar wind-magnetosphere interaction during the peak of this geomagnetic storm. Robertson et aL then modeled the expected 50ft X-ray emission due to solar wind charge exchange with geocoronal neutrals in the dayside cusp and magnetosheath. The locations of the bow shock, magnetopause and cusps were clearly evident in their simulations. Another geomagnetic storm took place on July 14, 2000 (Bastille Day). We again modeled X-ray emission due to solar wind charge exchange, but this time as observed from a moving spacecraft. This paper discusses the impact of spacecraft location on observed X-ray emission and the degree to which the locations of the bow shock and magnetopause can be detected in images.

  2. Geomagnetic storm and equatorial spread-F

    Directory of Open Access Journals (Sweden)

    F. Becker-Guedes

    2004-09-01

    Full Text Available In August 2000, a new ionospheric sounding station was established at Sao Jose dos Campos (23.2° S, 45.9° W; dip latitude 17.6° S, Brazil, by the University of Vale do Paraiba (UNIVAP. Another ionospheric sounding station was established at Palmas (10.2° S, 48.2° W; dip latitude 5.5° S, Brazil, in April 2002, by UNIVAP in collaboration with the Lutheran University Center of Palmas (CEULP, Lutheran University of Brazil (ULBRA. Both the stations are equipped with digital ionosonde of the type known as Canadian Advanced Digital Ionosonde (CADI. In order to study the effects of geomagnetic storms on equatorial spread-F, we present and discuss three case studies, two from the ionospheric sounding observations at Sao Jose dos Campos (September and November 2000 and one from the simultaneous ionospheric sounding observations at Sao Jose dos Campos and Palmas (July 2003. Salient features from these ionospheric observations are presented and discussed in this paper. It has been observed that sometimes (e.g. 4-5 November 2000 the geomagnetic storm acts as an inhibitor (high strong spread-F season, whereas at other times (e.g. 11-12 July 2003 they act as an initiator (low strong spread-F season, possibly due to corresponding changes in the quiet and disturbed drift patterns during different seasons.

  3. Spatiotemporal representation of cardiac vectorcardiogram (VCG signals

    Directory of Open Access Journals (Sweden)

    Yang Hui

    2012-03-01

    Full Text Available Abstract Background Vectorcardiogram (VCG signals monitor both spatial and temporal cardiac electrical activities along three orthogonal planes of the body. However, the absence of spatiotemporal resolution in conventional VCG representations is a major impediment for medical interpretation and clinical usage of VCG. This is especially so because time-domain features of 12-lead ECG, instead of both spatial and temporal characteristics of VCG, are widely used for the automatic assessment of cardiac pathological patterns. Materials and methods We present a novel representation approach that captures critical spatiotemporal heart dynamics by displaying the real time motion of VCG cardiac vectors in a 3D space. Such a dynamic display can also be realized with only one lead ECG signal (e.g., ambulatory ECG through an alternative lag-reconstructed ECG representation from nonlinear dynamics principles. Furthermore, the trajectories are color coded with additional dynamical properties of space-time VCG signals, e.g., the curvature, speed, octant and phase angles to enhance the information visibility. Results In this investigation, spatiotemporal VCG signal representation is used to characterize various spatiotemporal pathological patterns for healthy control (HC, myocardial infarction (MI, atrial fibrillation (AF and bundle branch block (BBB. The proposed color coding scheme revealed that the spatial locations of the peak of T waves are in the Octant 6 for the majority (i.e., 74 out of 80 of healthy recordings in the PhysioNet PTB database. In contrast, the peak of T waves from 31.79% (117/368 of MI subjects are found to remain in Octant 6 and the rest (68.21% spread over all other octants. The spatiotemporal VCG signal representation is shown to capture the same important heart characteristics as the 12-lead ECG plots and more. Conclusions Spatiotemporal VCG signal representation is shown to facilitate the characterization of space-time cardiac

  4. The assessment of the december 1999 storms; Le bilan des tempetes de decembre 1999

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2000-12-01

    During december 1999, big storms have greatly damage and sometimes destroy electric power transport and distribution networks. An assessment of the damages is evaluated and measures to repair and reinforce the future national grid system are presented. In this framework, the organization FIRE (Force d'Intervention Rapide Electricite) has been created by EDF to operate quickly in France and also abroad to restore the current. In the same time RTE implemented, Task Force, an organization able to outline quickly a diagnostic of damages, propose solutions and repair. These both organizations are presented. (A.L.B.)

  5. The effects of magnetic storm phases on F-layer irregularities from auroral to equatorial latitudes

    Science.gov (United States)

    Aarons, Jules; Mendillo, Michael

    1990-12-01

    Some topics of discussion in this journal include the following: The effects of electric field and ring current energy increases on F-layer irregularities at auroral and sub-auroral latitudes; The role of the ring current in generating or inhibiting equatorial F-layer irregularities during magnetic storms; Auroral and sub-auroral F-layer irregularities and high plasma convection during the magnetically active periods of September 17-24, 1984; and Simultaneous All-Sky Optical Airglow Imaging Observations and San Marco Satellite Measurements in the Pacific Sector.

  6. Storm-Time Substorms and Sawtooth Events: Test for Substorm Models

    Science.gov (United States)

    Pulkkinen, T. I.; Tanskanen, E. I.; Reeves, G. D.; Donovan, E.; Singer, H. J.; Slavin, J. A.

    2005-12-01

    A substorm search engine is used to identify substorm onsets that occur during magnetic storms in the period 2001-2004. Each substorm is analyzed in detail using several parameters to classify the events. Peak amplitude of the substorm is defined from the AL-index. Existence and type of energetic particle injections are determined from the LANL energetic ion and electron data. Tail magnetic field measurements (GOES, Cluster, Geotail) are used to infer whether a thin current sheet was formed prior to the substorm onset. Latitudinal magnetometer chains (CANOPUS, IMAGE) are used to determine whether the main expansion direction was poleward or equatorward. Possible triggers for the onset and intensity of the driving electric field are identified from the solar wind and interplanetary magnetic field measurements (ACE, WIND). The goal of the study is to statistically examine to what extent the stormtime substorms show signatures typically associated classical non-storm substorms and to what extent the activity is characteristic only of storm periods. Furthermore, the goal is to identify the "sawtooth events" from the data set, and examine whether the activation characteristics differ from the other stormtime activations.

  7. Evaluation of electrical bioimpedance analyzer and NT-proBNP on load capacity and ;cardiac function in patients with MHD/cardiac function in patients with MHD%生物电阻抗分析仪和N末端脑钠肽前体在维持性血液透析患者容量负荷与心功能评估中的应用

    Institute of Scientific and Technical Information of China (English)

    王建爽; 王艳辉; 杨文艳; 安影丹; 朱艳香

    2016-01-01

    目的:探讨生物电阻抗分析仪和N末端脑钠肽前体(NT-proBNP)在维持性血液透析(MHD)患者容量负荷与心功能评估中的应用价值。方法:选取64例MHD患者为透析组,同时选取58名健康志愿者为对照组。采用生物电阻抗分析仪测量两组细胞外液(ECW)及身体水分总量(TBW);采用电化学发光法检测透析组患者透析前及透析3个月后血浆NT-proBNP水平;应用彩色多普勒超声心动仪测定左心室舒张末内径(LVDd)、左心室收缩末内径(LVDs)、左心室后壁厚度(LVPWT)、左心室心肌质量指数(LVMI)以及左心室射血分数(LVEF)。肾小球滤过率估计值(eGFR)根据肾脏病饮食改良(MDRD)公式测定。结果:①MHD患者透析后与透析前比较,血NT-proBNP水平、TBW以及ECW/TBW明显降低,其差异显著(t=7.462,t=2.321, t=4.605;P<0.05);LVPMT、LVMI及LVEF明显改善,其差异显著(t=3.982,t=4.736, t=3.837;P<0.05),而LVDd与LVDs变化不明显;②MHD患者治疗后与对照组比较,其TBW、ECW/TBW无明显差异(t=1.098,t=0.503;P>0.05),提示治疗后患者的容量负荷参数已接近正常人群水平;③血NT-proBNP水平与ECW/TBW、NYHA分级、LVDd、LVDs、LVPWT以及LVMI呈正相关(r=0.246,r=0.809,r=0.341,r=0.249,r=0.253,r=0.329;P<0.05),与eGFR和LVEF呈负相关(r=-0.513,r=-0.360;P<0.05)。结论:生物电阻抗和NT-proBNP可有效用于MHD患者容量负荷及心功能评估,对于制定个体化治疗方案有一定应用价值。%Objective: To explore the evaluation value of electrical bioimpedance analyzer and NT-proBNP on load capacity and cardiac function in patients with MHD. Methods:64 cases of patients with MHD were choosed as the research objects (dialysis group), and 58 case of random healthy volunteers as the control group. Extracellular water (ECW) and total body water (TBW) were measured by the electrical bioimpedance analyzer in the two

  8. Intra-beat Scaling Properties of Cardiac Arrhythmias and Sudden Cardiac Death

    Science.gov (United States)

    Rodríguez, Eduardo; Lerma, Claudia; Echeverría, Juan C.; Alvarez-Ramirez, Jose

    2008-02-01

    We applied detrended fluctuation analysis (DFA) to characterize the intra-beat scaling dynamics of electrocardiographic (ECG) recordings from the PhysioNet Sudden Cardiac Death Holter Database. The main finding of this contribution is that, in such recordings involving different types of arrhythmias; the ECG waveform, besides showing a less-random intra-beat dynamics, becomes more regular during bigeminy, ventricular tachycardia (VT) or even atrial fibrillation (AFIB) and ventricular fibrillation (VF) despite the appearance of erratic traces. Thus, notwithstanding that these cardiac rhythm abnormalities are generally considered as irregular and some of them generated by random impulses or wavefronts, the intra-beat scaling properties suggest that regularity dominates the underlying mechanisms of arrhythmias. Among other explanations, this may result from shorted or restricted -less complex- pathways of conduction of the electrical activity within the ventricles.

  9. Mechanical communication in cardiac cell synchronized beating

    Science.gov (United States)

    Nitsan, Ido; Drori, Stavit; Lewis, Yair E.; Cohen, Shlomi; Tzlil, Shelly

    2016-05-01

    Cell-cell communication, which enables cells to coordinate their activity and is essential for growth, development and function, is usually ascribed a chemical or electrical origin. However, cells can exert forces and respond to environment elasticity and to mechanical deformations created by their neighbours. The extent to which this mechanosensing ability facilitates intercellular communication remains unclear. Here we demonstrate mechanical communication between cells directly for the first time, providing evidence for a long-range interaction that induces long-lasting alterations in interacting cells. We show that an isolated cardiac cell can be trained to beat at a given frequency by mechanically stimulating the underlying substrate. Deformations are induced using an oscillatory mechanical probe that mimics the deformations generated by a beating neighbouring cardiac cell. Unlike electrical field stimulation, the probe-induced beating rate is maintained by the cell for an hour after the stimulation stops, implying that long-term modifications occur within the cell. These long-term alterations provide a mechanism for cells that communicate mechanically to be less variable in their electromechanical delay. Mechanical coupling between cells therefore ensures that the final outcome of action potential pacing is synchronized beating. We further show that the contractile machinery is essential for mechanical communication.

  10. Responses of the low-latitude ionosphere to very intense geomagnetic storms

    Science.gov (United States)

    Sobral, J. H. A.; Abdu, M. A.; Yamashita, C. S.; Gonzalez, W. D.; de Gonzalez, A. C.; Batista, I. S.; Zamlutti, C. J.; Tsurutani, B. T.

    2001-01-01

    In this work, we investigate the ionospheric responses to exceptionally high-intensity and long-duration magnetic storms over Brazil. Disturbed ionospheric F-region vertical drifts and peak electron density changes observed at the equatorial station Fortaleza - Fz (/3°55'S /38°25'W /dip-3.5°) and the low-latitude station Cachoeira Paulista - CP /(22°41'S /45°00'W dip24°S), for three magnetospheric storm events that occurred in December 1980, April 1981 and September 1982, are analyzed. These storms had minimum Dst indexes /-240,-311 and /-289nT, respectively. The interplanetary magnetic field (Bz) data from the ISEE-3 satellite, the auroral activity index AE, and the ring current index Dst are used as indicators of the magnetospheric conditions. The ionospheric response features are analyzed using the F-layer critical parameters h'F, hpF2 and foF2, from ionograms obtained at Fz and CP. The Bz and the AE index variations were much higher than those in many previous studies. Therefore, many of the observations reported here either have not been observed or are not readily explained by current models for predicting the penetration//dynamo disturbance electric fields. The altitude of the nocturnal ionospheric F-layer at low latitudes may undergo significant variations during storm-time, caused by magnitude variations on the local zonal component of the F-region electric field intensity. During the period studied here, clear association of the F-layer rise (vertical velocity and altitude) and spread-F occurrence is observed. It is shown that the storm-time layer rise has a dominant role on the equatorial spread-F. An attempt is made to identify the origin of electric fields responsible for the disturbed F-layer alterations. The main conclusions of this study are that (a) some effects on the F-layer height and peak electron concentrations are consistent with model predictions. Some others are in discrepancy or have not been either predicted by model studies or

  11. Indeterminacy of Spatiotemporal Cardiac Alternans

    CERN Document Server

    Zhao, Xiaopeng

    2007-01-01

    Cardiac alternans, a beat-to-beat alternation in action potential duration (at the cellular level) or in ECG morphology (at the whole heart level), is a marker of ventricular fibrillation, a fatal heart rhythm that kills hundreds of thousands of people in the US each year. Investigating cardiac alternans may lead to a better understanding of the mechanisms of cardiac arrhythmias and eventually better algorithms for the prediction and prevention of such dreadful diseases. In paced cardiac tissue, alternans develops under increasingly shorter pacing period. Existing experimental and theoretical studies adopt the assumption that alternans in homogeneous cardiac tissue is exclusively determined by the pacing period. In contrast, we find that, when calcium-driven alternans develops in cardiac fibers, it may take different spatiotemporal patterns depending on the pacing history. Because there coexist multiple alternans solutions for a given pacing period, the alternans pattern on a fiber becomes unpredictable. Usin...

  12. Ativação elétrica ventricular na ressincronização cardíaca caracterizada pelo mapeamento eletrocardiográfico de superfície Ventricular electrical activation in cardiac resynchronization as characterized by body surface potential mapping

    Directory of Open Access Journals (Sweden)

    Carlos Alberto Pastore

    2007-03-01

    Full Text Available OBJETIVOS: Avaliar a ativação elétrica cardíaca usando Mapeamento Eletrocardiográfico de Superfície (MES, em pacientes com ICC e bloqueio de ramo esquerdo [BRE] submetidos a terapia de ressincronização cardíaca (CRT com implante de marca-passo átrio-biventricular (MP-BIV. MÉTODOS: Foram analisados os tempos médios de ativação elétrica cardíaca no ventrículo direito (tempo médio de ativação do VD [mVD], área ântero-septal (mAS, e ventrículo esquerdo (mVE, de 28 pacientes (idade média 61,2±9,5 anos, ICC classe III-IV NYHA, fração de ejeção OBJECTIVES: To assess cardiac electrical activation by using body surface potential mapping (BSPM, in patients with congestive heart failure (CHF and left bundle branch block (LBBB undergoing cardiac resynchronization therapy (CRT with biventricular pacemaker (BIV-PM implantation. METHODS: Mean cardiac electrical activation times were analyzed in the right ventricle (RV (mean RV activation time = mRV, anteroseptal area (mAS, and left ventricle (mLV of 28 patients (mean age 61.2 ± 9.5 years; NYHA class III-IV CHF; ejection fraction <40%; LBBB of mean QRS 181.2±19.4ms, SÂQRS -8.5º±68.6º, as shown in their BSPM isochronous maps, before and after implantation of atriobiventricular pacemaker, comparing those with values obtained from a control group of normal individuals [CG], in three situations: (1 native LBBB; (2 RV pacing; and (3 atriobiventricular pacing. RESULTS: Situation (1: mRV and mAS values were similar (41.0±11.8ms x 43.6±13.4ms, with delayed mLV (81.0±12.5ms, p<0.01 and asynchronous with RV and AS areas; situation (2: mRV was greater than in CG (86.8±22.9ms, p<0.001, with greater difference between mAS and mLV (63.4±20.7ms vs. 102.7±20.3ms; p<0,001; situation (3: mLV and mRV were similar (72.0±32.0ms vs. 71.6±32.3ms, mRV was greater than in CG and native LBBB (71.6±32.3ms vs. 35.1±10.9ms and 41.0±11.8ms; p<0.001, and mAS was close to CG and native LBBB values

  13. Comparison of Van Allen Probes radiation belt proton data with test particle simulation for the 17 March 2015 storm

    Science.gov (United States)

    Engel, M. A.; Kress, B. T.; Hudson, M. K.; Selesnick, R. S.

    2016-11-01

    The loss of protons in the outer part of the inner radiation belt (L = 2 to 3) during the 17 March 2015 geomagnetic storm was investigated using test particle simulations that follow full Lorentz trajectories with both magnetic and electric fields calculated from an empirical model. The simulation results presented here are compared with proton pitch angle measurements from the Van Allen Probe satellites Relativistic Electron Proton Telescope (REPT) instrument before and after the coronal mass ejection-shock-driven storm of 17-18 March 2015, with minimum Dst =- 223 nT, the strongest storm of Solar Cycle 24, for four different energy ranges with 30, 38, 50, and 66 MeV mean energies. Two simulations have been run, one with an inductive electric field and one without. All four energy channels show good agreement with the Van Allen Probes REPT measurements for low L (L 2.4. A previous study using the Highly Elliptical Orbiter 3 spacecraft also showed improved agreement when including the inductive electric field but was unable to compare effects on the pitch angle distributions.

  14. The Challenge of Predicting the Occurrence of Intense Storms

    Indian Academy of Sciences (India)

    Nandita Srivastava

    2006-06-01

    Geomagnetic super-storms of October and November 2003 are compared in order to identify solar and interplanetary variables that influence the magnitude of geomagnetic storms. Although these super-storms (DST < -300 nT) are associated with high speed CMEs, their DST indices show large variation. The most intense storm of November 20, 2003 (DST ∼ -472 nT) had its source in a comparatively small active region and was associated with a relatively weaker, M-class flare, while the others had their origins in large active regions and were associated with strong X-class flares. An attempt has been made to implement a logistic regression model for the prediction of the occurrence of intense/super-intense geomagnetic storms. The model parameters (regression coefficients) were estimated from a training data-set extracted from a data-set of 64 geo-effective CMEs observed during 1996–2002. The results indicate that logistic regression models can be effectively used for predicting the occurrence of major geomagnetic storms from a set of solar and interplanetary factors. The model validation shows that 100% of the intense storms (-200 nT < DST < -100 nT) and only 50% of the super-intense (DST < -200 nT) storms could be correctly predicted.

  15. Interannual variability of planet-encircling dust storms on Mars

    Science.gov (United States)

    Zurek, Richard W.; Martin, Leonard J.

    1993-01-01

    A recent review of earth-based telescopic observations of Mars together with Viking orbiter and lander data are employed to estimate the frequency of occurrence of planet-encircling dust storms over the past century and to test whether the period spanned by the Mariner 9 and Viking missions to Mars is representative of the decades prior to 1950. Both spacecraft and earth-based observations suggest that planet-encircling dust storms on Mars occur during a 'dust storm season' in southern spring and summer. Viking data show that planet-encircling dust storms could have occurred in the past on Mars without being detected from earth during years in which Mars was far from earth during the dust storm season. Planet-encircling storms were absent during the dust storm seasons monitored during several favorable oppositions prior to 1956 and after 1986. The change of a planet-encircling dust storm occurring in any arbitrary Mars year is estimated to be approximately one in three, if this occurrence is random from year to year and yet restricted seasonally to southern spring and summer.

  16. Wind fields of storms from surface isobars for wave hindcasting

    Digital Repository Service at National Institute of Oceanography (India)

    Varkey, M.J.; Vaithiyanathan, R.; Santanam, K.

    in plenty. The situation can be improved by hindcasting waves using wind fields of past storms. A method to hindcast storm wind fields is presented in this paper. The method is based on the standard Hydromet pressure profile. The input variables are, (1...

  17. Large-scale coastal impact induced by a catastrophic storm

    DEFF Research Database (Denmark)

    Fruergaard, Mikkel; Andersen, Thorbjørn Joest; Johannessen, Peter N

    of marine sand accumulated in an aggrading-prograding shoal and on a prograding shoreface during and within 3 to 4 decades (“healing phase”) after the most destructive storm documented for the Wadden Sea. Furthermore, we show that the impact of this storm caused large-scale shoreline erosion and barrier...

  18. Storm track processes and the opposing influences of climate change

    Science.gov (United States)

    Shaw, T. A.; Baldwin, M.; Barnes, E. A.; Caballero, R.; Garfinkel, C. I.; Hwang, Y.-T.; Li, C.; O'Gorman, P. A.; Rivière, G.; Simpson, I. R.; Voigt, A.

    2016-09-01

    Extratropical cyclones are storm systems that are observed to travel preferentially within confined regions known as storm tracks. They contribute to precipitation, wind and temperature extremes in mid-latitudes. Cyclones tend to form where surface temperature gradients are large, and the jet stream influences their speed and direction of travel. Storm tracks shape the global climate through transport of energy and momentum. The intensity and location of storm tracks varies seasonally, and in response to other natural variations, such as changes in tropical sea surface temperature. A hierarchy of numerical models of the atmosphere-ocean system -- from highly idealized to comprehensive -- has been used to study and predict responses of storm tracks to anthropogenic climate change. The future position and intensity of storm tracks depend on processes that alter temperature gradients. However, different processes can have opposing influences on temperature gradients, which leads to a tug of war on storm track responses and makes future projections more difficult. For example, as climate warms, surface shortwave cloud radiative changes increase the Equator-to-pole temperature gradient, but at the same time, longwave cloud radiative changes reduce this gradient. Future progress depends on understanding and accurately quantifying the relative influence of such processes on the storm tracks.

  19. Trauma induced thyroid storm complicated by multiple organ failure

    Institute of Scientific and Technical Information of China (English)

    Mehmet Kanbay; Aysegul Sengul; Nilgün Güvener

    2005-01-01

    @@ Thyroid storm is a state of severe hyperthyroidism perhaps accompanied by systemic organ decompensation. This is a life threatening condition. In this report, we present a case of thyroid storm caused by trauma, with several atypical features including multiple organ failure, elevated transaminases and acute renal failure. Prompt recognition and treatment is important in limiting the morbidity and mortality associated with this condition.

  20. Report on Damage in Storm 05.01.08

    DEFF Research Database (Denmark)

    Kofoed, Jens Peter; Friis-Madsen, Erik; Christensen, Lars;

    The report describes a number of observations at the energy converter Wave Dragon, Nissum Bredning, during the storm on January 8th 2005.......The report describes a number of observations at the energy converter Wave Dragon, Nissum Bredning, during the storm on January 8th 2005....

  1. Saline dust storms and their ecological impacts in arid regions

    Institute of Scientific and Technical Information of China (English)

    Jilili; Abuduwaili

    2010-01-01

    In many arid and semiarid regions,saline playas represent a significant source of unconsoli-dated sediments available for aeolian transport,and severe saline dust storms occur frequently due to human disturbance.In this study,saline dust storms are reviewed systematically from the aspects of con-cept,general characteristics,conditions of occurrence,distribution and ecological impact.Our researches showed that saline dust storms are a kind of chemical dust storm originating in dry lake beds in arid and semiarid regions;large areas of unconsolidated saline playa sediments and frequent strong winds are the basic factors to saline dust storm occurrence;there are differentiation characteristics in deposition flux and chemical composition with wind-blown distance during saline dust storm diffusion;and saline dust storm diffusion to some extent increases glacier melt and results in soil salinization in arid regions.An under-standing of saline dust storms is important to guide disaster prevention and ecological rehabilitation.

  2. Assessment of Modeling Capability for Reproducing Storm Impacts on TEC

    Science.gov (United States)

    Shim, J. S.; Kuznetsova, M. M.; Rastaetter, L.; Bilitza, D.; Codrescu, M.; Coster, A. J.; Emery, B. A.; Foerster, M.; Foster, B.; Fuller-Rowell, T. J.; Huba, J. D.; Goncharenko, L. P.; Mannucci, A. J.; Namgaladze, A. A.; Pi, X.; Prokhorov, B. E.; Ridley, A. J.; Scherliess, L.; Schunk, R. W.; Sojka, J. J.; Zhu, L.

    2014-12-01

    During geomagnetic storm, the energy transfer from solar wind to magnetosphere-ionosphere system adversely affects the communication and navigation systems. Quantifying storm impacts on TEC (Total Electron Content) and assessment of modeling capability of reproducing storm impacts on TEC are of importance to specifying and forecasting space weather. In order to quantify storm impacts on TEC, we considered several parameters: TEC changes compared to quiet time (the day before storm), TEC difference between 24-hour intervals, and maximum increase/decrease during the storm. We investigated the spatial and temporal variations of the parameters during the 2006 AGU storm event (14-15 Dec. 2006) using ground-based GPS TEC measurements in the selected 5 degree eight longitude sectors. The latitudinal variations were also studied in two longitude sectors among the eight sectors where data coverage is relatively better. We obtained modeled TEC from various ionosphere/thermosphere (IT) models. The parameters from the models were compared with each other and with the observed values. We quantified performance of the models in reproducing the TEC variations during the storm using skill scores. This study has been supported by the Community Coordinated Modeling Center (CCMC) at the Goddard Space Flight Center. Model outputs and observational data used for the study will be permanently posted at the CCMC website (http://ccmc.gsfc.nasa.gov) for the space science communities to use.

  3. A Bayesian network approach to coastal storm impact modeling

    NARCIS (Netherlands)

    Jäger, W.S.; Den Heijer, C.; Bolle, A.; Hanea, A.M.

    2015-01-01

    In this paper we develop a Bayesian network (BN) that relates offshore storm conditions to their accompagnying flood characteristics and damages to residential buildings, following on the trend of integrated flood impact modeling. It is based on data from hydrodynamic storm simulations, information

  4. Real-time analytics with Storm and Cassandra

    CERN Document Server

    Saxena, Shilpi

    2015-01-01

    If you want to efficiently use Storm and Cassandra together and excel at developing production-grade, distributed real-time applications, then this book is for you. No prior knowledge of using Storm and Cassandra together is necessary. However, a background in Java is expected.

  5. The Perfect Storm and the Privatization of Public Higher Education

    Science.gov (United States)

    Ehrenberg, Ronald G.

    2006-01-01

    During the last quarter of a century, public higher education institutions have found themselves buffeted by a perfect storm. This storm has led to discussions about the privatization of those institutions, which has implications for their ability to improve, or at least maintain, their quality and their accessibility to students from all…

  6. The interplanetary origins and the main-phase development of moderate geomagnetic storms (1978 - 1979). Ph. D. Thesis

    Energy Technology Data Exchange (ETDEWEB)

    Mendes, O. Jr.

    1992-08-01

    Geomagnetic storms are related to the ring current, which is driven by energy injection primarily during energetic solar wind-magnetosphere coupling due to reconnection at the magnetopause. This work identified the interplanetary origins of moderate geomagnetic storms (-100 nT less than or equal to Dst(MIN) less than -50 nT) and analyzed the coupling processes during the storm main phase. For this purpose the interplanetary magnetic field, solar-wind temperature, density and velocity data, obtained by the ISEE-3 satellite, were used together with the equatorial-Dst and auroral-AE geomagnetic indices, provided by the World Data Center, for the interval August/1978 - December/1979. 78 moderate storms were identified, in which 40 storm events (Dst beginning at approximately 0 nT) were selected. Related to these well defined events the following interplanetary origins were found: coronal mass ejections phenomena - CME (40 percent related to interplanetary shocks; 22.5 percent to single streams; 17.5 percent to streams interactions; 10 percent to non-compressive density enhancement) and non-CME phenomena (7.5 percent related to Alfven-like waves and 2.5 percent to no-identified feature). 47 percent of CME-phenomena occurred near the heliospheric current sheet. Regarding the main-phase development all energy coupling functions showed a similar behavior, that is, the south component of the interplanetary magnetic field (in the magnetospheric coordinate frame) controls basically this coupling. The best linear fits were given by Ey electric field-like and epsilon electric power-like functions. However the complexities in these coupling relations point to other simultaneous energy transfer processes such as non-proportional transference, viscous transference, and unloading' process.

  7. Storm Signatures and Irregularities in the Equatorial Ionosphere Observed by Using FORMOSAT-3/COSMIC (Invited)

    Science.gov (United States)

    Liu, J. G.; Chen, L.; Hsu, R.; Lee, I.; Chang, G.; Yu, S.; Liu, T.

    2013-12-01

    This paper reports that fluctuations in the vertical electron density triggering by magnetic storms and irregularities of S4 scintillations in the equatorial ionosphere probed by FORMOSAT-3/COSMIC (F3/C). For the storm study, the electron density profiles derived by the F3/C RO (radio occultation) in high-, mid- and low-latitudes during the quiet time and disturbed periods are subdivided into four sectors, noon, dusk, midnight, and dawn, to find wavy characteristics. The wavelet transformation is further applied to examine the profiles before and during the storm period. Above 300km, the ionosphere becomes very structured, and the amplitude in fluctuations of 15~30km wavelength significantly enhances during the storm period, especially high latitude region. The concurrence in changes of the geomagnetic index and the ionospheric density suggest that penetration electric fields and energy inputs at high latitudes play important roles. On the other hand, the F3/C RO provides an excellent opportunity to monitor three-dimensional structures and dynamics of the ionospheric scintillations during the low solar activity year of 2007-2013. Measurements of the global F3/C S4 index are subdivided and examined in various latitudes, longitudes, altitudes, and seasons. The F-region scintillations in the equatorial and low-latitude ionosphere start around post-sunset period and often persist till post-midnight hours (0300 MLT, magnetic local time) during the March and September equinox as well as December Solstice seasons. The E-region scintillations reveal a clear solar zenith effect and yield pronounced intensities in mid-latitudes during the Summer Solstice seasons, which are well correlated with occurrences of the sporadic E-layer. Finally, impact of the F3/C follow-on, FORMOSAT-7/COSMIC-2, mission on ionospheric space weather monitoring will be briefed.

  8. Investigation of a strong positive ionospheric storm during geomagnetic disturbances occurred in the Brazilian sector

    Science.gov (United States)

    de Abreu, A. J.; Sahai, Y.; Fagundes, P. R.; de Jesus, R.; Bittencourt, J. A.; Pillat, V. G.

    2012-12-01

    In this paper, we have investigated the responses of the ionospheric F region at equatorial and low latitude regions in the Brazilian sector during the super geomagnetic storm on 15-16 May 2005. The geomagnetic storm reached a minimum Dst of -263 nT at 0900 UT on 15 May. In this paper, we present vertical total electron content (vTEC) and phase fluctuations (in TECU/min) from Global Positioning System (GPS) observations obtained at Belém (BELE), Brasília (BRAZ), Presidente Prudente (UEPP), and Porto Alegre (POAL), Brazil, during the period 14-17 May 2005. Also, we present ionospheric parameters h'F, hpF2, and foF2, using the Canadian Advanced Digital Ionosonde (CADI) obtained at Palmas (PAL) and São José dos Campos (SJC), Brazil, for the same period. The super geomagnetic storm has fast decrease in the Dst index soon after SSC at 0239 UT on 15 May. It is a good possibility of prompt penetration of electric field of magnetospheric origin resulting in uplifting of the F region. The vTEC observations show a trough at BELE and a crest above UEPP, soon after SSC, indicating strengthening of nighttime equatorial anomaly. During the daytime on 15 and 16 May, in the recovery phase, the variations in foF2 at SJC and the vTEC observations, particularly at BRAZ, UEPP, and POAL, show large positive ionospheric storm. There is ESF on the all nights at PAL, in the post-midnight (UT) sector, and phase fluctuations only on the night of 14-15 May at BRAZ, after the SSC. No phase fluctuations are observed at the equatorial station BELE and low latitude stations (BRAZ, UEPP, and POAL) at all other times. This indicates that the plasma bubbles are generated and confined on this magnetically disturbed night only up to the low magnetic latitude and drifted possibly to west.

  9. 心内组织多普勒超声显像标测心脏传导系统心肌兴奋心肌电和机械兴奋多参数显像%Cardiac conductive system excitation maps using intracardiac ultrasound catheter with tissue Doppler imaging:multiparametric imaging of electrical and mechanical activation

    Institute of Scientific and Technical Information of China (English)

    尹立雪; 蔡力; 李春梅; 邓燕; 罗芸; 郑昌琼; 李德舆; 赵树魁

    2001-01-01

    feasible tissue Doppler maps of myocardial contraction in response to electrical activation of cardiac conductive system using intracardiac ultrasound catheter with high resolution tissue Doppler imaging (TDI).Methods Open-chest model of five dogs were used. An intracardiac ultrasound catheter with TDI capabilities was introduced into SVC, right atria and ventricle. The stimulating electrode was placed within ventricular subepicardium and subendocardium. 2D gray-scale ultrasonic examination was performed to observe the anatomic structure of sino-atrial node (SAN), right Koch's triangle, IVS and free ventricular wall. M-mode and 2D TDI were obtained to map myocardial velocity and acceleration with normal sinus rhyme at different sites of cardiac conductive system described above. Mapping of ventricular myocardial velocity and acceleration was performed during pacing. The regional myocardial excitation on the 2D TDI images was analyzed using a dedicated method for quantification.Results The detail anatomic structure of SAN with a dramatic increase of velocity and acceleration of SAN was presented at the beginning of atrial electrical excitation. The changes of velocity and acceleration of SAN as a time sequence curve quantitatively demonstrated the process of SAN′s excitation. A high value distribution of velocity and acceleration within right Koch′s triangle progressed into upper IVS before the early ventricular electrical excitation. The ventricular onset of myocardial velocity and acceleration induced by electrical stimulation was exactly at the location of electrical stimulating sites with size less than 5 mm, and coextended as concentric circle within ventricular wall. The delay of myocardial contraction is less than 7 ms.Conclusions The onset and propagation of myocardial velocity and acceleration can be defined within cardiac conductive system using intracardiac ultrasonic catheter with TDI. This techniqne will provide a simultaneous single visualization of

  10. Case Report: Penetrating Cardiac Injury

    Directory of Open Access Journals (Sweden)

    Adem Grbolar

    2013-10-01

    Full Text Available Summary: Penetrating cardiac injurys caused by gunshots and penetrating tools have high mortality rates. The way of injury, how the cardiac area is effected and the presence of cardiac tamponadecauses mortality in different rates. However the better treatment quality of hospitals, increasingoperative techniques, and internel care unit quality has not been change during the years. Searching the literature, we want to present a 42 years old male patient whowas injured by knife and had a 1 cm skin wound on chest with cardiac tamponade. After sternotomy a 7 cm laseration was observed in heart. Cardioraphy was performed.

  11. Cardiac surgery for Kartagener syndrome.

    Science.gov (United States)

    Tkebuchava, T; von Segesser, L K; Niederhäuser, U; Bauersfeld, U; Turina, M

    1997-01-01

    Two patients (one girl, one boy) with Kartagener syndrome (situs inversus, bronchiectasis, sinusitis), despite pulmonary problems and associated congenital cardiac anomalies, were operated on at the ages of 4 years and 7 years, respectively. They had had previous palliative treatment at the age of 3 months and 1.3 years, respectively. Both postoperative periods after total correction were without significant complications. Long-term follow-up was available for 9 and 19 years, respectively, with no manifestations of heart insufficiency. Both patients are physically active, and neither requires cardiac medication. Patients with Kartagener syndrome and associated congenital cardiac anomalies can successfully undergo multiple cardiac operations with good long-term outcome.

  12. Aconitine Challenge Test Reveals a Single Exposure to Air Pollution Causes Increased Cardiac Arrhythmia Risk in Hypertensive Rats - Abstract

    Science.gov (United States)

    Epidemiological studies demonstrate a significant association between arrhythmias and air pollution exposure. Sensitivity to aconitine-induced arrhythmia has been used repeatedly to examine the factors that increase the risk of such cardiac electrical dysfunction. In this study, ...

  13. Coastal Storm Modeling System (CoSMoS)

    Science.gov (United States)

    Barnard, Patrick; Erikson, Li; Foxgrover, Amy; Herdman, Liv; Limber, Patrick W; O'Neill, Andrea; Vitousek, Sean

    2015-01-01

    The Coastal Storm Modeling System (CoSMoS) makes detailed predictions (meter-scale) over large geographic scales (100s of kilometers) of storm-induced coastal flooding and erosion for both current and future SLR scenarios, as well as long-term shoreline change and cliff retreat. CoSMoS v3.0 for Southern California shows projections for future climate scenarios (sea-level rise and storms) to provide emergency responders and coastal planners with critical storm-hazards information that can be used to increase public safety, mitigate physical damages, and more effectively manage and allocate resources within complex coastal settings. Phase I data for Southern California includes 100-year storm flood hazard information for the coast from the Mexican Border to Pt. Conception. Flood projection data in the initial November release is limited to coastal areas within Los Angeles, San Diego, and Orange counties.

  14. A Review of Adsorbents Used for Storm Water Runoff Cleaning

    Directory of Open Access Journals (Sweden)

    Andrius Agintas

    2011-04-01

    Full Text Available Heavy metals, petroleum products, sediments and other pollutants get in the environment with insufficiently cleaned storm water runoff. Contaminated storm water runoff is one of the most significant sources for pollution in rivers, lakes and estuaries. Storm water runoff must be treated using not only simple methods but also using adsorption processes. Adsorbents can be natural organic, natural nonorganic and synthetic. Main adsorption characteristic, way of utilization and storm water runoff inflow rate, quantity and pollution need to be investigated when trying to use adsorbents in reasonably way. It is very important to treat storm water properly during the primary mechanical treatment otherwise adsorbents will act as mechanical filters.Article in Lithuanian

  15. Modeling the recovery phase of extreme geomagnetic storms

    CERN Document Server

    Cid, C; Saiz, E; Cerrato, Y; Aguado, J; Guerrero, A

    2014-01-01

    The recovery phase of the largest storms ever recorded has been studied. These events provide an extraordinary opportunity for two goals: (1) to validate the hyperbolic model by Aguado et al. [2010] for the recovery phase after disturbances as severe as the Carrington event, or that related to the Hydro-Quebec blackout in March 1989, and (2) to check whether the linear relationship between the recovery time and the intensity of the storm still complies. Our results reveal the high accuracy of the hyperbolic decay function to reproduce the recovery phase of the magnetosphere after an extreme storm. Moreover, the characteristic time that takes the magnetosphere to recover depends in an exponential way on the intensity of the storm, as indicated by the relationship between the two parameters involved in the hyperbolic decay. This exponential function can be approached by a linear function when the severity of the storm diminishes.

  16. Variation of curve number with storm depth

    Science.gov (United States)

    Banasik, K.; Hejduk, L.

    2012-04-01

    The NRCS Curve Number (known also as SCS-CN) method is well known as a tool in predicting flood runoff depth from small ungauged catchment. The traditional way of determination the CNs, based on soil characteristics, land use and hydrological conditions, seemed to have tendency to overpredict the floods in some cases. Over 30 year rainfall-runoff data, collected in two small (A=23.4 & 82.4 km2), lowland, agricultural catchments in Center of Poland (Banasik & Woodward 2010), were used to determine runoff Curve Number and to check a tendency of changing. The observed CN declines with increasing storm size, which according recent views of Hawkins (1993) could be classified as a standard response of watershed. The analysis concluded, that using CN value according to the procedure described in USDA-SCS Handbook one receives representative value for estimating storm runoff from high rainfall depths in the analyzes catchments. This has been confirmed by applying "asymptotic approach" for estimating the watershed curve number from the rainfall-runoff data. Furthermore, the analysis indicated that CN, estimated from mean retention parameter S of recorded events with rainfall depth higher than initial abstraction, is also approaching the theoretical CN. The observed CN, ranging from 59.8 to 97.1 and from 52.3 to 95.5, in the smaller and the larger catchment respectively, declines with increasing storm size, which has been classified as a standard response of watershed. The investigation demonstrated also changeability of the CN during a year, with much lower values during the vegetation season. Banasik K. & D.E. Woodward (2010). "Empirical determination of curve number for a small agricultural watrshed in Poland". 2nd Joint Federal Interagency Conference, Las Vegas, NV, June 27 - July 1, 2010 (http://acwi.gov/sos/pubs/2ndJFIC/Contents/10E_Banasik_ 28_02_10. pdf). Hawkins R. H. (1993). "Asymptotic determination of curve numbers from data". Journal of Irrigation and Drainage

  17. Images as drivers of progress in cardiac computational modelling.

    Science.gov (United States)

    Lamata, Pablo; Casero, Ramón; Carapella, Valentina; Niederer, Steve A; Bishop, Martin J; Schneider, Jürgen E; Kohl, Peter; Grau, Vicente

    2014-08-01

    Computational models have become a fundamental tool in cardiac research. Models are evolving to cover multiple scales and physical mechanisms. They are moving towards mechanistic descriptions of personalised structure and function, including effects of natural variability. These developments are underpinned to a large extent by advances in imaging technologies. This article reviews how novel imaging technologies, or the innovative use and extension of established ones, integrate with computational models and drive novel insights into cardiac biophysics. In terms of structural characterization, we discuss how imaging is allowing a wide range of scales to be considered, from cellular levels to whole organs. We analyse how the evolution from structural to functional imaging is opening new avenues for computational models, and in this respect we review methods for measurement of electrical activity, mechanics and flow. Finally, we consider ways in which combined imaging and modelling research is likely to continue advancing cardiac research, and identify some of the main challenges that remain to be solved.

  18. Optogenetics for in vivo cardiac pacing and resynchronization therapies.

    Science.gov (United States)

    Nussinovitch, Udi; Gepstein, Lior

    2015-07-01

    Abnormalities in the specialized cardiac conduction system may result in slow heart rate or mechanical dyssynchrony. Here we apply optogenetics, widely used to modulate neuronal excitability, for cardiac pacing and resynchronization. We used adeno-associated virus (AAV) 9 to express the Channelrhodopsin-2 (ChR2) transgene at one or more ventricular sites in rats. This allowed optogenetic pacing of the hearts at different beating frequencies with blue-light illumination both in vivo and in isolated perfused hearts. Optical mapping confirmed that the source of the new pacemaker activity was the site of ChR2 transgene delivery. Notably, diffuse illumination of hearts where the ChR2 transgene was delivered to several ventricular sites resulted in electrical synchronization and significant shortening of ventricular activation times. These findings highlight the unique potential of optogenetics for cardiac pacing and resynchronization therapies.

  19. European Winter Storms in the ECMWF Ensemble Prediction System

    Science.gov (United States)

    Osinski, Robert; Lorenz, Philip; Kruschke, Tim; Leckebusch, Gregor C.; Ulbrich, Uwe

    2013-04-01

    As European winter storms can provoke very large damages, estimations of the probability of occurrence are of economical and sociological importance. The estimations of return periods for the strongest events underlie large uncertainties, which arise from the limited available data, available from historical meteorological records or reanalysis data. A gain of information can be obtained from ensemble forecasts. In this work the Ensemble Prediction System (EPS) from the European Center of Medium-Range Weather Forecast (ECMWF) is analyzed for its suitability to improve the estimates of return periods of very rare and severe events. The EPS dataset contains up to 51 ensemble members, starting twice a day and each integrated over 10 days. The storm systems are identified and characterized using a wind field tracking algorithm developed by Leckebusch et al. (2008). Exceedances of the local 98th percentile of 10m wind speed are used, and calculating the cube of these exceedances, accumulated spatially and temporally, an objective storm severity measure (SSI) is determined. Taking the distribution of values into account, the measure of storm severity relates to storm damages. Using ERA-Interim as a reference dataset, it is shown that the general distributions of storm properties in the EPS are realistic. The EPS representations of a single ERA-Interim storm show a wide range of variability in terms of size, duration and severity. Hence better estimations of return periods of winter storms are possible using the EPS, as well as studies of general aspects of storms, like the correlation between intensification and storm duration. Nevertheless for an estimation of return periods, it must be taken into account, that the simulated events in the EPS are not independent of each other.

  20. Characteristics and sources of 2002 super dust storm in Beijing

    Institute of Scientific and Technical Information of China (English)

    SUN Yele; ZHUANG Guoshun; YUAN Hui; ZHANG Xingying; GUO Jinghua

    2004-01-01

    On 20 March, 2002, a super dust storm attacked Beijing, which was stronger than any dust storm ever recorded. The concentration of total suspended particulates air quality standard. The concentrations of major crustal elements, such as Ca, Al, Fe, Na, Mg and Ti, were 30-58times higher than those in non-dust storm days. The concentrations of pollution elements, such as Zn, Cu, Pb, As, Cd and S, were also about several or even nearly ten times higher than those in normal days. The enrichment factors of Pb, As, Cd and S in PM2.5 were as high as 12.7, 29.6, 43.5,28.4, indicating that these pollutants came from the mixing of mineral aerosol with pollution aerosol emitted by pollution sources on the way of dust storm's long-range transport. The overlap of invaded air mass from dust with pollution air mass from Beijing local area was another reason for the enhancement of pollutants. During dust storm, fine particles (PM2.5) accounted for 30% of TSP and pollutants in PM2.5accounted for even as high as 45%-69% of TSP. The increase of pollutants after dust storm proved further that mineral aerosol, especially the fine particles from dust storm favored the transformation and accumulation of pollutants.It must be noted that Fe (Ⅱ) was detected again in this dust storm, which provided new evidence for the mechanism of coupling and feedback between iron and sulfur in the atmosphere and the ocean. The increase of both pollutants and nutrient, Fe(Ⅱ), during dust storm illuminated that dust storm is an important factor affecting the global environment change.

  1. Selection of an appropriately simple storm runoff model

    Directory of Open Access Journals (Sweden)

    A. I. J. M. van Dijk

    2009-09-01

    Full Text Available Alternative conceptual storm runoff models, including several published ones, were evaluated against storm flow time series for 260 catchments in Australia (23–1902 km2. The original daily streamflow data was separated into baseflow and storm flow components and from these, event rainfall and storm flow totals were estimated. For each tested model structure, the number of free parameters was reduced in stages. The appropriate balance between simplicity and explanatory power was decided based on Aikake's Final Prediction Error Criterion and evidence of parameter equivalence. The majority of catchments showed storm recession half-times in the order of a day, with more rapid drainage in dry catchments. Overland and channel travel time did not appear to be an important driver of storm flow recession. A storm runoff model with two free parameters (one related to storm event size, the other to antecedent baseflow and a fixed initial loss of 12 mm provided the optimal model structure. The optimal model had some features similar to the Soil Conservation Service Curve Number technique, but performed an average 12 to 19% better. The non-linear relationship between event rainfall and event runoff may be associated with saturated area expansion during storms and/or the relationship between storm event size and peak rainfall intensity. Antecedent baseflow was a strong predictor of runoff response. A simple conceptual relationship between groundwater storage and saturated catchment area proved adequate and produced realistic estimates of saturated area of <0.1% for the driest and >5% for the wettest catchments.

  2. Dynamical Systems, Cytokine Storms, and Blood Filtration

    Science.gov (United States)

    Foster, Glenn; Hubler, Alfred

    2008-03-01

    Various infections and non-infectious diseases can trigger immune cells and the proteins (cytokines) the cells use to communicate with each other to be caught in a positive feedback loop; this ``cytokine storm'' is frequently fatal. By examining the network of cytokine-immune cell interactions we will illustrate why anti-mediator drugs have been generally ineffective in stopping this feedback. A more effective approach may be to try and reduce interactions by dampening many signals at once by filtering the cytokines out of the blood directly (think dialysis). We will argue that feedback on an out of control nonlinear dynamical system is easier to understand than its normal healthy state and apply filtration to a toy model of immune response.

  3. Apollo 12 - On the Ocean of Storms

    CERN Document Server

    Harland, David

    2011-01-01

    With its two moonwalks, deployment of a geophysical station and geological sampling, Apollo 12 did what many had hoped would be achieved by the first men to land on the Moon. It spectacularly demonstrated the precision landing capability required for the success of future lunar surface explorations. Apollo 12 - On the Ocean of Storms contains over 30 page of color images, including high-resolution scans recently produced by NASA from the original Hasselblad film; covers the mission from its planning through to completion; includes conversations among the crew in the spacecraft that were not transmitted; in the definitive 'popular' account of this mission. This is the first time in 40 years that the story of the Apollo 12 mission to the Moon has bene told in its entirety, using official documents, flight transcripts, and post-mission debriefing to recreate the drama.

  4. nuSTORM: Neutrinos from STORed Muons

    CERN Document Server

    Kyberd, P; Coney, L; Pascoli, S; Ankenbrandt, C; Brice, S J; Bross, A D; Cease, H; Kopp, J; Mokhov, N; Morfin, J; Neuffer, D; Popovic, M; Rubinov, P; Striganov, S; Blondel, A; Bravar, A; Noah, E; Bayes, R; Soler, F J P; Dobbs, A; Long, K; Pasternak, J; Santos, E; Wascko, M O; Agarwalla, S K; Bogacz, S A; Mori, Y; Lagrange, J B; de Gouvêa, A; Kuno, Y; Sato, A; Blackmore, V; Cobb, J; Tunnell, C D; Link, J M; Huber, P; Winter, W

    2012-01-01

    The results of LSND and MiniBooNE, along with the recent papers on a possible reactor neutrino flux anomaly give tantalizing hints of new physics. Models beyond the neutrino-SM have been developed to explain these results and involve one or more additional neutrinos that are non-interacting or "sterile." Neutrino beams produced from the decay of muons in a racetrack-like decay ring provide a powerful way to study this potential new physics. In this Letter of Intent, we describe a facility, nuSTORM, "Neutrinos from STORed Muons," and an appropriate far detector for neutrino oscillation searches at short baseline. We present sensitivity plots that indicated that this experimental approach can provide over 10 sigma confirmation or rejection of the LSND/MinBooNE results. In addition we indicate how the facility can be used to make precision neutrino interaction cross section measurements important to the next generation of long-baseline neutrino oscillation experiments.

  5. nuSTORM: Neutrinos from STORed Muons

    Energy Technology Data Exchange (ETDEWEB)

    Bross, Alan [Fermi National Accelerator Laboratory, Batavia, IL 60510 (United States)

    2015-05-15

    The results of LSND and MiniBooNE, along with the recent papers on a possible reactor neutrino flux anomaly, give tantalizing hints of new physics. Models beyond the νSM have been developed to explain these results and involve one or more additional neutrinos that are non-interacting or “sterile.” Neutrino beams produced from the decay of muons in a racetrack-like decay ring provide a powerful way to study this potential new physics. In this paper, I will describe the facility, nuSTORM, and an appropriate far detector for neutrino oscillation searches at short baseline. I will present sensitivity plots that indicated that this experimental approach can provide well over 5 σ confirmation or rejection of the LSND/MinBooNE results.

  6. Eicosanoid storm in infection and inflammation.

    Science.gov (United States)

    Dennis, Edward A; Norris, Paul C

    2015-08-01

    Controlled immune responses to infection and injury involve complex molecular signalling networks with coordinated and often opposing actions. Eicosanoids and related bioactive lipid mediators derived from polyunsaturated fatty acids constitute a major bioactive lipid network that is among the most complex and challenging pathways to map in a physiological context. Eicosanoid signalling, similar to cytokine signalling and inflammasome formation, has primarily been viewed as a pro-inflammatory component of the innate immune response; however, recent advances in lipidomics have helped to elucidate unique eicosanoids and related docosanoids with anti-inflammatory and pro-resolution functions. This has advanced our overall understanding of the inflammatory response and its therapeutic implications. The induction of a pro-inflammatory and anti-inflammatory eicosanoid storm through the activation of inflammatory receptors by infectious agents is reviewed here.

  7. NASA's Radiation Belt Storm Probe Mission

    Science.gov (United States)

    Sibeck, David G.

    2011-01-01

    NASA's Radiation Belt Storm Probe (RBSP) mission, comprising two identically-instrumented spacecraft, is scheduled for launch in May 2012. In addition to identifying and quantifying the processes responsible for energizing, transporting, and removing energetic particles from the Earth's Van Allen radiation, the mission will determine the characteristics of the ring current and its effect upon the magnetosphere as a whole. The distances separating the two RBSP spacecraft will vary as they move along their 1000 km altitude x 5.8 RE geocentric orbits in order to enable the spacecraft to separate spatial from temporal effects, measure gradients that help identify particle sources, and determine the spatial extent of a wide array of phenomena. This talk explores the scientific objectives of the mission and the manner by which the mission has been tailored to achieve them.

  8. Review of techniques for magnetic storm forecasting

    Science.gov (United States)

    Detman, Thomas R.; Vassiliadis, Dimitris

    Today a wide variety of techniques are available for nowcasting and forecasting magnetic storm activity. A brief review of linear time series prediction techniques, with examples, is used to lay a foundation for the description of newer non-linear techniques based on state-space reconstruction. We illustrate the state-space prediction technique in application to predict Dst from ISEE-3 solar wind data. Upstream solar wind data, such as from ISEE-3 or WTND close to the L1 libration point, provide a prediction lead time of 0.5-1.5 hours. To go beyond the L1 prediction lead time some information about the solar wind between the Li point and the Sun is required. Remote sensing is the measurement of something from a distance, like solar magnetograms or X-ray images. Both empirical and physically based models, driven by remote sensing data, promise a way to make forecasts a few days into the future. A combination of the statistical time series prediction techniques operating on the output of physically based models, driven by remote sensing data, may offer the first capability of predicting magnetic storms a few days in advance. We illustrate this combination of techniques using the output of a potential field model [Wang and Sheeley, 1988] as input to a linear prediction filter to forecast the planetary geomagnetic index. Finally, practical forecasting requires verification. We describe some of the standard measures of forecast performance: skill score, prediction efficiency, and correlation coefficient. The value of cross validation testing is emphasized.

  9. September 2013 Storm and Flood Assessment Report

    Energy Technology Data Exchange (ETDEWEB)

    Walterscheid, J. C. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2015-12-21

    Between September 10 and 17, 2013, New Mexico and Colorado received a historically large amount of precipitation (Figure 1). This report assesses the damage caused by flooding along with estimated costs to repair the damage at Los Alamos National Laboratory (the Laboratory) on the Pajarito Plateau. Los Alamos County, New Mexico, received between 200% and 600% of the normal precipitation for this time period (Figure 2), and the Laboratory received approximately 450% percent of its average precipitation for September (Figure 3). As a result, the Laboratory was inundated with rain, including the extremely large, greater-than-1000-yr return period event that occurred between September 12 and 13 (Table 1). With saturated antecedent soil conditions from the September 10 storm, when the September 12 to September 13 storm hit, the flooding was disastrous to the Laboratory’s environmental infrastructure, including access roads, gage stations, watershed controls, control measures installed under the National Pollutant Discharge Elimination System Permit (hereafter, the Individual Permit), and groundwater monitoring wells (Figures 4 through 21). From September 16 to October 1, 2013, the Laboratory completed field assessments of environmental infrastructure and generated descriptions and estimates of the damage, which are presented in spreadsheets in Attachments 1 to 4 of this report. Section 2 of this report contains damage assessments by watershed, including access roads, gage stations, watershed controls, and control measures installed under the Individual Permit. Section 3 contains damage assessments of monitoring wells by the groundwater monitoring groups as established in the Interim Facility-Wide Groundwater Monitoring Plan for Monitoring Year 2014. Section 4 addresses damage and loss of automated samplers. Section 5 addresses sediment sampling needs, and Section 6 is the summary of estimated recovery costs from the significant rain and flooding during September 2013.

  10. Cardiac Catheterization (For Teens)

    Science.gov (United States)

    ... heart's electrical activity. Doctors also might do an echocardiogram (ECHO), a test that uses sound waves to ... stomach can increase the risk of complications from anesthesia. You'll be able to eat and drink ...

  11. BmKⅠ,an α-like scorpion neurotoxin,specifically modulates isolated rat cardiac mechanical and electrical activity%类α-蝎神经毒素BmKⅠ对离体大鼠心脏收缩力及电活动的特异调控

    Institute of Scientific and Technical Information of China (English)

    孙海英; 朱海峰; 吉永华

    2003-01-01

    本研究探讨了一种特异性钠通道调制剂(Buthus martensi Karsch,BmKⅠ)对离体大鼠心脏收缩力及电活动的调制作用.离体心脏灌流实验显示:(1)BmKⅠ(0.5-10 μmol/L)剂量依赖地增强大鼠心肌收缩力,左心室最大发展压(LVDPmax)以及dp/dtmax与对照组相比均显著增强(n=6,P<0.05),同时可触发正性变时作用(n=6,P<0.05);(2)大剂量BmKⅠ(20μmol/L)引起负性肌力作用及心动过缓;(3)冠脉流量随心脏收缩力的增强反而减小,应用500nmol/L BmKⅠ时冠脉流量由14.5 ml/min降至8.6 ml/min(n=6,P<0.05);此外,心电图记录表明BmKⅠ(0.5-10μmol/L)可触发心动过速及复杂的心律失常等电活动变化;正常灌流液洗脱后BmKI引起的大鼠心脏收缩力及电活动的改变可部分恢复.由于β-肾上腺素能受体阻滞剂普奈洛尔预先应用抑制了儿茶酚胺类神经递质的释放,提示BmKⅠ引起的大鼠心脏收缩力及电活动的改变不是由于其调节儿茶酚胺类神经递质的释放及随后β-肾上腺素能受体的激活,而可能与其对心肌电压门控钠通道的调控有关.%In this study, cardiotonic and cardiotoxic effects of Buthus martensi Karsch (BmK)Ⅰ, a modulator of voltage-gated sodium channels, were investigated on the isolated rat hearts. The results showed that BmKⅠ evoked complex effects characterized by a change in both cardiac mechanical and electrical activity. Langendorff perfusion showed that: ( 1 ) maximal left ventricular developed pressure (LVDPmax) and dp/dtmax were markedly increased by BmKⅠ (0.5 -10 mol/L) in a dose-dependent manner (n =6, P<0.05), positive chronotropic effects were also induced by BmKⅠ (n=6, P<0.05); (2) negative inotropic action and bradycardia could be elicited at a larger dose of BmKⅠ(20μ mol/L); (3) the coronary flow varied inversely with the positive inotropic effects, coronary flow reduced during positive inotropic effects from 14. 5 to 8. 6 ml/min after

  12. Analysis of the monitoring data of geomagnetic storm interference in the electrification system of a high-speed railway

    Science.gov (United States)

    Liu, Lianguang; Ge, Xiaoning; Zong, Wei; Zhou, You; Liu, Mingguang

    2016-10-01

    To study the impact of geomagnetic storm on the equipment of traction electrification system in the high-speed railway, geomagnetically induced current (GIC) monitoring devices were installed in the Hebi East traction power supply substation of the Beijing-Hong Kong Dedicated Passenger Line in January 2015, and GICs were captured during the two geomagnetic storms on 17 March and 23 June 2015. In order to investigate the GIC flow path, both in the track circuit and in the traction network adopting the autotransformer feeding system, a GIC monitor plan was proposed for the electrical system in the Hebi East traction power supply substation. This paper analyzes the correlation between the GIC captured on 17 March and the geomagnetic data obtained from the Malingshan Geomagnetic Observatory and presents a regression analysis between the measured GIC and the calculated geoelectric fields on 23 June in the high-speed railway. The maximum GICs measured in the track circuit are 1.08 A and 1.74 A during the two geomagnetic storms. We find that it is necessary to pay attention on the throttle transformers and track circuits, as the most sensitive elements responding to the extreme geomagnetic storms in the high-speed railway.

  13. Positive ionospheric storm effects at Latin America longitude during the superstorm of 20–22 November 2003: revisit

    Directory of Open Access Journals (Sweden)

    B. Zhao

    2012-05-01

    Full Text Available Positive ionospheric storm effects that occurred during the superstorm on 20 November 2003 are investigated using a combination of ground-based Global Positioning System (GPS total electron content (TEC, and the meridian chain of ionosondes distributed along the Latin America longitude of ~280° E. Both the ground-based GPS TEC and ionosonde electron density profile data reveal significant enhancements at mid-low latitudes over the 280° E region during the main phase of the November 2003 superstorm. The maximum enhancement of the topside ionospheric electron content is 3.2–7.7 times of the bottomside ionosphere at the locations of the ionosondes distributed around the mid- and low latitudes. Moreover, the height of maximum electron density exceeds 400 km and increases by 100 km compared with the quiet day over the South American area from middle to low latitudes, which might have resulted from a continuous eastward penetration electric field and storm-generated equatorward winds. Our results do not support the conclusions of Yizengaw et al. (2006, who suggested that the observed positive storm over the South American sector was mainly the consequence of the changes of the bottomside ionosphere. The so-called "unusual" responses of the topside ionosphere for the November 2003 storm in Yizengaw et al. (2006 are likely associated with the erroneous usage of magnetometer and incomplete data.

  14. Electricity Customers

    Science.gov (United States)

    This page discusses key sectors and how they use electricity. Residential, commercial, and industrial customers each account for roughly one-third of the nation’s electricity use. The transportation sector also accounts for a small fraction of electricity.

  15. Energy balance during intense and super-intense magnetic storms using an Akasofu ɛ parameter corrected by the solar wind dynamic pressure

    Science.gov (United States)

    de Lucas, A.; Gonzalez, W. D.; Echer, E.; Guarnieri, F. L.; Dal Lago, A.; da Silva, M. R.; Vieira, L. E. A.; Schuch, N. J.

    2007-11-01

    Geomagnetic storms are large disturbances in the Earth's magnetosphere caused by enhanced solar wind magnetosphere energy transfer. One of the main manifestations of a geomagnetic storm is the ring current enhancement. It is responsible for the decrease in the geomagnetic field observed at ground stations. In this work, we study the ring current dynamics during two different levels of magnetic storms. Thirty-three events are selected during the period 1981 2004. Eighteen out of 33 events are very intense (or super-intense) magnetic storms (Dst ⩽-250 nT) and the remaining are intense magnetic storms (-250ISEE-3) and geomagnetic indices (Dst and Sym-H) are analyzed. Our aim is to evaluate the interplanetary characteristics (interplanetary dawn dusk electric field, interplanetary magnetic field component BS), the ɛ parameter, and the total energy input into the magnetosphere (Wɛ) for these two classes of magnetic storms. Two corrections on the ɛ energy coupling function are made: the first one is an already known correction in the magnetopause radius to take into account the variation in the solar wind pressure. The second correction on the Akasofu parameter, first proposed in this work, accounts for the reconnection efficiency as a function of the solar wind ram pressure. Geomagnetic data/indices are also employed to study the ring current dynamics and to search for the differences in the storm evolution during these events. Our corrected ɛ parameter is shown to be more adequate to explain storm energy balance because the energy input and the energy dissipated in the ring current are in better agreement with modern estimates as compared with previous works. For super-intense storms, the correction of the Akasofu ɛ is on average a scaling factor of 3.7, whilst for intense events, this scaling factor is on average 3.4. The injected energy during the main phase using corrected ɛ can be considered a criterion to separate intense from very intense storms. Other

  16. Hypokalemia and sudden cardiac death

    DEFF Research Database (Denmark)

    Kjeldsen, Keld

    2010-01-01

    Worldwide, approximately three million people suffer sudden cardiac death annually. These deaths often emerge from a complex interplay of substrates and triggers. Disturbed potassium homeostasis among heart cells is an example of such a trigger. Thus, hypokalemia and, also, more transient...... of fatal arrhythmia and sudden cardiac death a patient is, the more attention should be given to the potassium homeostasis....

  17. The Danish Cardiac Rehabilitation Database

    DEFF Research Database (Denmark)

    Zwisler, Ann-Dorthe; Rossau, Henriette Knold; Nakano, Anne

    2016-01-01

    AIM OF DATABASE: The Danish Cardiac Rehabilitation Database (DHRD) aims to improve the quality of cardiac rehabilitation (CR) to the benefit of patients with coronary heart disease (CHD). STUDY POPULATION: Hospitalized patients with CHD with stenosis on coronary angiography treated with percutane...

  18. Biosynthesis of cardiac natriuretic peptides

    DEFF Research Database (Denmark)

    Goetze, Jens Peter

    2010-01-01

    . An inefficient post-translational prohormone maturation will also affect the biology of the cardiac natriuretic peptide system. This review aims at summarizing the myocardial synthesis of natriuretic peptides focusing on B-type natriuretic peptide, where new data has disclosed cardiac myocytes as highly...

  19. [Cardiac myxoma with cerebral metastases].

    Science.gov (United States)

    Bazin, A; Peruzzi, P; Baudrillard, J C; Pluot, M; Rousseaux, P

    1987-01-01

    A 56 year old woman developed multiple metastases in the cerebrum and cerebellum, four years after cardiac intervention on a left atrial myxoma. The absence of stroke is noteworthy. Multiple high density lesions with contrast enhancement were seen by CT scan, suggesting metastatic neoplasms. Histological examination confirmed the diagnosis of metastases of cardiac myxoma. Only four cases were recorded in the literature.

  20. Health Instruction Packages: Cardiac Anatomy.

    Science.gov (United States)

    Phillips, Gwen; And Others

    Text, illustrations, and exercises are utilized in these five learning modules to instruct nurses, students, and other health care professionals in cardiac anatomy and functions and in fundamental electrocardiographic techniques. The first module, "Cardiac Anatomy and Physiology: A Review" by Gwen Phillips, teaches the learner to draw…

  1. Pneumothorax in cardiac pacing

    DEFF Research Database (Denmark)

    Kirkfeldt, Rikke Esberg; Johansen, Jens Brock; Nohr, Ellen Aagaard;

    2012-01-01

    AIM: To identify risk factors for pneumothorax treated with a chest tube after cardiac pacing device implantation in a population-based cohort.METHODS AND RESULTS: A nationwide cohort study was performed based on data on 28 860 patients from the Danish Pacemaker Register, which included all Danish...... patients who received their first pacemaker (PM) or cardiac resynchronization device from 1997 to 2008. Multiple logistic regression was used to estimate adjusted odds ratios (aOR) with 95% confidence intervals for the association between risk factors and pneumothorax treated with a chest tube. The median...... age was 77 years (25th and 75th percentile: 69-84) and 55% were male (n = 15 785). A total of 190 patients (0.66%) were treated for pneumothorax, which was more often in women [aOR 1.9 (1.4-2.6)], and in patients with age >80 years [aOR 1.4 (1.0-1.9)], a prior history of chronic obstructive pulmonary...

  2. Leadership in cardiac surgery.

    Science.gov (United States)

    Rao, Christopher; Patel, Vanash; Ibrahim, Michael; Ahmed, Kamran; Wong, Kathie A; Darzi, Ara; von Segesser, Ludwig K; Athanasiou, Thanos

    2011-06-01

    Despite the efficacy of cardiac surgery, less invasive interventions with more uncertain long-term outcomes are increasingly challenging surgery as first-line treatment for several congenital, degenerative and ischemic cardiac diseases. The specialty must evolve if it is to ensure its future relevance. More importantly, it must evolve to ensure that future patients have access to treatments with proven long-term effectiveness. This cannot be achieved without dynamic leadership; however, our contention is that this is not enough. The demands of a modern surgical career and the importance of the task at hand are such that the serendipitous emergence of traditional charismatic leadership cannot be relied upon to deliver necessary change. We advocate systematic analysis and strategic leadership at a local, national and international level in four key areas: Clinical Care, Research, Education and Training, and Stakeholder Engagement. While we anticipate that exceptional individuals will continue to shape the future of our specialty, the creation of robust structures to deliver collective leadership in these key areas is of paramount importance.

  3. Graphene induces spontaneous cardiac differentiation in embryoid bodies.

    Science.gov (United States)

    Ahadian, Samad; Zhou, Yuanshu; Yamada, Shukuyo; Estili, Mehdi; Liang, Xiaobin; Nakajima, Ken; Shiku, Hitoshi; Matsue, Tomokazu

    2016-04-07

    Graphene was embedded into the structure of mouse embryoid bodies (EBs) using the hanging drop technique. The inclusion of 0.2 mg per mL graphene in the EBs did not affect the viability of the stem cells. However, the graphene decreased the stem cell proliferation, probably by accelerating cell differentiation. The graphene also enhanced the mechanical properties and electrical conductivity of the EBs. Interestingly, the cardiac differentiation of the EB-graphene was significantly greater than that of the EBs at day 5 of culture, as confirmed by high-throughput gene analysis. Electrical stimulation (voltage, 4 V; frequency, 1 Hz; and duration, 10 ms for 2 continuous days) further enhanced the cardiac differentiation of the EBs, as demonstrated by analyses of the cardiac protein and gene expression and the beating activity of the EBs. Taken together, the results demonstrated that graphene played a major role in directing the cardiac differentiation of EBs, which has potential cell therapy and tissue regeneration applications.

  4. Modelling of an oesophageal electrode for cardiac function tomography.

    Science.gov (United States)

    Tehrani, J Nasehi; Jin, C; McEwan, A L

    2012-01-01

    There is a need in critical care units for continuous cardiopulmonary monitoring techniques. ECG gated electrical impedance tomography is able to localize the impedance variations occurring during the cardiac cycle. This method is a safe, inexpensive and potentially fast technique for cardiac output imaging but the spatial resolution is presently low, particularly for central locations such as the heart. Many parameters including noise deteriorate the reconstruction result. One of the main obstacles in cardiac imaging at the heart location is the high impedance of lungs and muscles on the dorsal and posterior side of body. In this study we are investigating improvements of the measurement and initial conductivity estimation of the internal electrode by modelling an internal electrode inside the esophagus. We consider 16 electrodes connected around a cylindrical mesh. With the random noise level set near 0.05% of the signal we evaluated the Graz consensus reconstruction algorithm for electrical impedance tomography. The modelling and simulation results showed that the quality of the target in reconstructed images was improved by up to 5 times for amplitude response, position error, resolution, shape deformation and ringing effects with perturbations located in cardiac related positions when using an internal electrode.

  5. Modelling of an Oesophageal Electrode for Cardiac Function Tomography

    Directory of Open Access Journals (Sweden)

    J. Nasehi Tehrani

    2012-01-01

    Full Text Available There is a need in critical care units for continuous cardiopulmonary monitoring techniques. ECG gated electrical impedance tomography is able to localize the impedance variations occurring during the cardiac cycle. This method is a safe, inexpensive and potentially fast technique for cardiac output imaging but the spatial resolution is presently low, particularly for central locations such as the heart. Many parameters including noise deteriorate the reconstruction result. One of the main obstacles in cardiac imaging at the heart location is the high impedance of lungs and muscles on the dorsal and posterior side of body. In this study we are investigating improvements of the measurement and initial conductivity estimation of the internal electrode by modelling an internal electrode inside the esophagus. We consider 16 electrodes connected around a cylindrical mesh. With the random noise level set near 0.05% of the signal we evaluated the Graz consensus reconstruction algorithm for electrical impedance tomography. The modelling and simulation results showed that the quality of the target in reconstructed images was improved by up to 5 times for amplitude response, position error, resolution, shape deformation and ringing effects with perturbations located in cardiac related positions when using an internal electrode.

  6. 3D engineered cardiac tissue models of human heart disease: learning more from our mice.

    Science.gov (United States)

    Ralphe, J Carter; de Lange, Willem J

    2013-02-01

    Mouse engineered cardiac tissue constructs (mECTs) are a new tool available to study human forms of genetic heart disease within the laboratory. The cultured strips of cardiac cells generate physiologic calcium transients and twitch force, and respond to electrical pacing and adrenergic stimulation. The mECT can be made using cells from existing mouse models of cardiac disease, providing a robust readout of contractile performance and allowing a rapid assessment of genotype-phenotype correlations and responses to therapies. mECT represents an efficient and economical extension to the existing tools for studying cardiac physiology. Human ECTs generated from iPSCMs represent the next logical step for this technology and offer significant promise of an integrated, fully human, cardiac tissue model.

  7. Klaus, an exceptional winter storm over Northern Iberia and Southern France - a comparison between storm diagnostics

    Science.gov (United States)

    Liberato, M. L. R.; Pinto, J. G.; Trigo, I. F.; Trigo, R. M.

    2010-05-01

    The synoptic evolution and dynamical characteristics of storm "Klaus" (23 and 24 January 2009) are analysed. "Klaus" was an extratropical cyclone which developed over the subtropical North Atlantic Ocean on the 21st January 2009, then moved eastward embedded in the strong westerly flow and experienced a notorious strengthening on the 23rd January. The storm moved into the Bay of Biscay and deepened further before hitting Northern Spain and Southwestern France with gusts of up to 198 km/h. Afterwards, it steered southeastwards across Southern France into Northern Italy and the Adriatic. "Klaus" was the most intense and damaging wind storm in the region in a decade, provoked more than 20 casualties and insured losses of several billion Euros. The evolution of "Klaus" is analysed using two standard cyclone detecting and tracking schemes: a) the vorticity maxima based algorithm originally developed by Murray and Simmonds [1991], adapted for Northern Hemisphere cyclone characteristics [Pinto et al. 2005]; and b) the pressure minima based algorithm first developed for the Mediterranean region [Trigo et al. 1999; 2002] and later extended to a larger Euro-Atlantic region [Trigo 2006]. Additionally, the synoptic and mesoscale features of the storm are analysed. The vorticity based method detects the storm earlier than the pressure minima one. Results show that both tracks exhibited similar features and positions throughout almost all of their lifecycles, with minor discrepancies being probably related to different ways of both methods handling the spatio-temporal evolution of multiple candidates for cyclonic centres. In its strengthening phase, "Klaus" presents deepening rates above 37 hPa/24h, a value that after geostrophically adjusted to the reference latitude of 60°N increases to 44 hPa/24h, implying an exceptional event with bomb characteristics. During maximum intensity change within 24 hours was 1.165hPa/(deglat)2. References: Murray RJ, Simmonds I (1991) Aust

  8. Multiple ionospheric perturbations during the Saint Patrick's Day storm 2015 in the European-African sector

    Science.gov (United States)

    Borries, Claudia; Mahrous, Ayman M.; Ellahouny, Nada M.; Badeke, Ronny

    2016-11-01

    Strong ionospheric perturbations were generated by the intense geomagnetic storm on 17 March 2015. In this article, we are studying perturbations in the European-African sector observed in the total electron content (TEC). Focal points are wavelike phenomena considered as large-scale traveling ionospheric disturbances (LSTIDs). In the European-African sector, the storm produced three different types of LSTIDs: (1) a concurrent TEC perturbation at all latitudes simultaneously; (2) one LSTID propagating toward the equator, having very large wave parameters (wavelength: ≈3600 km, period: ≈120 min, and speed: ≈500 m/s); and (3) several LSTIDs propagating toward the equator with typical wave parameters (wavelength: ≈2100 km, period: ≈60 min, and speed ≈600 m/s). The third type of LSTIDs is considered to be exited as most LSTIDs either due to variations in the Joule heating or variations in the Lorentz force, whereas the first two perturbation types are rather unusual in their appearance. They occurred during the partial recovery phase when the geomagnetic perturbations were minor and the interplanetary magnetic field turned northward. A westward prompt penetration electric field is considered to excite the first perturbation signature, which indicates a sudden TEC depletion. For the second LSTID type, variations in the Lorentz force because of perturbed electric fields and a minor particle precipitation effect are extracted as possible excitation mechanisms.

  9. Geomagnetically induced currents in the Irish power network during geomagnetic storms

    Science.gov (United States)

    Blake, Seán. P.; Gallagher, Peter T.; McCauley, Joe; Jones, Alan G.; Hogg, Colin; Campanyà, Joan; Beggan, Ciarán. D.; Thomson, Alan W. P.; Kelly, Gemma S.; Bell, David

    2016-12-01

    Geomagnetically induced currents (GICs) are a well-known terrestrial space weather hazard. They occur in power transmission networks and are known to have adverse effects in both high-latitude and midlatitude countries. Here we study GICs in the Irish power transmission network (geomagnetic latitude 54.7-58.5°N) during five geomagnetic storms (6-7 March 2016, 20-21 December 2015, 17-18 March 2015, 29-31 October 2003, and 13-14 March 1989). We simulate electric fields using a plane wave method together with two ground resistivity models, one of which is derived from magnetotelluric measurements (magnetotelluric (MT) model). We then calculate GICs in the 220, 275, and 400 kV transmission network. During the largest of the storm periods studied, the peak electric field was calculated to be as large as 3.8 V km-1, with associated GICs of up to 23 A using our MT model. Using our homogenous resistivity model, those peak values were 1.46 V km-1 and 25.8 A. We find that three 400 and 275 kV substations are the most likely locations for the Irish transformers to experience large GICs.

  10. Oxidant enhancement in martian dust devils and storms: implications for life and habitability.

    Science.gov (United States)

    Atreya, Sushil K; Wong, Ah-San; Renno, Nilton O; Farrell, William M; Delory, Gregory T; Sentman, Davis D; Cummer, Steven A; Marshall, John R; Rafkin, Scot C R; Catling, David C

    2006-06-01

    We investigate a new mechanism for producing oxidants, especially hydrogen peroxide (H2O2), on Mars. Large-scale electrostatic fields generated by charged sand and dust in the martian dust devils and storms, as well as during normal saltation, can induce chemical changes near and above the surface of Mars. The most dramatic effect is found in the production of H2O2 whose atmospheric abundance in the "vapor" phase can exceed 200 times that produced by photochemistry alone. With large electric fields, H2O2 abundance gets large enough for condensation to occur, followed by precipitation out of the atmosphere. Large quantities of H2O2 would then be adsorbed into the regolith, either as solid H2O2 "dust" or as re-evaporated vapor if the solid does not survive as it diffuses from its production region close to the surface. We suggest that this H2O2, or another superoxide processed from it in the surface, may be responsible for scavenging organic material from Mars. The presence of H2O2 in the surface could also accelerate the loss of methane from the atmosphere, thus requiring a larger source for maintaining a steady-state abundance of methane on Mars. The surface oxidants, together with storm electric fields and the harmful ultraviolet radiation that readily passes through the thin martian atmosphere, are likely to render the surface of Mars inhospitable to life as we know it.

  11. Geomagnetically Induced Currents in the Irish Power Network during Geomagnetic Storms

    CERN Document Server

    Blake, Seán P; Jones, Alan G; Hogg, Colin; Campanyà, Joan; Beggan, Ciarán; Thomson, Alan W P; Kelly, Gemma S; Bell, David

    2016-01-01

    Geomagnetically induced currents (GICs) are a well-known terrestrial space weather hazard. They occur in power transmission networks and are known to have adverse effects in both high and mid-latitude countries. Here, we study GICs in the Irish power transmission network (geomagnetic latitude 54.7--58.5$^{\\circ}$ N) during five geomagnetic storms (06-07 March 2016, 20-21 December 2015, 17-18 March 2015, 29-31 October 2003 and 13-14 March 1989). We simulate electric fields using a plane wave method together with two ground resistivity models, one of which is derived from magnetotelluric measurements (MT model). We then calculate GICs in the 220, 275 and 400~kV transmission network. During the largest of the storm periods studied, the peak electric field was calculated to be as large as 3.8~V~km\\textsuperscript{-1}, with associated GICs of up to 23~A using our MT model. Using our homogenous resistivity model, those peak values were 1.46~V~km\\textsuperscript{-1} and 25.8~A. We find that three 400 and 275~kV subs...

  12. Scenario-based Storm Surge Vulnerability Assessment of Catanduanes

    Science.gov (United States)

    Suarez, J. K. B.

    2015-12-01

    After the devastating storm surge effect of Typhoon Haiyan, the public recognized an improved communication about risks, vulnerabilities and what is threatened by storm surge. This can be provided by vulnerability maps which allow better visual presentations and understanding of the risks and vulnerabilities. Local implementers can direct the resources needed for protection of these areas. Moreover, vulnerability and hazard maps are relevant in all phases of disaster management designed by the National Disaster Risk Reduction Council (NDRRMC) - disaster preparedness, prevention and mitigation and response and recovery and rehabilitation. This paper aims to analyze the vulnerability of Catanduanes, a coastal province in the Philippines, to storm surges in terms of four parameters: population, built environment, natural environment and agricultural production. The vulnerability study relies on the storm surge inundation maps based on the Department of Science and Technology Nationwide Operational Assessment of Hazards' (DOST-Project NOAH) proposed four Storm Surge Advisory (SSA) scenarios (1-2, 3, 4, and 5 meters) for predicting storm surge heights. To determine total percent affected for each parameter elements, an overlay analysis was performed in ArcGIS Desktop. Moreover, vulnerability and hazard maps are generated as a final output and a tool for visualizing the impacts of storm surge event at different surge heights. The result of this study would help the selected province to know their present condition and adapt strategies to strengthen areas where they are found to be most vulnerable in order to prepare better for the future.

  13. Cardiac stimulation with high voltage discharge from stun guns.

    Science.gov (United States)

    Nanthakumar, Kumaraswamy; Massé, Stephane; Umapathy, Karthikeyan; Dorian, Paul; Sevaptsidis, Elias; Waxman, Menashe

    2008-05-20

    The ability of an electrical discharge to stimulate the heart depends on the duration of the pulse, the voltage and the current density that reaches the heart. Stun guns deliver very short electrical pulses with minimal amount of current at high voltages. We discuss external stimulation of the heart by high voltage discharges and review studies that have evaluated the potential of stun guns to stimulate cardiac muscle. Despite theoretical analyses and animal studies which suggest that stun guns cannot and do not affect the heart, 3 independent investigators have shown cardiac stimulation by stun guns. Additional research studies involving people are needed to resolve the conflicting theoretical and experimental findings and to aid in the design of stun guns that are unable to stimulate the heart.

  14. Potential Effects of Heliogeophysical Activity on the Dynamics of Sudden Cardiac Death at Earth Middle Latitudes

    Science.gov (United States)

    Dimitrova, S.; Babayev, E.; Mustafa, F.

    2017-01-01

    Limited studies exist on comparing the possible effects of heliogeophysical activity (solar and geomagnetic) on the dynamics of sudden cardiac death (SCD) as a function of latitude on Earth. In this work we continue our earlier studies concerning the changing space environment and SCD dynamics at middle latitudes. The study covered 25 to 80-year old males and females, and used medical data provided by all emergency and first medical aid stations in the Grand Baku Area, Azerbaijan. Data coverage includedthe second peak of Solar Cycle 23 and its descending activity years followed by its long-lasting minimum. Gradation of geomagnetic activity into six levels was introduced to study the effect of space weather on SCD. The ANalysis Of VAriance (ANOVA) test was applied to study the significance of the geomagnetic activity effect, estimated by different geomagnetic indices, on SCD dynamics. Variations inthe number of SCDs occurring on days preceding and following the development of geomagnetic storms were also studied. Results revealed that the SCD number was largest on days of very low geomagnetic activity and on days proceeding and following geomagnetic storms with different intensities. Vulnerability for males was found to be higher around days of major and severe geomagnetic storms. Females, on the other hand, were more threatened around days of lower intensity storms. It is concluded that heliogeophysical activity could be considered as one of the regulating external/environmental factors in human homeostasis.

  15. Electric Current Circuits in Astrophysics

    CERN Document Server

    Kuijpers, Jan; Fletcher, Lyndsay

    2014-01-01

    Cosmic magnetic structures have in common that they are anchored in a dynamo, that an external driver converts kinetic energy into internal magnetic energy, that this magnetic energy is transported as Poynting flux across the magnetically dominated structure, and that the magnetic energy is released in the form of particle acceleration, heating, bulk motion, MHD waves, and radiation. The investigation of the electric current system is particularly illuminating as to the course of events and the physics involved. We demonstrate this for the radio pulsar wind, the solar flare, and terrestrial magnetic storms.

  16. Flash flooding in small urban watersheds: Storm event hydrologic response

    Science.gov (United States)

    Yang, Long; Smith, James A.; Baeck, Mary Lynn; Zhang, Yan

    2016-06-01

    We analyze flash flooding in small urban watersheds, with special focus on the roles of rainfall variability, antecedent soil moisture, and urban storm water management infrastructure in storm event hydrologic response. Our results are based on empirical analyses of high-resolution rainfall and discharge observations over Harry's Brook watershed in Princeton, New Jersey, during 2005-2006, as well as numerical experiments with the Gridded Surface Subsurface Hydrologic Analysis (GSSHA) model. We focus on two subwatersheds of Harry's Brook, a 1.1 km2 subwatershed which was developed prior to modern storm water management regulations, and a 0.5 km2 subwatershed with an extensive network of storm water detention ponds. The watershed developed prior to modern storm water regulations is an "end-member" in urban flood response, exhibiting a frequency of flood peaks (with unit discharge exceeding 1 m3 s-1 km-2) that is comparable to the "flashiest" watersheds in the conterminous U.S. Observational analyses show that variability in storm event water balance is strongly linked to peak rain rates at time intervals of less than 30 min and only weakly linked to antecedent soil moisture conditions. Peak discharge for both the 1.1 and 0.5 km2 subwatersheds are strongly correlated with rainfall rate averaged over 1-30 min. Hydrologic modeling analyses indicate that the sensitivity of storm event hydrologic response to spatial rainfall variability decreases with storm intensity. Temporal rainfall variability is relatively more important than spatial rainfall variability in representing urban flood response, especially for extreme storm events.

  17. Model simulation of storm surge potential for Andaman islands

    Digital Repository Service at National Institute of Oceanography (India)

    Kumar, V.S.; RameshBabu, V.; Babu, M.T.; Dhinakaran, G.; Rajamanickam, G.V.

    .K., and Chittibbu, P., 1994. Finite difference techniques applied to the simulation of surges and currents around Srilanka and Southern Indian Peninsula, Computer Fluid Dynamics., 3, pp. 71 -77. India Meteorological Department, 1979. Tracks of storms and depressions... in the Bay of Bengal and Arabian Sea: 1877-1970, IMD, New Delhi, 186 p. India Meteorological Department, 1996.Tracks of storms and depressions in the Bay of Bengal and Arabian Sea: 1971 -1990 - An addendum to the storm track atlas (1877-1970), IMD, New Delhi...

  18. Evaluation of NO{sub x} produced by storms

    Energy Technology Data Exchange (ETDEWEB)

    Laroche, P.; Mary, C.; Defer, E. [Office National d`Etudes et de Recherches Aerospatiales (ONERA), 92 - Chatillon (France)

    1997-12-31

    The evaluations of NO{sub x} production by lightning within storms are commonly based on modeling, laboratory and field experiments. To apply laboratory experiment and physical modeling to observed storms or at global scale, a schematic representation of a lightning flash is used. The actually observed 3D structure of a lightning flash is described, and the NO{sub x} production process is evaluated. Case studies are presented of actual storm observation, and the evaluation of NO{sub x} produced is compared to what could be derived from the literature. (author) 12 refs.

  19. Migrating Storms and Optimal Control of Urban Sewer Networks

    Directory of Open Access Journals (Sweden)

    Upaka Rathnayake

    2015-11-01

    Full Text Available Uniform storms are generally applied in most of the research on sewer systems. This is for modeling simplicity. However, in the real world, these conditions may not be applicable. It is very important to consider the migration behavior of storms not only in the design of combined sewers, but also in controlling them. Therefore, this research was carried out to improve Rathnayake and Tanyimboh’s optimal control algorithm for migrating storms. Promising results were found from the model improvement. Feasible solutions were obtained from the multi-objective optimization and, in addition, the role of on-line storage tanks was well placed.

  20. Response of Coastal Groundwater Table to Offshore Storms

    Institute of Scientific and Technical Information of China (English)

    L. Li(李 凌); N. Cartwright; P. Nielsen; D. Lockington

    2004-01-01

    Large groundwater table fluctuations were observed in a coastal aquifer during an offshore storm. The storm induced significant changes of the mean shoreline elevation, characterized by a pulse-like oscillation. This pulse propagated in the aquifer, resulting in the water table fluctuations. A general analytical solution is derived to quantify this new mechanism of water table fluctuation. The solution is applied to field observations and is found to be able to predict reasonably well the observed storm-induced water table fluctuations. Based on the analytical solution, the damping characteristics and phase shift of the oscillation as it propagates inland are exanfined.

  1. Cardiac Autonomic Nerve Stimulation in the Treatment of Heart Failure

    OpenAIRE

    Kobayashi, Mariko; Massiello, Alex; Karimov, Jamshid H.; Van Wagoner, David R.; Fukamachi, Kiyotaka

    2013-01-01

    Research on the therapeutic modulation of cardiac autonomic tone by electrical stimulation has yielded encouraging early clinical results. Vagus nerve stimulation has reduced the rates of morbidity and sudden death from heart failure, but therapeutic vagus nerve stimulation is limited by side effects of hypotension and bradycardia. Sympathetic nerve stimulation that has been implemented in the experiment may exacerbate the sympathetic-dominated autonomic imbalance. In contrast, concurrent sti...

  2. Cardiac arrhythmia and heart failure: From bench to bedside

    Institute of Scientific and Technical Information of China (English)

    Yong-Fu Xiao

    2011-01-01

    @@ Cardiac arrhythmia is an abnormal rate and/or rhythm of a heart due to its abnormal electrical impulse origination and/or propagation.Various etiologies can cause arrhythnuas.Heart failure(HF)is a clinical syndrome due to an impaired heart that can not pump sufficient blood to meet the systemic metabolic needs.The common causes of HF include myocardial infarction,hypertension,valvular heart disease,and cardiomyopathy.

  3. Application of HTS technology to cardiac dysrhythmia detection

    Energy Technology Data Exchange (ETDEWEB)

    Sobel, A.L. [Sandia National Labs., Albuquerque, NM (United States); Avrin, W.F. [Quantum Magnetics, Inc., San Diego, CA (United States)

    1994-12-01

    This paper discusses the conceptual design considerations and challenges for development of a contactless, mobile, single channel biomagnetic sensor system based on High-Temperature Superconductor (HTS) Superconducting Quantum Interference Devices (SQUIDs) and employing the Three-SQUID Gradiometer (TSG) concept. Operating in magnetically unshielded environments, as are encountered in many medical scenarios, this instrument class would monitor cardiac electrical activity with minimal patient preparation and intrusiveness, and would notionally be coupled with a clinically adaptive human-system interface (HSI).

  4. Effects of Blood Flow on the Heating of Cardiac Stents Due to Radio Frequency Fields

    OpenAIRE

    Elder, Nate Ian

    2013-01-01

    A safety concern during MRI scans with implanted medical devices is heating induced by the incident RF field. This research was performed to better understand the heating of cardiac stents during MRI. Heating of cardiac stents tends to occur at their ends. The temperature rise will be affected by blood flow through the lumen of the stent. In this work, an experiment was performed to simulate heating of a cardiac stent in the presence of blood flow during exposure to the electric field induced...

  5. Damageability of overhead lines during ice storms in Ukraine

    Energy Technology Data Exchange (ETDEWEB)

    Turbin, S. [Donbas National Academy of Civil Engineering and Architecture, Makeyevka, Donetsk (Ukraine); Grimud, G. [NEC Ukrenergo, Kiev (Ukraine)

    2005-07-01

    Statistical data of an icing event in the Ukraine where significant failures in overhead transmission occurred were presented. The icing event led to the damage of 20,931 overhead lines (OHLs). Approximately 3420 conductors were destroyed. Nearly 4 million people lived without electricity, heat, gas and water supplies for over a week, and in some cases for nearly 4 months. Most of the ice was deposited within 10 to 12 hours, and covered an area of over 226,000 square kilometers. Damage was compounded in some areas due to winds with a mean speed of 14-17 m/s. The density of ice deposits was estimated at over 800 kilograms per cubic meter. It was determined that the OHL damages sustained in icing events can be attributed mostly to the lack of codes and regulations in the design process, as well as the absence of ice melting devices, emergency stocks of towers, cables and wires. It was noted that at the time of the storm, methods for calculating ice loads and changes in ice thickness above ground level and from the diameter of conductors proved to be inaccurate. Unbalanced icing on conductors led to the collapse of towers, and cascade damages were caused by the absence of anti-cascade towers and devices. It was suggested that the use of prevention methods such as the reduction of insulator carrying capacity may have prevented tower damage. It was concluded that since the icing event, new Ukrainian rules and regulations for the design of OHLs have been put into place, and rules for OHL exploitation were determined. Automated icing monitoring systems to predict icing and wind events have been installed. Ice melting equipment, and emergency stocks of towers, cables, wires and new methods for the erection of towers are also being used. 2 refs., 3 tabs., 9 figs.

  6. Fetal cardiac activity analysis during twin pregnancy using a multi-channel SQUID system

    Science.gov (United States)

    Costa Monteiro, E.; Schleussner, E.; Kausch, S.; Grimm, B.; Schneider, A.; Hall Barbosa, C.; Haueisen, J.

    2001-05-01

    The use of SQUID magnetometers for non-invasive in utero assessment of cardiac electrical disturbances has already been shown to be a valuable clinical tool. In this way, its applicability also for the complicated case of twin pregnancy, in which the proximity of the cardiac magnetic source of each fetus can hamper the individual analysis of cardiac electrical activity, is of clinical interest. In this paper, we present fetal magnetocardiography performed on a mother pregnant of twins with 26 weeks gestational age, measured inside a magnetically shielded room, by using two identical 31-channel low- Tc SQUID magnetometer systems. Each sensor array has been positioned over one of the fetuses, according to its heart position previously assessed with the aid of ultrasound measurements. The raw data is initially averaged in time and, afterwards, analyzed by means of time plots and isofield maps. The time recordings allow the study of the morphology of each fetus’ cardiac signal and the cardiac time intervals. The resultant equivalent dipole obtained from the isofield maps indicates the position and orientation of each fetus heart. The results agree with the ultrasound analysis performed immediately before the measurements and used to obtain the approximate location of the fetuses’ hearts. Since a distinct analysis of the cardiac electrical activity of each fetus could be achieved, the results indicate the potential of the fetal magnetocardiography in the individual antenatal diagnosis of each one of the fetuses of a twin pregnancy.

  7. The Strength-Interval Curve in Cardiac Tissue

    Directory of Open Access Journals (Sweden)

    Sunil M. Kandel

    2013-01-01

    Full Text Available The bidomain model describes the electrical properties of cardiac tissue and is often used to simulate the response of the heart to an electric shock. The strength-interval curve summarizes how refractory tissue is excited. This paper analyzes calculations of the strength-interval curve when a stimulus is applied through a unipolar electrode. In particular, the bidomain model is used to clarify why the cathodal and anodal strength-interval curves are different, and what the mechanism of the “dip” in the anodal strength-interval curve is.

  8. Platelets and cardiac arrhythmia

    Directory of Open Access Journals (Sweden)

    Jonas S De Jong

    2010-12-01

    Full Text Available Sudden cardiac death remains one of the most prevalent modes of death in industrialized countries, and myocardial ischemia due to thrombotic coronary occlusion is its primary cause. The role of platelets in the occurrence of SCD extends beyond coronary flow impairment by clot formation. Here we review the substances released by platelets during clot formation and their arrhythmic properties. Platelet products are released from three types of platelet granules: dense core granules, alpha-granules, and platelet lysosomes. The physiologic properties of dense granule products are of special interest as a potential source of arrhythmic substances. They are released readily upon activation and contain high concentrations of serotonin, histamine, purines, pyrimidines, and ions such as calcium and magnesium. Potential arrhythmic mechanisms of these substances, e.g. serotonin and high energy phosphates, include induction of coronary constriction, calcium overloading, and induction of delayed after-depolarizations. Alpha-granules produce thromboxanes and other arachidonic acid products with many potential arrhythmic effects mediated by interference with cardiac sodium, calcium and potassium channels. Alpha-granules also contain hundreds of proteins that could potentially serve as ligands to receptors on cardiomyocytes. Lysosomal products probably do not have an important arrhythmic effect. Platelet products and ischemia can induce coronary permeability, thereby enhancing interaction with surrounding cardiomyocytes. Antiplatelet therapy is known to improve survival after myocardial infarction. Although an important part of this effect results from prevention of coronary clot formation, there is evidence to suggest that antiplatelet therapy also induces anti-arrhythmic effects during ischemia by preventing the release of platelet activation products.

  9. Mediastinitis after cardiac transplantation

    Directory of Open Access Journals (Sweden)

    Noedir A. G. Stolf

    2000-05-01

    Full Text Available OBJECTIVE: Assessment of incidence and behavior of mediastinitis after cardiac transplantation. METHODS: From 1985 to 1999, 214 cardiac transplantations were performed, 12 (5.6% of the transplanted patients developed confirmed mediastinitis. Patient's ages ranged from 42 to 66 years (mean of 52.3±10.0 years and 10 (83.3% patients were males. Seven (58.3% patients showed sternal stability on palpation, 4 (33.3% patients had pleural empyema, and 2 (16.7% patients did not show purulent secretion draining through the wound. RESULTS: Staphylococcus aureus was the infectious agent identified in the wound secretion or in the mediastinum, or both, in 8 (66.7% patients. Staphylococcus epidermidis was identified in 2 (16.7% patients, Enterococcus faecalis in 1 (8.3% patient, and the cause of mediastinitis could not be determined in 1 (8.3% patient. Surgical treatment was performed on an emergency basis, and the extension of the débridement varied with local conditions. In 2 (16.7% patients, we chose to leave the surgical wound open and performed daily dressings with granulated sugar. Total sternal resection was performed in only 1 (8.3% patient. Out of this series, 5 (41.7% patients died, and the causes of death were related to the infection. Autopsy revealed persistence of mediastinitis in 1 (8.3% patient. CONCLUSION: Promptness in diagnosing mediastinitis and precocious surgical drainage have changed the natural evolution of this disease. Nevertheless, observance of the basic precepts of prophylaxis of infection is still the best way to treat mediastinitis.

  10. Identification of storm surge vulnerable areas in the Philippines through the simulation of Typhoon Haiyan-induced storm surge levels over historical storm tracks

    Directory of Open Access Journals (Sweden)

    J. P. Lapidez

    2015-02-01

    Full Text Available Super Typhoon Haiyan entered the Philippine Area of Responsibility (PAR 7 November 2013, causing tremendous damage to infrastructure and loss of lives mainly due to the storm surge and strong winds. Storm surges up to a height of 7 m were reported in the hardest hit areas. The threat imposed by this kind of natural calamity compelled researchers of the Nationwide Operational Assessment of Hazards (Project NOAH, the flagship disaster mitigation program of the Department of Science and Technology (DOST, Government of the Philippines, to undertake a study to determine the vulnerability of all Philippine coastal communities to storm surges of the same magnitude as those generated by Haiyan. This study calculates the maximum probable storm surge height for every coastal locality by running simulations of Haiyan-type conditions but with tracks of tropical cyclones that entered PAR from 1948–2013. One product of this study is a list of the 30 most vulnerable coastal areas that can be used as basis for choosing priority sites for further studies to implement appropriate site-specific solutions for flood risk management. Another product is the storm tide inundation maps that the local government units can use to develop a risk-sensitive land use plan for identifying appropriate areas to build residential buildings, evacuation sites, and other critical facilities and lifelines. The maps can also be used to develop a disaster response plan and evacuation scheme.

  11. Identification of storm surge vulnerable areas in the Philippines through the simulation of Typhoon Haiyan-induced storm surge levels over historical storm tracks

    Directory of Open Access Journals (Sweden)

    J. P. Lapidez

    2015-07-01

    Full Text Available Super Typhoon Haiyan entered the Philippine Area of Responsibility (PAR on 7 November 2013, causing tremendous damage to infrastructure and loss of lives mainly due to the storm surge and strong winds. Storm surges up to a height of 7 m were reported in the hardest hit areas. The threat imposed by this kind of natural calamity compelled researchers of the Nationwide Operational Assessment of Hazards (Project NOAH which is the flagship disaster mitigation program of the Department of Science and Technology (DOST of the Philippine government to undertake a study to determine the vulnerability of all Philippine coastal communities to storm surges of the same magnitude as those generated by Haiyan. This study calculates the maximum probable storm surge height for every coastal locality by running simulations of Haiyan-type conditions but with tracks of tropical cyclones that entered PAR from 1948–2013. One product of this study is a list of the 30 most vulnerable coastal areas that can be used as a basis for choosing priority sites for further studies to implement appropriate site-specific solutions for flood risk management. Another product is the storm tide inundation maps that the local government units can use to develop a risk-sensitive land use plan for identifying appropriate areas to build residential buildings, evacuation sites, and other critical facilities and lifelines. The maps can also be used to develop a disaster response plan and evacuation scheme.

  12. Metoclopramide-induced cardiac arrest

    Directory of Open Access Journals (Sweden)

    Martha M. Rumore

    2011-11-01

    Full Text Available The authors report a case of cardiac arrest in a patient receiving intravenous (IV metoclopramide and review the pertinent literature. A 62-year-old morbidly obese female admitted for a gastric sleeve procedure, developed cardiac arrest within one minute of receiving metoclopramide 10 mg via slow intravenous (IV injection. Bradycardia at 4 beats/min immediately appeared, progressing rapidly to asystole. Chest compressions restored vital function. Electrocardiogram (ECG revealed ST depression indicative of myocardial injury. Following intubation, the patient was transferred to the intensive care unit. Various cardiac dysrrhythmias including supraventricular tachycardia (SVT associated with hypertension and atrial fibrillation occurred. Following IV esmolol and metoprolol, the patient reverted to normal sinus rhythm. Repeat ECGs revealed ST depression resolution without pre-admission changes. Metoclopramide is a non-specific dopamine receptor antagonist. Seven cases of cardiac arrest and one of sinus arrest with metoclopramide were found in the literature. The metoclopramide prescribing information does not list precautions or adverse drug reactions (ADRs related to cardiac arrest. The reaction is not dose related but may relate to the IV administration route. Coronary artery disease was the sole risk factor identified. According to Naranjo, the association was possible. Other reports of cardiac arrest, severe bradycardia, and SVT were reviewed. In one case, five separate IV doses of 10 mg metoclopramide were immediately followed by asystole repeatedly. The mechanism(s underlying metoclopramide’s cardiac arrest-inducing effects is unknown. Structural similarities to procainamide may play a role. In view of eight previous cases of cardiac arrest from metoclopramide having been reported, further elucidation of this ADR and patient monitoring is needed. Our report should alert clinicians to monitor patients and remain diligent in surveillance and

  13. Fetal cardiac rhabdomyoma: case report

    Directory of Open Access Journals (Sweden)

    Seyed Mostafa Ghavami

    2016-07-01

    Full Text Available Background: The primary manifestation of cardiac tumors in embryonic period is a very rare condition. Cardiac rhabdomyomas most frequently arise in the ventricular myocardium, they may also occur in the atria and the epicardial surface. In spite of its benign nature, the critical location of the tumor inside the heart can lead to lethal arrhythmias and chamber obstruction. Multiple rhabdomyomas are strongly associated with tuberous sclerosis which is associated with mental retardation and epilepsy of variable severity. Ultrasonography as a part of routine prenatal screening, is the best method for the diagnosis of cardiac rhabdomyomas. In the review of articles published in Iran, fetal cardiac rhabdomyoma was not reported. Case presentation: We report a case of cardiac rhabdomyoma on a 24-year-old gravid 1, referred to Day Medical Imaging Center for routine evaluation of fetal abnormalities at 31 weeks of her gestational age. Ultrasonographic examination displayed a homogenous echogenic mass (13×9mm, originating from the left ventricle of the fetal heart. It was a normal pregnancy without any specific complications. Other organs of the fetus were found normal and no cardiac abnormalities were appeared. No Pericardial fluid effusion was found. The parents did not have consanguineous marriage. They did not also have any specific disease such as tuberous sclerosis. Conclusion: The clinical features of cardiac rhabdomyomas vary widely, depending on the location, size, and number of tumors in the heart. Although cardiac rhabdomyoma is a benign tumor in many affected fetuses, an early prenatal diagnosis of the tumor is of great significance in making efficient planning and providing adequate follow up visits of the patients and the complications such as, heart failure and outlet obstruction of cardiac chambers.

  14. Hormones and sex differences: changes in cardiac electrophysiology with pregnancy.

    Science.gov (United States)

    Bett, Glenna C L

    2016-05-01

    Disruption of cardiac electrical activity resulting in palpitations and syncope is often an early symptom of pregnancy. Pregnancy is a time of dramatic and dynamic physiological and hormonal changes during which numerous demands are placed on the heart. These changes result in electrical remodelling which can be detected as changes in the electrocardiogram (ECG). This gestational remodelling is a very under-researched area. There are no systematic large studies powered to determine changes in the ECG from pre-pregnancy, through gestation, and into the postpartum period. The large variability between patients and the dynamic nature of pregnancy hampers interpretation of smaller studies, but some facts are consistent. Gestational cardiac hypertrophy and a physical shift of the heart contribute to changes in the ECG. There are also electrical changes such as an increased heart rate and lengthening of the QT interval. There is an increased susceptibility to arrhythmias during pregnancy and the postpartum period. Some changes in the ECG are clearly the result of changes in ion channel expression and behaviour, but little is known about the ionic basis for this electrical remodelling. Most information comes from animal models, and implicates changes in the delayed-rectifier channels. However, it is likely that there are additional roles for sodium channels as well as changes in calcium homoeostasis. The changes in the electrical profile of the heart during pregnancy and the postpartum period have clear implications for the safety of pregnant women, but the field remains relatively undeveloped.

  15. Surface-Borne Time-of-Reception Measurements (STORM) Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Invocon proposes the Surface-borne Time-Of-Reception Measurements (STORM) system as a method to locate the position of lightning strikes on aerospace vehicles....

  16. China's Auto Industry,Survive and Thrive in the Storm

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    @@ The increasingly grave financial crisis has had an effect on all sectors of the economy both big and small,as such.the world's automobile industry could not have saved itself from this financial storm.

  17. Distant storms as drivers of environmental change at Pacific atolls.

    Directory of Open Access Journals (Sweden)

    Jonathan P A Gardner

    Full Text Available The central Pacific Ocean with its many low lying islands and atolls is under threat from sea level rise and increased storm activity. Here, we illustrate how increasing frequency and severity of large scale storm events associated with global climate change may be particularly profound at the local scale for human populations that rely on lagoon systems for provision of a variety of goods and services. In August 2011 a storm originating in the Southern Ocean caused a large amplitude ocean swell to move northward through the Pacific Ocean. Its arrival at Palmyra Atoll coincided with transient elevated sea surface height and triggered turnover of the lagoon water column. This storm-induced change to the lagoon reflects long distance connectivity with propagated wave energy from the Southern Ocean and illustrates the increasing threats generated by climate change that are faced by human populations on most low-lying Pacific islands and atolls.

  18. Cerebrovascular Accident due to Thyroid Storm: Should We Anticoagulate?

    Directory of Open Access Journals (Sweden)

    Alex Gonzalez-Bossolo

    2016-01-01

    Full Text Available Thyroid storm is a life-threatening condition that occurs secondary to an uncontrolled hyperthyroid state. Atrial fibrillation is a cardiovascular complication occurring in up to 15% of patients experiencing thyroid storm, and if left untreated this condition could have up to a 25% mortality rate. Thyroid storm with stroke is a rare presentation. This case report details a left middle cerebral artery (MCA stroke with global aphasia and thyroid storm in a 53-year-old Hispanic male patient. Although uncommon, this combination has been reported in multiple case series. Although it is well documented that dysfunctional thyroid levels promote a hypercoagulable state, available guidelines from multiple entities are unclear on whether anticoagulation therapy is appropriate in this situation.

  19. Statistical Study of False Alarms of Geomagnetic Storms

    DEFF Research Database (Denmark)

    Leer, Kristoffer; Vennerstrøm, Susanne; Veronig, A.;

    Coronal Mass Ejections (CMEs) are known to cause geomagnetic storms on Earth. However, not all CMEs will trigger geomagnetic storms, even if they are heading towards the Earth. In this study, front side halo CMEs with speed larger than 500 km/s have been identified from the SOHO LASCO catalogue....... A subset of these halo CMEs did not cause a geomagnetic storm the following four days and have therefore been considered as false alarms. The properties of these events are investigated and discussed here. Their statistics are compared to the geo-effective CMEs. The ability to identify potential false...... alarms is considered as an important factor when forecasting geomagnetic storms. It would therefore be very helpful if there were a signature in the solar data that could indicate that a CME is a false alarm. The strength and position of associated flares have been considered as possible candidates...

  20. The Causes of Geomagnetic Storms During Solar Maximum

    Science.gov (United States)

    Tsurutani, B. T.; Gonzalez, W. D.

    1998-01-01

    One of the oldest mysteries in geomagnetism is the linkage between solar and geomagnetic activity. The 11-year cycles of both the numbers of sunspots and Earth geomagnetic storms were first noted by Sabine (1852).

  1. Storm Water General Permit 3 for Rock and Asphalt

    Data.gov (United States)

    Iowa State University GIS Support and Research Facility — General permit #3 for storm water discharges associated with industrial activity for Asphalt Plants, Concrete Batch Plants, Rock Crushing Plants and Construction...

  2. Storm Water General Permit 1 for Industrial Facilities

    Data.gov (United States)

    Iowa State University GIS Support and Research Facility — General permit #1 for storm water discharges associated with industrial facilities in Iowa for the National Pollutant Discharge Elimination System (NPDES) program.

  3. Estimation of cold plasma outflow during geomagnetic storms

    CERN Document Server

    Haaland, S; André, M; Maes, L; Baddeley, L; Barakat, A; Chappell, R; Eccles, V; Johnsen, C; Lybekk, B; Li, K; Pedersen, A; Schunk, R; Welling, D

    2016-01-01

    Low-energy ions of ionospheric origin constitute a significant contributor to the magnetospheric plasma population. Measuring cold ions is difficult though. Observations have to be done at sufficiently high altitudes and typically in regions of space where spacecraft attain a positive charge due to solar illumination. Cold ions are therefore shielded from the satellite particle detectors. Furthermore, spacecraft can only cover key regions of ion outflow during segments of their orbit, so additional complications arise if continuous longtime observations, such as during a geomagnetic storm, are needed. In this paper we suggest a new approach, based on a combination of synoptic observations and a novel technique to estimate the flux and total outflow during the various phases of geomagnetic storms. Our results indicate large variations in both outflow rates and transport throughout the storm. Prior to the storm main phase, outflow rates are moderate, and the cold ions are mainly emanating from moderately sized ...

  4. Atmospheric Bioaerosols Transported Via Dust Storms in Western United States

    Science.gov (United States)

    Mccubbin, I. B.; Hallar, A. G.; Painter, T. H.; Wiedinmyer, C.; Chirokova, G.

    2011-12-01

    Measurements are presented showing the presence of biological material within frequent dust storms in the Western United States. Previous work has indicated that biological particles were enhancing the impact of dust storms on the formation of clouds. This paper presents multiple case studies, between April and May 2010, showing the presence of and quantifying the amount of biological material via an Ultraviolet Aerodynamic Particle Sizer during dust events. All dust storms originated in the Four Corners region in the Western U.S. and were measured at Storm Peak Laboratory, a high elevation facility in northwestern Colorado. From an Aerodynamic Particle Sizer, the mean dust particle size during these events was approximately 23 1μm, with number concentrations between 6 cm-3 and 12 cm-3. Approximately 0.2% of these dust particles had fluorescence signatures, indicating the presence of biological material.

  5. Leach’s Storm-petrel Assessment 1999

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This report outlines the natural history of the Leach’s Storm-petrel. In addition it describes management efforts for the species, and assesses habitat and...

  6. Storm surges in the Western Black Sea. Operational forecasting

    Directory of Open Access Journals (Sweden)

    G. MUNGOV

    2012-12-01

    Full Text Available The frequency of the storm surges in the Black Sea is lower than that in other regions of the World Ocean but they cause significant damages as the magnitude of the sea level set-up is up to 7-8 times greater than that of other sea level variations. New methods and systems for storm surge forecasting and studying their statistical characteristics are absolutely necessary for the purposes of the coastal zone management. The operational forecasting storm surge model of Meteo-France was adopted for the Black Sea in accordance with the bilateral agreement between Meteo-France and NINMH. The model was verified using tide-gauge observations for the strongest storms observed along the Bulgarian coast over the last 10 years.

  7. Storm surge model based on variational data assimilation method

    Institute of Scientific and Technical Information of China (English)

    Shi-li HUANG; Jian XU; De-guan WANG; Dong-yan LU

    2010-01-01

    By combining computation and observation information,the variational data assimilation method has the ability to eliminate errors caused by the uncertainty of parameters in practical forecasting.It was applied to a storm surge model based on unstructured grids with high spatial resolution meant for improving the forecasting accuracy of the storm surge.By controlling the wind stress drag coefficient,the variation-based model was developed and validated through data assimilation tests in an actual storm surge induced by a typhoon.In the data assimilation tests,the model accurately identified the wind stress drag coefficient and obtained results close to the true state.Then,the actual storm surge induced by Typhoon 0515 was forecast by the developed model,and the results demonstrate its efficiency in practical application.

  8. Epigenetic regulation in cardiac fibrosis

    Institute of Scientific and Technical Information of China (English)

    Li-Ming; Yu; Yong; Xu

    2015-01-01

    Cardiac fibrosis represents an adoptive response in the heart exposed to various stress cues. While resolution of the fibrogenic response heralds normalization of heart function, persistent fibrogenesis is usually associated with progressive loss of heart function and eventually heart failure. Cardiac fibrosis is regulated by a myriad of factors that converge on the transcription of genes encoding extracellular matrix proteins, a process the epigenetic machinery plays a pivotal role. In this minireview, we summarize recent advances regarding the epigenetic regulation of cardiac fibrosis focusing on the role of histone and DNA modifications and non-coding RNAs.

  9. Cardiac Involvement in Ankylosing Spondylitis

    Science.gov (United States)

    Ozkan, Yasemin

    2016-01-01

    Ankylosing spondylitis is one of the subgroup of diseases called “seronegative spondyloarthropathy”. Frequently, it affects the vertebral colon and sacroiliac joint primarily and affects the peripheral joints less often. This chronic, inflammatory and rheumatic disease can also affect the extraarticular regions of the body. The extraarticular affections can be ophthalmologic, cardiac, pulmonary or neurologic. The cardiac affection can be 2-10% in all patients. Cardiac complications such as left ventricular dysfunction, aortitis, aortic regurgitation, pericarditis and cardiomegaly are reviewed. PMID:27222669

  10. Acupuncture therapy related cardiac injury.

    Science.gov (United States)

    Li, Xue-feng; Wang, Xian

    2013-12-01

    Cardiac injury is the most serious adverse event in acupuncture therapy. The causes include needling chest points near the heart, the cardiac enlargement and pericardial effusion that will enlarge the projected area on the body surface and make the proper depth of needling shorter, and the incorrect needling method of the points. Therefore, acupuncture practitioners must be familiar with the points of the heart projected area on the chest and the correct needling methods in order to reduce the risk of acupuncture therapy related cardiac injury.

  11. Similarity and scale in catchment storm response

    Science.gov (United States)

    Wood, Eric F.; Sivapalan, Murugesu; Beven, Keith

    1993-01-01

    Until recently, very little progress had been made in understanding the relationship between small-scale variability of topography, soil, and rainfalls and the storm response seen at the catchment scale. The work reviewed here represents the first attempt at a systematic theoretical framework for such understanding in the context of surface runoff generation by different processes. The parameterization of hydrological processes over a range of scales is examined, and the concept of the 'representative elementary area' (REA) is introduced. The REA is a fundamental scale for catchment modeling at which continuum assumptions can be applied for the spatially variable controls and parameters, and spatial patterns no longer have to be considered explicitly. The investigation of scale leads into the concept of hydrologic similarity in which the effects of the environmental controls on runoff generation and flood frequency response be investigated independently of catchment scale. The paper reviews the authors' initial results and hopefully will motivate others to also investigate the issues of hydrologic scale and similarity.

  12. Storm surges formation in the White and Barents Seas

    Science.gov (United States)

    Arkhipkin, Victor; Dobrolyubov, Sergey; Korablina, Anastasia; Myslenkov, Stanislav

    2016-04-01

    Investigation of storm surges in the Arctic seas are of high priority in Russia due to the active development of offshore oil and gas, construction of facilities in the coastal zone, as well as for the safety of navigation. It is important to study the variability of surges, to predict this phenomena and subsequent economic losses, thus including such information into the Russian Arctic Development Program 2020. Surges in the White and Barents Seas are caused mainly by deep cyclones of two types: "diving" from the north (88% of all cyclones) and western. The average height of the storm surges in the White Sea is 0.6-0.9 m. An average duration of storm surges is about 80 hours. Mathematical modeling is used to analyze the characteristics of storm surges formation in the Dvina Bay of the White Sea, and in the Varandey village on the Barents Sea coast. Calculating storm surge heights in the White and Barents seas is performed using the ADCIRC model on an unstructured grid with a step from 20 km in the Barents Sea to 100 m in the White Sea. Unstructured grids allowed keeping small features of the coastline of the White and Barents seas, small islands and shallow banks, and assessing their impact on the development and transformation of wind-generated waves. The ADCIRC model used data of wind field reanalysis CFSv2. The storm surges were simulated for the time period from 1979 to 2010 and included scenarios with / without direct atmospheric pressure forcing, waves and tides. Numerical experiments have revealed distribution of storm surges in channels of the Northern Dvina River delta. The storm surges spreads in the model from the north-north-west of the Dvina Bay. As storm surge moves from the wellhead to the seaside estuary of the Northern Dvina (district Solombala), its height increases from 0.5 to 2 m. We also found a non-linear interaction of the surge and tide during the phase of surge destruction. This phenomenon is the highest in the period of low water, and the

  13. Functional cardiac imaging by random access microscopy

    Directory of Open Access Journals (Sweden)

    Claudia eCrocini

    2014-10-01

    Full Text Available Advances in the development of voltage sensitive dyes and Ca2+ sensors in combination with innovative microscopy techniques allowed researchers to perform functional measurements with an unprecedented spatial and temporal resolution. At the moment, one of the shortcomings of available technologies is their incapability of imaging multiple fast phenomena while controlling the biological determinants involved. In the near future, ultrafast deflectors can be used to rapidly scan laser beams across the sample, performing optical measurements of action potential and Ca2+ release from multiple sites within cardiac cells and tissues. The same scanning modality could also be used to control local Ca2+ release and membrane electrical activity by activation of caged compounds and light-gated ion channels. With this approach, local Ca2+ or voltage perturbations could be induced, simulating arrhythmogenic events, and their impact on physiological cell activity could be explored. The development of this optical methodology will provide fundamental insights in cardiac disease, boosting new therapeutic strategies, and, more generally, it will represent a new approach for the investigation of the physiology of excitable cells.

  14. Cardiac ion channels in health and disease.

    Science.gov (United States)

    Amin, Ahmad S; Tan, Hanno L; Wilde, Arthur A M

    2010-01-01

    Cardiac electrical activity depends on the coordinated propagation of excitatory stimuli through the heart and, as a consequence, the generation of action potentials in individual cardiomyocytes. Action potential formation results from the opening and closing (gating) of ion channels that are expressed within the sarcolemma of cardiomyocytes. Ion channels possess distinct genetic, molecular, pharmacologic, and gating properties and exhibit dissimilar expression levels within different cardiac regions. By gating, ion channels permit ion currents across the sarcolemma, thereby creating the different phases of the action potential (e.g., resting phase, depolarization, repolarization). The importance of ion channels in maintaining normal heart rhythm is reflected by the increased incidence of arrhythmias in inherited diseases that are linked to mutations in genes encoding ion channels or their accessory proteins and in acquired diseases that are associated with changes in ion channel expression levels or gating properties. This review discusses ion channels that contribute to action potential formation in healthy hearts and their role in inherited and acquired diseases.

  15. Gene therapy to treat cardiac arrhythmias.

    Science.gov (United States)

    Bongianino, Rossana; Priori, Silvia G

    2015-09-01

    Gene therapy to treat electrical dysfunction of the heart is an appealing strategy because of the limited therapeutic options available to manage the most-severe cardiac arrhythmias, such as ventricular tachycardia, ventricular fibrillation, and asystole. However, cardiac genetic manipulation is challenging, given the complex mechanisms underlying arrhythmias. Nevertheless, the growing understanding of the molecular basis of these diseases, and the development of sophisticated vectors and delivery strategies, are providing researchers with adequate means to target specific genes and pathways involved in disorders of heart rhythm. Data from preclinical studies have demonstrated that gene therapy can be successfully used to modify the arrhythmogenic substrate and prevent life-threatening arrhythmias. Therefore, gene therapy might plausibly become a treatment option for patients with difficult-to-manage acquired arrhythmias and for those with inherited arrhythmias. In this Review, we summarize the preclinical studies into gene therapy for acquired and inherited arrhythmias of the atria or ventricles. We also provide an overview of the technical advances in the design of constructs and viral vectors to increase the efficiency and safety of gene therapy and to improve selective delivery to target organs.

  16. Normal cardiac function in mice with supraphysiological cardiac creatine levels.

    Science.gov (United States)

    Santacruz, Lucia; Hernandez, Alejandro; Nienaber, Jeffrey; Mishra, Rajashree; Pinilla, Miguel; Burchette, James; Mao, Lan; Rockman, Howard A; Jacobs, Danny O

    2014-02-01

    Creatine and phosphocreatine levels are decreased in heart failure, and reductions in myocellular phosphocreatine levels predict the severity of the disease and portend adverse outcomes. Previous studies of transgenic mouse models with increased creatine content higher than two times baseline showed the development of heart failure and shortened lifespan. Given phosphocreatine's role in buffering ATP content, we tested the hypothesis whether elevated cardiac creatine content would alter cardiac function under normal physiological conditions. Here, we report the creation of transgenic mice that overexpress the human creatine transporter (CrT) in cardiac muscle under the control of the α-myosin heavy chain promoter. Cardiac transgene expression was quantified by qRT-PCR, and human CrT protein expression was documented on Western blots and immunohistochemistry using a specific anti-CrT antibody. High-energy phosphate metabolites and cardiac function were measured in transgenic animals and compared with age-matched, wild-type controls. Adult transgenic animals showed increases of 5.7- and 4.7-fold in the content of creatine and free ADP, respectively. Phosphocreatine and ATP levels were two times as high in young transgenic animals but declined to control levels by the time the animals reached 8 wk of age. Transgenic mice appeared to be healthy and had normal life spans. Cardiac morphometry, conscious echocardiography, and pressure-volume loop studies demonstrated mild hypertrophy but normal function. Based on our characterization of the human CrT protein expression, creatine and phosphocreatine content, and cardiac morphometry and function, these transgenic mice provide an in vivo model for examining the therapeutic value of elevated creatine content for cardiac pathologies.

  17. Snoozing through the storm: torpor use during a natural disaster

    OpenAIRE

    Nowack, Julia; Rojas, A. Daniella; Körtner, Gerhard; Geiser, Fritz

    2015-01-01

    Although storms provide an extreme environmental challenge to organisms and are predicted to increase in frequency and intensity due to climate change, there are no quantitative observations on the behaviour and physiology of animals during natural disasters. We provide the first data on activity and thermal biology of a free-ranging, arboreal mammal during a storm with heavy rain and category 1 cyclone wind speeds. We studied a population of sugar gliders (Petaurus breviceps), a species vuln...

  18. Cardiac magnetic resonance imaging: patient safety considerations.

    Science.gov (United States)

    Giroletti, Elio; Corbucci, Giorgio

    Magnetic Resonance Imaging (MRI) is widely used in medicine. In cardiology, it is used to assess congenital or acquired diseases of the heat: and large vessels. Unless proper precautions are taken, it is generally advisable to avoid using this technique in patients with implanted electronic stimulators, such as pacemakers and defibrillators, on account of the potential risk of inducing electrical currents on the endocardial catheters, since these currents might stimulate the heart at a high frequency, thereby triggering dangerous arrhythmias. In addition to providing some basic information on pacemakers, defibrillators and MRI, and on the possible physical phenomena that may produce harmful effects, the present review examines the indications given in the literature, with particular reference to coronary stents, artificial heart valves and implantable cardiac stimulators.

  19. Use of cardiac biomarkers in neonatology.

    Science.gov (United States)

    Vijlbrief, Daniel C; Benders, Manon J N L; Kemperman, Hans; van Bel, Frank; de Vries, Willem B

    2012-10-01

    Cardiac biomarkers are used to identify cardiac disease in term and preterm infants. This review discusses the roles of natriuretic peptides and cardiac troponins. Natriuretic peptide levels are elevated during atrial strain (atrial natriuretic peptide (ANP)) or ventricular strain (B-type natriuretic peptide (BNP)). These markers correspond well with cardiac function and can be used to identify cardiac disease. Cardiac troponins are used to assess cardiomyocyte compromise. Affected cardiomyocytes release troponin into the bloodstream, resulting in elevated levels of cardiac troponin. Cardiac biomarkers are being increasingly incorporated into clinical trials as indicators of myocardial strain. Furthermore, cardiac biomarkers can possibly be used to guide therapy and improve outcome. Natriuretic peptides and cardiac troponins are potential tools in the diagnosis and treatment of neonatal disease that is complicated by circulatory compromise. However, clear reference ranges need to be set and validation needs to be carried out in a population of interest.

  20. Thyroid Storm Complicated by Bicytopenia and Disseminated Intravascular Coagulation

    Science.gov (United States)

    Tokushima, Yoshinori; Sakanishi, Yuta; Nagae, Kou; Tokushima, Midori; Tago, Masaki; Tomonaga, Motosuke; Yoshioka, Tsuneaki; Hyakutake, Masaki; Sugioka, Takashi; Yamashita, Shu-ichi

    2014-01-01

    Patient: Male, 23 Final Diagnosis: Thyroid storm Symptoms: Delirium • diarrhea • fever • hypertension • hyperventilation • tachycardia • weight loss Medication: — Clinical Procedure: — Specialty: Endocrinology and Metabolic Objective: Unusual clinical course Background: The clinical presentation of thyroid storm includes fever, tachycardia, hypertension, and neurological abnormalities. It is a serious condition with a high mortality rate. Furthermore, some other complications affect the clinical course of thyroid storm. Although it is reported that prognosis is poor when thyroid storm is complicated by disseminated intravascular coagulation syndrome (DIC) and leukopenia, reports of such cases are rare. Case Report: A 23-year-old man presented with delirium, high pyrexia, diarrhea, and weight loss of 18 kg over 2 months. According to the criteria of Burch and Wartofsky, he was diagnosed with thyroid storm on the basis of his symptom-complex and laboratory data that confirmed the presence of hyperthyroidism. Investigations also found leukopenia, thrombocytopenia, and disseminated intravascular coagulation, all of which are very rare complications of thyroid storm. We successfully treated him with combined therapy including anti-thyroid medication, despite leukopenia. Conclusions: Early diagnosis and treatment are essential in ensuring a good outcome for patients with this rare combination of medical problems. PMID:25072662