RESUMEN
A pulse-echo ultrasonic method is presented to measure elastic parameter variations during thermal loading with high accuracy. Using a dry coupling configuration dedicated to high temperature investigation, this technique has been applied on 6061-T6 aluminium samples up to 220 degrees C. Experimental settings are described to assess the measurement reproducibility estimated at a value of 0.2%. Consequently, the anisotropy of this aluminium between the rolling direction and two orthogonal axes has been clearly detected and also measured versus temperature. As regards the temperature dependence of these elastic parameters, these results are compared with the estimations of the Young's modulus obtained during mechanical tests in conditions of low cycle fatigue (LCF). The same linear variation versus temperature is found but with a shift of 7GPa. This difference has been classically attributed to systematic experimental error sources and to the distinction existing between dynamic and static elastic modulus.
Asunto(s)
Aleaciones , Ensayo de Materiales/métodos , Ultrasonido , Aluminio , Anisotropía , Elasticidad , TemperaturaRESUMEN
Hereditary factor VII deficiency is a rare autosomal recessive condition. Factor VII's level elevates during pregnancy in normal patients, as well in deficient individuals for some authors. Various treatments (fresh frozen plasma, prothrombin complex or factor VII concentrate) have been used to lessen the peri-partum hemorrhage in those factor VII-deficient pregnant women. We report the case of a pregnant woman presenting a factor VII deficiency (level 4%), without variation of level during her pregnancy. The single infusion of factor VII concentrate, prior to delivery, has elevated factor VII's level at 17% and has likely permitted minimal post-partum bleeding. The peripartum management of factor VII deficiency is discussed.
Asunto(s)
Deficiencia del Factor VII/terapia , Complicaciones Hematológicas del Embarazo , Adulto , Factor VII/administración & dosificación , Factor VII/uso terapéutico , Femenino , Humanos , Hemorragia Posparto/prevención & control , EmbarazoRESUMEN
OBJECTIVES: To determine whether the presence of cervico-vaginal prolactin during pregnancy is significantly associated with preterm delivery. STUDY DESIGN: A cohort of 64 pregnant women between 21 and 34 weeks of amenorrhea underwent a washing of the exocervix and vaginal fornices with a normal saline solution. The fluid was then aspirated and centrifuged. Samples were stored at -70 degrees C and later prolactin level was determined by radioimmunoassay. Test was considered as positive for a prolactin concentration higher than 2 ng/ml. Statistical analysis were realized by Student's t test, Fisher's exact test and chi 2 test. RESULTS: In patients with preterm labor, positive cervico-vaginal prolactin had a positive predictive value of 36% and a negative predictive value of 94% for a preterm delivery before 34 weeks of gestation (respectively 45% and 79% before 37 weeks). The sensitivity of a positive test was 31% for preterm delivery before 37 weeks of gestation and specificity was 87% (respectively 57% and 88% before 34 weeks). Patients with a positive prolactin test had a significantly shorter latency between testing and delivery (33.7 days vs 52.4 days; p < 10(-9)). No delivery occurred during the following weeks for patients with a negative prolactin test and, among those, only one delivery occurred during the second week following the test. Positive prolactin tests correlated with a mean cervical dilatation of 1 centimetre at the time of testing, while it was of 0.6 centimetre for patients with a negative prolactin test. CONCLUSIONS: Cervico-vaginal prolactin seems to be a non convincing marker for preterm delivery but indicative of a shorter latency from testing to delivery in symptomatic patients. Further investigations are necessary to evaluate accuracy of cervico-vaginal prolactin as a biochemical marker for imminent delivery in patients with preterm labor.