Electrophysiologic actions of pirmenol in dogs with recent myocardial infarction

The electrophysiologic actions of pirmenol, an investigational class I antiarrhythmic agent, were evaluated in eight anesthetized dogs, 5 to 10 days after anterior myocardial infarction. Before administration of the drug, programmed ventricular stimulation failed to initiate nonsustained or sustained ventricular tachyarrhythmias (VT) in any of the postinfarction dogs. After the cumulative administration of 2.5, 5.0, and 10.0 mg/kg pirmenol, programmed stimulation initiated sustained VT in six of the eight postinfarction dogs tested, with one additional dog responding with reproducible nonsustained VT (15 to 20 monomorphic complexes) after pirmenol adminstration. Only one of eight postinfarction dogs tested remained noninducible throughout the primenol dosing schedule. Administration of pirmenol tended to increase ventricular excitation thresholds, relative (p p p < 0.01 after 2.5, 5, and 10, mg/kg) refractory periods between ischemically injured and normal noninjured ventricular myocardium. These findings suggest a potential for the provocation or aggravation of ventricular arrhythmias by pirmenol in the setting of recent myocardial infarction.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/26034/1/0000107.pd

The Zwicky Transient Facility: System Overview, Performance, and First Results

The Zwicky Transient Facility (ZTF) is a new optical time-domain survey that uses the Palomar 48 inch Schmidt telescope. A custom-built wide-field camera provides a 47 deg 2 field of view and 8 s readout time, yielding more than an order of magnitude improvement in survey speed relative to its predecessor survey, the Palomar Transient Factory. We describe the design and implementation of the camera and observing system. The ZTF data system at the Infrared Processing and Analysis Center provides near-real-time reduction to identify moving and varying objects. We outline the analysis pipelines, data products, and associated archive. Finally, we present on-sky performance analysis and first scientific results from commissioning and the early survey. ZTF’s public alert stream will serve as a useful precursor for that of the Large Synoptic Survey Telescope

The Zwicky Transient Facility: Science Objectives

The Zwicky Transient Facility (ZTF), a public–private enterprise, is a new time-domain survey employing a dedicated camera on the Palomar 48-inch Schmidt telescope with a 47 deg2 field of view and an 8 second readout time. It is well positioned in the development of time-domain astronomy, offering operations at 10% of the scale and style of the Large Synoptic Survey Telescope (LSST) with a single 1-m class survey telescope. The public surveys will cover the observable northern sky every three nights in g and r filters and the visible Galactic plane every night in g and r. Alerts generated by these surveys are sent in real time to brokers. A consortium of universities that provided funding (“partnership”) are undertaking several boutique surveys. The combination of these surveys producing one million alerts per night allows for exploration of transient and variable astrophysical phenomena brighter than r∼20.5 on timescales of minutes to years. We describe the primary science objectives driving ZTF, including the physics of supernovae and relativistic explosions, multi-messenger astrophysics, supernova cosmology, active galactic nuclei, and tidal disruption events, stellar variability, and solar system objects. © 2019. The Astronomical Society of the Pacific

The Zwicky Transient Facility: System Overview, Performance, and First Results

The Zwicky Transient Facility (ZTF) is a new optical time-domain survey that uses the Palomar 48 inch Schmidt telescope. A custom-built wide-field camera provides a 47 deg^2 field of view and 8 s readout time, yielding more than an order of magnitude improvement in survey speed relative to its predecessor survey, the Palomar Transient Factory. We describe the design and implementation of the camera and observing system. The ZTF data system at the Infrared Processing and Analysis Center provides near-real-time reduction to identify moving and varying objects. We outline the analysis pipelines, data products, and associated archive. Finally, we present on-sky performance analysis and first scientific results from commissioning and the early survey. ZTF's public alert stream will serve as a useful precursor for that of the Large Synoptic Survey Telescope

Operating System and Window System Research for Distributed Multi-media Applications: A Status Report

We are currently researching general operating system and window system mechanisms necessary to support distributed multi-media applications, specifically applications which have audio and video I/O components. Digital audio and motion video I/O have such high bandwidth and low delay requirements that special underlying software support mechanisms are needed. Our goal is to determine how functionality is divided between the window system and the operating system, and what types of mechanisms support this functionality. As a first step toward achieving this goal, we are building a distributed real-time I/O-intensive application: multi-media conferencing. These conferences are between geographically distributed users on personal workstations connected by high-speed networks. These conferences include the presentation of real-time digital audio and video I/O of the participants so that they may effectively collaborate despite their physical separation. From the experience we gain by buil..

Estimation of right atrial and ventricular hemodynamics by CT coronary angiography.

BACKGROUND: Computed tomography coronary angiography (CTCA) provides an accurate noninvasive alternative to the invasive assessment of coronary artery disease. However, a specific limitation of CTCA is inability to assess hemodynamic data. OBJECTIVE: We hypothesized that CTCA-derived measurements of contrast within the superior vena cava (SVC) and inferior vena cava (IVC) would correlate to echocardiographic estimations of right atrial and right ventricular pressures. METHODS: Medical records of all patients who underwent both echocardiography and CTCA in our center were reviewed (n = 32). Standard CTCA was performed with a 64-detector CT using test-bolus method for image acquisition timing and iso-osmolar contrast injection through upper extremity vein. The length of the column of contrast reflux into the inferior vena cava (IVC) was correlated to echocardiographically determine tricuspid regurgitation jet velocity (TRV). SVC area change with contrast injection at the level of the bifurcation of the pulmonary artery was also correlated with IVC sniff response by echocardiogram. RESULTS: The reflux column length was interpretable in 27 of 32 patients with a mean length of 10.1 ± 1.1 mm, and a significant bivariate correlation was observed between reflux column length and the tricuspid regurgitant jet velocity (r = 0.84; P \u3c .0001). Mean SVC distensibility ratio was 0.63 ± 0.03; mean IVC sniff response ratio was 0.53 ± 0.03. SVC distensibility correlated to IVC sniff response with a Pearson r of 0.57 (P = .04). CONCLUSION: Quantification of IVC and SVC contrast characteristics during CTCA provides a feasible and potentially accurate method of estimating right atrial and ventricular pressure