Inelastic mean-free path and mean escape depth of 10-140 eV electrons in SiO2 nanoparticles determined by Si 2p photoelectron yields.

We report on photoelectron spectra of SiO2 nanoparticles (d = 157 ± 6 nm) above the Si 2p threshold in the photon energy range 118-248 eV with electron kinetic energy 10-140 eV and analyze the photoelectron yield as a function of photon energy. Comparison of the experimental results with Monte-Carlo simulations on electron transport allows us to quantify the inelastic mean-free path and mean escape depth of photoelectrons in the nanoparticle samples. The influence of the nanoparticle geometry and electron elastic scattering on photoelectron yields is highlighted. The results show that the previously proposed direct proportionality of the photoelectron signal to the inelastic mean-free path or the mean escape depth does not hold for photoelectron kinetic energies below 30 eV due to the strong influence of electron elastic scattering. The present results deviate for photoelectron kinetic energies below 30 eV from the previously proposed direct proportionality of the photoelectron signal to the inelastic mean-free path or the mean escape depth, which is the result of a strong influence of electron elastic scattering. The presented inelastic mean-free paths and mean escape depths appear to be useful for the quantitative interpretation of photoemission experiments on nanoparticles and for modeling of the experimental results.

Clinical profiles of placenta accreta spectrum: the PACCRETA population-based study.

OBJECTIVE: To describe and compare the characteristics of women with placenta accreta spectrum (PAS) and their pregnancy outcomes according to the presence of placenta praevia and a prior caesarean section. DESIGN: Prospective population-based study. SETTING: All 176 maternity hospitals of eight French regions. POPULATION: Two hundred and forty-nine women with PAS, from a source population of 520 114 deliveries. METHODS: Women with PAS were classified into two risk-profile groups, with or without the high-risk combination of placenta praevia (or an anterior low-lying placenta) and at least one prior caesarean. These two groups were described and compared. MAIN OUTCOME MEASURES: Population-based incidence of PAS, characteristics of women, pregnancies, deliveries and pregnancy outcomes. RESULTS: The PAS population-based incidence was 4.8/10 000 (95% CI 4.2-5.4/10 000). After exclusion of women lost to follow up from the analysis, the group with placenta praevia and a prior caesarean included 115 (48%) women and the group without this combination included 127 (52%). In the group with both factors, PAS was more often suspected antenatally (77% versus 17%; P < 0.001) and more often percreta (38% versus 5%; P < 0.001). This group also had more hysterectomies (53% versus 21%, P < 0.001) and higher rates of blood product transfusions, maternal complications, preterm births and neonatal intensive care unit admissions. Sensitivity analysis showed similar results after exclusion of women who delivered vaginally. CONCLUSION: More than half the cases of PAS occurred in women without the combination of placenta praevia and a prior caesarean delivery, and these women had better maternal and neonatal outcomes. We cannot completely rule out that some of the women who delivered vaginally had placental retention rather than PAS; however, we found similar results among women who delivered by caesarean. TWEETABLE ABSTRACT: Half the women with PAS do not have both placenta praevia and a prior caesarean delivery, and they have better maternal outcomes.

[Propositions for perinatal care at extremely low gestational ages - Working group on "Extremely low gestational ages" for SFMP, CNGOF, and SFN]. / Propositions sur la prise en charge en cas d'extrême prématurité ­ Le groupe de travail « Extrême Prématurité ¼ pour la SFMP, le CNGOF et la SFN.

OBJECTIVES: International literature suggests that active perinatal management at extremely low gestational ages improves survival without increasing the risk of impairment in survivors, compared to less active management. Although these results are limited to a small number of countries, they question current practices in France. New propositions on perinatal management of extremely preterm infants have carried out by the French Society of Perinatal Medicine, the French Society of Neonatology and the National College of French Obstetricians and Gynecologists. METHODS: This group was set up in 2015 on the initiative of the professional societies and in collaboration with parents' and users' associations. The work was based on a review of the literature on the prognosis of extremely preterm children, as well as on recommendations by European societies. Based on this information, a text was produced, submitted to all members of the working group and definitively validated in April 2019. RESULTS: This text offers a decision-making guideline for the management at extremely low gestational ages. Its principles are: the administration of steroids independently of management (resuscitation or comfort care); a prognostic evaluation and a collegial decision, outside the context of the emergency; a consensus on the information to be given to parents before going to inform them and gather their opinion. CONCLUSIONS: These new propositions will contribute to modifying perinatal care at extremely low gestational ages in France.

TSPO PET Identifies Different Anti-inflammatory Minocycline Treatment Response in Two Rodent Models of Epileptogenesis.

Epileptogenesis-associated brain inflammation might be a promising target to prevent or attenuate epileptogenesis. Positron emission tomography (PET) imaging targeting the translocator protein (TSPO) was applied here to quantify effects of different dosing regimens of the anti-inflammatory drug minocycline during the latent phase in two rodent models of epileptogenesis. After induction of epileptogenesis by status epilepticus (SE), rats were treated with minocycline for 7 days (25 or 50 mg/kg) and mice for 5 or 10 days (50 or 100 mg/kg). All animals were subjected to scans at 1 and 2 weeks post-SE. Radiotracer distribution was analyzed and statistical parametric mapping (SPM) was performed, as well as histological analysis of astroglial activation and neuronal cell loss. Atlas-based analysis of [18F]GE180 PET in rats revealed a dose-dependent regional decrease of TSPO expression at 2 weeks post-SE. Results of SPM analysis depicted a treatment effect already at 1 week post-SE in rats treated with the higher minocycline dose. In mice, TSPO PET imaging did not reveal any treatment effects whereas histology identified only a treatment-related reduction in dispersion of dentate gyrus neurons. TSPO PET served as an auspicious tool for temporal monitoring and quantification of anti-inflammatory effects during epileptogenesis. Importantly, the findings underline the need to applying more than one animal model to avoid missing treatment effects. For future studies, the setup is ready to be applied in combination with seizure monitoring to investigate the relationship between individual early treatment response and disease outcome.

Size-dependent ion emission asymmetry of free NaCl nanoparticles excited by intense femtosecond laser pulses.

We report on asymmetric ion emission of size-selected NaCl nanoparticles (d = 100-600 nm) ionized by intense femtosecond laser pulses (λ = 800 nm, peak intensity ∼1013 W cm-2). Velocity map imaging indicates that a higher ion yield is observed in the propagation direction of the laser pulses than in the opposite direction. This asymmetric ion emission is found to be size-dependent and increases with particle size. This pronounced size dependence is interpreted in terms of discrete dipole simulations of the internal electric field in the nanoparticles, which reveal that the internal field is enhanced in the forward propagation direction of the laser pulses, occurring for nanoparticles >100 nm. The ion emission asymmetry is further found to depend on the peak intensity of the laser radiation. Nanoparticles of 100 nm show a symmetric distribution of ion emission, while the ion emission for 600 nm particles is found to become increasingly symmetric as the peak intensity is increased. In addition to single pulse ionization experiments, we explore the angular distribution of ion emission of resonantly heated NaCl nanoparticles using a pump-probe setup. Here, ion emission is found to be more symmetric for resonantly heated nanoparticles than for single pulse excitation. These differences are explained by the absorption mechanism, where the probe pulse in a dual pulse experiment can be efficiently absorbed by plasmonic excitation for suitable delays between both laser pulses.

Surface Composition of Free Mixed NaCl/Na2SO4 Nanoscale Aerosols Probed by X-ray Photoelectron Spectroscopy.

The local chemical surface composition of unsupported mixed solid NaCl/Na2SO4 aerosols ( d ∼ 70 nm) is studied by X-ray photoelectron spectroscopy. The solid aerosols are generated by drying aqueous droplets containing mixtures of the two salts in different mole fractions. The mole fraction of these salts is found to deviate at the solid aerosol surface significantly from the initial droplet composition. The minority species in the droplets are found to be enhanced at the surface of the solid mixed aerosols. This surface enhancement is rationalized in terms of the nucleation/crystallization process, where the salts evidently do not cocrystallize, rather than each salt forms pure crystal moieties. Characteristic variations of the surface ion concentration as a function of the mole fraction of the salts in the initial droplet are observed in the nanometer size regime. This is unlike core-shell architectures previously found in mixed micron salt aerosols, indicating that aerosol models derived from micron-sized aerosols are evidently not fully reliable to describe the surface composition of nanosized aerosols. Furthermore, surface enhancement of the minority component in mixed NaCl/Na2SO4 aerosols is also different from previous results on surface segregation of mixed NaCl/NaBr aerosols, where one of the anionic species is surface segregated for all mole fractions, which was explained in terms of the ability of the involved salts to cocrystallize and forming solid solutions. The present results rather indicate that mixed NaCl/Na2SO4 aerosols do not cocrystallize. Electron microscopy of deposited mixed salt aerosols reveals mostly a cubic structure of pure NaCl aerosols, whereas mixed salt aerosols are found to show a grainy structure composed of multiple small crystals which supports the present findings obtained from photoelectron spectroscopy.

HEART Score and Stress Test Emergency Department Bayesian Decision Scheme: Results from the Acute Care Diagnostic Collaboration.

BACKGROUND: Accurate identification of patients at risk of major adverse cardiac events (MACE) places a substantial burden on emergency physicians (EPs). Bayesian nomogram for risk stratification in low- to intermediate-risk cardiovascular patients has not been investigated previously. OBJECTIVE: The objective of this study was to develop a comparative diagnostic model using Bayesian statistics for exercise treadmill test (ETT) and stress echocardiogram (ECHO) to calculate post-test diagnostic risk of MACE using HEART (history, electrocardiogram, age, risk factors, and troponin) risk score as predictor of pretest probability. METHODS: Stratification was made by applying HEART scores for the prediction of MACE. Likelihood ratios (LR) were calculated using pooled sensitivity and specificity of ETT and ECHO from the American College of Cardiology Foundation/American Heart Association systematic review. Post-test probabilities were obtained after inserting HEART score and LR into Bayesian nomogram. Analysis of variance was used to assess statistical association. RESULTS: Positive LR (LR+) for ETT was 4.56 and negative LR (LR-) was 0.27; for ECHO, LR+ 5.65 and LR- 0.15. Bayesian statistical modeling post-test probabilities for LR+ and low HEART risk yielded a post-test probability for ETT of 7.75% and 9.09% for ECHO; intermediate risk gave 47.62% and 52.63%, respectively. For LR-, low HEART risk post-test probability for ETT was 0.46% and for ECHO 0.26%; intermediate risk probabilities were 4.48% and 2.49%, respectively. LR- was statistically significant in ruling out MACE with ECHO (p < 0.001), but no significant differences were seen for LR+ (p = 0.64). CONCLUSIONS: This Bayesian analysis demonstrated slight superiority of stress ECHO over ETT in low- and intermediate-risk patients in ruling out MACE.

Expectant management and laser photocoagulation in isolated selective intra-uterine growth restriction: A single-center series.

INTRODUCTION: The objective was to report on a consecutive series of monochorionic diamniotic pregnancies complicated by selective Intra-Uterine Growth Restriction (sIUGR) and to describe perinatal outcomes based on whether or not there were umbilical Doppler findings, and specifically to study those pregnancies treated by laser. MATERIAL AND METHODS: This was a retrospective cohort study enrolling monochorionic diamniotic pregnancies presenting isolated sIUGR after 16 weeks' gestation (WG). RESULTS: Of the 25 cases of sIUGR, 16 were type I and 9 type II or III. Types II and III occurred earlier than type I (22.3 versus 24.3 WG), were more severe (discordance of 37% versus 23%), and delivered earlier (31.3 versus 33.9 WG). Survival was 12/18 (66.7%) for types II or III versus 32/32 (100%) for type I. Five laser photocoagulation procedures were attempted and allowed the survival of both twins in 2 cases. Overall survival after laser was 6/10 (60%). DISCUSSION: Isolated sIUGR is associated with high perinatal morbidity and mortality. Laser photocoagulation treatment is feasible and may enable survival of both twins in some cases, but may be technically difficult.

Photoelectron angular distribution from free SiO2 nanoparticles as a probe of elastic electron scattering.

In order to gain quantitative information on the surface composition of nanoparticles from X-ray photoelectron spectroscopy, a detailed understanding of photoelectron transport phenomena in these samples is needed. Theoretical results on the elastic and inelastic scattering have been reported, but a rigorous experimental verification is lacking. We report in this work on the photoelectron angular distribution from free SiO2 nanoparticles (d = 122 ± 9 nm) after ionization by soft X-rays above the Si 2p and O 1s absorption edges, which gives insight into the relative importance of elastic and inelastic scattering channels in the sample particles. The photoelectron angular anisotropy is found to be lower for photoemission from SiO2 nanoparticles than that expected from the theoretical values for the isolated Si and O atoms in the photoelectron kinetic energy range 20-380 eV. The reduced angular anisotropy is explained by elastic scattering of the outgoing photoelectrons from neighboring atoms, smearing out the atomic distribution. Photoelectron angular distributions yield detailed information on photoelectron elastic scattering processes allowing for a quantification of the number of elastic scattering events the photoelectrons have undergone prior to leaving the sample. The interpretation of the experimental photoelectron angular distributions is complemented by Monte Carlo simulations, which take inelastic and elastic photoelectron scattering into account using theoretical values for the scattering cross sections. The results of the simulations reproduce the experimental photoelectron angular distributions and provide further support for the assignment that elastic and inelastic electron scattering processes need to be considered.

[Fetoscopic laser coagulation in 200 consecutive monochorionic pregnancies with twin-twin transfusion syndrome]. / Photocoagulation laser par fœtoscopie pour syndrome transfuseur-transfusé : analyse d'une série consécutive unicentrique de 200 cas.

OBJECTIVES: To report preoperative data, surgical characteristics, complications and perinatal outcome of twin-twin transfusion syndrome (TTTS) managed with laser ablation surgery, to analyze predictors of neonatal survival and to compare the 100 most recent cases with the older 100. MATERIALS AND METHODS: Observational cohort moncentric study of 200 cases of TTTS consecutively treated with fetoscopic laser coagulation between January 2004 and December 2014. RESULTS: There were 49 stage I, 88 stage II, 55 stage III and eight stage IV. Median gestation at time of laser was 20.1±3.0 weeks' gestation (WG) whereas median gestation at delivery was 31.6±5.4 WG. Overall perinatal survival rate was 68.0% and 84.0% have one or more surviving twins. Preterm premature rupture of membranes occurred in 39 cases with and the median gestational age for this complication was 28.8±4.6 SA. Predictive factors to have at least one living birth were Quintero stage and gestational age at delivery. In the most recent period, there were significantly more TTTS Quintero stage I treated with laser, more coagulation by the Solomon technique and a larger number of coagulated vessels. CONCLUSION: The neonatal survival of TTTS is improved by fetoscopic laser coagulation, preferely by using Solomon tecnhique. The use of active management of stage I is currently on research.

Evaluation of a most probable number method for the enumeration of Legionella pneumophila from potable and related water samples.

This study compared the performance of a novel MPN method (Legiolert/Quanti-Tray) with the ISO 11731-2 membrane filtration method for the enumeration of Legionella pneumophila from 100 ml potable water and related samples. Data from a multi-laboratory study analysed according to ISO 17994 showed that Legiolert™/Quanti-Tray® yielded on average higher counts of L. pneumophila. The Legiolert medium had a high specificity of 96·4%. The new method represents a significant improvement in the enumeration of L. pneumophila from drinking water-related samples. SIGNIFICANCE AND IMPACT OF THE STUDY: Legionella pneumophila is an opportunistic pathogen of major concern. The current large volume quantitative method employs membrane filtration (MF) and selective culture on GVPC agar followed by confirmation of isolates by serology (ISO 11731-2) We present here the results of a multi-laboratory evaluation of a most probable number (MPN) in-situ confirmed method (Legiolert™/Quanti-Tray®). The results indicate that Legiolert/Quanti-Tray yielded on average higher counts of L. pneumophila than ISO 11731-2. This development significantly improves and simplifies the enumeration of L. pneumophila from potable water samples.

Textile foreign body in a Green Iguana (Iguana iguana): Diagnostic imaging for localisation.

INTRODUCTION: This case report includes different diagnostic imaging methods for localization of textile foreign bodies in reptiles and shows the limitations and advantages of these methods. A six-year-old, male, green iguana was presented to our clinic after ingesting a sock 5 days earlier. Ultrasound, contrast x-ray, computed tomography and endoscopy were used to locate the foreign body before surgery. Attempts to remove the sock endoscopically failed. The sock was surgically removed via celiotomy and enterotomy.

[Prevention of spontaneous preterm birth (excluding preterm premature rupture of membranes): Guidelines for clinical practice - Text of the Guidelines (short text)]. / Recommandations pour la pratique clinique : prévention de la prématurité spontanée et de ses conséquences (hors rupture des membranes) ­ Texte des recommandations (texte court).

OBJECTIVES: To determine the measures to prevent spontaneous preterm birth (excluding preterm premature rupture of membranes)and its consequences. MATERIALS AND METHODS: The PubMed database, the Cochrane Library and the recommendations from the French and foreign obstetrical societies or colleges have been consulted. RESULTS: In France, premature birth concerns 60,000 neonates every year (7.4 %), half of them are delivered after spontaneous onset of labor. Among preventable risk factors of spontaneous prematurity, only cessation of smoking is associated to a decrease of prematurity (level of evidence [LE] 1). This is therefore recommended (grade A). Routine screening and treatment of vaginal bacteriosis in general population is not recommended (grade A). Asymptomatic women with single pregnancy without history of preterm delivery and a short cervix between 16 and 24 weeks is the only population in which vaginal progesterone is recommended (grade B). A history-indicated cerclage is not recommended in case of only past history of conisation (grade C), uterine malformation (Professional consensus), isolated history of pretem delivery (grade B) or twin pregnancies in primary (grade B) or secondary (grade C) prevention of preterm birth. A history-indicated cerclage is recommended for single pregnancy with a history of at least 3 late miscarriages or preterm deliveries (grade A).). In case of past history of a single pregnancy delivery before 34 weeks gestation (WG), ultrasound cervical length screening is recommended between 16 and 22 WG in order to propose a cerclage in case of length<25mm before 24 WG (grade C). Cervical pessary is not recommended for the prevention of preterm birth in a general population of asymptomatic women with a twin pregnancy (grade A) and in populations of asymptomatic women with a short cervix (Professional consensus). Although the implementation of a universal transvaginal cervical length screening at 18-24 weeks of gestation in women with a singleton gestation and no history of preterm birth can be considered by individual practitioners, this screening cannot be universally recommended. In case of preterm labor, (i) it is not possible to recommend one of the methods over another (ultrasound of the cervical length, vaginal examination, fetal fibronectin) to predict preterm birth (grade B); (ii) routine antibiotic therapy is not recommended (grade A); (iii) prolonged hospitalization (grade B) and bed rest (grade C) is not recommended. Compared with placebo, tocolytics are not associated with a reduction in neonatal mortality or morbidity (LE2) and maternal severe adverse effects may occur with all tocolytics (LE4). Atosiban and nifedipine (grade B), contrary to betamimetics (grade C), can be used for tocolysis in spontaneous preterm labour without preterm premature rupture of membranes. Maintenance tocolysis is not recomended (grade B). Antenatal corticosteroid administration is recommended to every woman at risk of preterm delivery before 34 weeks of gestation (grade A). After 34 weeks, evidences are not consistent enough to recommend systematic antenatal corticosteroid treatment (grade B), however, a course might be indicated in the clinical situations associated with the higher risk of severe respiratory distress syndrome, mainly in case of planned cesarean delivery (grade C). Repeated courses of antenatal corticosteroids are not recommended (grade A). Rescue courses are not recommended (Professional consensus). Magnesium sulfate administration is recommended to women at high risk of imminent preterm birth before 32WG (grade A). Cesarean is not recommended in case of vertex presentation (Professional consensus). Both planned vaginal or elective cesarean delivery is possible in case of breech presentation (Professional consensus). A delayed cord clamping may be considered if the neonatal or maternal state so permits (Professional consensus). CONCLUSION: Except for antenatal corticosteroid and magnesium sulfate administration, diagnostic tools or prenatal pharmacological treatments implemented since 30 years to prevent preterm birth and its consequences have not matched expectations of caregivers and families.

[The practice of neonatal umbilical blood gas analysis in the "Alsace" regional French perinatal network]. / La pratique de l'analyse des gaz du sang au cordon ombilical dans le réseau périnatal alsacien.

OBJECTIVE: The assessment of neonatal well-being is paramount in delivery rooms. For that purpose, it is recommended in France to carry out a systematic neonatal umbilical cord blood gas analysis. The aim of this study is to evaluate how umbilical cord blood gas sampling is realised, analysed and interpreted by midwives in a French regional perinatal network. MATERIALS AND METHODS: We conducted a survey focused on randomly selected midwives partitioning in different maternities that constitute the "Alsace" regional perinatal network. A questionnaire concerning the modalities of umbilical cord blood sampling, its analysis and the interpretation of results was used during interviews with included midwives. RESULTS: Fifty-one midwives were included in the study (15.8% of whom were working in delivery rooms). Only 13% of maternities constituting the perinatal network did not realise systematic neonatal umbilical cord blood analysis. Among interviewed midwives, 78.4% reported umbilical cord clamping after the first breath of the child. Among the midwives included, 86.3% of them realise sampling from the umbilical artery and 29.4% from both umbilical artery and vein. For 86.3% of interviewed midwives, the leitmotif of realising umbilical blood sampling was medico-legal. More than two third of included midwives interpret blood gas taking into account two parameters (either pH and base excess, or lactate). They settled at 7.0-7.2, the limit below which a newborn might present sequelae. DISCUSSION AND CONCLUSION: This study shows that the neonatal umbilical cord blood gas analysis at birth is almost systematic in this regional French perinatal network. It is realised primarily for medico-legal purpose. However, there are significant variations in sampling procedures and interpretation. This should lead to the establishment within each maternity of a neonatal umbilical cord blood gas sampling protocol along with a midwifery training program.

[Maternal morbidity and mortality associated with conservative management for placenta morbidly adherent (accreta) diagnosed during pregnancy. Report of 15 cases]. / Morbimortalité maternelle associée au traitement conservateur d'un placenta anormalement adhérent (accreta) diagnostiqué en anténatal. À propos d'une série continue de 15 cas.

BACKGROUND: High risk of morbidly adherent placenta increased during past years. Their management is controversial. Cesarean hysterectomy, considered the gold standard treatment by American Society, is associated with high risk of maternal morbimortality. Conservative management has been sought to reduce maternal morbidity associated with caesarean hysterectomy while maintaining fertility. It consists of leaving the placenta in place but long-term monitoring. Our main objective was to determine advantage/disadvantage of conservative management on patient with an antenatal diagnosis of placenta accreta, increta or percreta. MATERIAL AND METHODS: This retrospective study included all patients with an antenatal diagnosis of placenta accreta, increta or percreta between 2007 and 2014. Conservative treatment was systematically attempted according to our protocol. The primary outcome was defined as uterine conservation and the secondary outcome as maternal morbimortality defined as any medical or surgical condition occurring after childbirth. RESULTS: Fifteen patients (0.07 % of all living childbirths) were included. Conservative management was successful in 80 % of patients. There was no case of maternal death. Severe post-partum hemorrhage occurred in 4 patients (33.3 %) requiring uterine arteries embolization in one patient and hysterectomy in the 3 others. They underwent immediate blood transfusion of 13.5±4.5 average of red blood cell units. No severe septic condition occurred but 4 patients suffered from endometritis, 2.6±0.5 months after birth requiring intravenous antibiotics treatment in conventional hospitalization. Mean duration for spontaneous abortion of the placenta was 23.0±7.2 weeks. Three spontaneous pregnancies occurred in 2 patients after 19±16.9 months. CONCLUSION: Conservative management seems encouraging but is associated with a non-insignificant risk of secondary complication requiring long-term monitoring in conciliant patients.