Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Proceed order?

Export
  • 1
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 90 (2001), S. 5878-5883 
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: We evaluated influences of charge exchange on ion collection of laser isotope separation of uranium. We made a two-dimensional code based on fluid dynamics taking the charge exchange term into consideration. Parametric study was performed in terms of electric amplitude, ion density, and electron temperature. In addition to parallel electrode arrangement, calculations were performed for Π- and M-type arrangements. The ratio of charge exchanged ions is found to largely depend on the collection time. © 2001 American Institute of Physics.
    Type of Medium: Electronic Resource
    Signatur Availability
    BibTip Others were also interested in ...
  • 2
    ISSN: 1540-8167
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Introduction: Previous studies have suggested that paroxysmal atrial fibrillation (PAF) of vagal origin often occurs at night and PAF of sympathetic origin occurs during the daytime; however, autonomic tone after spontaneous termination of PAF has not been determined. The aim of this study was to evaluate by heart rate variability (HRV) analysis the relationship between the time of PAF onset and autonomic tone before and after PAF. Methods and Results: Twenty-three patients ( 65 ± 2 years) who underwent 24-hour ambulatory monitoring, had one or more episodes of PAF (〉30 min), and had maintained normal sinus rhythm for 〉60 min before/after PAF were enrolled in this study. Mean duration of PAF was 6.2 ± 1.2 hours. HRV parameters were analyzed in a 10-minutes section at 60 minutes, 20 minutes, and immediately before the onset of PAF and after its termination. PAF began at night in 14 patients (group N) and during the daytime in 9 patients (group D). In group N, the high-frequency (HF) component and low-frequency (LF) component showed a significant decrease after PAF; PAF was preceded by a gradual increase in HF and LF. Changes in the LF/HF ratio, however, did not occur before or after PAF. Conversely, group D showed a significant increase in the LF/HF ratio before PAF and a decrease in LF and the LF/HF ratio after PAF, but no changes in HF. These changes in HRV parameters were not influenced by the duration or termination time of PAF. Conclusion: This study suggests that the autonomic nervous system plays an important role in both the initiation and termination of PAF. Furthermore, the time of PAF onset influences the autonomic tone at the initiation and termination of PAF. (J Cardiovasc Electrophysiol, Vol. 14, pp. 559-564, June 2003)
    Type of Medium: Electronic Resource
    Signatur Availability
    BibTip Others were also interested in ...
  • 3
    ISSN: 1540-8167
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Autonomic Effects of M Region. Introduction: The initiation of ventricular arrhythmias is in part associated with autonomic nervous tone. We investigated the effects of sympathetic and parasympathetic stimulation on the monophasic action potentials (MAPs) of the epicardium (EPi), mid-myocardial (M) region, and endocardium (Endo) in vivo. Methods and Results: In 12 mongrel open chest anesthetized dogs, both sides of the cervical vagus nerves and stellate ganglia were crushed with a tight ligature. Right atrial pacing at 600 msec cycle length was begun after the sinus nodal area had been crushed. MAPs from the M region were measured by two needle electrodes that were supported by a W-shaped plastic frame. The epicardial, M region, and endocardial MAP durations at 90% repolarization (MAPD90) were 287 ± 7, 315 ± 7, and 290 ± 8 msec, respectively. The MAPD90 from M cells was longer than that from Epi or Endo. Sympathetic stimulation shortened MAPD90 more in the M region (53 ± 4 msec) than that in the Epi (27 ± 3 msec) or Endo (26 ± 4 msec). The transmural dispersion of repolarization during sympathetic stimulation was shorter than that of the control. Parasympathetic stimulation did not significantly affect any of the MAPD90 values. Simultaneous sympathetic and parasympathetic stimulation produced changes not significantly to those produced by sympathetic stimulation alone. Conclusion: Our results suggest that sympathetic activity can reduce transmural dispersion of repolarization under autonomic control in the canine heart under baseline conditions.
    Type of Medium: Electronic Resource
    Signatur Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...