Preeclampsia: The Relationship between Uterine Artery Blood Flow and Trophoblast Function.

Maternal uterine artery blood flow is critical to maintaining the intrauterine environment, permitting normal placental function, and supporting fetal growth. It has long been believed that inadequate transformation of the maternal uterine vasculature is a consequence of primary defective trophoblast invasion and leads to the development of preeclampsia. That early pregnancy maternal uterine artery perfusion is strongly associated with placental cellular function and behaviour has always been interpreted in this context. Consistently observed changes in pre-conceptual maternal and uterine artery blood flow, abdominal pregnancy implantation, and late pregnancy have been challenging this concept, and suggest that abnormal placental perfusion may result in trophoblast impairment, rather than the other way round. This review focuses on evidence that maternal cardiovascular function plays a significant role in the pathophysiology of preeclampsia

Constraining supersymmetric models from B_d - B-bar_d mixing and the B_d --> J/psi K_S asymmetry

We analyze the chargino contributions to B_d - B-bar_d mixing and CP asymmetry of the B_d --> J/psi K_S decay, in the framework of the mass insertion approximation. We derive model independent bounds on the relevant mass insertions. Moreover, we study these contributions in supersymmetric models with minimal flavor violation, Hermitian flavor structure, and small CP violating phases and universal strength Yukawa couplings. We show that in supersymmetric models with large flavor mixing, the observed values of sin(2 beta) may be entirely due to the chargino-up-squark loops.Comment: 22 pages, 1 figure, minor corrections, version to appear in Phys. Rev.

Fetuses with right aortic arch Multicentre cohort study and meta-analysis.

OBJECTIVES: Recent antenatal screening guidelines for cardiac abnormalities has increased fetal diagnosis of right aortic arch (RAA). We aimed to establish outcome of fetal RAA without intra-cardiac abnormalities (ICA) to guide postnatal management. METHODOLOGY: Retrospective cohort study. Outcome measures were rates of chromosomal abnormalities, 22q11.2 deletion, fetal extra-cardiac abnormalities (ECA), postnatal ICA and ECA, symptoms and surgery for vascular ring. A systematic review and meta-analysis (reference: CRD42015016097) was performed; results are reported as proportions. Kaplan Meier analysis of vascular ring cases with surgery as endpoint was performed. RESULTS: Our cohort included 86 cases; 41 had a vascular ring. Rates of chromosomal abnormalities, 22q11.2 deletion, and fetal ECA were 14.1%, 6.4% and 17.4% respectively. Sixteen studies including our cohort (312 fetuses) were included in the systematic review. Overall chromosomal abnormalities and 22q11.2 deletion rates were 9.0% (95% CI 6.0-12.5) and 6.1% (95% CI 3.6-9.3) whilst rates for cases with no ECA were 4.6% (95% CI 2.3-7.8) and 5.1% (95% CI 2.4-8.6). ECA were seen in 14.6% (95% CI 10.6-19.0) prenatally and 4.0% (95%CI 1.5-7.6) after birth. Postnatal ICA were identified in 5.0% (95% CI 2.7-7.9). Rate of symptoms (follow up ≥24 months) was 25.2% (95% CI 16.6-35.0) while 17.1% (95% CI 9.9-25.7) had surgery. Two-year freedom from surgery was 83.0% (95% CI 74.3-90.1) CONCLUSIONS: Fetal RAA without ICA is more frequently associated with ECA than chromosomal abnormalities. Most cases however, are isolated. Vascular ring symptoms occur in about 25% of cases. Postnatal surveillance is required mainly in the first 2 years of life

Are Twin Pregnancies Complicated by Weight Discordance or Fetal Growth Restriction at Higher Risk of Preeclampsia?

Studies have reported controversial findings on the association between fetal growth restriction (FGR) or intertwin weight discordance and the risk of hypertensive disorders of pregnancy (HDP) in twin pregnancies. The aim of this study was to investigate the association between twin growth disorders and HDP. Twin pregnancies resulting in two live births at St George's Hospital between 2000 and 2019 were included. FGR or small-for-gestational-age (SGA) at birth was assessed using singleton and twin reference charts. Intertwin discordance [(large birthweight - small birthweight)/(large birthweight) × 100%)] was calculated. Logistic regression models were performed. SGA (aOR 2.34, 95% CI 1.60-3.44, p < 0.001), intertwin discordance ≥25% (aOR 2.10, 95% CI 1.26-3.49, p = 0.004) and their co-existence (aOR 2.03, 95% CI 1.16-3.54, p = 0.013) were significantly associated with HDP. After adjusting for the known maternal risk factors of HDP and the intertwin discordance, SGA (using the twin charts) was the strongest independent risk factor associated with HDP (aOR 2.12, 95% CI 1.40-3.22, p < 0.001) and preeclampsia (aOR 2.34, 95% CI 1.45-3.76, p < 0.001). This study highlights that the presence of at least one SGA twin is significantly associated with HDP during pregnancy. Therefore, maternal blood pressure should be closely monitored in twin pregnancies complicated by SGA with or without intertwin discordance

Incidence of postpartum hypertension within 2 years of a pregnancy complicated by pre-eclampsia: a systematic review and meta-analysis.

BACKGROUND: Women with a history of hypertensive disorders of pregnancy (HDP) are at increased long-term risk of cardiovascular disease. However, there has been increasing evidence on the same risks in the months following birth. OBJECTIVES: This review aims to estimate the incidence of hypertension in the first 2 years after HDP. SEARCH STRATEGY: MEDLINE, Embase and Cochrane databases were systematically searched in October 2019. SELECTION CRITERIA: Observational studies comparing hypertension rate following HDP and normotensive pregnancies up to 2 years. DATA COLLECTION AND ANALYSIS: A meta-analysis to calculate the odds ratio (OR) with a 95% confidence interval (CI) and a sub-group analysis excluding women with chronic hypertension were performed. MAIN RESULTS: Hypertension was diagnosed within the first 2 years following pregnancy in 468/1646 (28.4%) and 584/6395 (9.1%) of the HDP and control groups, respectively (OR 6.28; 95% CI 4.18-9.43; I2  = 56%). The risk of hypertension in HDP group was significantly higher in the first 6 months following delivery (OR 18.33; 95% CI 1.35-249.48; I2  = 84%) than at 6-12 months (OR 4.36; 95% CI 2.81-6.76; I2  = 56%) or between 1-2 years postpartum (OR 7.24; 95% CI 4.44-11.80; I2  = 9%). A sub-group analysis demonstrated a similar increase in the risk of developing postpartum hypertension after HDP (OR 5.75; 95% CI 3.92-8.44; I2  = 49%) and pre-eclampsia (OR 6.83; 95% CI 4.25-10.96; I2  = 53%). CONCLUSIONS: The augmented risk of hypertension after HDP is highest in the early postpartum period, suggesting that diagnosis and targeted interventions to improve maternal cardiovascular health may need to be commenced in the immediate postpartum period. TWEETABLE ABSTRACT: The risk of hypertension within 2 years of birth is six-fold higher in women who experienced pre-eclampsia

Accuracy of the fetal cerebroplacental ratio for the detection of intrapartum compromise in nonsmall fetuses.

OBJECTIVE: To study the accuracy of the cerebroplacental ratio (CPR) for the detection of intrapartum fetal compromise (IFC) in fetuses growing over the 10th centile. METHODS: This was a prospective study of 569 nonsmall fetuses attending the day hospital unit of a tertiary hospital that underwent an ultrasound examination at 36-40 weeks, and were delivered within 4 weeks of examination. IFC was defined as a composite of: abnormal intrapartum fetal heart rate or intrapartum fetal scalp pH < 7.20 requiring cesarean section, neonatal umbilical cord pH < 7.20, 5' Apgar score < 7 and postpartum admission to neonatal or pediatric intensive care units. The accuracy of CPR for the prediction of IFC was calculated alone and in combination with other perinatal parameters using univariate and multivariate logistic regression models, which alternatively included the onset of labor to evaluate the influence of induction of labor (IOL) on IFC and a brief composite adverse outcome of two parameters to prove the strength of the approach. RESULTS: The incidence of IFC was 17.9%. CPR sensitivity was 30.4% for a false positive rate (FFR) of 10 and 14.7% for a FPP of 5% (AUC = 0.62, p < 0.001). The multivariate analysis showed that only fetal gender and parity increased the predictive accuracy of CPR alone, although the improvement was poor (AUC = 0.67, p < 0.001). No differences were observed using any of the alternative models. Finally, IOL had no influence of IFC. CONCLUSION: Despite their apparent normality, a proportion of fetuses growing over the 10th centile suffer IFC. Some of them are suitable for detection by means of CPR

Evaluation of the microstructure and mechanical properties of a new modified cast and laser-melted AA7075 alloy

The mechanical properties and microstructure of as-cast and homogenized AA7075 were investigated. This alloy was modified by adding transition elements 0.3%Sc + 0.5%Zr, 1%Ti + 0.2%B, and 1%Fe + 1%Ni for use in additive manufacturing applications. After adding Ti + B and Sc + Zr, the structure became uniform and finer with the formation of the Al3(Sc, Zr) and TiB2 phases. Coarse structures were obtained with the formation of an extremely unfavorable morphology, close to a needle-like structure when Fe + Ni was added. The mechanical properties of the modified alloys were increased compared to those of the standard alloy, where the best ultimate tensile strength (UTS) and yield strength (YS) were obtained in the AA7075-TiB alloy compared to the standard alloy in as-cast and homogenized conditions, and the highest hardness value was provided by Fe + Ni additives. The effect of the laser melting process on the microstructure and mechanical properties was investigated. Single laser melts were performed on these alloys using 330 V and a scanning speed of 8 mm/s. During the laser melting, the liquation of the alloying elements occurred due to non-equilibrium solidification. A change in the microstructures was observed within the melt zone and heat-affected zone (HAZ). The hardness of the laser-melted zone (LMZ) after adding the modification elements was increased in comparison with that of the standard alloy. Corrosion testing was performed using a solution of 100 mL distilled water, 3.1 g NaCl, and 1 mL HCl over 5, 10, and 30 min and 1 and 2 h. The corrosion resistance of the alloy modified with FeNi was low because of the non-uniform elemental distribution along the LMZ, but in the case of modification with ScZr and TiB, the corrosion resistance was better compared to that of the standard alloy. © 2019 by the authors.Ministry of Science and Higher Education of the Russian FederationThe author (Asmaa M. Khalil) gratefully acknowledges financial support from the Ministry of Science and Higher Education of the Russian Federation in the framework of Increase Competitiveness Program of MISiS (Support project for young research engineers)

Analysis of a spatio-temporal advection-diffusion model for human behaviors during a catastrophic event

In this work, using the theory of first-order macroscopic crowd models, we introduce a compartmental advection-diffusion model, describing the spatio-temporal dynamics of a population in different human behaviors (alert, panic and control) during a catastrophic event. For this model, we prove the local existence, uniqueness and regularity of a solution, as well as the positivity and $L^1$--boundedness of this solution. Then, in order to study the spatio-temporal behavioral dynamics of a population during a catastrophic event, we present several numerical simulations for different evacuation scenarios.Comment: I will correct and modify some facts and I will submit again the new versio

On the usage of average Hausdorff distance for segmentation performance assessment: Hidden error when used for ranking

Average Hausdorff distance is a widely used performance measure to calculate the distance between two point sets. In medical image segmentation, it is used to compare ground truth images with segmentations allowing their ranking. We identified, however, ranking errors of average Hausdorff distance making it less suitable for applications in segmentation performance assessment. To mitigate this error, we present a modified calculation of this performance measure that we have coined “balanced average Hausdorff distance”. To simulate segmentations for ranking, we manually created non-overlapping segmentation errors common in magnetic resonance angiography cerebral vessel segmentation as our use-case. Adding the created errors consecutively and randomly to the ground truth, we created sets of simulated segmentations with increasing number of errors. Each set of simulated segmentations was ranked using both performance measures. We calculated the Kendall rank correlation coefficient between the segmentation ranking and the number of errors in each simulated segmentation. The rankings produced by balanced average Hausdorff distance had a significantly higher median correlation (1.00) than those by average Hausdorff distance (0.89). In 200 total rankings, the former misranked 52 whilst the latter misranked 179 segmentations. Balanced average Hausdorff distance is more suitable for rankings and quality assessment of segmentations than average Hausdorff distance

An evaluation of performance measures for arterial brain vessel segmentation

Background: Arterial brain vessel segmentation allows utilising clinically relevant information contained within the cerebral vascular tree. Currently, however, no standardised performance measure is available to evaluate the quality of cerebral vessel segmentations. Thus, we developed a performance measure selection framework based on manual visual scoring of simulated segmentation variations to find the most suitable measure for cerebral vessel segmentation. Methods: To simulate segmentation variations, we manually created non-overlapping segmentation errors common in magnetic resonance angiography cerebral vessel segmentation. In 10 patients, we generated a set of approximately 300 simulated segmentation variations for each ground truth image. Each segmentation was visually scored based on a predefined scoring system and segmentations were ranked based on 22 performance measures common in the literature. The correlation of visual scores with performance measure rankings was calculated using the Spearman correlation coefficient. Results: The distance-based performance measures balanced average Hausdorff distance (rank = 1) and average Hausdorff distance (rank = 2) provided the segmentation rankings with the highest average correlation with manual rankings. They were followed by overlap-based measures such as Dice coefficient (rank = 7), a standard performance measure in medical image segmentation. Conclusions: Average Hausdorff distance-based measures should be used as a standard performance measure in evaluating cerebral vessel segmentation quality. They can identify more relevant segmentation errors, especially in high-quality segmentations. Our findings have the potential to accelerate the validation and development of novel vessel segmentation approaches