Analysis of the effects of wall temperature swing on reciprocating internal combustion engine processes

[EN] A thermal wall temperature swing model was built to capture the transient effects of various material properties and coating layers on the intra-cycle wall temperature of an internal combustion engine. This model was used with a thermodynamic engine simulation to predict and analyze the effects of different types of in-cylinder insulation on engine performance. Coatings that allow the surface temperature to swing in response to the gas' cyclical heat flux enable approximately 1/3 of the energy that was prevented from leaving the gas during expansion to be recovered while improving volumetric efficiency. Reductions in compression work due to better volumetric efficiency and less heat transfer from the walls to the gas accounted for half of the improvements, while additional work extraction during combustion and expansion accounted for the other half. As load increases, the temperature swing and benefits derived from it also increase. NSFC improvements of 0.5% to 1% were seen with a highly swinging coating in the throttled regime for a realistic engine geometry and coating area, up to 2.5% at high loadsAndruskiewicz, P.; Najt, P.; Durrett, R.; Biesboer, S.; Schaedler, T.; Payri, R. (2018). Analysis of the effects of wall temperature swing on reciprocating internal combustion engine processes. International Journal of Engine Research. 19(4):461-473. https://doi.org/10.1177/1468087417717903S461473194Ramesh Kumar, C., & Nagarajan, G. (2012). Performance and emission characteristics of a low heat rejection spark ignited engine fuelled with E20. Journal of Mechanical Science and Technology, 26(4), 1241-1250. doi:10.1007/s12206-012-0206-0Hoffman, M. A., Lawler, B. J., Güralp, O. A., Najt, P. M., & Filipi, Z. S. (2014). The impact of a magnesium zirconate thermal barrier coating on homogeneous charge compression ignition operational variability and the formation of combustion chamber deposits. International Journal of Engine Research, 16(8), 968-981. doi:10.1177/146808741456127

Is there yet a role for internal iliac artery ligation in obstetric hemorrhage with the current gain in popularity of other uterus sparing techniques?

PMID = 2740579

Which uterine sparing technique should be used for uterine atony during cesarean section? The Bakri balloon or the B-Lynch suture?

PMID = 2678126

Systemic lupus erythematosus and pregnancy

We present a retrospective study of 42 consecutive cases of systemic lupus erythematosus (SLE) and pregnancy followed and delivered during the period 2002-2007 in our department. The mean patient age was 28.6 years and the nulliparity rate was 45.2%. Disease flare up occurred in 9.5% of patients. Lupus anticoagulants, anticardiolipin IgG and IgM antibodies were positive in 33%, 16.6% and 19% of patients, respectively. Mean gestational age at delivery was 36.9 +/- 4.2 and mean birth weight was 2,750 +/- 844 g. Stillbirth, fetal growth restriction, pre-eclampsia and pre-term delivery rates were 7.1%, 14.3%, 2.4% and 23.1%, respectively. Cases with uterine artery Doppler abnormalities had significantly poorer obstetric outcomes. Antiphospholipid antibodies, renal involvement and lupus activation did not have any significant influence on poor obstetric outcome. Multidisciplinary approach to the care of pregnant women with SLE is mandatory for good maternal and fetal outcomes. Uterine artery Doppler seems to be a good prognostic factor for adverse obstetric outcomes

Sperm selection based on motility in polyvinylpyrrolidone is associated with successful pregnancy and embryo development

The aim of this study was to investigate whether spermatozoon motility in polyvinylpyrrolidone (PVP) is associated with better embryo development and pregnancy rates in ICSI cycles. A total of 123 primary ICSI treatment cycles were included in this study. Semen samples were tested for motility before ICSI procedure in PVP. Within 3min, the presence or absence of motility was recorded. Sperm functions were examined by the aniline blue (AB) chromatin condensation test and the hypoosmotic swelling test, and the chromatin stability was evaluated by inducing its decondensation with sodium dodecyl sulphate and ethylenediaminetetraacetic acid (EDTA). Fertilisation and embryo scoring were evaluated. Fifty (64%) of 78 women conceived in the PVP (+) group; and 12 (26%) of 45 women conceived in the PVP (-) group; the pregnancy rate was significantly higher in the PVP (+) group (P=0.003). Semen parameters were observed to be similar in both groups. The mean number of total embryos obtained in ICSI procedure and transferred grade 1 embryos were significantly higher in PVP (+) group (P=0.01 and P=0.003 respectively). The presence of sperm motility in PVP is associated with increased pregnancy rate, higher percentage of good quality embryos, sperm chromatin condensation and decondensation

Pregnancy outcomes and prognostic factors in patients with intrahepatic cholestasis of pregnancy

The aim of this study was to describe maternal and fetal characteristics associated with intrahepatic cholestasis of pregnancy (ICP) and to determine clinical and biochemical predictors of fetal complications. A total of 89 singleton pregnancies with ICP were analysed, retrospectively. All data concerning laboratory results, symptom onset time, treatment response, delivery time and infant information were recorded in the study protocol. The mean gestational age at diagnosis was 32.6 +/- 3.4 weeks; mean time of delivery was 36.8 +/- 1.9 weeks. Binary logistic regression revealed that gestational age at diagnosis was predictive of preterm delivery (OR +/- 2.3, 95% CI: 1.5-3.3, p = 0.001). The incidence of respiratory distress syndrome (RDS), fetal growth restriction, fetal distress and preterm delivery were significantly higher in patients who were diagnosed before 30 weeks than after 34 weeks 'gestation (p < 0.01). Gestational age at diagnosis is an important independent factor predicting adverse perinatal outcomes in patients with ICP

Neonatal morbidity mortality outcomes in pre-term premature rupture of membranes

We present a retrospective review of 228 pre-term premature rupture of membranes (PPROM) singleton pregnancies followed-up in our clinic between 1996 and 2005. The most common neonatal morbidities in PPROM cases are respiratory distress syndrome (RDS), sepsis and intraventricular haemorrhage (IVH). The route of delivery does not affect newborn intensive care unit (NICU) requirements, perinatal asphyxia, sepsis and IVH rates in PPROM cases. NICU and PPV requirements, RDS, sepsis and IVH rates increase if the Apgar score is <5. Neonatal morbidity and mortality rates increase as the latent period lengthens. C reactive protein (CRP) on admission, last CRP, birth weight and the 5 min Apgar score was found to be associated with NICU requirements; only the 5 min Apgar score was found to be associated with RDS; and last leukocyte count and maternal haemotocrit was found to be associated with sepsis and pneumonia, independently. In PPROM cases, CRP on admission, last CRP, birth weight, the 5 min Apgar score, last leukocyte count and maternal haemotocrit, should be considered to predict neonatal outcomes