Preterm membranes are mechanically more resistant than term membranes.

OBJECTIVE: To compare the biomechanical properties of fetal preterm membranes (20 + 0 weeks to 30 + 0 weeks) to those of the term (37 + 0 to 41 + 0 weeks). METHOD: Amnion and chorion were manually separated and samples were cut to the required geometry. Rectangular samples with (mode 1) and without (uniaxial) a notch, were tested for tearing energy, critical elongation, and tangent stiffness. Suture retention and inter-suture distance testing investigated the effect of suture placement. RESULTS: From the 15 preterm and 10 term placentas studied, no notable differences were observed in uniaxial testing. Mode 1 fracture testing showed a difference in tearing energy between the preterm and term chorion (0.025 ± 0.005 vs. 0.017 ± 0.005 J/m-1 ; p = 0.027) but not in the amnion (0.030 ± 0.017 vs. 0.029 ± 0.009 J/m-1 ; p = 0.895). Both preterm amnion and chorion showed a higher critical elongation compared with term (1.229 ± 0.057 vs. 1.166 ± 0.046; p = 0.019 and 1.307 ± 0.049 vs. 1.218 ± 0.058; p = 0.012). Preterm amnion had a higher suture retention strength than its term counterpart (0.189 ± 0.065 vs. 0.121 ± 0.031 N; p = 0.023). In inter-suture distance tests, no significant interaction was observed beyond 3 mm, but the preterm chorion showed less interaction at 1-2 mm distances. CONCLUSION: Preterm membranes have equivalent or superior tensile properties to term membranes. The chorion appears to contribute to the mechanical integrity of fetal membranes, particularly in preterm stages.

Urogenital cultures and preterm birth in women with cervical cerclage: a single center retrospective cohort study.

BACKGROUND: The leading hypothesis of the pathogenesis of cervical insufficiency suggests a role of cervical inflammation. Urogenital tract infections could play a causative role in this process. To test this hypothesis in women with a cervical cerclage, we aimed to retrospectively examine the relationship between gestational age (GA) at delivery and positive urogenital cultures. METHODS: This single center retrospective study reviewed the records of all women with a singleton pregnancy that underwent cervical cerclage (n = 203) between 2010 and 2020 at the University Hospital of Leuven, Belgium. Transvaginal cerclages were categorized as history indicated (TVC I, n = 94), ultrasound indicated (TVC II, n = 79) and clinically indicated (TVC III, n = 20). Additionally, ten women received transabdominal cerclage (TAC). Urogenital cultures (vaginal and urine) were taken before and after cerclage with 4-week intervals. Urogenital cultures were reported 'positive' if urine and/or vaginal cultures showed significant growth of a microorganism. Treatment decision depended on culture growth and clinical presentation. The primary aim was to evaluate the association between the urogenital culture results and the GA at delivery, for each of the cerclage groups. Secondarily, to investigate the effect of antibiotic treatment of positive cultures on GA at delivery. RESULTS: Positive pre-cerclage urogenital cultures were associated with lower GA at delivery in TVC III (positive culture 26w4d ± 40d vs. negative 29w6d ± 54d, p = 0.036). For TVC I, GA at delivery was longer when pre-cerclage urogenital cultures were positive (positive culture 38w0d ± 26d vs. negative 35w4d ± 42d, p = 0.035). Overall post-cerclage urogenital cultures status was not associated with a different GA at delivery. Treating patients with pre- or post-cerclage positive urogenital cultures did also not change GA at delivery. CONCLUSION: Positive urogenital cultures taken before clinically indicated cerclage intervention may be associated with lower GA at delivery. However, there seems to be no benefit of antibiotic treatment or routine urogenital cultures during follow-up of asymptomatic women after cerclage placement.

Interventional radiology for prevention and management of postpartum haemorrhage: a single centre retrospective cohort study.

PURPOSE: Postpartum haemorrhage (PPH) remains a leading cause of maternal death despite current medical management. Surgical interventions are still needed for refractory bleeding. Interventional radiology (IR) can be a successful intermediary that avoids the need for hysterectomy. Nevertheless, IR outcome data in a peripartum setting are limited. The objective of this study is to document the efficacy and safety of IR. METHODS: Retrospective study reviewed the records of consecutive patients who underwent peripartum IR from 01/01/2010 until 31/12/2020 in a tertiary academic centre. Patients were divided in a prophylactic and a therapeutic group. Information about interventions before and after IR, and IR specific complications was retrieved. Efficacy was defined by the number of transfusions and additional surgical interventions needed after IR, and safety was assessed by the incidence of IR related complications. RESULTS: Fifty-four patients, prophylactic group (n = 24) and therapeutic group (n = 30), were identified. In both groups, IR was successful with 1.5 ± 2.9 packed cells transfused post-IR (1.0 ± 2.1 prophylactic vs 1.9 ± 3.3 therapeutic; p = 0.261). Additional surgical interventions were required in n = 5 patients (9.2%), n = 1 (4.2%) in the prophylactic vs. n = 4 (13.3%) in the therapeutic group. Complications were reported in n = 12 patients (22.2%), n = 2 (8.3%) prophylactic vs. n = 10 (33.3%) in therapeutic group. Mostly minor complications, as puncture site hematoma or bleeding, were reported in n = 4 (7.4%). Severe complications as necrosis and metabolic complications were reported in n = 2 patients (3.9%). CONCLUSION: IR for prevention and treatment of PPH was highly successful and associated with minor complications.

Subsequent fertility, pregnancy, and gynaecological and psychological outcomes after maternal-fetal surgery for open spina bifida: A prospective cohort study.

OBJECTIVE: To determine the medium-term maternal impact of open fetal spina bifida repair. DESIGN: Prospective cohort study. SETTING: University Hospitals Leuven, Belgium. POPULATION: Mothers who had open maternal-fetal spina bifida repair between March 2012 and December 2021. METHODS: A patient-reported survey on subsequent fertility, pregnancy, and gynaecological and psychological outcomes. MAIN OUTCOME MEASURES: Complications during subsequent pregnancies, and gynaecological and psychological problems. RESULTS: Seventy-two out of 100 invited women completed the questionnaire (72%). Despite being advised not to, seven of 13 women attempting to conceive became pregnant within 2 years after fetal surgery and one woman delivered vaginally. Two of the 16 subsequent pregnancies were complicated by an open neural tube defect. One pregnancy was complicated by a placenta accreta and one pregnancy was complicated by a uterine rupture, both with good neonatal outcomes. Nearly half of respondents who did not attempt to conceive reported that this was because of their experience of the index pregnancy and caring for the index child. Three out of four respondents reported medium-term psychological problems, mostly anxiety for the health of the index child, fear for recurrence in subsequent pregnancies and feelings of guilt. CONCLUSIONS: Open maternal-fetal surgery for spina bifida did not appear to affect fertility in our cohort. Half of the attempts to conceive took place within 2 years. One uterine rupture and one placenta accreta occurred in 16 subsequent pregnancies. Most respondents reported psychological problems linked to the index pregnancy, which reinforces the need for long-term psychological support.

Evaluation of Low-Complexity Adaptive Full Direct-State Kalman Filter for Robust GNSS Tracking.

This paper evaluates the implementation of a low-complexity adaptive full direct-state Kalman filter (DSKF) for robust tracking of global navigation satellite system (GNSS) signals. The full DSKF includes frequency locked loop (FLL), delay locked loop (DLL), and phase locked loop (PLL) tracking schemes. The DSKF implementation in real-time applications requires a high computational cost. Additionally, the DSKF performance decays in time-varying scenarios where the statistical distribution of the measurements changes due to noise, signal dynamics, multi-path, and non-line-of-sight effects. This study derives the full lookup table (LUT)-DSKF: a simplified full DSKF considering the steady-state convergence of the Kalman gain. Moreover, an extended version of the loop-bandwidth control algorithm (LBCA) is presented to adapt the response time of the full LUT-DSKF. This adaptive tracking technique aims to increase the synchronization robustness in time-varying scenarios. The proposed tracking architecture is implemented in an GNSS hardware receiver with an open software interface. Different configurations of the adaptive full LUT-DSKF are evaluated in simulated scenarios with different dynamics and noise cases for each implementation. The results confirm that the LBCA used in the FLL-assisted-PLL (FAP) is essential to maintain a position, velocity, and time (PVT) fix in high dynamics.

Low-Cost COTS GNSS Interference Monitoring, Detection, and Classification System.

Interference signals cause position errors and outages to global navigation satellite system (GNSS) receivers. However, to solve these problems, the interference source must be detected, classified, its purpose determined, and localized to eliminate it. Several interference monitoring solutions exist, but these are expensive, resulting in fewer nodes that may miss spatially sparse interference signals. This article introduces a low-cost commercial-off-the-shelf (COTS) GNSS interference monitoring, detection, and classification receiver. It employs machine learning (ML) on tailored signal pre-processing of the raw signal samples and GNSS measurements to facilitate a generalized, high-performance architecture that does not require human-in-the-loop (HIL) calibration. Therefore, the low-cost receivers with high performance can justify significantly more receivers being deployed, resulting in a significantly higher probability of intercept (POI). The architecture of the monitoring system is described in detail in this article, including an analysis of the energy consumption and optimization. Controlled interference scenarios demonstrate detection and classification capabilities exceeding conventional approaches. The ML results show that accurate and reliable detection and classification are possible with COTS hardware.

Drug concentration at the site of disease in children with pulmonary tuberculosis.

BACKGROUND: Current TB treatment for children is not optimized to provide adequate drug levels in TB lesions. Dose optimization of first-line antituberculosis drugs to increase exposure at the site of disease could facilitate more optimal treatment and future treatment-shortening strategies across the disease spectrum in children with pulmonary TB. OBJECTIVES: To determine the concentrations of first-line antituberculosis drugs at the site of disease in children with intrathoracic TB. METHODS: We quantified drug concentrations in tissue samples from 13 children, median age 8.6 months, with complicated forms of pulmonary TB requiring bronchoscopy or transthoracic surgical lymph node decompression in a tertiary hospital in Cape Town, South Africa. Pharmacokinetic models were used to describe drug penetration characteristics and to simulate concentration profiles for bronchoalveolar lavage, homogenized lymph nodes, and cellular and necrotic lymph node lesions. RESULTS: Isoniazid, rifampicin and pyrazinamide showed lower penetration in most lymph node areas compared with plasma, while ethambutol accumulated in tissue. None of the drugs studied was able to reach target concentration in necrotic lesions. CONCLUSIONS: Despite similar penetration characteristics compared with adults, low plasma exposures in children led to low site of disease exposures for all drugs except for isoniazid.

Neurocognitive sequelae of antenatal corticosteroids in a late preterm rabbit model.

BACKGROUND: Late preterm birth is associated with short-term respiratory and adaptive problems. Although antenatal corticosteroids seem to reduce the respiratory burden, this may come at the cost of adverse neuropsychological outcomes later in life. This impact has not been investigated. OBJECTIVE: Herein, we investigate what the short- and long-term neurodevelopmental effects of a single course of betamethasone in simulated late preterm birth. STUDY DESIGN: Time-mated pregnant does received 0.1 mg/kg betamethasone (n=8) or 1 mL saline intramuscular (n=6) at the postconceptional ages of 28 and 29 days. The antenatal corticosteroid dose and scheme were based on previous studies and were comparable with routine clinical use. Cesarean delivery was done on postconceptional age 30 days (term=31 days), and new-born rabbits were foster-cared for 28 days and were thereafter cared for in group housing. Neonatal lung function testing and short-term neurobehavioral testing was done. Open field, spontaneous alternation, and novel object recognition tests were subsequently performed at 4 and 8 weeks of age. On postnatal day 1 and at 8 weeks, a subgroup was euthanized and transcardially perfuse fixated. Ex vivo high-resolution Magnetic Resonance Imaging was used to calculate the Diffusion Tensor Imaging-derived fractional anisotropy and mean diffusivity. Fixated brains underwent processing and were serial sectioned, and a set of 3 coronal sections underwent anti-NeuN, Ki67, and terminal deoxynucleotidyl transferase dUTP nick end labeling staining. RESULTS: Antenatal corticosteroid exposure was associated with improved neonatal lung function, yet resulted in a long-term growth deficit that coincided with a persistent neurobehavioral deficit. We demonstrated lower neonatal motor scores; a persistent anxious behavior in the open field test with more displacements, running, and self-grooming episodes; persistent lower alternation scores in the T-Maze test; and lower discriminatory indexes in the novel object recognition. On neuropathological assessment, antenatal corticosteroid exposure was observed to result in a persistent lower neuron density and fewer Ki67+ cells, particularly in the hippocampus and the corpus callosum. This coincided with lower diffusion tensor imaging-derived fractional anisotropy scores in the same key regions. CONCLUSION: Clinical equivalent antenatal corticosteroid exposure in this late preterm rabbit model resulted in improved neonatal lung function. However, it compromised neonatal and long-term neurocognition.

Outcomes of Monoamniotic Twin Pregnancies from the First Trimester Onward.

INTRODUCTION: Monochorionic monoamniotic (MCMA) twins are rare, and information is lacking on pregnancy outcomes from the first trimester onward. This study compares the pregnancy and neonatal outcomes between MCMA and monochorionic diamniotic (MCDA) twin pregnancies from the first trimester onward. We also report on the outcomes of MCMA twin pregnancies continuing after 28 weeks and on the neurodevelopmental outcomes of MCMA twins. METHODS: A retrospective single-center cohort study of MCMA and MCDA twin pregnancies followed from the first trimester with a fortnightly ultrasound scan. We excluded pregnancies with a major anomaly diagnosed on the first-trimester ultrasound scan. MCMA twin pregnancies were offered inpatient monitoring from 28 weeks onward, and an elective cesarean section was advised between 32 and 33 weeks. MCDA pregnancies were managed as inpatients only if medically indicated, and an elective birth between 36 and 37 weeks was recommended. RESULTS: We analyzed the outcomes of 52 MCMA and 671 MCDA twin pregnancies. In MCMA twins, the fetal and neonatal survival rate was 81/104 (78%) versus 1,192/1,342 (89%) in MCDA twins (p = 0.016). Double intrauterine demise (IUD) was more common in MA than in DA pairs (13% vs. 3%) (p = 0.002). No IUD occurred in the 40 MCMA pregnancies that continued after 28 weeks, but five women (13%) required an urgent cesarean section for fetal distress. Thirty-eight of 52 eligible infants (73%) underwent a neurodevelopmental assessment. Thirty-three (87%) had cognitive and motor development scores within normal limits. Four infants had mild cognitive or motor impairment, and one infant was diagnosed with spastic diplegia. CONCLUSION: MCMA twins are associated with decreased survival rates compared to MCDA due to increased rates of double IUD. After 28 weeks, about one in eight women required an urgent delivery for fetal distress. Most infants had normal neurodevelopmental outcomes.

Performance Evaluation of Adaptive Tracking Techniques with Direct-State Kalman Filter.

This paper evaluates the performance of robust adaptive tracking techniques with the direct-state Kalman filter (DSKF) used in modern digital global navigation satellite system (GNSS) receivers. Under the assumption of a well-known Gaussian distributed model of the states and the measurements, the DSKF adapts its coefficients optimally to achieve the minimum mean square error (MMSE). In time-varying scenarios, the measurements' distribution changes over time due to noise, signal dynamics, multipath, and non-line-of-sight effects. These kinds of scenarios make difficult the search for a suitable measurement and process noise model, leading to a sub-optimal solution of the DSKF. The loop-bandwidth control algorithm (LBCA) can adapt the DSKF according to the time-varying scenario and improve its performance significantly. This study introduces two methods to adapt the DSKF using the LBCA: The LBCA-based DSKF and the LBCA-based lookup table (LUT)-DSKF. The former method adapts the steady-state process noise variance based on the LBCA's loop bandwidth update. In contrast, the latter directly relates the loop bandwidth with the steady-state Kalman gains. The presented techniques are compared with the well-known state-of-the-art carrier-to-noise density ratio (C/N0)-based DSKF. These adaptive tracking techniques are implemented in an open software interface GNSS hardware receiver. For each implementation, the receiver's tracking performance and the system performance are evaluated in simulated scenarios with different dynamics and noise cases. Results confirm that the LBCA can be successfully applied to adapt the DSKF. The LBCA-based LUT-DSKF exhibits superior static and dynamic system performance compared to other adaptive tracking techniques using the DSKF while achieving the lowest complexity.

Wide-Band Interference Mitigation in GNSS Receivers Using Sub-Band Automatic Gain Control.

The performance of global navigation satellite system (GNSS) receivers is significantly affected by interference signals. For this reason, several research groups have proposed methods to mitigate the effect of different kinds of jammers. One effective method for wide-band interference mitigation (IM) is the high-rate DFT-based data manipulator (HDDM) pulse blanker (PB). It provides good performance to pulsed and frequency sparse interference. However, it and many other methods have poor performance against wide-band noise signals, which are not frequency-sparse. This article proposes to include automatic gain control (AGC) in the HDDM structure to attenuate the signal instead of removing it: the HDDM-AGC. It overcomes the wide-band noise limitation for IM at the cost of limiting mitigation capability to other signals. Previous studies with this approach were limited to only measuring the carrier-to-noise density ratio (C/N0) performance of tracking, but this article extends the analysis to include the impact of the HDDM-AGC algorithm on the position, velocity, and time (PVT) solution. It allows an end-to-end evaluation and impact assessment of mitigation to a GNSS receiver. This study compares two commercial receivers: one high-end and one low-cost, with and without HDDM IM against laboratory-generated interference signals. The results show that the HDDM-AGC provides a PVT availability and precision comparable to high-end commercial receivers with integrated mitigation for most interference types. For pulse interferences, its performance is superior. Further, it is shown that degradation is minimized against wide-band noise interferences. Regarding low-cost receivers, the PVT availability can be increased up to 40% by applying an external HDDM-AGC.

Alterations to microbial secretome by estrogen may contribute to sex bias in irritable bowel syndrome.

INTRODUCTION: Irritable bowel syndrome (IBS) is a female predominant functional gastrointestinal disorder, underpinned by microbial dysbiosis and microinflammation. We suggest that changes in trace amine (TA) load and metabolism may link together diet, inflammation and sex in this context. METHODS: The effect of E2 treatment on microbial growth and TA generation was assessed using liquid chromatography and tandem mass spectrometry methodology. To investigate the effects of TAs on the gut, WST-1, prostaglandin E2 and tight junction protein dynamics were investigated in TA treated (HT-29) colon epithelial monolayer cultures. RESULTS: Differential E2-dependent alterations of the TA production capabilities of microbes were observed. Significantly, E2 treatment resulted in a 50% increase in tryptamine secretion from a probiotic microbe (p < 0.0001). Moreover, in vitro experiments indicated that TA treatment exerted type-specific effects in the gut, e.g., reducing mitochondrial functionality, even at low doses of tryptamine (p < 0.0001) and ρ-tyramine (p < 0.001). Additionally, prostaglandin E2 levels were significantly increased following ρ-tyramine and agmatine treatment (p < 0.05). In terms of functionality, all investigated TAs resulted in occludin redistribution and loss of zona occludens-1 and occludin co-localization. CONCLUSION: Increases in the gastrointestinal TA load may contribute to a relatively pro-inflammatory outcome in the intestine, along with tight junction protein disruption. Additionally, fluctuating levels of endogenous E2 may modulate microbially-derived TA levels, potentially explaining exaggerating gastrointestinal symptomology in females during low E2 phases. Thus, current data warrants subsequent investigations in appropriate in vivo models to fully elucidate the role of the trace aminergic system in the sex bias observed in IBS.

Stretch increases alveolar type 1 cell number in fetal lungs through ROCK-Yap/Taz pathway.

Accurate fluid pressure in the fetal lung is critical for its development, especially at the beginning of the saccular stage when alveolar epithelial type 1 (AT1) and type 2 (AT2) cells differentiate from the epithelial progenitors. Despite our growing understanding of the role of physical forces in lung development, the molecular mechanisms that regulate the transduction of mechanical stretch to alveolar differentiation remain elusive. To simulate lung distension, we optimized both an ex vivo model with precision cut lung slices and an in vivo model of fetal tracheal occlusion. Increased mechanical tension showed to improve alveolar maturation and differentiation toward AT1. By manipulating ROCK pathway, we demonstrate that stretch-induced Yap/Taz activation promotes alveolar differentiation toward AT1 phenotype via ROCK activity. Our findings show that balanced ROCK-Yap/Taz signaling is essential to regulate AT1 differentiation in response to mechanical stretching of the fetal lung, which might be helpful in improving lung development and regeneration.

'We did everything we could'- a qualitative study exploring the acceptability of maternal-fetal surgery for spina bifida to parents.

OBJECTIVE: To explore the concepts and strategies parents employ when considering maternal-fetal surgery (MFS) as an option for the management of spina bifida (SB) in their fetus, and how this determines the acceptability of the intervention. METHODS: A two-centre interview study enrolling parents whose fetuses with SB were eligible for MFS. To assess differences in acceptability, parents opting for MFS (n = 24) were interviewed at three different moments in time: prior to the intervention, directly after the intervention and 3-6 months after birth. Parents opting for termination of pregnancy (n = 5) were interviewed only once. Themes were identified and organised in line with the framework of acceptability. RESULTS: To parents opting for MFS, the intervention was perceived as an opportunity that needed to be taken. Feelings of parental responsibility drove them to do anything in their power to improve their future child's situation. Expectations seemed to be realistic yet were driven by hope for the best outcome. None expressed decisional regret at any stage, despite substantial impact and, at times, disappointing outcomes. For the small group of participants, who decided to opt for termination of pregnancy (TOP), MFS was not perceived as an intervention that substantially could improve the quality of their future child's life. CONCLUSION: Prospective parents opting for MFS were driven by their feelings of parental responsibility. They recognise the fetus as their future child and value information and care focusing on optimising the child's future health. In the small group of parents opting for TOP, MFS was felt to offer insufficient certainty of substantial improvement in quality of life and the perceived severe impact of SB drove their decision to end the pregnancy.

Evaluation of Adaptive Loop-Bandwidth Tracking Techniques in GNSS Receivers.

GNSS receivers use tracking loops to lock onto GNSS signals. Fixed loop settings limit the tracking performance against noise, receiver dynamics, and the current scenario. Adaptive tracking loops adjust these settings to achieve optimal performance for a given scenario. This paper evaluates the performance and complexity of state-of-the-art adaptive scalar tracking techniques used in modern digital GNSS receivers. Ideally, a tracking channel should be adjusted to both noisy and dynamic environments for optimal performance, defined by tracking precision and loop robustness. The difference between the average tracking jitter of the discriminator's output and the square-root CRB indicates the loops' tracking capability. The ability to maintain lock characterizes the robustness in highly dynamic scenarios. From a system perspective, the average lock indicator is chosen as a metric to measure the performance in terms of precision, whereas the average number of visible satellites being tracked indicates the system's robustness against dynamics. The average of these metrics' product at different noise levels leads to a reliable system performance metric. Adaptive tracking techniques, such as the FAB, the FL, and the LBCA, facilitate a trade-off for optimal performance. These adaptive tracking techniques are implemented in an open software interface GNSS hardware receiver. All three methods steer a third-order adaptive PLL and are tested in simulated scenarios emulating static and high-dynamic vehicular conditions. The measured tracking performance, system performance, and time complexity of each algorithm present a detailed analysis of the adaptive techniques. The results show that the LBCA with a piece-wise linear approximation is above the other adaptive loop-bandwidth tracking techniques while preserving the best performance and lowest time complexity. This technique achieves superior static and dynamic system performance being 1.5 times more complex than the traditional tracking loop.

Effects of Maternal Abdominal Surgery on Fetal Brain Development in the Rabbit Model.

INTRODUCTION: Anesthesia during pregnancy can impair fetal neurodevelopment, but effects of surgery remain unknown. The aim is to investigate effects of abdominal surgery on fetal brain development. Hypothesis is that surgery impairs outcome. METHODS: Pregnant rabbits were randomized at 28 days of gestation to 2 h of general anesthesia (sevoflurane group, n = 6) or to anesthesia plus laparoscopic appendectomy (surgery group, n = 13). On postnatal day 1, neurobehavior of pups was assessed and brains harvested. Primary outcome was neuron density in the frontal cortex, and secondary outcomes included neurobehavioral assessment and other histological parameters. RESULTS: Fetal survival was lower in the surgery group: 54 versus 100% litters alive at birth (p = 0.0442). In alive litters, pup survival until harvesting was 50 versus 69% (p = 0.0352). No differences were observed for primary outcome (p = 0.5114) for surviving pups. Neuron densities were significantly lower in the surgery group in the caudate nucleus (p = 0.0180), but not different in other regions. No differences were observed for secondary outcomes. Conclusions did not change after adjustment for mortality. CONCLUSION: Abdominal surgery in pregnant rabbits at a gestational age corresponding to the end of human second trimester results in limited neurohistological changes but not in neurobehavioral impairments. High intrauterine mortality limits translation to clinical scenario, where fetal mortality is close to zero.

Long-term neuropathological and/or neurobehavioral effects of antenatal corticosteroid therapy in animal models: a systematic review.

BACKGROUND: Antenatal corticosteroids (ACSs) are recommended to all women at risk for preterm delivery; currently, there is controversy about the subsequent long-term neurocognitive sequelae. This systematic review summarizes the long-term neurodevelopmental outcomes after ACS therapy in animal models. METHODS: An electronic search strategy incorporating MeSH and keywords was performed using all known literature databases and in accordance with PRISMA guidance (PROSPERO CRD42019119663). RESULTS: Of the 669 studies identified, eventually 64 were included. The majority of studies utilized dexamethasone at relative high dosages and primarily involved rodents. There was a high risk of bias, mostly due to lack of randomization, allocation concealment, and blinding. The main outcomes reported on was neuropathological, particularly glucocorticoid receptor expression and neuron densities, and neurobehavior. Overall there was an upregulation of glucocorticoid receptors with lower neuron densities and a dysregulation of the dopaminergic and serotonergic systems. This coincided with various adverse neurobehavioral outcomes. CONCLUSIONS: In animal models, ACSs consistently lead to deleterious long-term neurocognitive effects. This may be due to the specific agents, i.e., dexamethasone, or the repetitive/higher total dosing used. ACS administration varied significantly between studies and there was a high risk of bias. Future research should be standardized in well-characterized models.

HDDM Hardware Evaluation for Robust Interference Mitigation.

Interference can significantly degrade the performance of global navigation satellite system (GNSS) receivers. Therefore, mitigation methods are required to ensure reliable operations. However, as there are different types of interference, robust, multi-purpose mitigation algorithms are needed. This paper describes the most popular state-of-the-art interference mitigation techniques. The high-rate DFT-based data manipulator (HDDM) is proposed as a possible solution to overcome their limitations. This paper presents a hardware implementation of the HDDM algorithm. The hardware HDDM module is integrated in three different receivers equipped with analog radio-frequency (RF) front-ends supporting signals with different dynamic range. The resource utilization and power consumption is evaluated for the three cases. The algorithm is compared to a low-end mass-market receiver and a high-end professional receiver with basic and sophisticated interference mitigation capabilities, respectively. Different type of interference are used to compare the mitigation capabilities of the receivers under test. Results of the HDDM hardware implementation achieve the similar or improved performance to the state of the art. With more complex interferences, like frequency hopping or pulsed, the HDDM shows even better performance.

Maternal surgery during pregnancy has a transient adverse effect on the developing fetal rabbit brain.

BACKGROUND: Recently, the US Food and Drug Administration called for cautious use of anesthetic drugs during pregnancy. In 0.2-2% of pregnancies, nonobstetric surgery is being performed. The consequences of anesthesia during pregnancy on fetal development remain unclear, and preclinical studies in relevant animal models may help to elucidate them. OBJECTIVE: To assess the effect of maternal anesthesia and surgery during pregnancy on the developing fetal brain, using a rabbit model. MATERIALS AND METHODS: This is a randomized, sham-controlled study in time-mated pregnant does at 28 days of gestation (term = 31 days), which corresponds to the end of the second trimester in humans. Anesthesia was induced in 14 does (155 pups) with propofol and maintained with 4 vol% (equivalent to 1 minimum alveolar concentration) sevoflurane for 2 hours, and a laparotomy with minimal organ manipulation was performed (surgery group). Maternal vital signs (blood pressure, heart rate, peripheral and cerebral oxygen saturation, temperature, end-tidal CO2, pH, lactate) were continuously monitored. Sham controls consisted of 7 does (74 pups) undergoing invasive hemodynamic monitoring for 2 hours without sedation. At term, does underwent cesarean delivery under ketamine-medetomidine sedation and local anesthesia. Pups either underwent motor and sensory neurologic testing followed by euthanasia at day 1 or daily neurodevelopment testing for 2 weeks and extensive neurologic assessment at 5 and 7 weeks (open field and object recognition test, T-maze, and radial-arm maze). Brains were harvested for histologic assessment of neuron density and synaptophysin expression. RESULTS: Blood gases and vital parameters were stable in both groups. On postnatal day 1, surgery pups had significant lower motor (25 ± 1 vs 23 ± 3; P = .004) and sensory (16 ± 2 vs 15 ± 2; P = .005) neurobehavioral scores and lower brain-to-body weight ratios (3.7% ± 0.6% vs 3.4% ± 0.6%; P = .001). This was accompanied by lower neuron density in multiple brain regions (eg, hippocampus 2617 ± 410 vs 2053 ± 492 neurons/mm2; P = .004) with lower proliferation rates and less synaptophysin expression. Furthermore, surgery pups had delayed motor development during the first week of life, for example with hopping appearing later (6 ± 5 vs 12 ± 3 days; P = .011). Yet, by 7 weeks of age, neurobehavioral impairment was limited to a reduced digging behavior, and no differences in neuron density or synaptophysin expression were seen. CONCLUSION: In rabbits, 2 hours of maternal general anesthesia and laparotomy, with minimal organ and no fetal manipulation, had a measurable impact on neonatal neurologic function and brain morphology. Pups had a slower motoric neurodevelopment, but by 7 weeks the effect became almost undetectable.

Blind Spoofing GNSS Constellation Detection Using a Multi-Antenna Snapshot Receiver.

Spoofing of global navigation satellite system (GNSS) signals threatens positioning systems. A counter-method is to detect the presence of spoofed signals, followed by a warning to the user. In this paper, a multi-antenna snapshot receiver is presented to detect the presence of a spoofing attack. The spatial similarities of the array steering vectors are analyzed, and different metrics are used to establish possible detector functions. These include subset methods, Eigen-decomposition, and clustering algorithms. The results generated within controlled spoofing conditions show that a spoofed constellation of GNSS satellites can be successfully detected. The derived system-level detectors increase performance in comparison to pair-wise methods. A controlled test setup achieved perfect detection; however, in real-world cases, the performance would not be as ideal. Some detection metrics and features for blind spoofing detecting, with an array of antennas, are identified, which opens the field for future advanced multi-detector developments.