A simulation study of the reaction of human heart to biphasic electrical shocks

BACKGROUND: This article presents a study, which examines the effects of biphasic electrical shocks on human ventricular tissue. The effects of this type of shock are not yet fully understood. Animal experiments showed the superiority of biphasic shocks over monophasic ones in defibrillation. A mathematical computer simulation can increase the knowledge of human heart behavior. METHODS: The research presented in this article was done with different models representing a three-dimensional wedge of ventricular myocardium. The electrophysiology was described with Priebe-Beuckelmann model. The realistic fiber twist, which is specific to human myocardium was included. Planar electrodes were placed at the ends of the longest side of the virtual cardiac wedge, in a bath medium. They were sources of electrical shocks, which varied in magnitude from 0.1 to 5 V. In a second arrangement ring electrodes were placed directly on myocardium for getting a better view on secondary electrical sources. The electrical reaction of the tissue was generated with a bidomain model. RESULTS: The reaction of the tissue to the electrical shock was specific to the initial imposed characteristics. Depolarization appeared in the first 5 ms in different locations. A further study of the cardiac tissue behavior revealed, which features influence the response of the considered muscle. It was shown that the time needed by the tissue to be totally depolarized is much shorter when a biphasic shock is applied. Each simulation ended only after complete repolarization was achieved. This created the possibility of gathering information from all states corresponding to one cycle of the cardiac rhythm. CONCLUSIONS: The differences between the reaction of the homogeneous tissue and a tissue, which contains cleavage planes, reveals important aspects of superiority of biphasic pulses. ..

Status of the Two-Dimensional Synchrotron Radiation Interferometer at PETRA III

Synchrotron radiation based emittance diagnostics at modern 3rd generation light sources is mainly based on beam profile imaging in the X-ray region in order to overcome the resolution limit imposed by diffraction. A possibility to circumvent this limitation is to probe the spatial coherence with a double-slit interferometer in the optical spectral region. The light source PETRA III at DESY is using this type of interferometer since several years in order to resolve vertical emittances of about 10 pm.rad. The device is set up behind a 30 m long optical beamline, connecting the accelerator tunnel and the optical hutch. In order to increase the measurement stability, a much shorter optical beamline with reduced number of optical elements was recently commissioned. At the end of the beamline, a two-dimensional interferometer was installed which allows to deduce transverse emittances in both planes simultaneously. This contribution summarizes the status of beamline and interferometer commissioning

Proposal of a Girder Realignment Test in PETRA III

PETRA IV can benefit from the fine control of the girders that carry the storage ring elements to achieve the design beam performance. Based on the corrector magnet strength pattern it is desired to realign girders to stay within the alignment tolerances. In the current PETRA III configuration, the girders in the Max von Laue Hall are equipped for remote alignment, however, those have not been moved since their initial installation and the alignment system is currently not connected to the control system. In preparation for PETRA IV, a movement test of one of the PETRA III girders should confirm the ability to safely and precisely remote control the equipment based on an optics model that describes the effect of the girder movement on the orbit. This paper studies the feasibility of this test and prepares an initial mock-up experiment to be performed on a spare girder

Cardiac cell modelling: observations from the heart of the cardiac physiome project

In this manuscript we review the state of cardiac cell modelling in the context of international initiatives such as the IUPS Physiome and Virtual Physiological Human Projects, which aim to integrate computational models across scales and physics. In particular we focus on the relationship between experimental data and model parameterisation across a range of model types and cellular physiological systems. Finally, in the context of parameter identification and model reuse within the Cardiac Physiome, we suggest some future priority areas for this field

Impact of sleep disturbance on patients in treatment for mental disorders

<p>Abstract</p> <p>Background</p> <p>In clinical practice, sleep disturbance is often regarded as an epiphenomenon of the primary mental disorder. The aim of this study was to test if sleep disturbance, independently of primary mental disorders, is associated with current clinical state and benefit from treatment in a sample representative of public mental health care clinics.</p> <p>Method</p> <p>2246 patients receiving treatment for mental disorders in eight public mental health care centers in Norway were evaluated in a cross-sectional study using patient and clinician reported measures. Patients reported quality of life, symptom severity, and benefit from treatment. Clinicians reported disorder severity, level of functioning, symptom severity and benefit from treatment. The hypothesis was tested using multiple hierarchical regression analyses.</p> <p>Results</p> <p>Sleep disturbance was, adjusted for age, gender, time in treatment, type of care, and the presence of any primary mental disorder, associated with lower quality of life, higher symptom severity, higher disorder severity, lower levels of functioning, and less benefit from treatment.</p> <p>Conclusion</p> <p>Sleep disturbance ought to be considered a stand-alone therapeutic entity rather than an epiphenomenon of existing diagnoses for patients receiving treatment in mental health care.</p

First Experience with the Standard Diagnostics at the European XFEL Injector

International audienceThe injector of the European XFEL is in operation since December 2015. It includes, beside the gun and the accelerating section, containing 1.3 and a 3.9 GHz accelerating module, a variety of standard diagnostics systems specially designed for this facility. With very few exceptions, all types of diagnostics systems are installed in the injector. Therefore the operation of the injector is served to validate and prove the diagnostics characteristics for the complete European XFEL. Most of the standard diagnostics has been available for the start of beam operation and showed the evidence of first beam along the beam line. In the following months the diagnostics has been optimized and used for improvements of beam quality. First operational experiences and results from the standard beam diagnostics in the injector of the European XFEL will be reported in this contribution

Status of the Standard Electron Beam Diagnostics of the EU-XFEL

Outline• Setup and status accelerator• Diagnostics• BPMs• Toroids• Beam Loss Monitors• Wirescanner• Dosimetry• Summar

First Experience with the Standard Diagnostics at the European XFEL Injector

The injector of the European XFEL started beam operation in December 2015. Besides the gun and the accelerating section, containing a 1.3 and a 3.9 GHz accelerating module, it contains a variety of standard diagnostics systems specially designed for this facility. With very few exceptions, all types of diagnostics systems of the whole XFEL are installed in the injector. Therefore the injector operation allows validating and proving of the diagnostics performances for the entire facility. Most of the standard diagnostics have been available from the very beginning of the beam operation and have been used for the monitoring of the first beam. In the following months the diagnostics have been optimized and used for improvements of beam quality. In this contribution, the first results and the operation experience of the standard beam diagnostics of the European XFEL are reported