Bibliothek

feed icon rss

Ihre E-Mail wurde erfolgreich gesendet. Bitte prüfen Sie Ihren Maileingang.

Leider ist ein Fehler beim E-Mail-Versand aufgetreten. Bitte versuchen Sie es erneut.

Vorgang fortführen?

Exportieren
Filter
  • Gastric motility  (6)
  • ELECTROGASTROGRAPHY  (4)
  • Engineering General  (4)
  • 74.60.Ge  (3)
  • 1
    Digitale Medien
    Digitale Medien
    Springer
    The European physical journal 94 (1994), S. 249-254 
    ISSN: 1434-6036
    Schlagwort(e): 74.60.Ge ; 74.70.Vy
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Physik
    Notizen: Abstract Bardeen-Stephen dissipation in the regime of thermally activated flux flow (TAFF) and flux creep has been considered with respect to its contribution to the activation energy for thermally initiated flux movement. The inclusion of this flux flow dissipation term leads to a new expression for the voltage-current (V-I, or E-J) characteristics. The extended model describes the flux dynamics in the three regimes of flux movement: TAFF, creep, and flux flow, in a satisfactory way and explains the main experimental observations.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 2
    ISSN: 1432-0630
    Schlagwort(e): 74.60.Ge ; 74.25.Fy ; 74.20.De
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Maschinenbau , Physik
    Notizen: Abstract The measurement of the c-axis resistivity of single crystalline La1.86Sr0.14CuO4 is performed at different constant temperatures as a function of magnetic field H and angle θ between H and the ab-plane. It is shown that the 2D- or 3D-scaling rule proposed for high-T c superconductors does not work well for the present system. Taking into account unusual vortex dynamics in the high-T c systems, an extension is made to the 3D-scaling rule developed on the basis of the effective-mass model. Based on this extended rule, it is shown that at each given temperature the observed resistivity as a function of H and θ could be consistently scaled onto the corresponding Lorentz-force-free magnetoresistivity curves directly measured in H‖I‖c.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 3
    Digitale Medien
    Digitale Medien
    Springer
    Annals of biomedical engineering 27 (1999), S. 88-95 
    ISSN: 1573-9686
    Schlagwort(e): Electrogastrography ; Gastric motility ; Stomach ; Filter banks ; Neural networks
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin , Technik allgemein
    Notizen: Abstract Dysrhythmia in gastric myoelectrical activity has been frequently observed in patients with gastric motor disorders and gastrointestinal symptoms. The assessment of the regularity of gastric myoelectrical activity is of great clinical significance. The aim of this study was to develop an automated assessment method for the regularity of gastric myoelectrical activity from the surface electrogastrogram (EGG). The method proposed in this paper was based on the filter bank and neural network. First, the EGG signal was divided into frequency subbands using filter bank analysis. Second, a parameter called the subband energy ratio (SER) was computed for each subband signal. A multilayer perceptron neural network was then used to automatically classify the EGG signal into four categories: bradygastria, normal, tachygastria, and arrhythmia, using the SER as the input. The EGG recording was made using the standard method of electrogastrography by placing electrodes on the abdominal surface. The study was performed in 40 patients with various gastric motor disorders, ten healthy adults, and ten healthy children. The neural network was trained and tested using the EGG data obtained from the patients. The regularity of gastric myoelectrical activity was assessed based on the classification of the minute-by-minute EGG segments. Using the running spectral analysis method as a gold standard, the proposed automated method had an accuracy of 100% for the training set and 97% for the test set. It was concluded that the proposed method provides an accurate and automatic assessment of the regularity of gastric myoelectrical activity from the EGG. © 1999 Biomedical Engineering Society. PAC99: 8780-y, 8717-d, 0705Mh, 0270Hm
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 4
    Digitale Medien
    Digitale Medien
    Springer
    Journal of low temperature physics 105 (1996), S. 509-514 
    ISSN: 1573-7357
    Schlagwort(e): 74.60.Ec ; 74.25.Ha ; 74.60.Ge ; 74.62.Bf
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Physik
    Notizen: Abstract The paramagnetic Meissner effect (PME), in which the field-cooled-magnetization (FCM) of superconducting samples is positive below the superconducting transition temperature Tc, has been observed in certain ceramic and single-crystal samples of the high-Tc cuprate superconductors and more recently in disk-shaped Nb samples. Through systematic investigations of the conditions for observing the PME in Nb disks, various surface treatments to the Nb disks were found to change both the zero-field-cooled-magnetization (ZFCM) and the FCM, including the appearance of a positive FCM in samples previously not exhibiting the PME as well as the elimination of the PME through surface abrasion. These results suggest that the PME arises from the field distributions created by the flux pinning associated with microstructural defects on the surface layer of the disk.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 5
    Digitale Medien
    Digitale Medien
    Springer
    Digestive diseases and sciences 43 (1998), S. 2384-2391 
    ISSN: 1573-2568
    Schlagwort(e): ELECTROGASTROGRAPHY ; FUNCTIONAL DYSPEPSIA ; GASTROINTESTINAL MOTILITY ; GASTRIC EMPTYING
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract The aim of this study was to investigateabnormalities in pediatric patients with functionaldyspepsia. Fifteen symptomatic pediatric patientsdiagnosed with functional dyspepsia and 17 aged-matchedhealthy controls were studied. Gastric myoelectricalactivity was recorded using surface electrogastrographyfor 1 hr in the fasting state and 1 hr after a testmeal. It was found that, in comparison with thecontrols, the children with functional dyspepsia had alower percentage of 2- to 4-cpm slow waves in bothfasting state (66.0 ± 4.7% vs 79.7 ± 3.1%,P 〈 0.07) and fed state (72.4 ± 5.4% vs 85.0± 2.9%, P 〈 0.04), and a significantly higherinstability of the dominant frequency in both fastingstate (0.50 ± 0.05 vs 0.31 ± 0.04, P 〈0.01) and fed state (0.39 ± 0.05 vs 0.25 ±0.03, P 〈 0.05). It was also found the postprandial increase inEGG dominant power in the patients was inverselycorrelated with the total symptom score (r = 0.63, P =0.03). It was concluded that abnormal gastricmyoelectrical activity may play a role in the pathogenesis ofpediatric functional dyspepsia.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 6
    Digitale Medien
    Digitale Medien
    Springer
    Digestive diseases and sciences 43 (1998), S. 1023-1030 
    ISSN: 1573-2568
    Schlagwort(e): ELECTROGASTROGRAPHY ; GASTROINTESTINAL MOTILITY ; GASTRIC EMPTYING ; STOMACH
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract The efficiency and efficacy of theelectrogastrogram (EGG) involve a few practical factors,including recording length, sample size, and thecharacteristics of subjects. The aim of this study wasto investigate the effect of these factors on the accuracy ofEGG analysis. Gastric myoelectrical activity wasrecorded using electrogastrography in 24 subjects (ages22-91 years) for 1 hr in the fasting state and 2 hr after a test meal. Computerized spectralanalysis was performed to compute EGG parameters,including dominant frequency, dominant power, and thepercentage of 2-4 cycles per minute (cpm) slow waves. A parameter called misinterpretation was definedto investigate the effect of recording length. Theresults were as follows: (1) Using the recording lengthof 1 hr in each state as a gold standard, themisinterpretation for the recording length of 30 min was 27% forthe dominant frequency and 17% for the dominant power.When the recording length was reduced to 15 min, themisinterpretation increased to 61% for the dominant frequency and 38% for the dominant power. (2)With a sample size of 10 subjects and a recording lengthof 60 min, a statistically significant postprandialincrease was observed in the dominant frequency and power, and a trend in the postprandialincrease of the regularity of the EGG was noted. Whenthe sample size increased to 24 subjects, a significantpostprandial increase was found in all these parameters. (3) None of the EGG parameters exhibited anysignificant difference between the younger and oldersubjects or between men and women. In conclusion, arecording length of 30-60 min seems to be appropriate and produces reliable and predictable results.Age and gender do not affect any of the EGGparameters.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 7
    Digitale Medien
    Digitale Medien
    Springer
    Digestive diseases and sciences 43 (1998), S. 1678-1684 
    ISSN: 1573-2568
    Schlagwort(e): ELECTROGASTROGRAPHY ; GASTROINTESTINAL MOTILITY ; FUNCTIONAL DYSPEPSIA ; GASTRIC EMPTYING
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract The aim of this study was to investigate gastricmyoelectrical activity in patients with functionaldyspepsia. Thirteen healthy subjects and 14 patientswith functional dyspepsia participated in the study. The electrogastrogram (EGG) recording was madein each subject for 30 min in the fasting state and 120min after a standard test meal of 475 calories. Spectralanalysis methods were applied to derive quantitative EGG parameters. There was no difference in theEGG between the patients and controls in the fastingstate. However, abnormalities in the postprandial EGGwere found in the patients. The percentage of 2-4 cpmwaves was significantly lower (74.4 ± 4.0% vs85.7 ± 1.6%, P 〈 0.03) and the postprandialincrease in EGG dominant power was significantly less(–0.52 ± 0.92 dB vs 2.24 ± 0.88 dB,P 〈 0.03) in patients than in controls. It was alsofound that the percentage of postprandial 2-4 cpm wavescould be used to differentiate the patients withfunctional dyspepsia from the healthy controls with a specificity of 100% and a sensitivity of 43%. It was concluded that a subset of patients withfunctional dyspepsia have impaired gastric myoelectricalactivity in the fed state.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 8
    Digitale Medien
    Digitale Medien
    Springer
    Digestive diseases and sciences 44 (1999), S. 56-62 
    ISSN: 1573-2568
    Schlagwort(e): GASTRIC SLOW WAVES ; GASTRIC MOTILITY ; GASTRIC EMPTYING ; ELECTROACUPUNCTURE ; ELECTROGASTROGRAPHY
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract The aim of this study was to investigate thecharacteristics of the gastric slow wave duringdifferent phases of the migrating myoelectrical complex(MMC) and the effect of electroacupuncture on the MMC. The experiment was performed in eight hounddogs implanted with one pair of bipolar serosalelectrodes 2 cm proximal to the pylorus. Gastricmyoelectrical activity was recorded for three completecycles of the MMC in two sessions, one withelectroacupuncture at points ST36 and PC6 and the otherat sham points. The acupuncture was performed for 30 minin phase I of the second cycle of the MMC. Spectral analysis was performed to compute the frequencyand power (amplitude) of the gastric slow wave, whereasblind visual analysis was applied to compute theappearance of spike potentials and the length of each phase of the MMC. It was found that therewas a significant difference in the frequency and powerof the gastric slow wave during different phases of theMMC (P 〈 0.05). Phase I was characterized with the highest frequency and lowest power ofthe gastric slow wave, whereas phase III exhibited thehighest power in the slow wave. It was also found thatin comparison with the sham points, electroacupuncture at the acupoints increased the number of spikebursts. This increase was not significant during the MMCcycle with electroacupuncture (34.4 ± 4.1 vs 27.5± 2.5%, P 〉 0.05) but became significant during the cycle after electroacupuncture (39.8± 3.3% vs 27.5 ± 2.5%, P 〈 0.0005).Similarly, during the MMC cycle after electroacupunctureat the acupoints, there was a significant decrease in the length of phase I (14.8 ± 2.2 vs46.9 ± 6.1 min, P 〈 0.003) and a significantincrease in the length of phase II (75.6 ± 9.9 vs30.6 ± 4.1 min, P 〈 0.003) and phase III (25.8± 0.6 vs 22.1 ± 0.7 min, P 〈 0.003). A similarincrease was observed during the MMC cycle withelectroacupuncture but was not statisticallysignificant. In conclusion, the gastric slow wave hasthe highest power during phase III of the MMC, indicatingthat the antral contraction is characterized not only bythe appearance of spikes, but also by the increasedpower of the slow wave. Electroacupuncture at acupoints of ST36 and PC6 enhances the gastric MMC byreducing the length of phase I and increasing the lengthof phases II and III.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 9
    Digitale Medien
    Digitale Medien
    Chichester [u.a.] : Wiley-Blackwell
    International Journal for Numerical Methods in Engineering 23 (1986), S. 831-846 
    ISSN: 0029-5981
    Schlagwort(e): Engineering ; Engineering General
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Mathematik , Technik allgemein
    Notizen: As an effort to predict effectively the actual collapse load of a structure, a series of numerical studies on the stability of shell structures are made. The difference in formulation between the two types of linear buckling loads, the classical and the fully linearized, is first demonstrated. Their correlations with respect to the actual stability limit of the structure are compared, and finally the two types of critical load approximations are obtained at various stages of a nonlinear analysis to study the pattern of convergence to the actual collapse load. It is found that the fully linearized buckling analysis, when combined with nonlinear analysis, can serve as a useful tool for prediction of the stability limit of a structure. While for most types of structures the approximation is within engineering accuracy, the rate of convergence of the extrapolated critical load also gives some insight to the accuracy of the approximation.
    Zusätzliches Material: 11 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 10
    Digitale Medien
    Digitale Medien
    Springer
    Medical & biological engineering & computing 28 (1990), S. 531-536 
    ISSN: 1741-0444
    Schlagwort(e): Autoregressive moving average modelling ; Electrogastrography ; Gastric motility ; Gastric slow wave ; Spectral analysis
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Chemie und Pharmazie , Medizin
    Notizen: Abstract The recording of the human, gastric myoelectrical activity, by means of cutaneous electrodes is called electrogastrography (EGG). It provides a noninvasive method of studying electrogastric behaviour. The normal frequency of the gastric signal is about 0·05 Hz. However, sudden changes of its frequency have been observed and are generally considered to be related to gastric motility disorders. Thus, spectral analysis, especially online spectral analysis, can serve as a valuable tool for practical purposes. The paper presents a new method of the adaptive spectral analysis of cutaneous electrogastric signals using autoregressive moving average (ARMA) modelling. It is based on an adaptive ARMA filter and provides both time and frequency information of the signal. Its performance is investigated in comparison with the conventional FFT-based periodogram method. Its properties in tracking time-varying instantaneous frequencies are shown. Its applications to the running spectral analysis of cutaneous electrogastric signals are presented. The proposed adaptive ARMA spectral analysis method is easy to implement and is efficient in computations. The results presented in the paper show that this new method provides a better performance and is very useful for the online monitoring of cutaneous electrogastric signals.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
Schließen ⊗
Diese Webseite nutzt Cookies und das Analyse-Tool Matomo. Weitere Informationen finden Sie hier...