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Carnot's general proposition, also referred to as one of Carnot's principles, states that the work producing potential of heat—harvested by reversible heat engines—is independent of the working fluid and of engine internal details, being only a function of the temperatures of the reservoirs with which the engine exchanges heat. This concept, usually presented in introductory thermodynamics courses to ME students in the context of the second law of thermodynamics before entropy is introduced, is customarily proven by contradiction, i.e., by a violation of the second law, using second law concepts and abstractions such as 'thermal reservoirs' and 'reversible engines', without concrete examples, even though Carnot's proposition mentions concrete things such as working fluids and engine internal details. This work proposes to document the usage of different reversible Stirling engine models that take the engine arrangement down to engine constructive parameters, crankshaft angles, and the like, as well as fluid properties into account towards illustrating the validity of Carnot's general proposition without using entropy. [ABSTRACT FROM AUTHOR]

Objective: To compare the long-term effects of tocolysis with nifedipine or atosiban on child outcome at age 2.5-5.5 years.Design: The APOSTEL III trial was a multicentre randomised controlled trial that compared tocolysis with nifedipine or atosiban in 503 women with threatened preterm birth. Neonatal outcomes did not differ between both treatment arms, except for a higher incidence of intubation in the atosiban group.Methods: Parents were asked to complete four questionnaires regarding neurodevelopment, executive function, behaviour problems and general health.Main Outcome Measures: The main long-term outcome measure was a composite of abnormal development at the age of 2.5-5.5 years.Results: Of the 426 women eligible for follow-up, 196 (46%) parents returned the questionnaires for 115 children in the nifedipine group and 110 children in the atosiban group. Abnormal development occurred in 32 children (30%) in the nifedipine group and in 38 children (38%) in the atosiban group (OR 0.74, 95% CI 0.41-1.34). The separate outcomes for neurodevelopment, executive function, behaviour, and general health showed no significant differences between the groups. Sensitivity analysis for all children of the APOSTEL III trial, including a comparison of deceased children, resulted in a higher rate of healthy survival in the nifedipine group (64 versus 54%), but there was no significant difference in the overall mortality rate (5.4 versus 2.7%). There were no significant subgroup effects.Conclusion: Outcomes on broad child neurodevelopment, executive function, behaviour and general health were comparable in both groups. Neither nifedipine nor atosiban can be considered as the preferred treatment for women with threatened preterm birth.Tweetable Abstract: Nifedipine- and atosiban-exposed children had comparable long-term outcomes, including neurodevelopment, executive function and behaviour. [ABSTRACT FROM AUTHOR]

Objective: Brain injury in neonates born prematurely is associated strongly with poor neurodevelopmental outcome. The aim of this study was to evaluate whether tocolysis with nifedipine or atosiban in women with threatened preterm birth can reduce the incidence of overall brain injury in neonates born prematurely. Methods: This was a secondary analysis of the APOSTEL‐III trial (Dutch Clinical Trial Registry, no. NTR2947), a randomized clinical trial in which women with threatened preterm labor between 25 and 34 weeks of gestation were allocated to treatment with nifedipine or atosiban. In this secondary analysis, women delivered at ≤ 32 weeks of gestational age in the two main contributing centers were included. Primary outcome was the presence of neonatal brain injury, which was defined as presence of abnormalities on ultrasound investigation and classified into mild and severe. To evaluate type and severity of brain injury, all neonatal ultrasounds performed during neonatal intensive and medium care admission were analyzed. To test the robustness of our results, a sensitivity analysis was performed assessing differences in baseline or known risk factors for brain injury. Results: A total of 117 neonates (from 102 women) were studied, of which 51 had been exposed to nifedipine and 66 to atosiban. Brain injury was observed in 22 (43.1%) neonates in the nifedipine group compared with 37 (56.1%) in the atosiban group (OR, 0.60; 95% CI, 0.29–1.24). Presence of mild brain injury was comparable between the nifedipine (33.3%) and atosiban (48.5%) groups (OR, 0.53; 95% CI, 0.25–1.13). Severe brain injury was also comparable between the groups, observed in 9.8% of neonates in the nifedipine vs 7.6% of those in the atosiban group (OR, 1.33; 95% CI, 0.36–4.85). Intraventricular hemorrhage (≥ Grade I) was the most frequently seen ultrasound abnormality, observed in 18 (35.3%) neonates in the nifedipine group vs 25 (37.9%) in the atosiban group (OR, 0.90; 95% CI, 0.42–1.91). The sensitivity analysis, with adjustment for maternal age and gestational age at randomization, showed no statistical difference between the groups for presence of brain injury (OR, 0.58; 95% CI, 0.27–1.27). Conclusion: In children born before 32 weeks of gestation after the use of tocolytics, the prevalence of brain injury was high. No significant differences were found with respect to overall brain injury between neonates exposed to nifedipine and those exposed to atosiban. However, as this study was a secondary analysis of the APOSTEL III trial, it was underpowered for brain injury. Copyright © 2017 ISUOG. Published by John Wiley & Sons Ltd. [ABSTRACT FROM AUTHOR]

Study Question: Is curettage more effective than expectant management in case of an incomplete evacuation after misoprostol treatment for first trimester miscarriage?Summary Answer: Curettage leads to a higher chance of complete evacuation but expectant management is successful in at least 76% of women with an incomplete evacuation of the uterus after misoprostol treatment for first trimester miscarriage.What Is Known Already: In 5-50% of the women treated with misoprostol, there is a suspicion of incomplete evacuation of the uterus on sonography. Although these women generally have minor symptoms, such a finding often leads to additional curettage.Study Design, Size, Duration: From June 2012 until July 2014, we conducted a nationwide multicenter randomized controlled trial (RCT). Women who had had primary misoprostol treatment for miscarriage with sonographic evidence of incomplete evacuation of the uterus were randomly allocated to either curettage or expectant management (1:1), using a web-based application.Participants/materials, Setting, Methods: We included 59 women in 27 hospitals; 30 were allocated to curettage and 29 were allocated to expectant management. A successful outcome was defined as sonographic finding of an empty uterus 6 weeks after randomization.Main Results and the Role Of Chance: Baseline characteristics of both groups were comparable. Empty uterus on sonography or uneventful clinical follow-up was seen in 29/30 women (97%) allocated to curettage compared with 22/29 women (76%) allocated to expectant management (RR 1.3, 95% CI 1.03-1.6) with complication rates of 10% versus 10%, respectively (RR 0.97, 95% CI 0.21-4.4). In the group allocated to curettage, no woman required re-curettage, while two women (6.7%) underwent hysteroscopy (for other or unknown reasons). In the women allocated to expectant management, curettage was performed in four women (13.8%) and three women (10.3%) underwent hysteroscopy.Limitations, Reasons For Caution: Due to a strong patient preference, mainly for expectant management, the targeted sample size could not be included and the trial was stopped prematurely.Wider Implications Of the Findings: In women suspected of incomplete evacuation of the uterus after misoprostol, curettage is more effective than expectant management. However, expectant management is equally safe and prevents curettage for most of the women. This finding could further restrain the use of curettage in the treatment of first trimester miscarriage.Study Funding/competing Interests: This study was funded by ZonMw, a Dutch organization for Health Research and Development, project number 80-82310-97-12066. There were no conflicts of interests.Trial Registration Number: Dutch Trial Register NTR3310, http://www.trialregister.nl TRIAL REGISTRATION DATE: 27 February 2012.Date Of First Patient's Enrolment: 12 June 2012. [ABSTRACT FROM AUTHOR]

The determination of permeability K and form coefficient C, defined by the Hazen-Dupuit-Darcy (HDD) equation of flow through a porous medium, requires the measurement of the total pressure drop caused by the porous medium (i.e., inlet, core, and outlet) per unit of porous medium length. The inlet and outlet pressure-drop contributions, however, are not related to the porous medium length. Hence, for situations in which these pressure drops are not negligible, e.g.,for short or very permeable porous media core, the definition of K and C via the HDD equation becomes ambiguous. This aspect is investigated analytically and numerically using the flow through a restriction in circular pipe and parallel plates channels. Results show that inlet and outlet pressure-drop effects become increasingly important when the inlet and outlet fluid surface-fraction φ decreases and the Reynolds number Re increases for both laminar and turbulent flow regimes. A conservative estimate of the minimum porous medium length beyond which the core pressure drop predominates over the inlet and outlet pressure drop is obtained by considering a least restrictive porous medium core. Finally, modified K and C are proposed and predictive equations, accurate to within 2.5%, are obtained for both channel configurations with Re ranging from 10-2 to 10² and φ from 6% to 95%. [ABSTRACT FROM AUTHOR]

The article provides an overview of several analytical solutions for addressing missing reference standard results in a diagnostic accuracy study such as multiple imputation and inverse probability weighting.