New-born infants are likely to suffer excessive vibration during neonatal transport, but there is no effective method to attenuate the transmission of vibration from the ambulance floor to an infant. This would be particularly detrimental to premature or sick new-born babies. In this paper, a quasi-zero-stiffness (QZS) vibration isolation method is proposed to improve the comfort of the infant in an incubator. The infant compartment is supported by quasi-zero-stiffness isolators, which are realized each by combining a pair of mutually repelling permanent magnets in parallel connection with a coil spring, and their parameters are obtained by design optimization to maximize the displacement range with smaller stiffness than that of the coil spring. A lumped-mass model of the transport incubator is developed, and the vibration isolation performance is estimated in terms of displacement and acceleration transmissibility. Numerical results reveal that a comparatively heavy damping is needed to completely avoid the jump phenomenon inherent in polynomial nonlinearity and suppress resonance, and thus achieve smooth and effective vibration attenuation starting from an ultra-low frequency. Under a random disturbance, magnification of vibration is observed in the original transport incubator, but notable attenuations of root mean square (RMS) acceleration and displacement in the modified one, which indicates that the proposed quasi-zero-stiffness isolator should be a good solution to eliminate vibration-induced injuries in neonatal transport.

BackgroundCongenital hydrocephalus is a descriptive diagnosis of symptoms, that are present for numerous reasons, including chromosomal disorders, genetic mutations, intrauterine infection and hemorrhage, amongst other factors. Mutation of L1CAM gene is the most frequent cause of congenital hydrocephalus, contributing to approximately 30% of X‐linked congenital hydrocephalus.MethodsIn the present study, we used whole‐exome sequencing and Sanger sequencing to investigate an aborted male fetus present with severe congenital hydrocephalus at 24 weeks of gestation, whose mother had a history of two previous voluntary terminations of pregnancies as a result of hydrocephalus. Magnetic resonance imaging, an autopsy and electron microscopy were performed and the phenotypic changes were described.ResultsWhole‐exome sequencing in the fetus, as well as variant segregation analysis, revealed a novel maternally derived hemizygous nonsense mutation (c.2865G>A; p. Y955*) in exon 21 of the L1CAM gene (NM_000425.4). Severe hydrocephalus was observed along with marked dilatation of lateral ventricles. An electron micrograph of the surface of lateral ventricle walls revealed a lack of ependymal cilia.ConclusionThe present study suggests that L1CAM mutation screening should be considered for a male fetus with isolated hydrocephalus, especially with a family history, which could facilitate prenatal diagnosis in a subsequent pregnancy.

Objective To determine the effect of mid‐trimester emergency cerclage in women with twin pregnancies with cervical dilation and prolapsed membranes, and to identify risk factors predicting spontaneous preterm birth (sPTB) before 28 weeks, after cerclage. Methods Retrospective analysis of twin gestations with cervical dilation and prolapsed membranes treated with emergency cerclage or expectant management (2015–2020). The primary outcomes were the rate of sPTB before 28 weeks and the gestational latency. Multiple logistic regression analysis was used to determine the factors associated with sPTB before 28 weeks, after cerclage. Results Ninety‐seven women were included, cerclage (n = 58) or no cerclage (n = 39). Cerclage placement was associated with significantly lower incidence of sPTB before 28 weeks of pregnancy (34.5% vs 82.1%) and prolongation of the gestational latency (46.71 ± 27.52 vs 10.95 ± 11.71 days). Positive cervical culture (odds ratio [OR] 10.69, 95% confidence interval [CI] 1.82–62.95), pregnancy duration at diagnosis less than 22 weeks (OR 9.42; 95% CI 1.69–52.69) and cervical dilation at least 4 cm (OR 7.92; 95% CI 1.40–44.71) were found to be independent risk factors for sPTB before 28 weeks, after cerclage. Conclusion Emergency cerclage in women with twin pregnancies with cervical dilation and prolapsed membranes was associated with an overall 40% decrease in sPTB before 28 weeks and a prolongation of latency by 5 weeks. The strongest predictor of sPTB before 28 weeks after cerclage was a positive cervical culture.

Congenital aneurysm of the left atrium is a rare cardiac anomaly, most commonly detected between the 2nd and 4th decades of life in a symptomatic patient. We report a congenital aneurysm of the left atrium diagnosed at 24 weeks of gestational age, associated with other congenital heart diseases and 47XY, +18 karyotype. The literature of the left atrial aneurysm diagnosed by fetal echocardiography is also reviewed in this report.

No abstract