Observation of a Nuclear Recoil Peak at the 100 eV Scale Induced by Neutron Capture.

Coherent elastic neutrino-nucleus scattering and low-mass dark matter detectors rely crucially on the understanding of their response to nuclear recoils. We report the first observation of a nuclear recoil peak at around 112 eV induced by neutron capture. The measurement was performed with a CaWO_{4} cryogenic detector from the NUCLEUS experiment exposed to a ^{252}Cf source placed in a compact moderator. We identify the expected peak structure from the single-γ de-excitation of ^{183}W with 3σ and its origin by neutron capture with 6σ significance. This result demonstrates a new method for precise, in situ, and nonintrusive calibration of low-threshold experiments.

Origin of the Reactor Antineutrino Anomalies in Light of a New Summation Model with Parametrized ß

We investigate the possible origins of the reactor antineutrino anomalies in norm and shape within the framework of a summation model where ß^{-} transitions are simulated by a phenomenological model of Gamow-Teller decay strength. The general trends of divergence from the Huber-Mueller model on the antineutrino side can be reproduced in both norm and shape. From the exact electron-antineutrino correspondence of the summation model, we predict similar distortions in the electron spectra, suggesting that biases on the reference spectra of fission electrons could be the cause of the anomalies.

Joint Measurement of the

The PROSPECT and STEREO collaborations present a combined measurement of the pure ^{235}U antineutrino spectrum, without site specific corrections or detector-dependent effects. The spectral measurements of the two highest precision experiments at research reactors are found to be compatible with χ^{2}/ndf=24.1/21, allowing a joint unfolding of the prompt energy measurements into antineutrino energy. This ν[over ¯]_{e} energy spectrum is provided to the community, and an excess of events relative to the Huber model is found in the 5-6 MeV region. When a Gaussian bump is fitted to the excess, the data-model χ^{2} value is improved, corresponding to a 2.4σ significance.

Searching for Hidden Neutrons with a Reactor Neutrino Experiment: Constraints from the STEREO Experiment.

Different extensions of the standard model of particle physics, such as braneworld or mirror matter models, predict the existence of a neutron sterile state, possibly as a dark matter candidate. This Letter reports a new experimental constraint on the probability p for neutron conversion into a hidden neutron, set by the STEREO experiment at the high flux reactor of the Institut Laue-Langevin. The limit is p<3.1×10^{-11} at 95% C.L. improving the previous limit by a factor of 13. This result demonstrates that short-baseline neutrino experiments can be used as competitive passing-through-walls neutron experiments to search for hidden neutrons.

Prenatal stomach position predicts gastrointestinal morbidity at 2 years in fetuses with left-sided congenital diaphragmatic hernia.

OBJECTIVE: The long-term morbidity associated with isolated left-sided congenital diaphragmatic hernia (CDH) has been described previously. However, antenatal criteria impacting gastrointestinal morbidity (GIM) are not yet defined. The objective of this study was to evaluate the effect of fetal stomach position on the risk of GIM at 2 years of age in children with left-sided CDH. METHODS: This was a retrospective, observational multicenter cohort study of data obtained from January 2010 to January 2014, that included patients whose fetus had isolated left-sided CDH, with or without fetal endoscopic tracheal occlusion (FETO). Prenatal maternal, fetal and pediatric data were collected. Fetal stomach position was evaluated a posteriori by two observers, using ultrasound images at the level of the four-chamber view of the heart that had been obtained to calculate the observed-to-expected lung-area-to-head-circumference ratio (O/E-LHR). Fetal stomach position was graded as follows: Grade 1, stomach not visualized; Grade 2, stomach visualized anteriorly, next to the apex of the heart, with no structure in between the stomach and the sternum; Grade 3, stomach visualized alongside the left ventricle of the heart, and abdominal structures anteriorly; or Grade 4, as Grade 3 but with stomach posterior to the level of the atrioventricular heart valves. The primary outcome was GIM at 2 years of age, assessed in a composite manner, including the occurrence of gastroesophageal reflux disease, need for gastrostomy, duration of parenteral and enteral nutrition and persistence of oral aversion. Regression analysis was performed in order to investigate the effect of O/E-LHR, stomach position and FETO on various GIM outcome variables. RESULTS: Forty-seven patients with fetal left-sided CDH were included in the analysis. Thirteen (27.7%) infants did not meet the criterion of exclusive oral feeding at 2 years of age. Fetal stomach position grade was associated significantly and independently with the duration of parenteral nutrition (odds ratio (OR), 19.86; P = 0.031) and persistence of oral aversion at 2 years (OR, 3.40; P = 0.006). On multivariate analysis, O/E-LHR was predictive of the need for prosthetic patch repair, but not for GIM. FETO did not seem to affect the risk of GIM at 2 years. CONCLUSION: In isolated left-sided CDH, fetal stomach position is the only factor that is predictive of GIM at 2 years of age. © 2020 International Society of Ultrasound in Obstetrics and Gynecology.

Accurate Measurement of the Electron Antineutrino Yield of

We report a measurement of the antineutrino rate from the fission of ^{235}U with the STEREO detector using 119 days of reactor turned on. In our analysis, we perform several detailed corrections and achieve the most precise single measurement at reactors with highly enriched ^{235}U fuel. We measure an IBD cross section per fission of σ_{f}=(6.34±0.06[stat]±0.15[sys]±0.15[model])×10^{-43} cm^{2}/fission and observe a rate deficit of (5.2±0.8[stat]±2.3[sys]±2.3[model])% compared to the model, consistent with the deficit of the world average. Testing ^{235}U as the sole source of the deficit, we find a tension between the results of lowly and highly enriched ^{235}U fuel of 2.1 standard deviations.

[Antenatal ultrasound prediction of esophageal atresia type]. / Prédiction échographique anténatale du type d'atrésie de l'œsophage.

BACKGROUND: Esophageal atresia (EA) is a rare congenital malformation of the upper aerodigestive tract, which can be diagnosed antenatally in 50-65% of cases. Postnatal management differs according to the type of EA. No studies have evaluated the correlation of antenatal ultrasound findings with the type of EA. OBJECTIVE: The main objective is to study the association between antenatal ultrasound signs and the type of EA. The secondary objective is to study the association between postnatal morbidity and the type of EA. METHOD: We conducted a single-center retrospective study between May 2010 and August 2019. Fetuses with suspected prenatal EA and postnatal diagnosis confirmation were included. Postnatal confirmation of EA was performed during surgery for live births and by fetopathological examination for termination of pregnancy. Prenatal signs and postnatal morbidity were compared according to the type of EA. RESULTS: We included 15 cases of postnatally confirmed EA, including 9 type 1EA, 5 type 3EA and 1 type 4EA (11 live births and 4 terminations of pregnancy). The gestational age at diagnosis was earlier in type 1EA: 22+0 [6-21,21-24] versus 30+0 [28+0-32+0] (P=0.03). Compared to type 3EA, type 1EA had a higher incidence of non-visible stomach bubble (89% versus 40%, P=0.09) and upper esophageal cul-de-sac dilatation (56% versus 0%, P=0.09). Neonatal morbidity in type 1EA was more severe with a longer hospital stay in neonatal intensive care. CONCLUSION: The antenatal ultrasound signs seem to be more pronounced in case of type 1EA. Type 1EA is associated with severe morbidity compared to Type 3EA. Improving prenatal diagnosis of EA and its type allows a more accurate prognostic evaluation.

Prognostic value of diffusion-weighted magnetic resonance imaging of brain in fetal growth restriction: results of prospective multicenter study.

OBJECTIVE: To measure prospectively apparent diffusion coefficient (ADC) values between 28 and 32 weeks of gestation in different cerebral territories of fetuses with estimated fetal weight (EFW) ≤ 5th centile, and analyze their association with adverse perinatal outcome. METHODS: This was a prospective study involving six tertiary-level perinatal centers. In the period 22 November 2016 to 11 September 2017, we included singleton, small-for-gestational-age (SGA) fetuses with EFW ≤ 5th percentile, between 28 and 32 weeks of gestation, regardless of the umbilical artery Doppler and maternal uterine artery Doppler findings. A fetal magnetic resonance imaging (MRI) examination with diffusion-weighted sequences (DWI) was performed within 14 days following inclusion and before 32 weeks. ADC values were calculated in the frontal and occipital white matter, basal ganglia and cerebellar hemispheres. An ultrasound examination was performed within 1 week prior to the MRI examination. The primary outcome was a composite measure of adverse perinatal outcome, defined as any of the following: perinatal death; admission to neonatal intensive care unit with mechanical ventilation > 48 h; necrotizing enterocolitis; Grade III-IV intraventricular hemorrhage; periventricular leukomalacia. A univariate comparison of median ADC values in all cerebral territories between fetuses with and those without adverse perinatal outcome was performed. The association between ADC values and adverse perinatal outcome was then analyzed using multilevel logistic regression models to adjust for other common prognostic factors for growth-restricted fetuses. RESULTS: MRI was performed in 64 patients, of whom five were excluded owing to fetal movement artifacts on DWI and two were excluded for termination of pregnancy with no link to fetal growth restriction (FGR). One intrauterine death occurred secondary to severe FGR. Among the 56 liveborn neonates, delivered at a mean ± SD gestational age of 33.6 ± 3.0 weeks, with a mean birth weight of 1441 ± 566 g, four neonatal deaths occurred. In addition, two neonates required prolonged mechanical ventilation, one of whom also developed necrotizing enterocolitis. Overall, therefore, seven out of 57 (12.3%) cases had an adverse perinatal outcome (95% CI, 3.8-20.8%). The ADC values in the frontal region were significantly lower in the group with adverse perinatal outcome vs those in the group with favorable outcome (mean values of both hemispheres, 1.68 vs 1.78 × 10-3 mm2 /s; P = 0.04). No significant difference in ADC values was observed between the two groups in any other cerebral territory. A cut-off value of 1.70 × 10-3 mm2 /s was associated with a sensitivity of 57% (95% CI, 18-90%), a specificity of 78% (95% CI, 63-88%), a positive predictive value of 27% (95% CI, 8-55%) and a negative predictive value of 93% (95% CI, 80-98%) for the prediction of adverse perinatal outcome. A mean frontal ADC value < 1.70 × 10-3 mm2 /s was not associated significantly with an increased risk of adverse perinatal outcome, either in the univariate analysis (P = 0.07), or when adjusting for gestational age at MRI and fetal sex (odds ratio (OR), 6.06 (95% CI, 0.9-37.1), P = 0.051) or for umbilical artery Doppler (OR, 6.08 (95% CI, 0.89-41.44)). CONCLUSION: This first prospective, multicenter, cohort study using DWI in the setting of SGA found lower ADC values in the frontal white-matter territory in fetuses with, compared with those without, adverse perinatal outcome. To determine the prognostic value of these changes, further standardized evaluation of the neurodevelopment of children born with growth restriction is required. Copyright © 2019 ISUOG. Published by John Wiley & Sons Ltd.

Determination of rubella virus-specific humoral and cell-mediated immunity in pregnant women with negative or equivocal rubella-specific IgG in routine screening.

BACKGROUND: Immunity to rubella-virus (RV) is commonly determined by measuring specific IgG (RV-IgG). However, RV-IgG results may be different and even discordant, depending on the assay used. Cell-mediated immunity is not routinely investigated for diagnostic purposes. OBJECTIVES: Our aim was to investigate humoral and cellular immunity of women with negative or equivocal RV-IgG before, and after post-partum vaccination. STUDY DESIGN: A total of 186 pregnant women were included in the study. During pregnancy, humoral immunity was investigated with two RV-IgG immunoassays, an immunoblot and a T-cell mediated immunity test. In the post-partum vaccination period, measuring RV-IgM and RV-IgG avidity allowed us to determine whether women raised a primary or a secondary immune response. RESULTS: Before vaccination, 52.2% women, supposed to be susceptible, had positive anti-E1 RV-IgG indicating strong evidence of previous exposure to RV. All (100%) pregant women who had a positive immunoblot before immunization raised a secondary immune response to vaccination, and 96.8% who had a negative immunoblot before immunization, raised a primary immune response to vaccination. All women who raised a primary immune response after vaccination had negative anti-E1 RV-IgG and negative cell-mediated immunity. DISCUSSION: These results indicate that individuals can have evidence of protective immunity against rubella despite negative RV-IgG.

Sterile Neutrino Constraints from the STEREO Experiment with 66 Days of Reactor-On Data.

The reactor antineutrino anomaly might be explained by the oscillation of reactor antineutrinos toward a sterile neutrino of eV mass. In order to explore this hypothesis, the STEREO experiment measures the antineutrino energy spectrum in six different detector cells covering baselines between 9 and 11 m from the compact core of the ILL research reactor. In this Letter, results from 66 days of reactor turned on and 138 days of reactor turned off are reported. A novel method to extract the antineutrino rates has been developed based on the distribution of the pulse shape discrimination parameter. The test of a new oscillation toward a sterile neutrino is performed by comparing ratios of cells, independent of absolute normalization and of the prediction of the reactor spectrum. The results are found to be compatible with the null oscillation hypothesis and the best fit of the reactor antineutrino anomaly is excluded at 97.5% C.L.

[Cell-free fetal DNA analysis in maternal plasma as a screening test for trisomy 21 in twin pregnancies]. / Analyse de l'ADN fœtal dans le sang maternel comme test de dépistage pour la trisomie 21 pour les grossesses gémellaires.

OBJECTIVES: To evaluate the performance of noninvasive prenatal testing by cell-free circulating fetal DNA in maternal blood (cfDNA) in screening for trisomies 21 in twin pregnancies. METHODS: CfDNA was performed in 492 patients with twin pregnancies without ultrasound anomalies in the first trimester as a first-line screening test or after serum screening. Data were collected prospectively and a retrospective analysis was done. CfDNA was executed by massive parallel technique. The fetal fraction threshold for test evaluation was 8%. Regression analysis was performed to evaluate the effect of different parameters on the test failure rate. Performance of the test was also considered. RESULTS: In 377 patients, the test was prescribed first line and in 115 after standard serum screening. Twelve tests (2.9%) have initially failed on the 420 pregnancies with available outcomes and regression analysis found only maternal weight as a significant independent factor of test failure. A second test was performed on 10 patients, all of them had an available result. cfDNA identified all 3 cases of trisomy 21. The sensitivity was 100.0% (95% CI [29.2-100.0%]) and specificity was 99.8% (95% CI [98.7-100.0%]). There was no significant difference between spontaneous pregnancies and those induced by assisted reproductive technologies (ART), in terms of fetal fraction percentage, no-call results for cfDNA screening, maternal weight, or test performance between the two groups. CONCLUSION: In twin pregnancies without fetal ultrasound abnormalities, the performance and success rate of the cfDNA are excellent. Therefore, cfDNA could be offered in routine practice as a first-line screening test in this population.

Therapeutic drug monitoring of antitubercular agents for disseminated Mycobacterium tuberculosis during intermittent haemodialysis and continuous venovenous haemofiltration.

WHAT IS KNOWN AND OBJECTIVE: There is a lack of data regarding therapeutic drug monitoring (TDM) of antitubercular agents in the setting of continuous venovenous haemofiltration (CVVH). We describe TDM results of numerous antitubercular agents in a critically ill patient during CVVH and haemodialysis. CASE SUMMARY: A 49-year-old man was initiated on treatment for disseminated Mycobacterium tuberculosis. During hospital admission, the patient developed critical illness and required renal replacement therapy. TDM results and pharmacokinetic calculations showed adequate serum concentrations of rifampin, ethambutol and amikacin during CVVH and of rifampin, pyrazinamide, ethambutol and levofloxacin during intermittent haemodialysis. WHAT IS NEW AND CONCLUSION: The presence of critical illness and renal replacement therapy can induce pharmacokinetic changes that may warrant vigilant TDM to ensure optimal therapy. To our knowledge, this is the first report to describe TDM for several antitubercular agents during CVVH in a critically patient with disseminated M. tuberculosis.

Cell-free fetal DNA analysis in maternal plasma as screening test for trisomies 21, 18 and 13 in twin pregnancy.

OBJECTIVES: To evaluate in twin pregnancy the utility of non-invasive prenatal testing using circulating cell-free fetal DNA (cfDNA) in screening for the three main autosomal fetal trisomies. METHODS: cfDNA testing was offered to 492 patients with a twin pregnancy without ultrasound anomaly as a first-line screening test or after routine serum screening. Data were collected prospectively and a retrospective analysis was performed. cfDNA analysis was performed by massively parallel sequencing. The fetal-fraction threshold used for test evaluation was 8%. Regression analysis was performed to investigate the effect on the test failure rate of maternal and pregnancy characteristics, and the performance of the test was also reported. RESULTS: cfDNA analysis was performed as a first-line test (after the first-trimester scan) in 377 patients and following serum screening in 115. Of the 420 pregnancies for which outcome was available and cfDNA screening was assessed, 78.7% were dichorionic-diamniotic. The test failed on the first attempt in 12 (2.9%) pregnancies, and regression analysis demonstrated that only maternal weight was a significant independent predictor of test failure. A result was subsequently achieved in the 10 cases for which a second sample was obtained. cfDNA analysis identified all three cases of trisomy 21 and the only case of trisomy 18. For trisomy 21, the specificity was 99.8% (95% CI, 98.7-100.0%). When considering pregnancies according to whether they were conceived spontaneously or after assisted reproductive technology, there were no significant differences in terms of maternal weight or no-result rate for cfDNA screening between these two groups. CONCLUSIONS: In twin pregnancy without fetal ultrasound abnormality, cfDNA screening for trisomies 21, 18 and 13 had a high success rate and good performance. Therefore, in routine practice, cfDNA analysis could be considered as a first- or second-line screening test. Copyright © 2017 ISUOG. Published by John Wiley & Sons Ltd.

[Performance and indications of noninvasive prenatal testing using cell free circulating fetal DNA (cffDNA) for the detection of fetal trisomy 21, 18 and 13 in France]. / Performance et indication du dépistage des trisomies 21, 18 et 13 en France par l'analyse de l'ADN fœtal dans le sang maternel.

OBJECTIVES: To evaluate de performances of noninvasive prenatal testing using cell free circulating fetal DNA (cffDNA) for the detection of fetal trisomy 21, 18 and 13 in a French population. MATERIALS AND METHODS: cffDNA analysis was performed by massive parallel sequencing during a multicenter, non interventional, prospective study and the results were compared with a standard fetal karyotype. RESULTS: Results were available for 886 patients who have been classified as high- or moderate-risk depending on the presence of fetal abnormalities on ultrasound examination. For the high-risk group (n=376), the sensitivity and specificity of the test were 100% and 99.9% for trisomy 21, 88% and 99.9% for trisomy 18 and 100% and 99.9% for trisomy 13. The rate of other pathogenic chromosomal abnormalities with a negative NIPT was 7.9%. In the low-risk group (n=510), the sensitivity was 100% and the specificity 99.8% for trisomy 21, and only 0.4% of pathogenic chromosomal abnormalities were revealed by fetal karyotyping but not detected by cffDNA analysis. CONCLUSION: Noninvasive prenatal testing using cffDNA for high risk patients without fetal anomalies at ultrasound could be recommended in France after counseling on the possible risk of undiagnosed anomalies.

[First trimester screening for Down syndrome in a French perinatal healthcare network]. / Mise en place du dépistage de la trisomie 21 au premier trimestre dans un réseau périnatal de santé: exemple du réseau Périnat 92-Sud.

OBJECTIVES: French policy in terms of screening for Down Syndrome has been modified in 2010. It is presently based on combined screening based on maternal age, serum markers, and ultrasound measurement of fetal nuchal translucency between 11 and 13+6 weeks of gestation. The objective of this study was to observe the consequences of this new policy on the professional practices, using as example the professionals working in the healthcare network (Perinat 92-Sud). MATERIALS AND METHODS: A semi-quantitative survey was conducted between December 2010 and April 2011. A questionnaire on screening for Down Syndrome in the first trimester was sent to 110 ultrasound professionals performing on the territory of the network. RESULTS: Seventy-eight sonographers returned the questionnaire. Among them, 73.1% of sonographers who answered had an identifying number required for Down syndrome screening in France. Practitioners engaged in a private or mixed private/public practice or those over 40years had more often an identifying number. Among sonographers who do not have identifying number, 55% said they will perform an evaluation of professional practices, including a majority of hospital practitioners. CONCLUSION: The implementation of evaluations of professional practices brings the focus on perinatal networks. It modified the organization of the network Perinat 92-Sud and required the creation of a sonographer network.

Bk and Cf chromatographic separation and ²49Bk/²48Cm and ²49Cf/²48Cm elemental ratios determination by inductively coupled plasma quadrupole mass spectrometry.

The French Atomic Energy Commission has carried out several experiments for the study of minor-actinide transmutation processes in high intensity thermal neutron flux. In this context a Cm sample enriched in (248)Cm (∼97%) was irradiated in a thermal neutron flux at the High Flux Reactor (HFR) of the Laue-Langevin Institute (ILL). The precise and accurate determination of Cf isotope ratios and of (249)Bk/(248)Cm and (249)Cf/(248)Cm elemental ratios in the (248)Cm irradiated sample is crucial for the calculation of actinide neutron capture cross-sections. This work describes an analytical procedure for the separation and the isotope ratio measurement of Bk and Cf in the irradiated sample. The Bk and Cf separation is based on a lanthanides separation protocol previously developed by the laboratory. Well-defined retention times for Bk and Cf were obtained by coupling the Ionic Chromatography (IC) with an ICP-QMS. All conditions of element separation by IC and the different steps of the analytical protocol in order to obtain the isotopic and elemental ratios are presented. Relative uncertainties of Cf isotopic ratios range from 0.3% to 0.5% and the uncertainty of the (249)Bk/(248)Cm and (249)Cf/(248)Cm elemental ratios are respectively 6.1% and 3.2%. This level of uncertainty for both isotopic and elemental ratios is in perfect agreement with the requirement for transmutation studies.

A large HPGe detector for the non-destructive radioassay of an ultra-low-background counting facility.

We present the use of a low background counting facility, equipped with a p-type 80% relative efficiency HPGe detector, protected by active and passive shielding, and large enough to count a 10 in photo-multiplier tube (PMT). A GEANT4 Monte-Carlo of this detector was developed and tuned to 3% accuracy. We report the U, Th, and K content in three different types of PMTs used in current neutrino experiments, with accuracies of ~10ppb for U and Th and of ~15ppm for K.

Emission probabilities of gamma-rays from 238Np and their use for determination of the thermal neutron capture cross section of 237Np.

The relevant absolute gamma-ray emission probabilities from the beta-decay of (238)Np were measured by means of alpha- and gamma-spectroscopic techniques. We obtained values of (25.6+/-0.4)%, (8.9+/-0.2)% and (18.8+/-0.3)% for the 984.45-, 1025.87- and 1028.54-keV gamma-rays, respectively, in agreement with the previous measured ones. These intensities were used to deduce the thermal neutron capture cross section of (237)Np for which a value of (182.2+/-4.5)b is obtained higher by 11% than the recommended value.