15 research outputs found
Dislocation dynamics in alkali halide single crystals investigated by nuclear spin relaxation measurements
La rĂ©sonance magnĂ©tique nuclĂ©aire est appliquĂ©e Ă l'Ă©tude de la variation de la vitesse des dislocations avec la contrainte de compression appliquĂ©e dans des cristaux d'halogĂ©nures alcalins. T1Ï a Ă©tĂ© mesurĂ©e en fonction du taux [MATH] de la dĂ©formation plastique. La route moyenne des dislocations mobiles a Ă©tĂ© dĂ©terminĂ©e. Nous indiquons les rĂ©sultats des expĂ©riences sur de diffĂ©rents noyaux, sur de diffĂ©rentes orientations des cristaux et sur des tempĂ©ratures diffĂ©rentes.Dislocations moving at various velocities in deforming alkali halide single crystals were studied using the technique of pulsed nuclear magnetic resonance. The spin lattice relaxation rate in the rotating frame is measured as a function of the plastic deformation rate [MATH]. From this the mean free path of mobile dislocations can be determined. The results for different resonant nuclei, different crystal orientations with respect to the crystal axis and different temperatures are presented
Monitoring of fetuses with intrauterine growth restriction: a longitudinal study
To describe the time sequence of changes in fetal monitoring variables in intrauterine growth restriction and to correlate these findings with fetal outcome at delivery. This was a prospective longitudinal observational multicenter study on 110 singleton pregnancies with growth-restricted fetuses after 24 weeks of gestation. Short-term variation of fetal heart rate, pulsatility indices of fetal arterial and venous Doppler waveforms and amniotic fluid index were assessed at each monitoring session. The study population was divided into two groups: Group 1 comprised pregnancies with severely premature fetuses, which were delivered < or =32 weeks and Group 2 included pregnancies delivered after 32 completed weeks. Logistic regression was used for modeling the probability for abnormality of a variable in relation to the time interval before delivery. Trends over time were analyzed for all variables by multilevel analysis. Ninety-three (60 in Group 1 and 33 in Group 2) fetuses had at least three data sets (median, 4; range, 3-27) and had the last measurements taken within 24 h of delivery or intrauterine death. The percentage of abnormal test results and the degree of abnormality were higher in Group 1 compared to Group 2. Amniotic fluid index and umbilical artery pulsatility index were the first variables to become abnormal, followed by the middle cerebral artery, aorta, short-term variation, ductus venosus and inferior vena cava. In Group 1, short-term variation and ductus venosus pulsatility index showed mirror images of each other in their trend over time. Perinatal mortality was significantly higher if both variables were abnormal compared to only one or neither being abnormal (13/33 (39%) vs. 4/60 (7%); P = 0.0002; Fisher's exact test). Ductus venosus pulsatility index and short-term variation of fetal heart rate are important indicators for the optimal timing of delivery before 32 weeks of gestation. Delivery should be considered if one of these parameters becomes persistently abnorma
Management der postpartalen Blutung (PPH): Algorithmus der InterdisziplinĂ€ren D-A-CH-Konsensusgruppe PPH (Deutschland â Ăsterreich â Schweiz)
Postpartum hemorrhage (PPH) is one of the main causes of maternal deaths even in industrialized countries. It represents an emergency situation which necessitates a rapid decision and in particular an exact diagnosis and root cause analysis in order to initiate the correct therapeutic measures in an interdisciplinary cooperation. In addition to established guidelines, the benefits of standardized therapy algorithms have been demonstrated. A therapy algorithm for the obstetric emergency of postpartum hemorrhage in the German language is not yet available. The establishment of an international (Germany, Austria and Switzerland D-A-CH) "treatment algorithm for postpartum hemorrhage" was an interdisciplinary project based on the guidelines of the corresponding specialist societies (anesthesia and intensive care medicine and obstetrics) in the three countries as well as comparable international algorithms for therapy of PPH.The obstetrics and anesthesiology personnel must possess sufficient expertise for emergency situations despite lower case numbers. The rarity of occurrence for individual patients and the life-threatening situation necessitate a structured approach according to predetermined treatment algorithms. This can then be carried out according to the established algorithm. Furthermore, this algorithm presents the opportunity to train for emergency situations in an interdisciplinary team.Die postpartale Blutung (PPH) zĂ€hlt zu den Hauptursachen der MĂŒttersterblichkeit auch in der westlichen Welt. Die PPH stellt eine Notfallsituation dar, die eine rasche Entscheidung und v. a. eine exakte Diagnose und Ursachenanalyse notwendig macht, um die korrekten therapeutischen MaĂnahmen in interdisziplinĂ€rer Zusammenarbeit rechtzeitig einzuleiten. Neben etablierten Leitlinien ist der Nutzen standardisierter Therapiealgorithmen belegt. Ein Therapiealgorithmus fĂŒr den geburtshilflichen Notfall âpostpartale HĂ€morrhagieâ fehlte bisher im deutschsprachigen Raum. Die Erstellung des lĂ€nderĂŒbergreifenden (Deutschland, Ăsterreich und Schweiz: D-A-CH) âHandlungsalgorithmus Postpartale Blutungâ erfolgte interdisziplinĂ€r, basierend auf den bisherigen Leitlinien der jeweiligen Fachgesellschaften (AnĂ€sthesie und Intensivmedizin, Geburtshilfe) der 3 LĂ€nder sowie internationalen vergleichbaren Algorithmen zur Therapie der PPH.
Das geburtshilfliche und anĂ€sthesiologische Personal muss fĂŒr den Notfall eine ausreichende Expertise trotz geringer Fallzahl besitzen. Die Seltenheit, mit der das Ereignis fĂŒr die einzelne Patientin auftritt, sowie die vitale Bedrohung in der Situation, erfordern ein strukturiertes Vorgehen nach vorgegebenen Handlungsalgorithmen. Dies kann mit dem nun ausgearbeiteten Algorithmus erfolgen. DarĂŒber hinaus bietet dieser Algorithmus die Möglichkeit, den Notfall im interdisziplinĂ€ren Team zu trainieren