Robust Reconstruction of the Void Fraction from Noisy Magnetic Flux Density Using Invertible Neural Networks

Electrolysis stands as a pivotal method for environmentally sustainable hydrogen production. However, the formation of gas bubbles during the electrolysis process poses significant challenges by impeding the electrochemical reactions, diminishing cell efficiency, and dramatically increasing energy consumption. Furthermore, the inherent difficulty in detecting these bubbles arises from the non-transparency of the wall of electrolysis cells. Additionally, these gas bubbles induce alterations in the conductivity of the electrolyte, leading to corresponding fluctuations in the magnetic flux density outside of the electrolysis cell, which can be measured by externally placed magnetic sensors. By solving the inverse problem of the Biot-Savart Law, we can estimate the conductivity distribution as well as the void fraction within the cell. In this work, we study different approaches to solve the inverse problem including Invertible Neural Networks (INNs) and Tikhonov regularization. Our experiments demonstrate that INNs are much more robust to solving the inverse problem than Tikhonov regularization when the level of noise in the magnetic flux density measurements is not known or changes over space and time.

In-Bulk Temperature Profile Mapping Using Fiber Bragg Grating in Fluids

The capabilities of Fiber Bragg Grating (FBG) sensors to measure temperature variations in the bulk of liquid flows were considered. In the first step of our research project, reported in this paper, we investigated to what extent the use of thin glass fibers without encapsulation, which only minimally disturb a flow, can fulfill the requirements for robustness and measurement accuracy. Experimental tests were performed in a benchmark setup containing 24 FBG measuring positions, which were instrumented in parallel with thermocouples for validation. We suggest a special assembly procedure in which the fiber is placed under a defined tension to improve its stiffness and immobility for certain flow conditions. This approach uses a single FBG sensor as a reference that measures the strain effect in real time, allowing accurate relative temperature measurements to be made at the other FBG sensor points, taking into account an appropriate correction term. Absolute temperature readings can be obtained by installing another well-calibrated, strain-independent thermometer on the reference FBG. We demonstrated this method in two test cases: (i) a temperature gradient with stable density stratification in the liquid metal GaInSn and (ii) the heating of a water column using a local heat source. In these measurements, we succeeded in recording both spatial and temporal changes in the linear temperature distribution along the fiber. We present the corresponding results from the tests and, against this background, we discuss the capabilities and limitations of this measurement technique with respect to the detection of temperature fields in liquid flows.

Erratum: Collapse of Coherent Large Scale Flow in Strongly Turbulent Liquid Metal Convection [Phys. Rev. Lett. 128, 164501 (2022)]

This corrects the article DOI: 10.1103/PhysRevLett.128.164501.

Eddy Current Flow Meter Measurements in Liquid Sodium at High Temperatures

We present measurement results for the flow rate of liquid sodium at temperatures up to 700°C that were obtained with a high temperature prototype of an immersed Eddy Current Flow Meter. The experimental campaign was conducted at the SOLTEC-2 sodium loop at KIT. The main objective of the experiments is the high temperature qualification of the Eddy Current Flow Meter as part of the safety instrumentation of generation IV liquid metal cooled fast reactors. There it is intended to be used for monitoring the flow rate of the coolant and to detect possible blockages of sub assemblies. Due to the large liquid metal volume, the sensor has to be located close to the sub assemblies, therefore measurements from outside of the vessel are not possible and an immersed sensor is required. We demonstrate the successful application of the immersed Eddy Current Flow Meter at such high temperatures and identify the relevant effects with impact on the sensor performance.

Collapse of Coherent Large Scale Flow in Strongly Turbulent Liquid Metal Convection

The large-scale flow structure and the turbulent transfer of heat and momentum are directly measured in highly turbulent liquid metal convection experiments for Rayleigh numbers varied between 4×10^{5} and ≤5×10^{9} and Prandtl numbers of 0.025≤Pr≤0.033. Our measurements are performed in two cylindrical samples of aspect ratios Γ=diameter/height=0.5 and 1 filled with the eutectic alloy GaInSn. The reconstruction of the three-dimensional flow pattern by 17 ultrasound Doppler velocimetry sensors detecting the velocity profiles along their beam lines in different planes reveals a clear breakdown of coherence of the large-scale circulation for Γ=0.5. As a consequence, the scaling laws for heat and momentum transfer inherit a dependence on the aspect ratio. We show that this breakdown of coherence is accompanied with a reduction of the Reynolds number Re. The scaling exponent β of the power law Nu∝Ra^{β} crosses eventually over from β=0.221 to 0.124 when the liquid metal flow at Γ=0.5 reaches Ra≳2×10^{8} and the coherent large-scale flow is completely collapsed.

Predicting concurrent structural mechanical mechanisms during microstructure evolution

The interdependence between structural mechanics and microstructure solidification has been widely observed experimentally as a factor leading to undesirable macroscopic properties and casting defects. Despite this, numerical modelling of microstructure solidification often neglects this interaction and is therefore unable to predict key mechanisms such as the development of misoriented grains. This paper presents a numerical method coupling a finite volume structural mechanics solver to a cellular automata solidification solver, where gravity or pressure-driven displacements alter the local orientation and thereby growth behaviour of the solidifying dendrites. Solutions obtained using this model are presented which show fundamental behaviours observed in experiments. The results show that small, localized deformations can lead to significant changes in the crystallographic orientation of a dendrite and ultimately affect the overall microstructure development. This article is part of the theme issue 'Transport phenomena in complex systems (part 2)'.

Dynamics and length scales in vertical convection of liquid metals

Using complementary experiments and direct numerical simulations, we study turbulent thermal convection of a liquid metal (Prandtl number $\textit {Pr}\approx 0.03$ ) in a box-shaped container, where two opposite square sidewalls are heated/cooled. The global response characteristics like the Nusselt number ${\textit {Nu}}$ and the Reynolds number $\textit {Re}$ collapse if the side height $L$ is used as the length scale rather than the distance $H$ between heated and cooled vertical plates. These results are obtained for various Rayleigh numbers $5\times 10^3\leq {\textit {Ra}}_H\leq 10^8$ (based on $H$ ) and the aspect ratios $L/H=1, 2, 3$ and $5$ . Furthermore, we present a novel method to extract the wind-based Reynolds number, which works particularly well with the experimental Doppler-velocimetry measurements along vertical lines, regardless of their horizontal positions. The extraction method is based on the two-dimensional autocorrelation of the time–space data of the vertical velocity.

Eddy Current Flow Meter Performance in Liquid Metal Flows Inclined to the Sensor Axis

The Eddy Current Flow Meter is a reliable and robust inductive sensor for the measurement of flowrates in liquid metal flows. This kind of sensor is usually being used in pipe flows where the flow is mostly parallel to the sensor axis. When this sensor is used as part of the safety instrumentation above the subassemblies in liquid metal cooled fast reactors, the flow angle may change rapidly according to the conditions within the reactor. In this paper we investigate the performance of the Eddy Current Flow Meter in flows inclined to the sensor axis by numerical simulations as well as model experiments. We demonstrate that the Eddy Current Flow Meter yields reliable results for flow angles up to 30° while the sensitivity of the sensor is significantly reduced for larger angles.

Results of the multicenter, prospective, randomised STRENGTH (Study To evaluate the use of RENalGuard to proTect patients at High risk of acute kidney injury) study

Aim

Radio-contrast agents are widely used in coronary, peripheral and structural interventions. Use of these iodine-containing agents can be associated with contrast-induced acute kidney injury (CI-AKI) that can cause substantial morbidity and mortality. The RenalGuard system induces a forced diuresis with a matched hydration and has been shown beneficial in patients requiring coronary angiogram and PCI.

Methods

STRENGTH is a prospective, randomised (1:1), open-labeled, parallel-group, multicenter (10 centers in Germany and France) study where patients at high risk of CI-AKI were randomly assigned to RenalGuard® therapy or conventional strategy including preventive hydration before complex percutaneous cardiovascular intervention (PCI, peripheral and structural). In the RenalGuard arm, matched fluid replacement was started 60 minutes pre-procedure and maintained for up to 4 hours afterwards. Patients were given an initial i.v. bolus of up to 250 ml of normal saline over 30 minutes and then an i.v. bolus of furosemide (0.5 mg/kg). To be enrolled, patients had to have moderate to severe renal failure (defined as 15≤eGFR≤40 mL/min/m2) and a high-volume contrast requiring cardiovascular procedure (estimated contrast volume>3 times eGFR value). The main exclusion criterion was administration of iodine contrast media within 5 days before index procedure. The primary endpoint was CI-AKI defined as an increase in sCr ≥0.3 mg/dL or an increase of 25% of basal value or requiring dialysis within 5 days after procedure. The primary analysis for efficacy is performed in a modified intention-to-treat basis. The trial was designed and monitored by an independent CRO (Cardiovascular European Research Center, CERC, Massy, France).

Results

A total of 259 patients aged 79.1±8.8 yrs were included in the study. Among them, 129 were assigned to RenalGuard therapy and 130 to preventive saline hydration. Their mean baseline eGFR was 32 (25; 37) vs. 33 (25; 39) mL/min/m2, respectively (p=0.88). Total fluid intake volume within 24hrs before the procedure was 2383±1146 vs. 1386±842mL, respectively (p<0.0001). Procedure type was complex PCI (48%), TAVI (25%), peripheral intervention (18%), other structural intervention (9%) with no difference between groups (p=0.56). The total amount of contrast used for the procedure was 116.3±68.2mL in the RenalGuard arm vs. 104.1±56.7 mL in the conventional arm (p=0.26). A staged procedure was performed in 24 patients, including 16 in the RenalGuard and 8 in the control arm with a mean interval from the first intervention of 43±29 days and 24±19 days, respectively. For this second procedure, the total amount of contrast was 80±59 vs. 87±73mL.

Conclusion

The primary and secondary endpoints of the Study To evaluate the use of RENalGuard to proTect patients at High risk of CI-AKI comparing RenalGuard therapy to conventional hydration in 259 patients requiring complex percutaneous cardiovascular intervention will be presented.

Funding Acknowledgement

Type of funding source: Private grant(s) and/or Sponsorship. Main funding source(s): CERC

Disability Improvement Is Associated with Less Brain Atrophy Development in Multiple Sclerosis

BACKGROUND AND PURPOSE

It is unknown whether deceleration of brain atrophy is associated with disability improvement in patients with MS. Our aim was to investigate whether patients with MS with disability improvement develop less brain atrophy compared with those who progress in disability or remain stable.

MATERIALS AND METHODS

We followed 980 patients with MS for a mean of 4.8 ± 2.4 years. Subjects were divided into 3 groups: progress in disability (n = 241, 24.6%), disability improvement (n = 101, 10.3%), and stable (n = 638, 65.1%) at follow-up. Disability improvement and progress in disability were defined on the basis of the Expanded Disability Status Scale score change using standardized guidelines. Stable was defined as nonoccurrence of progress in disability or disability improvement. Normalized whole-brain volume was calculated using SIENAX on 3D T1WI, whereas the lateral ventricle was measured using NeuroSTREAM on 2D-T2-FLAIR images. The percentage brain volume change and percentage lateral ventricle volume change were calculated using SIENA and NeuroSTREAM, respectively. Differences among groups were investigated using ANCOVA, adjusted for age at first MR imaging, race, T2 lesion volume, and corresponding baseline structural volume and the Expanded Disability Status Scale.

RESULTS

At first MR imaging, there were no differences among progress in disability, disability improvement, and the stable groups in whole-brain volume (P = .71) or lateral ventricle volume (P = .74). During follow-up, patients with disability improvement had the lowest annualized percentage lateral ventricle volume change (1.6% ± 2.7%) followed by patients who were stable (2.1% ± 3.7%) and had progress in disability (4.1% ± 5.5%), respectively (P < .001). The annualized percentage brain volume change values were -0.7% ± 0.7% for disability improvement, -0.8% ± 0.7% for stable, and -1.1% ± 1.1% for progress in disability (P = .001).

CONCLUSIONS

Patients with MS who improve in their clinical disability develop less brain atrophy across time compared with those who progress.

X-ray particle tracking velocimetry in liquid foam flow

In this work, we introduce a novel approach to measure the flow velocity of liquid foam by tracking custom-tailored 3D-printed tracers in X-ray radiography. In contrast to optical observations of foam flow in flat cells, the measurement depth equals 100 mm in the X-ray beam direction. Light-weight tracers of millimetric size and tetrapod-inspired shape are additively manufactured from stainless steel powder by selective laser melting. Matching with the foam structure and bubble size, these tracers follow the foam flow. An X-ray beam passes through the radiotransparent foam channel and is detected by an X-ray image intensifier. The X-ray transmission images show the two-dimensional projections of the radiopaque tracers. Utilizing particle tracking velocimetry algorithms, the tracer trajectories are measured with both high spatial (0.2 mm) and temporal (25 fps) resolution. Fine and coarse liquid foam flow of different velocities are studied in a partly curved channel with rectangular cross section. The simultaneous time-resolved measurements of the tracers' translational motion and their intrinsic rotation reveal both the local velocity and vorticity of the foam flow. In the semi-circular curved channel section, the rigid-body-like flow pattern is investigated. Moreover, a relaxation of the foam structure in the transition zone between straight and curved section is observed.

Thermal dependence of large-scale freckle defect formation

The fundamental mechanisms governing macroscopic freckle defect formation during directional solidification are studied experimentally in a Hele-Shaw cell for a low-melting point Ga-25 wt.% In alloy and modelled numerically in three dimensions using a microscopic parallelized Cellular Automata Lattice Boltzmann Method. The size and distribution of freckles (long solute channels, or chimneys) are shown to be strongly dependent on the thermal profile of the casting, with flat, concave and convex isotherms being considered. For the flat isotherm case, no large-scale freckles form, while for concave or convex isotherms, large freckles appear but in different locations. The freckle formation mechanism is as expected buoyancy-driven, but the chimney stability, its long-term endurance and its location are shown to depend critically on the detailed convective transport through the inter-dendritic region. Flow is generated by curved isopleths of solute concentration. As solute density is different from that of the bulk fluid, gravity causes 'uphill' or 'downhill' lateral flow from the sample centre to the edges through the mush, feeding the freckle. An excellent agreement is obtained between the numerical model and real-time X-ray observations of a solidifying sample under strictly controlled temperature conditions. This article is part of the theme issue 'Heterogeneous materials: metastable and non-ergodic internal structures'.

A Parallel Cellular Automata Lattice Boltzmann Method for Convection-Driven Solidification

This article presents a novel coupling of numerical techniques that enable three-dimensional convection-driven microstructure simulations to be conducted on practical time scales appropriate for small-size components or experiments. On the microstructure side, the cellular automata method is efficient for relatively large-scale simulations, while the lattice Boltzmann method provides one of the fastest transient computational fluid dynamics solvers. Both of these methods have been parallelized and coupled in a single code, allowing resolution of large-scale convection-driven solidification problems. The numerical model is validated against benchmark cases, extended to capture solute plumes in directional solidification and finally used to model alloy solidification of an entire differentially heated cavity capturing both microstructural and meso-/macroscale phenomena.

Infectious exposure, antibiotic use, and multiple sclerosis: A population-based incident case-control study

BACKGROUND

The existing reports regarding the potential role of infections as well as antibiotic use in multiple sclerosis (MS) etiology are inconclusive.

OBJECTIVES

We aimed to investigate the association of viral infections as well as antibiotic use and the risk of developing MS.

MATERIALS & METHODS

This was a population-based incident case-control study of 547 incident cases and 1057 general population controls obtained from 22 municipality areas of Tehran (7/8/2013-17/2/2015). Multiple logistic regression models were used to determine the adjusted associations.

RESULTS

Overall antibiotic use for ≥14 days during 3 years before the index date, significantly decreased the odds of MS OR 0.69 (95%CI: 0.53-0.91, P = .008). The results were consistent for different types of antibiotics, including penicillin OR 0.50 (95%CI: 0.34-0.75, P = .001) and cephalosporins OR 0.25 (95%CI: 0.12-0.50, P < .001). History of IM was associated with a more than 5fold increased risk of MS OR = 5.7 (95%CI, 1.28-25.37). There was no statistically significant association between any other single or cumulative number of viral infections with subsequent risk of MS (P > .05).

CONCLUSIONS

Considering the possibility of reverse causation, the results of this large case-control study suggest that use of antibiotics may be associated with a decreased risk of MS. However, viral disease other than infectious mononucleosis was not associated with MS risk.

Myocardial perfusion after one year of spinal cord stimulation in patients with refractory angina

Aim: Spinal cord stimulation (SCS) is recommended for patients with coronary artery disease (CAD) and refractory angina. We used positron emission tomography (PET) to investigate the long-term effect of SCS on regional myocardial perfusion in patients suffering from angina pectoris refractory to medical treatment and without option for coronary intervention. Patients, methods: We analyzed data of 44 patients with stable CAD (91% three vessel disease). At baseline, we determined coronary flow reserve (CFR) using 13N-ammonia-PET and myocardial viability with 18F-FDG. SCS was performed for one year (Medtronic Itrell III or Synergy, Düsseldorf, Germany). During follow-up, no cardiac interventions were necessary and no myocardial infarctions occurred. At one year follow-up, CFR was measured again. Results: In the majority of patients (77%), SCS led to an improvement of clinical symptoms. CFR did not change significantly during follow-up. Subjective improvement did not correlate with an increase of CFR. Conclusions: Despite its clinical effect, SCS does not have a direct impact on CFR in patients with stable CAD. According to our results, the pain relief is not due to an improvement of the myocardial blood supply.

Myocardial sympathetic innervation in diabetic patients with symptomatic coronary artery disease

Aim: In non-diabetic patients, sympathetic innervation can be preserved even if there is major impairment of myocardial blood supply. Matters may be more complex in diabetic patients because denervation can be caused by cardiac autonomic neuropathy (CAN) or by ischemic injury. Our aim was to determine whether restrictions in myocardial blood supply have a pronounced influence on sympathetic innervation in diabetics and if this effect can be differentiated from CAN. Patients, methods: We analyzed 20 diabetics with advanced coronary artery disease (CAD) and without known CAN. We determined quantitative myocardial blood flow using 13N-ammonia-PET, myocardial viability with 18F-FDG, and cardiac innervation with 11C-HED. We investigated the relationship between regional HED retention, blood flow, and coronary flow reserve (CFR). Attenuated heart rate response to adenosine was taken as indicator for CAN (HR ratio). Results: There was minor correlation of segmental stress flow and HED retention (r2 = 0.063, p <0.0001). Correlation improved when stress flow as well as HED retention were normalized to the individual maximum (r2 = 0.162, p <0.0001). In nine patients, a HR ratio < 1.2 implicated subclinical CAN. Duration of diabetic disease or glycaemic control (HbA1c) did not correlate with mean HED retention in the viable segments, but with its variation coefficient. Conclusions: As in non-diabetic patients, a slight correlation exists between CFR and sympathetic innervation. The sensitivity of sympathetic nerves to reductions in CFR does not seem to be increased as compared to the results reported for non-diabetics. Besides impaired blood supply, long duration of diabetic disease and bad glycaemic control also seem to impair sympathetic innervation provoking higher heterogeneity.

Phased Array Ultrasound System for Planar Flow Mapping in Liquid Metals

Controllable magnetic fields can be used to optimize flows in technical and industrial processes involving liquid metals in order to improve quality and yield. However, experimental studies in magnetohydrodynamics often involve complex, turbulent flows and require planar, two-component (2c) velocity measurements through only one acoustical access. We present the phased array ultrasound Doppler velocimeter as a modular research platform for flow mapping in liquid metals. It combines the pulse wave Doppler method with the phased array technique to adaptively focus the ultrasound beam. This makes it possible to resolve smaller flow structures in planar measurements compared with fixed-beam sensors and enables 2c flow mapping with only one acoustical access via the cross beam technique. From simultaneously measured 2-D velocity fields, quantities for turbulence characterization can be derived. The capabilities of this measurement system are demonstrated through measurements in the alloy gallium-indium-tin at room temperature. The 2-D, 2c velocity measurements of a flow in a cubic vessel driven by a rotating magnetic field (RMF) with a spatial resolution of up to 2.2 mm are presented. The measurement results are in good agreement with a semianalytical simulation. As a highlight, two-point correlation functions of the velocity field for different magnitudes of the RMF are presented.

Exploratory study on the presence of GM oilseed rape near German oil mills

Seed losses from imported oilseed rape (OSR) and the genetically modified (GM) admixtures therein may potentially lead to the establishment of transgenic plants and their hybridization with wild crucifers. The post-market environmental monitoring (PMEM) must therefore also address problems related to seed spillages of GM OSR. Since detailed information on imported commodity flows, GM contents, means of transport, downstream users and efficient containment of GM OSR was lacking, we performed a field study in the vicinity of large oil mills and seed processing industries at the harbours along the river Rhine. One hundred thirty-six composite samples taken from one to 20 plants per site were collected near roads, railways and waterways. Individuals or large groups of feral OSR plants were detected in all of the nine study areas, but only one plant out of 1918 tested was confirmed to be transgenic (GT73). The results suggest that a spread of herbicide tolerant GM OSR has not occurred to date. In order to confirm the absence of GM feral OSR and potentially adverse effects of GM plants in the future, we recommend monitoring feral OSR on a routine basis. We present an approach for the sampling and testing of feral OSR that is based on floristic mapping and rapid tests for the determination of herbicide tolerances.

Regular flow reversals in Rayleigh-Bénard convection in a horizontal magnetic field

Magnetohydrodynamic Rayleigh-Bénard convection was studied experimentally using a liquid metal inside a box with a square horizontal cross section and aspect ratio of five. Systematic flow measurements were performed by means of ultrasonic velocity profiling that can capture time variations of instantaneous velocity profiles. Applying a horizontal magnetic field organizes the convective motion into a flow pattern of quasi-two-dimensional rolls arranged parallel to the magnetic field. The number of rolls has the tendency to decrease with increasing Rayleigh number Ra and to increase with increasing Chandrasekhar number Q. We explored convection regimes in a parameter range, at 2×10^{3}<Q<10^{4} and 5×10^{3}<Ra<3×10^{5}, thus extending the regime diagram provided by Yanagisawa et al. [T. Yanagisawa et al., Phys. Rev. E 88, 063020 (2013)PLEEE81539-375510.1103/PhysRevE.88.063020]. Three regimes were identified, of which the regime of regular flow reversals in which five rolls periodically change the direction of their circulation with gradual skew of the roll axes can be considered as the most remarkable one. The regime appears around a range of Ra/Q=10, where irregular flow reversals were observed in Yanagisawa et al. We performed the proper orthogonal decomposition (POD) analysis on the spatiotemporal velocity distribution and detected that the regular flow reversals can be interpreted as a periodic emergence of a four-roll state in a dominant five-roll state. The POD analysis also provides the definition of the effective number of rolls as a more objective approach.

Thermohydraulic safety issues for liquid metal cooled systems

In this paper recent developments of various techniques for single-phase and two-phase flow measurements with relevance to liquid metal cooled systems will be presented. Further, the status of the DRESDYN platform for large-scale experiments with liquid sodium is sketched.

Contactless Inductive Bubble Detection in a Liquid Metal Flow

The detection of bubbles in liquid metals is important for many technical applications. The opaqueness and the high temperature of liquid metals set high demands on the measurement system. The high electrical conductivity of the liquid metal can be exploited for contactless methods based on electromagnetic induction. We will present a measurement system which consists of one excitation coil and a pickup coil system on the opposite sides of the pipe. With this sensor we were able to detect bubbles in a sodium flow inside a stainless steel pipe and bubbles in a column filled with a liquid Gallium alloy.

Prediction of postnatal outcomes in fetuses with isolated congenital diaphragmatic hernias using different lung-to-head ratio measurements

OBJECTIVES

The purpose of this study was to compare different methods for measuring the fetal lung area-to-head circumference ratio and to investigate their prediction of postpartum survival and the need for neonatal extracorporeal membrane oxygenation (ECMO) therapy in fetuses with isolated congenital diaphragmatic hernias.

METHODS

This prospective study included 118 fetuses of at least 20 weeks' gestation with isolated left-sided congenital diaphragmatic hernias. The lung-to-head ratio was measured with 3 different methods (longest diameter, anteroposterior diameter, and tracing). To eliminate the influence of gestational age, the observed-to-expected lung-to-head ratio was calculated. Receiver operating characteristic (ROC) curves were calculated for the statistical prediction of survival and need for ECMO therapy by the observed-to-expected lung-to-head ratio measured with the different methods.

RESULTS

For survival and ECMO necessity 118 and 102 cases (16 neonates were not eligible for ECMO) were assessed, respectively. For prediction of postpartum survival and ECMO necessity, the areas under the ROC curves and 95% confidence intervals showed very similar results for the 3 methods for prediction of survival (tracing, 0.8445 [0.7553-0.9336]; longest diameter, 0.8248 [0.7360-0.9136]; and anteroposterior diameter, 0.8002 [0.7075-0.8928]) and for ECMO necessity (tracing, 0.7344 [0.6297-0.8391]; longest diameter, 0.7128 [0.6027-0.8228]; and anteroposterior diameter, 0.7212 [0.6142-0.8281]). Comparisons between the areas under the ROC curves showed that the tracing method was superior to the anteroposterior diameter method in predicting postpartum survival (P = .0300).

CONCLUSIONS

Lung-to-head ratio and observed-to-expected lung-to-head ratio measurements were shown to accurately predict postnatal survival and the need for ECMO therapy in fetuses with left-sided congenital diaphragmatic hernias. Tracing the limits of the lungs seems to be the favorable method for calculating the fetal lung area.

Pan-atlantic analysis of the overlap of a highly migratory species, the leatherback turtle, with pelagic longline fisheries

Large oceanic migrants play important roles in ecosystems, yet many species are of conservation concern as a result of anthropogenic threats, of which incidental capture by fisheries is frequently identified. The last large populations of the leatherback turtle, Dermochelys coriacea, occur in the Atlantic Ocean, but interactions with industrial fisheries could jeopardize recent positive population trends, making bycatch mitigation a priority. Here, we perform the first pan-Atlantic analysis of spatio-temporal distribution of the leatherback turtle and ascertain overlap with longline fishing effort. Data suggest that the Atlantic probably consists of two regional management units: northern and southern (the latter including turtles breeding in South Africa). Although turtles and fisheries show highly diverse distributions, we highlight nine areas of high susceptibility to potential bycatch (four in the northern Atlantic and five in the southern/equatorial Atlantic) that are worthy of further targeted investigation and mitigation. These are reinforced by reports of leatherback bycatch at eight of these sites. International collaborative efforts are needed, especially from nations hosting regions where susceptibility to bycatch is likely to be high within their exclusive economic zone (northern Atlantic: Cape Verde, Gambia, Guinea Bissau, Mauritania, Senegal, Spain, USA and Western Sahara; southern Atlantic: Angola, Brazil, Namibia and UK) and from nations fishing in these high-susceptibility areas, including those located in international waters.

New formulas for calculating the lung-to-head ratio in healthy fetuses between 20 and 40 weeks' gestation

OBJECTIVES

The purpose of this study was to develop new formulas for the expected fetal lung area-to-head circumference ratio in normal singleton pregnancies between 20 and 40 weeks' gestation.

METHODS

The lung-to-head ratio and complete fetal biometric parameters of 126 fetuses between 20 and 40 weeks' gestation were prospectively measured. The lung-to-head ratio was measured by 3 different methods (longest diameter, anteroposterior diameter, and tracing). Formulas for predicting right and left lung-to-head ratios with regard to gestational age and biometric parameters were derived by stepwise regression analysis.

RESULTS

New formulas for calculating right and left lung-to-head ratios by each measurement method were derived. The formulas included gestational age only and no biometric parameters.

CONCLUSIONS

The new formulas for estimating the expected lung-to-head ratio by the 3 different methods in normal singleton pregnancies up to 40 weeks' gestation may help improve the prognostic power of observed-to-expected lung-to-head ratio assessment in fetuses with congenital diaphragmatic hernias.

Prediction of mortality and the need for neonatal extracorporeal membrane oxygenation therapy by 3-dimensional sonography and magnetic resonance imaging in fetuses with congenital diaphragmatic hernias

OBJECTIVES

To compare different rotation angles for assessment of fetal lung volume by 3-dimensional (3D) sonography with magnetic resonance imaging (MRI) regarding prediction of mortality and the need for neonatal extracorporeal membrane oxygenation (ECMO) therapy in fetuses with congenital diaphragmatic hernias.

METHODS

One hundred patients with fetal congenital diaphragmatic hernias between 22 and 39 weeks' gestation were examined by 3D sonography and MRI. Sonographic contralateral fetal lung volumes were assessed by the rotational technique (virtual organ computer-aided analysis) at 3 different rotation angles: 6°, 15°, and 30°. The MRI fetal lung volumes were calculated based on multiplanar T2-weighted MRI. To eliminate the influence of gestational age, the observed to expected contralateral fetal lung volume on sonography and the observed to expected fetal lung volume on MRI were calculated. Receiver operating characteristic (ROC) curves were calculated for the statistical prediction of survival and need for ECMO therapy by the observed to expected contralateral fetal lung volume (sonography) and observed to expected fetal lung volume (MRI).

RESULTS

One hundred cases were assessed for survival and 89 for ECMO necessity (11 neonates were not eligible for ECMO). For prediction of postpartum survival and ECMO necessity, the areas under the ROC curves (AUCs) showed very similar results for MRI and 3D sonography: observed to expected fetal lung volume by MRI, 0.819 (95% confidence interval, 0.730-0.909) and 0.835 (0.748-0.922), respectively; 6° sonography, 0.765 (0.647-0.883) and 0.820 (0.734-0.905); 15° sonography, 0.784 (0.672-0.896) and 0.811 (0.719-0.903); and 30° sonography, 0.732 (0.609-0.855) and 0.772 (0.671-0.872). Comparisons between the AUCs revealed no statistical differences.

CONCLUSIONS

We have shown the good prognostic value of 3D sonography in fetuses with congenital diaphragmatic hernias compared with MRI, particularly when using small rotation angles. Therefore, it can be an appropriate diagnostic tool when counseling patients for congenital diaphragmatic hernias.

Structure-function relationship of the foam-like pomelo peel (Citrus maxima)-an inspiration for the development of biomimetic damping materials with high energy dissipation

The mechanical properties of artificial foams are mainly determined by the choice of bulk materials and relative density. In natural foams, in contrast, variation to optimize properties is achieved by structural optimization rather than by conscious substitution of bulk materials. Pomelos (Citrus maxima) have a thick foam-like peel which is capable of dissipating considerable amounts of kinetic energy and thus this fruit represents an ideal role model for the development of biomimetic impact damping structures. This paper focuses on the analysis of the biomechanics of the pomelo peel and on its structure-function relationship. It deals with the determination of the onset strain of densification of this foam-like tissue and on how this property is influenced by the arrangement of vascular bundles. It was found here that the vascular bundles branch in a very regular manner-every 16.5% of the radial peel thickness-and that the surrounding peel tissue (pericarp) attains its exceptional thickness mainly by the expansion of existing interconnected cells causing an increasing volume of the intercellular space, rather than by cell division. These findings lead to the discussion of the pomelo peel as an inspiration for fibre-reinforced cast metallic foams with the capacity for excellent energy dissipation.