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  • 1
    Digitale Medien
    Digitale Medien
    350 Main Street , Malden , MA 02148-5020 , USA and 9600 Garsington Road , Oxford OX4 2XG , England . : Blackwell Science Inc
    Journal of cardiac surgery 19 (2004), S. 0 
    ISSN: 1540-8191
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Medizin
    Notizen: Abstract  Background: We researched our data to determine whether use of radial artery (RA) led to similar hospital morbidity as use of pedicled internal thoracic artery (ITA) with vein grafts. We also investigated if use of RA, different RA operative techniques, or number of inflow grafts were predictors for hospital outcome. Method: Retrospectively the hospital outcome of the first 512 patients with RAs (RA group) was compared with 108 matched patients with left ITA (LITA) and vein grafts (LITA control group). Two subgroups of RA operative techniques were further analyzed: 327 patients with RA directly from aorta (aorta-RA group), and 185 patients with RA from ITA, as a composite graft, (ITA-RA group). Results: Hospital outcome of the RA group was similar to that of the LITA control group. When all ischemic events (IE) were grouped together, univariate analysis showed that aorta-RA group resulted in less IE than the ITA-RA group (2.1% versus 5.9%, respectively, p = 0.025). Number of inflow grafts did not influence IE. Multivariate analysis, however, did not show that technique of proximal RA anastomosis or number of inflow grafts were predictors for IE. Conclusions: Hospital outcome after the use of the RA is similar to that of LITA with vein grafts. Univariate analysis shows less IE after direct aorta-RA anastomoses, but multivariate analysis did not show that technique of proximal RA anastomosis and number of inflow grafts are important predictors for hospital outcome.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 2
    Digitale Medien
    Digitale Medien
    Oxford, UK : Blackwell Publishing Ltd
    Geophysical prospecting 29 (1981), S. 0 
    ISSN: 1365-2478
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Geologie und Paläontologie , Physik
    Notizen: Optimum multichannel filters can be designed to process seismic events falling on hyperbolic moveout curves using the conventional least-squares method. Contrary to the linear moveout filters, autocorrelation and crosscorrelation functions inherent in the normal equations have to be computed numerically. However, computation times of filter coefficients are comparable to linear moveout operators.For a given source-receiver geometry and assuming straight ray-path, relative moveout of a seismic reflection event is dependent on the two way arrival time and rms velocity. Consequently, to avoid overlapping of pass and reject moveout windows, hyperbolic moveout filters have to be designed over time gates rather than for the whole record lengths. Hyperbolic and hyperbolic-linear moveout filters applied to synthetic and field seismic reflection traces show good signal-to-noise (S/N) ratio improvements. Results of some combined synthetic and field data examples are presented.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 3
    Digitale Medien
    Digitale Medien
    Oxford, UK : Blackwell Publishing Ltd
    Geophysical prospecting 33 (1985), S. 0 
    ISSN: 1365-2478
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Geologie und Paläontologie , Physik
    Notizen: A seismic trace is modeled as a moving average (MA) process both in signal and noise: a signal wavelet convolved with a reflection coefficient series plus colored random noise. Seismic reflection coefficients can be estimated from seismic traces using suitable estimation algorithms if the input wavelet is known and vice versa. The maximum likelihood (ML) algorithm is used to estimate the system order and the reflection coefficients. The system order is related to the arrival time of the latest signal in a complex seismic reflection event. The least-squares (LS) method does not provide such information. The ML algorithm makes assumptions only about the Gaussian nature of the noise. It is better suited for seismic applications since the LS method inherits the white noise assumption. The Gauss-Newton (G-N) and Newton-Raphson (N-R) optimization algorithms are used to obtain the ML and the LS estimates.Reflection coefficient estimations are affected by the choice of sampling rate of seismic data. Theoretically, the optimum choice in system identification is the Nyquist rate. Experience with synthetic data confirms the theory.In practice, good estimates of reflection coefficients are possible only up to certain pulse separations (or, equivalently, orders). This is mostly due to numerical problems with the optimization algorithms used and partly due to the limited bandwidth of seismic signals. Good estimates from data simulated using three airgun array pulses recorded with 6–128 Hz filter setting are possible up to about 40.0 ms pulse separations. Successful estimations from pinchout and thin layer simulations and well controlled offshore “bright-spots” are given.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 4
    Digitale Medien
    Digitale Medien
    Springer
    Abdominal imaging 20 (1995), S. 267-269 
    ISSN: 1432-0509
    Schlagwort(e): Retroperitoneal space anatomy ; Urioma ; Polycystic kidney disease ; X-ray computed tomography
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract We report a unique case of adult-type polycystic kidney disease (PKD) having bilateral chronic perirenal fluid collection with unusual extension. Fluid collections at both sides are connected across the midline anterior to the abdominal aorta and inferior vena cava. In addition, supradiaphragmatic extension through aortic hiatus was well demonstrated by computed tomography (CT). Anatomical boundaries and relations between two perirenal spaces are evaluated.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 5
    Digitale Medien
    Digitale Medien
    Springer
    Abdominal imaging 21 (1996), S. 501-503 
    ISSN: 1432-0509
    Schlagwort(e): Key words: Hereditary hemorrhagic telangiectasia—Arteriovenous malformations, hepatic—Liver, ultrasound studies—Color Doppler ultrasonography.
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract. Liver involvement with hereditary hemorrhagic telangiectasia (HHT) is not a rare condition. Its angiographic abnormalities are well known, but reports of the sonographic and, especially, color Doppler sonographic findings are limited. We present a patient with HHT and describe the hepatic color Doppler sonographic findings.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 6
    ISSN: 1435-0130
    Schlagwort(e): Liposuction ; Perforator vessels ; Color Doppler ultrasonography
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract In this clinical study, the effect of conventional liposuction on musculocutaneous and fasciocutaneous perforator vessels was investigated. The perforator vessels in the abdominal and lateral and medial thigh regions in 7 patients and in the abdominal region in 3 patients (a total of 38 anatomic regions in 10 patients) were marked preoperatively by color Doppler ultrasonography. Following a standard liposuction procedure, the changes in the number of the perforators in those regions were detected by the same method postoperatively at 2 weeks and 3 months. The number of cannula passes employed and total volume of the aspirate for each region were also recorded. The results of the Doppler examinations showed that 57.8% of abdominal, 50.0% of lateral thigh and 53.8% of medial thigh perforators could not be detected at 2 weeks and 3 months (p〈0.01) postoperatively. Both the number and the locations of the perforators were found to be identical for each anatomic region at the two postoperative Doppler examinations at 2 weeks and 3 months. The changes in the number of the perforators did not show any type of correlation with the number of cannula passes and the aspirate volume. The results of this study have shown that conventional liposuction may have a traumatic effect on the perforator vessels passing from the deep fascia towards the overlying skin. This observation has led us to suggest that a history of previous liposuction should be an indication for preoperative evaluation of the perforators when a musculocutaneous or fasciocutaneous flap is planned in the suctioned regions. This may prevent problems related with flap viability.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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