bluuebunny/crossref_metadata_2025 huggingface dataset:
Imaging-Based Risk Stratification for Recurrence Risk in Women with a History of Peripartum Cardiomyopathy
Authors: Ma'ayeh Marwan , Slivnick Jeremy A. , McKiever Monique E. , Garrett Zachary D. , Lim Woobeen , Cackovic Michael , Rood Kara M. , Bradley Elisa A.
Published: December 2021

Objective Peripartum cardiomyopathy (PPCM) affects 1:1,000 U.S. pregnancies, and while many recover from the disease, the risk of recurrence in subsequent pregnancy (SSP) is high. This study aims to evaluate the utility of left ventricular ejection fraction (LVEF) and global longitudinal strain (GLS) to predict the risk of recurrence of PPCM in SSP.

Study Design We retrospectively evaluated outcomes in women with a history of PPCM and SSP at a large-volume cardioobstetrics program (2008–2019).

Results There were 18 women who had incident PPCM and pursued SSP. Of 24 pregnancies in these women, 8 (33%) were complicated by the development of recurrent PPCM. LVEF ≥ 52% or GLS ≤ −16 was associated with a low risk of recurrent PPCM.

Conclusion Approximately one-third of women with PPCM developed recurrent PPCM in SSP. LVEF and GLS on prepregnancy echocardiography may predict the risk of recurrence. Additional studies evaluating risk for recurrence are required to better understand which women are the safest to consider SSP.

Key Points
Comparing Two Testing Strategies: Universal versus Symptomatic SARS-CoV-2 Testing in Obstetric Patients
Authors: Aderibigbe Oluyemi A. , Lappen Justin R. , Albertini Megan , Gibson Kelly S.
Published: November 2021

Objective To compare universal severe acute respiratory syndrome coronvirus-2 (SARS-CoV-2) testing to symptomatic testing at two large academic centers.

Study Design We performed a retrospective cohort study comparing the approach to testing at two academic centers in Northeast Ohio. The study period started with the inception of symptomatic testing for SARS-CoV-2 at both institutions in March 2020. Women younger than 18 years were excluded. The primary outcome was the SARS-CoV-2 positivity rate in symptomatic pregnant patients at both institutions. Our coprimary outcome was the additional positivity rate obtained from universal testing at the University Hospitals. The secondary outcome of interest was the percentage of SARS-CoV-2 screen positive mothers with screen positive neonates. Data were analyzed using Mann–Whitney U test for continuous variables with chi-square and Fisher's exact tests for proportions.

Results During the study period, 144 pregnant women with symptoms of coronavirus disease 2019 (COVID-19) were tested at MetroHealth of which 27 resulted as positive for SARS-CoV-2 (18.7% positivity rate). University Hospitals tested 392 pregnant women with symptoms of COVID-19 of which 67 resulted as positive for SARS-CoV-2 (positivity rate 17.0%). In the universal testing program at University Hospitals, an additional 2,870 tests were performed on asymptomatic pregnant women of which 30 were positive for SARS-CoV-2 (1.0% positivity rate).There were no SARS-CoV-2 positive infants in our cohort, and all cases of maternal critical illness occurred in symptomatic patients.

Conclusion Universal and symptomatic testing approaches demonstrated similar clinical performance within a single geographic region in obstetric patients.

Key Points
Middle Cerebral Artery Dopplers and Abnormal Neonatal Outcomes among Pregnant Women with Zika Virus Infection
Authors: Mok Thalia , Pereira Jose Paulo , Sobhani Nasim C. , Cardozo Renan Fonseca , Valle Helena Abreu , Dutra Beatriz Ribeiro Torres , Gama Helder Dotta , Moreira Maria Elisabeth , Vasconcelos Zilton , Pone Marcos , Gaw Stephanie L.
Published: November 2021

Objective The aim of this study was to investigate the role of middle cerebral artery (MCA) Doppler measurements for the prediction of abnormal neonatal outcomes in pregnancies affected by Zika virus (ZIKV).

Methods Secondary analysis of a prospective cohort of pregnant women diagnosed with ZIKV infection from September 2015 to December 2016 at a single regional referral center. Ultrasonography with measurements of MCA peak systolic velocity (PSV), PSV multiples of the median (MoM) for gestational age, and pulsatility index (PI) were collected. The primary outcome was a composite abnormal neonatal outcome. MCA Doppler values of normal and abnormal neonatal outcomes were compared with Wilcoxon rank sum test. The predictive value of MCA Dopplers for development of abnormal neonatal outcome was calculated by logistic regression.

Results One-hundred twenty-seven ZIKV-positive pregnancies with MCA Doppler measurements and known neonatal outcomes were included. Of the 132 neonates, 66 (50%) had an abnormal neonatal outcome. Lower MCA PSV (p = 0.027) and PSV MoM (p = 0.008) were associated with abnormal neonatal outcomes. There was no significant difference in MCA PI. Abnormal neonatal outcomes had lower MCA PSV by 5.36 cm/s (95% confidence interval [CI]: 0.95–9.77, p = 0.018) and lower MCA PSV MoM by 0.13 (95% CI: 0.05–0.22, p = 0.002). MCA PSV of 30 cm/s had a 65% predicted probability of an abnormal neonatal outcome (95% CI: 51–79%).

Conclusion In ZIKV-infected pregnancies, lower MCA PSV and PSV MoM measurements were seen with abnormal neonatal outcomes. This may represent a physiologic response to fetal ZIKV infection. Evaluation of MCA Dopplers may be of clinical utility in the surveillance of ZIKV-affected pregnancies.

Key Points
Value of HbA1c in Obese Women with Gestational Diabetes
Authors: Oben Ayamo , Jauk Victoria , Battarbee Ashley , Longo Sherri , Szychowski Jeff , Tita Alan , Harper Lorie
Published: November 2021

Objective We sought to assess the association of hemoglobin A1c (HbA1c) with adverse perinatal outcomes in obese women with gestational diabetes mellitus (GDM).

Study Design This was a secondary analysis of a multicenter randomized controlled trial assessing early (14–20 weeks) versus routine (24–28 weeks) screening for GDM in obese women. Women were included if they were diagnosed with GDM at either time during pregnancy and had a HbA1c result available. The primary exposure was HbA1c at 24 to 28 weeks. The primary outcome was a composite of macrosomia, primary cesarean, pregnancy-induced hypertension, shoulder dystocia, neonatal hypoglycemia, or hyperbilirubinemia. Receiver operating characteristics (ROC) curves were used to assess the association of HbA1c with the composite outcome. The Liu method was used to select an optimal HbA1c cutoff, and the incidence of the outcome compared.

Results Of 125 women with GDM, 93 (74%) had a HbA1c at 24 to 28 weeks and 103 (82.4%) had a HbA1c at 14 to 20 weeks. Baseline characteristics were balanced between groups above and below the cutoff. The area under the ROC curve for HbA1c and its association with the adverse perinatal composite outcome was 0.6 (95% confidence interval [CI]: 0.5–0.7). The frequency of the primary outcome was similar among women with low and high HbA1c at 24 to 28 weeks (adjusted relative risk, 1.12, 95% CI: 0.97–1.29). Compared with women with a decreasing HbA1c during pregnancy, women with a stable or increasing HbA1c did not have a significant increase in the primary adverse perinatal composite outcome. However, the frequency of preterm delivery was higher among women with stable or increasing HbA1c compared with those with a decreasing HbA1c (26.1 vs. 6.7%, p = 0.03).

Conclusion A single HbA1c in women with GDM is not associated with a composite perinatal adverse outcome, but a HbA1c that increases or remains stable between 14 to 20 and 24 to 28 weeks is associated with an increase in preterm delivery.

Key Points
Do Genetic Variants Modify the Effect of Smoking on Risk of Preeclampsia in Pregnancy?
Authors: Bauer Anna E. , Avery Christy L. , Shi Min , Weinberg Clarice R. , Olshan Andrew F. , Harmon Quaker E. , Luo Jingchun , Yang Jenny , Manuck Tracy , Wu Michael C. , Klungsøyr Kari , Trogstad Lill , Magnus Per , Engel Stephanie M.
Published: November 2021

Objective Maternal smoking is associated with as much as a 50% reduced risk of preeclampsia, despite increasing risk of other poor pregnancy outcomes that often co-occur with preeclampsia, such as preterm birth and fetal growth restriction. Researchers have long sought to understand whether this perplexing association is biologically based, or a result of noncausal mechanisms. We examined whether smoking-response genes modify the smoking-preeclampsia association to investigate potential biological explanations.

Study Design We conducted a nested case–control study within the Norwegian Mother, Father and Child Birth Cohort (1999–2008) of 2,596 mother–child dyads. We used family-based log-linear Poisson regression to examine modification of the maternal smoking-preeclampsia relationship by maternal and fetal single nucleotide polymorphisms involved in cellular processes related to components of cigarette smoke (n = 1,915 with minor allele frequency ≥10%). We further investigated the influence of smoking cessation during pregnancy.

Results Three polymorphisms showed overall (p < 0.001) multiplicative interaction between smoking and maternal genotype. For rs3765692 (TP73) and rs10770343 (PIK3C2G), protection associated with smoking was reduced with two maternal copies of the risk allele and was stronger in continuers than quitters (interaction p = 0.02 for both loci, based on testing 3-level smoking by 3-level genotype). For rs2278361 (APAF1) the inverse smoking-preeclampsia association was eliminated by the presence of a single risk allele, and again the trend was stronger in continuers than in quitters (interaction p = 0.01).

Conclusion Evidence for gene–smoking interaction was limited, but differences by smoking cessation warrant further investigation. We demonstrate the potential utility of expanded dyad methods and gene–environment interaction analyses for outcomes with complex relationships between maternal and fetal genotypes and exposures.

Key Points
Lower Vitamin D Level as a Risk Factor for Late Onset Neonatal Sepsis: An Observational Case–Control Study
Authors: Abdelmaksoud Shaimaa Reda , Mostafa Mostafa Abdel-Azim , Khashaba Rana Atef , Assar Effat
Published: November 2021

Objective The aim of the study is to investigate the relation of neonatal and maternal vitamin D and late-onset sepsis (LOS).

Study Design One-hundred twenty term neonates along with their mothers were enrolled in this case–control study. Sixty neonates who were admitted in the neonatal intensive care unit by LOS and had not been previously admitted for last 48 hours and did not receive antibiotics or vitamin D were enrolled as cases (sepsis) group. On the other hand, 60 healthy term neonates were referred as control group. Maternal and neonatal serum 25-OH vitamin D levels were assessed in both the cohorts.

Results Maternal and neonatal 25-OH vitamin D levels in cases (17.2 and 16.1 ng/mL, respectively) were significantly lower than in controls (22.7 and 21 ng/mL, respectively) p = 0.001. In the study group, the neonatal 25-OH vitamin D was negatively correlated with C-reactive protein and length of hospital stay (r = −0.616 and −0.596, respectively) p <0.001 for both. With a cut-off value of 12.9 ng/mL, the specificity and positive predictive value of neonatal vitamin D were 83.3 and 74.4%, respectively. The odds ratio was 1.088 (95% CI = 1.034–1.144)) for LOS in vitamin D-deficient neonates.

Conclusion Neonates with higher vitamin D level are at lower risk of LOS than those with vitamin D deficiency. Maternal vitamin D correlates with neonatal vitamin D. These data suggest that maternal vitamin supplementation during pregnancy may lower the risk of LOS.

Key Points
Breastfeeding Intention, Knowledge, and Attitude of Pregnant Women in Treatment for Opioid Use Disorder
Authors: Short Vanessa L. , Abatemarco Diane J. , Gannon Meghan
Published: November 2021

Objective The objective of this study was to describe breastfeeding intention, knowledge, and attitude, and sources of infant feeding information during the prenatal period among a cohort of pregnant women in treatment for opioid use disorder (OUD).

Study Design Pregnant women who were receiving treatment for OUD and in the third trimester completed a questionnaire that measured demographic characteristics, infant feeding intentions, breastfeeding beliefs and attitudes, and sources of breastfeeding information. Frequency counts and percentages and means and standard deviations were used to describe data.

Results Sixty-five women completed the survey. Three-fourths reported some intention to breastfeeding. While attitudes around breastfeeding were generally positive, less than half of respondents knew the recommendations and infant health benefits of breastfeeding.

Conclusion Prenatal programs for women in treatment for OUD should consider addressing patient-reported concerns and gaps in knowledge regarding the benefits of and recommendation for breastfeeding.

Key Points
Understanding Food Security as a Social Determinant of Diabetes-Related Health during Pregnancy
Authors: Gomez Helen , DiTosto Julia D. , Niznik Charlotte M. , Yee Lynn M.
Published: November 2021

Gestational and pregestational diabetes during pregnancy are substantial and growing public health issues. Low-income individuals and individuals who identify as racial and ethnic minorities are disproportionately affected. Food security, which is defined as the degree to which individuals have capacity to access and obtain food, is at the center of nutritional resources and decisions for individuals with diabetes. While increasingly recognized as an important mediator of health disparities in the United States, food insecurity is understudied during pregnancy and specifically among pregnant individuals with diabetes, for whom the impact of food-related resources may be even greater. Previous research has suggested that food insecurity is associated with type 2 diabetes mellitus diagnoses and disease exacerbation in the general adult population. An emerging body of research has suggested that food insecurity during pregnancy is associated with gestational diabetes mellitus diagnoses and adverse diabetes-related outcomes. Additionally, food insecurity during pregnancy may be associated with adverse maternal and neonatal outcomes. Future research and clinical work should aim to further examine these relationships and subsequently develop evidence-based interventions to improve diabetes-related outcomes among pregnant individuals with food insecurity. The purpose of this article is to offer a working definition of food security, briefly review issues of food insecurity and diabetes, summarize research on food insecurity and diabetes-related pregnancy health, and discuss clinical recommendations and areas for future investigation.

Key Points
Urinary N-terminal Pro-Brain Natriuretic Peptide in Newborn Infants with Cardiac and Pulmonary Diseases
Authors: Elgendy Marwa M. , Elzayat Rania Salah , Abdo Mostafa , Elsharkawy Hamed M. , Allam Maha , Midan Dina Abdelrazek
Published: December 2021

Objectives The aim of this study was to assess the feasibility of urinary N-terminal pro-brain natriuretic peptide (NT-proBNP) as noninvasive screening tool for congenital heart diseases in full-term neonates with respiratory distress.

Study Design A prospective cohort study was conducted on 90 full-term infants. Newborn were assigned into three groups: pulmonary, cardiac, and control groups. Urinary NT-proBNP were measured in all studied groups at day 1 (NT-proBNP1) and day 5 (NT-proBNP5).

Results Urinary NT-proBNP1 was higher in cardiac group compared with pulmonary and control groups (488 ± 91, 321 ± 80, and 218 ± 41 ng/L, respectively; p ≤ 0.001). NT-proBNP5 was lower in pulmonary and control group than cardiac group (245 ± 84, 137 ± 39, and 546 ± 284 ng/L, respectively, with p ≤ 0.001). Receiver operating characteristic (ROC) analysis was performed to assess predictive value of NT-proBNP1 in cardiac and pulmonary populations. ROC showed area under curve of 0.97 and cutoff point of ≥386.5 ng/L referring to a cardiac etiology with sensitivity of 93.3%, specificity of 86.7%, negative predictive value of 93%, and positive predictive value of 88%.

Conclusion Urinary NT-proBNP is feasible to be a noninvasive screening tool to predict congenital heart diseases in full-term neonates. Further studies are needed to assess the correlation between plasma and urinary levels of NT-proBNP in congenital heart diseases in full-term and preterm infants.
Non-uniform dependence on initial data for the 2D MHD-Boussinesq equations
Authors: Yu Yanghai , Yang Xiaolei
Published: December 2021

In this paper, we will give the first result concerning the non-uniform dependence on initial data for the 2D magnetohydrodynamics (MHD)-Boussinesq equations as a hyperbolic-parabolic system. More precisely, we prove that the data-to-solution map of the Cauchy problem to the 2D MHD-Boussinesq equations is not uniformly continuous in Hs with s > 2.
Suppression of Leidenfrost effect on superhydrophobic surfaces
Authors: Shi Meng , Das Ratul , Arunachalam Sankara , Mishra Himanshu
Published: December 2021

The Leidenfrost phenomenon entails the levitation of a liquid droplet over a superheated surface, cushioned by its vapor layer. This vapor layer can obstruct boiling heat transfer in heat exchangers, thereby compromising energy efficiency and safety. For water, superhydrophobic surfaces are believed to reduce the Leidenfrost point (TL)—the temperature at which this phenomenon occurs. Therefore, superhydrophobic surfaces are not commonly utilized in thermal machinery despite their benefits such as reducing frictional drag. Here, we demonstrate that it is possible to achieve superhydrophobicity without lowering TL by surface engineering and fine-tuning liquid–solid adhesion. We demonstrate that TL of water on superhydrophobic surfaces comprising doubly reentrant pillars (DRPs) can exceed that on hydrophilic and even superhydrophilic surfaces. Via theory and computation, we disentangle the contributions of microtexture, heat transfer, and surface chemistry on the onset of the Leidenfrost phenomenon. Remarkably, coating-free and superhydrophobic DRP architecture can facilitate ∼300% greater heat transfer to water droplets at 200 °C in comparison with conventional superhydrophobic surfaces. These findings advance our understanding of the Leidenfrost phenomenon and herald technological applications of superhydrophobic surfaces in thermal machinery.
Structural and high-field magnetic properties of Laves phase RFe2-H hydrides
Authors: Tereshina I. S. , Karpenkov A. Yu. , Gorbunov D. I. , Doerr M. , Tereshina-Chitrova E. A. , Drulis H.
Published: December 2021

The crystal structure and magnetic properties of the multicomponent compounds (Tb1−xYx)0.8Sm0.2Fe2Hz (x = 0, 0.2, 0.4, 0.6, 0.8, 1; z = 0 and 3.7) are investigated. The compounds crystallize in the MgCu2 type of structure. While the parent compounds Tb0.8Sm0.2Fe2 and Y0.8Sm0.2Fe2 are single phase, we detect 5%–8% of a second phase with a crystal structure of the PuNi3 type (space group R3m) in the alloys with 0.2 ≤ x < 0.8. Hydrogen absorption does not change the space group of the (Tb,Y,Sm)Fe2 compounds but boosts significantly the lattice parameter a. A large volume change of ΔV/V ∼ 28% upon hydrogen absorption is observed. By applying high magnetic fields up to 58 T, we observed rotations of the magnetic sublattices and hence we were able to determine the critical transition fields, H, from the ferrimagnetic to the ferromagnetic state and the inter-sublattice exchange parameter λ. The magnetic compensation occurs at x ≈ 0.6 and 0.2 in (Tb1−xYx)0.8Sm0.2Fe2Hz at z = 0 and 3.7, respectively. While maintaining the collinear magnetic structure, the phenomenon of compensation in hydrides should be observed at x ≈ 0.4.
Ising density functional theory for weak polyelectrolytes with strong coupling of ionization and intrachain correlations
Authors: Gallegos Alejandro , Ong Gary M. C. , Wu Jianzhong
Published: December 2021

We report a theoretical framework for weak polyelectrolytes by combining the polymer density functional theory with the Ising model for charge regulation. The so-called Ising density functional theory provides an accurate description of the effects of polymer conformation on the ionization of individual segments and is able to account for both the intra- and interchain correlations due to the excluded-volume effects, chain connectivity, and electrostatic interactions. Theoretical predictions of the titration behavior and microscopic structure of ionizable polymers are found to be in excellent agreement with the experiment.
Transcritical transition of the fluid around the interface
Authors: Xu Bonan , Zhu Yanqi , Jin Hanhui , Guo Yu , Fan Jianren
Published: December 2021

In this paper, fundamental insights into the dynamic transcritical transition process were provided using molecular dynamics simulations. A transcritical region, which covers three different fluid states, was discovered as a substitute for the traditional interface. The physical properties, such as temperature and density, exhibited a highly nonlinear distribution in the transcritical region. Meanwhile, the surface tension was found to exist throughout the transcritical region, and the magnitude was directly proportional to −ρ∇2ρ.
Effects of magnetic field on the secondary electron asymmetry effect in capacitively coupled plasmas
Authors: Yang Shali , Zhang Tianxiang , Lin Hanlei , Wu Hao , Zhang Qiang
Published: December 2021

The secondary electron asymmetry effect (SEAE) provides the opportunity to generate the dc self-bias voltage and asymmetric plasma response, where secondary electron emission coefficients at both electrodes are unequal. In this work, we use one-dimensional implicit particle-in-cell/Monte Carlo collision simulation to investigate the effects of the homogeneous and inhomogeneous magnetic field on the SEAE. The magnetic field is applied parallel to electrodes, and the discharge is operated in a geometrically and electrically symmetric capacitively coupled argon plasma. By comparing the simulation results of the effects of the homogeneous and inhomogeneous magnetic field on the SEAE, the homogeneous magnetic field can increase the dc self-bias voltage to a certain extent and has little effect on the plasma density distribution. The inhomogeneous magnetic field is more advantageous in generating the dc self-bias but at the cost of uneven plasma density distribution. In addition, by comparing the results of inhomogeneous magnetic fields with opposite gradients, we found that the value of the self-bias voltage can be changed by adjusting the magnetic field gradient. Aside from that the roles of two electrodes can be easily reversed by changing the slopes of the magnetic field gradient. The results suggest that such a configuration could be desired in the microelectronics industry, since the controllable self-bias voltage is needed for deposition and etching processes.
Reaction microscope for investigating ionization dynamics of weakly bound alkali dimers
Authors: Kurz N. , Fischer D. , Pfeifer T. , Dorn A.
Published: December 2021

We report on the implementation of a far-off-resonant, optical dipole force trap in a reaction microscope combined with a magneto-optical trap. Kinematically complete multi-photon ionization experiments were performed on optically trapped 6Li atoms and photo-associated 6Li2 molecules in their highest vibrational state. The apparatus allows us to distinguish different ionization mechanisms related to the presence of the IR field of the optical dipole trap that can occur during ionization of 6Li and 6Li2 in strong fields. In a series of proof-of-principle experiments, we detect weakly bound dimers via three-photon ionization with femtosecond pulses (τ = 30 fs) at a central wavelength of 780 nm and measure directly the momenta of the photoelectrons in coincidence with recoil ions.
Object detection with an alkali-metal spin maser
Authors: Bevington P. , Gartman R. , Chalupczak W.
Published: December 2021

We present magnetic induction tomography measurements performed with a radio-frequency atomic magnetometer operating in the spin maser mode. We discuss different regimes of spin maser operation that are defined by the gain within the system’s feedback, i.e., below threshold, unsaturated, and saturated gain. Two configurations are explored: first, where an rf field continuously drives the spin maser operation and the object’s presence changes the gain in the system’s feedback loop, and the second, where the spin maser operation is triggered and sustained directly by the object response. The advantages and disadvantages of each configuration are discussed in the context of object detection.
Onset of submerged granular collapse in densely packed condition
Authors: Lee Cheng-Hsien , Kuan Yi-Hsuan
Published: December 2021

Granular materials are widespread in nature, and understanding their transport is important in geophysics. This study investigated the initiation of submerged granular collapse and collapse types, which affect transport processes. Laboratory experiments and failure analysis were performed; four particles and five liquids were experimentally examined. The experimental results reveal that the failure angle increases with decreasing particle size and increasing liquid viscosity. As the failure angle approaches π/2, the breaching collapse dominates; otherwise, sliding collapse occurs. Furthermore, the failure analysis indicated that the failure angle depends on the dimensionless parameter Darcy number; this was validated experimentally. The critical value of the Darcy number to distinguish between breaching and sliding collapse was devised on the basis of the experimental results.
Electrohydrodynamic behavior of polyelectrolyte vesicle accompanied with ions in solution through a narrow pore induced by electric field
Authors: Zhang Ruilin , Ding Mingming , Duan Xiaozheng , Shi Tongfei
Published: December 2021

We use finite element numerical simulations to study the electrohydrodynamic behavior of a polyelectrolyte vesicle passing through a narrow pore in an electrically neutral system. We systematically explain the deformation and migration of the vesicle, including the motion of ions in the solution, the strain energy and stress distribution of the vesicle under electric drive, and the minimum potential difference (critical potential difference) that allows the vesicle to pass through the narrow pore. The migration of the vesicle into the pore drives ion motion, causing rapid changes in the ion flux and potential difference in the pore, which may provide an important means to determine whether the vesicle passes through the pore. In addition, the changes in ion concentration and potential difference in the pore will not disappear when the radius of the vesicle is smaller than the pore diameter. We also find that the critical potential difference is independent of the pore diameter, but it does depend strongly on the vesicle's radius. When the vesicle's radius becomes larger than the pore diameter, the critical potential difference increases by an order of magnitude, which provides an effective method for separation of vesicles.
Effect of chemical substituents attached to the zwitterion cation on dielectric constant
Authors: Mei Wenwen , Han Aijie , Hickey Robert J. , Colby Ralph H.
Published: December 2021

Materials with high dielectric constant, εs, are desirable in a wide range of applications including energy storage and actuators. Recently, zwitterionic liquids have been reported to have the largest εs of any liquid and, thus, have the potential to replace inorganic fillers to modulate the material εs. Although the large εs for zwitterionic liquids is attributed to their large molecular dipole, the role of chemical substituents attached to the zwitterion cation on εs is not fully understood, which is necessary to enhance the performance of soft energy materials. Here, we report the impact of zwitterionic liquid cation chemical substituents on εs (50 < εs < 300 at room temperature). Dielectric relaxation spectroscopy reveals that molecular reorientation is the main contributor to the high εs. The low Kirkwood factor g calculated for zwitterionic liquids (e.g., 0.1–0.2) suggests the tendency for the antiparallel zwitterion dipole alignment expected from the strong electrostatic intermolecular interactions. With octyl cation substituents, the g is decreased due to the formation of hydrophobic-rich domains that restrict molecular reorientation under applied electric fields. In contrast, when zwitterion cations are functionalized with ethylene oxide (EO) segments, g increases due to the EO segments interacting with the cations, allowing more zwitterion rotation in response to the applied field. The reported results suggest that high εs zwitterionic liquids require a large molecular dipole, compositionally homogeneous liquids (e.g., no aggregation), a maximized zwitterion number density, and a high g, which is achievable by incorporating polar chemical substituents onto the zwitterion cations.
Charge collection and trapping mechanisms in hexagonal boron nitride epilayers
Authors: Almohammad M. , Li J. , Lin J. Y. , Jiang H. X.
Published: December 2021

Understanding charge collection and trapping mechanisms is crucial for using hexagonal boron nitride (h-BN) as active layers for many photonic and electronic devices such as deep UV detectors and emitters, neutron detectors, and single photon emitters. Charge collection and trapping mechanisms in h-BN epilayers have been investigated by probing impurity related optical emissions under an applied electrical field. Our results suggested that the existence of oxygen impurities affects the charge collection efficiency and results in an additional emission peak at 3.75 eV, corresponding to a donor-acceptor pair (DAP) recombination involving ON (oxygen residing on the nitrogen site) donors and the VB-H (boron vacancy bonded with hydrogen complex) deep level acceptors. Experimental results further revealed that the applied electric field induces an anti-correlation between the emission intensity of the DAP transition and the charge collection efficiency from which it was shown that it is possible to find an expression to quantitatively measure the maximum charge collection efficiency in h-BN. The results introduce not only a coherent picture for the relationship between common impurities in h-BN and charge collection and trapping mechanisms but also useful insights into possible approaches to improve the quality, purity, and charge collection of the h-BN epilayers.
Violation of Hund’s rule in molecules: Predicting the excited-state energy inversion by TD-DFT with double-hybrid methods
Authors: Sancho-García J. C. , Brémond E. , Ricci G. , Pérez-Jiménez A. J. , Olivier Y. , Adamo C.
Published: December 2021

The energy difference (ΔEST) between the lowest singlet (S1) state and the triplet (T1) excited state of a set of azaphenalene compounds, which is theoretically and experimentally known to violate Hund’s rule, giving rise to the inversion of the order of those states, is calculated here with a family of double-hybrid density functionals. That excited-state inversion is known to be very challenging to reproduce for time-dependent density functional theory employing common functionals, e.g., hybrid or range-separated expressions, but not for wavefunction methods due to the inclusion of higher-than-single excitations. Therefore, we explore here if the last developed family of density functional expressions (i.e., double-hybrid models) is able to provide not only the right excited-state energy order but also accurate ΔEST values, thanks to the approximate inclusion of double excitations within these models. We herein employ standard double-hybrid (B2-PLYP, PBE-QIDH, and PBE0-2), range-separated (ωB2-PLYP and RSX-QIDH), spin-scaled (SCS/SOS-B2PLYP21, SCS-PBE-QIDH, and SOS-PBE-QIDH), and range-separated spin-scaled (SCS/SOS-ωB2-PLYP, SCS-RSX-QIDH, and SOS-RSX-QIDH) expressions to systematically assess the influence of the ingredients entering into the formulation while concomitantly providing insights for their accuracy.
A tight-binding study of the electron transport through single-walled carbon nanotube–graphene hybrid nanostructures
Authors: Srivastava Juhi , Gaur Anshu
Published: December 2021

Hybrid carbon nanostructures based on the sp2 hybridized allotropes of carbon, such as graphene and single-walled carbon nanotubes (SWCNTs), hold vast potential for applications in electronics of various forms. Electronic properties of such hybrid structures are modified due to the interaction between atoms of the components, which can be utilized to tailor the properties of the hybrid structures to suite the application. In this study, we have explored charge (electron) transport through the hybrid structures of single-layer graphene (SLG) and SWCNTs (both metallic and semiconducting) using the nonequilibrium Green’s function formalism within the framework of tight-binding density functional theory. Our calculations show that the electronic transport in hybrid nanostructures is affected by the interactions between SWCNT and SLG in comparison to the individual components. The changes in the electronic structure and the transport properties with increasing interaction in hybrids (captured by decreasing the separation between SWCNT and SLG) are discussed, and it is demonstrated from this analysis that the hybrids with semiconducting SWCNTs and metallic SWCNTs show different behavior in the low bias regime while they show similar behavior at higher biases. The difference in the transport properties of hybrids with semiconducting and metallic SWCNTs is explained in terms of changes in the electronic structure, the local density of states, and the energy dispersion for electrons due to the interaction between atoms of the two components.
Qualitative and quantitative analyses of the plasmodesmata that accompany cell fate changes during the somatic embryogenesis of
Authors: Godel-Jędrychowska Kamila , Kurczyńska Ewa
Published: November 2021

Plasmodesmata (PD) are cytoplasmic and membrane-lined microchannels that enable symplasmic communication in plants, which is involved in the regulation of cell differentiation. The presented results emphasise the qualitative and quantitative analyses of PD, which are the basis of the symplasmic communication. The cells that initiate various development programmes create symplasmic domains that are characterised by different degrees of symplasmic communication. Changes in symplasmic communication are caused by the presence or absence of PD and/or the ability of signals to move through them. In the presented studies, somatic embryogenesis was used to describe the characteristics of the PD within and between the symplasmic domains in explants of the Arabidopsis thaliana (L.) Heynh ecotype Columbia-0 and 35S:BBM transgenic line. Transmission electron microscopy was used to describe the cells that regain totipotency/pluripotency during somatic embryogenesis, as well as the number and shape of the PD in the different symplasmic domains of the explants and somatic embryos. Array tomography was used to create a 3D reconstruction of the protodermal cells of the somatic embryos with particular emphasis on the PD distribution in the cell walls. The results showed that there were different frequencies of the PD within and between the symplasmic domain that emerges during somatic embryogenesis and between the Col-0 and 35S:BBM somatic embryos with regard to the differences in the shape of the PD.
Effects of farming systems, tillage, and traffic practices on deep drainage and soil salt loads in the Queensland Murray–Darling and Fitzroy Basins using soil chloride
Authors: Silburn D. M. , Tolmie P. E. , Biggs A. J. W. , Crawford M. H.
Published: November 2021

Context Cropping in the Queensland Murray–Darling and Fitzroy Basins has precursors for secondary salinity – high soil salt loads and increased drainage after clearing. Aims To measure changes in deep drainage, for key tillage, traffic, and cropping systems. Methods Steady-state and transient chloride (Cl) mass-balance were applied to Cl profiles from four tillage and crop rotation trials and one controlled traffic trial in southern and central Queensland, to determine deep drainage below the root zone. Key results Large downward movement of Cl occurred after clearing. Deep drainage from transient Cl balance for cropping was a small proportion of rainfall but considerably higher than under native vegetation. Deep drainage was consistently greater under zero than conventional tillage, for both winter and summer cropping. For example, deep drainage was greatest for zero tillage (∼45 mm/year) and least for conventional, stubble mulch, and reduced tillage (2–6.3 mm/year) at the highest-rainfall site (677 mm/year). Deep drainage was 12.7 and 7.9 mm/year for zero and conventional tillage, respectively, at the lowest-rainfall site (497 mm/year). Drainage under continuous wheat conventional tillage was more than twice that where some summer crops were included. At Billa Billa, continuous wheat had greater deep drainage by three to five times than continuous sorghum for three of four tillage systems. No drainage was detected during 6 years of opportunity cropping. A pasture legume ley had only 1.7 mm/year of deep drainage. Deep drainage was less for compacted than non-compacted treatments (23.3 vs 38.2 mm/year). Conclusion and implications Increased deep drainage with zero tillage and controlled traffic can be reduced using summer crops, particularly opportunity cropping where crops are planted when soil water is sufficient, and ley pastures.
Partial synthetic models of FeMoco with sulfide and carbyne ligands: Effect of interstitial atom in nitrogenase active site
Authors: Le Linh N. V. , Bailey Gwendolyn A. , Scott Anna G. , Agapie Theodor
Published: December 2021

Significance

Nitrogen, a common component of biomolecules, is sourced from abundant dinitrogen in the atmosphere through conversion to ammonia. Organisms capable of fixing N2employ nitrogenases, metalloproteins that display metal-sulfide clusters that facilitate electron transfers and substrate activation. The site of N2conversion to NH3is FeMco (M = Mo, Fe, or V), a cluster of notable complexity in bioinorganic chemistry, which displays an unusual interstitial carbon ligand. The function of this bridging ligand remains unclear, and systematic structure-function studies with bridging C-donors are challenged by a lack of synthetic methods for analogous clusters. Herein, we report the first synthetic cluster that models a cubane moiety of FeMco bearing a chelating carbyne ligand and related structure-property studies.
High performance simulations of a single X-pinch
Authors: Skoulakis A , Koundourakis G , Ciardi A , Kaselouris E , Fitilis I , Chatzakis J , Bakarezos M , Vlahakis N , Papadogiannis N A , Tatarakis M , Dimitriou V
Published: November 2021

The dynamics of plasmas produced by low current X-pinch devices are explored. This comprehensive computational study is the first step in the preparation of an experimental campaign aiming to understand the formation of plasma jets in table-top pulsed power X-pinch devices. Two state-of-the-art magneto-hydro-dynamic codes, GORGON and PLUTO, are used to simulate the evolution of the plasma and describe its key dynamic features. GORGON and PLUTO are built on different approximation schemes and the simulation results obtained are discussed and analyzed in relation to the physics adopted by each code. Both codes manage to accurately handle the numerical demands of the X-pinch plasma evolution and provide precise details on the mechanisms of the plasma expansion, the jet-formation, and the pinch generation. Furthermore, the influence of electrical resistivity, radiation transport and optically thin losses on the dynamic behaviour of the simulated X-pinch produced plasma is studied in PLUTO. Our findings highlight the capabilities of the GORGON and PLUTO codes in simulating the wide range of plasma conditions found in X-pinch experiments, enabling a direct comparison to the scheduled experiments.
Stimulated Brillouin scattering enhanced by the stimulated Raman process near the quarter-critical density
Authors: Liu Z J , Wang Q , Li B , Li J W , Cao L H , Zheng C Y , He X T
Published: November 2021

Stimulated Raman scattering can occur near the quarter critical density in direct-drive fusions, and the frequency of Raman-scattered light is about half of the incident light frequency. The second harmonic of the Raman-scattered light can be produced due to the inhomogeneity density profile. It can serve as the seed of stimulated Brillouin scattering (SBS). When the second harmonic of stimulated Raman-scattered light propagates against the incident light, some components will match the frequency of backward SBS, and SBS is induced. Thus, SBS could be greatly enhanced.
(Anti-)(hyper-)nuclei production in Pb–Pb collisions with ALICE at the Large Hadron Collider
Authors: Trogolo Stefano
Published: November 2021

In ultra-relativistic heavy-ion collisions a great variety of (anti-)(hyper-)nuclei are produced, namely deuteron, triton, 3He, 4He, hypertriton (

Λ
3

H

) and their antiparticles. The ALICE experiment is the most suited to investigate the production of (hyper-)nuclei at the LHC, thanks to an excellent particle identification and low-material budget detectors. Recent results on (hyper-)nuclei production as a function of transverse momentum (pT) and charged particle multiplicity (dN
ch/d
η
) in Pb–Pb collisions are presented. The evolution of the production yields with the system size is also shown, via comparison to the results obtained in small collision systems, like pp and p–Pb. The results on the production of (hyper-)nuclei are also compared with the predictions based on a naive coalescence approach and the statistical hadronization models.

Furthermore, the latest and currently most precise measurement of the hypertriton lifetime is presented. It is compared with results obtained by different experimental techniques and with theoretical predictions.
Search for eV Neutrino Sterile: Status of STEREO Experiment
Authors: Atmani Ilham El
Published: November 2021

Reactor neutrinos have played a key role in understanding neutrino physics since their discovery. The so-called reactor-anti-neutrino-anomaly RAA, a ∼6.5% deficit of the mean observed neutrino flux compared to the prediction appeared recently. This anomaly could be interpreted by the existence of a fourth, sterile, neutrino and this hypothesis is currently being tested by the very short baseline experiment STEREO. The latter is installed at very short distance (9-11m) from the compact core of the ILL research reactor in Grenoble-France and collecting data since November 2016. The ILL core is highly enriched in 235U and releases a nominal thermal power of 58.3 MW. The geometry of the STEREO detector, segmented into six identical cells filled with Gd-loaded liquid scintillator, is designed for a direct test of a new oscillation pattern in the L/E range around 1 m/MeV, relevant for the RAA. First published results of STEREO have demonstrated the mitigation of the background induced by the reactor and the cosmic-rays and a good energy response. The data taking is now in progress with very stable conditions favorable for an improved accuracy. We will present an overview of the experiment and an update of the sterile neutrino analysis. A refined prediction of the neutrino spectrum emitted by the ILL reactor is also presented.
Search for neutrinoless double-beta decays in Ge-76 in the LEGEND experiment
Authors: Salamida Francesco
Published: November 2021

The search for neutrinoless double-beta decay is the most sensitive technique to establish the Majorana nature of neutrinos. Two operating experiments that look for such decays in Ge-76, GERDA and MAJORANA DEMONSTRATOR have achieved the lowest backgrounds and the best energy resolution in the signal region. These are two of the most important detector characteristics for sensitive searches of this undiscovered decay. The Large Enriched Germanium Experiment for Neutrinoless Double-Beta Decay (LEGEND) Collaboration has been formed to pursue a tonne-scale Ge-76 experiment that integrates the best technologies from these two experiments and others in the field. The Collaboration is developing a phased experimental program that uses existing resources as appropriate to expedite physics results, with the ultimate discovery potential at a decay half-life beyond 1028 years.
Addressing the two-step scenario of high-energy ion collisions with 136Xe + p and 136Xe +12 C at 1 A.GeV in inverse kinematics, at the SPALADiN setup of GSI
Authors: Ducret Jean-Eric
Published: November 2021

We have measured at GSI-Darmstadt (Germany) the reactions 136
Xe + p and 136
Xe +12
C, using the inverse-kinematics technique at 1 A.GeV and the large acceptance SPALADiN setup. The combination of both provides a very good coverage of the phase-space of the excited system decay channels, allowing the study of the relative importance of those decay channels, as well as a very efficient filter to reject from the detection the particles and nuclear fragments of high energy in the projectile centre-of-mass frame, essentially produced in the first-instant nucleon-nucleon collisions, prior to the decay of the excited nuclear system. Our analysis in the two-step scenario permits one to estimate on an event basis E*/A, the excitation energy per nucleon of the decaying nuclear system, and to study the E*/A dependence of the different decay channels. The E*/A range of overlap of the 136
Xe + p and 136Xe+12
C reactions is large and allows for an extensive comparison between both reactions, and therefore provides a strong test bench of the entrance-channel-independence hypothesis of the excited-system decay. We address the two-step-scenario assumption in the light of our data and their comparison with different up-to-date models.
The concept of building training systems for training operators of liquefied hydrocarbon warehouses
Authors: Krivov M V , Kolmogorov A G , Kobozev V Y , Blagodarnyi N S , Sitosanova O V
Published: November 2021

The article deals with the concept of building computer training complexes as one of the effective aids for ensuring the safety of potentially dangerous technological processes which include the storage and transportation of liquefied hydrocarbon gases. The authors have developed and described simulator model of one of the key technological devices for the storage of liquefied hydrocarbons which underlies the proposed software platform for the synthesis of training simulator systems.
Evaluation and formation model of Cambrian high-quality source rocks in the southeast margin of North China Plate
Authors: Qin Shengfei , Wang Tongshan , Tao Shizhen
Published: November 2021

In response to the question of whether effective Cambrian source rocks are developed in the North China Plate, field investigations on the southern margin of North China have been carried out. High-quality marine argillaceous source rocks of continuous thickness of 35 m in the Lower Cambrian were discovered in the south-eastern margin of North China Plate. Phosphorus nodules are common in the source rocks. The TOC is 1.19%∼29.70%, with the average of 7.31%. The organic matter comes from low-level biological algae. Because the carbon isotope of kerogen is relatively more negative, it is judged to be mainly benthic algae. The converted vitrinite reflectance (Ro) from measured bitumen reflectance is 2.24%∼3.45%, which is an over-mature source rock. The Lower Cambrian source rocks in the southern margin of North China occurred under the background of rising sea levels. After the glaciers on the southern margin of the North China Plate melted, the Qinling rift trough developed and the stratum subsidence caused rapid transgression of seawater from southeast to northwest. At this time, algae multiply in large numbers, and after death they accumulate with phosphorus-containing materials to form phosphorus-containing organic matter. Benthic algae mainly live in deep-water shelf not affected by waves and tides. Therefore, the development of source rocks is mainly in the deep water shelf.