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Abstract In rare earth nickelates (RENiO3), electron-lattice coupling drives a concurrent metal-to-insulator and bond disproportionation phase transition whose microscopic origin has long been the subject of active debate. Of several proposed mechanisms, here we test the hypothesis that pairs of self-doped ligand holes spatially condense to provide local spin moments that are antiferromagnetically coupled to Ni spins. These singlet-like states provide a basis for long-range bond and spiral spin order. Using magnetic resonant X-ray scattering on NdNiO3 thin films, we observe the chiral nature of the spin-disproportionated state, with spin spirals propagating along the crystallographic (101)ortho direction. These spin spirals are found to preferentially couple to X-ray helicity, establishing the presence of a hitherto-unobserved macroscopic chirality. The presence of this chiral magnetic configuration suggests a potential multiferroic coupling between the noncollinear magnetic arrangement and improper ferroelectric behavior as observed in prior studies on NdNiO3 (101)ortho films and RENiO3 single crystals. Experimentally-constrained theoretical double-cluster calculations confirm the presence of an energetically stable spin-disproportionated state with Zhang-Rice singlet-like combinations of Ni and ligand moments.

Abstract Background There is an emerging need to systematically investigate the causes for the increased cesarean section rates in Greece and undertake interventions so as to substantially reduce its rates. To this end, the ability of the participating Greek obstetricians to follow evidence-based guidelines and respond to other educational and behavioral interventions while managing labor will be explored, along with barriers and enablers. Herein discussed is the protocol of a stepped-wedge designed intervention trial in Greek maternity units with the aforementioned goals in mind, named ENGAGE (ENhancinG vAGinal dElivery in Greece). Methods Twenty-two selected maternity units in Greece will participate in a multicenter stepped-wedge randomized prospective trial involving 20,000 to 25,000 births, with two of them entering the intervention period of the study each month (stepped randomization). The maternity care units entering the study will apply the suggested interventions for a period of 8–18 months depending on the time they enter the intervention stage of the study. There will also be an initial phase of the study lasting from 8 to 18 months including observation and recording of the routine practice (cesarean section, vaginal birth, and maternal and perinatal morbidity and mortality) in the participating units. The second phase, the intervention period, will include such interventions as the application of the HSOG (the Hellenic Society of Obstetrics and Gynecology) Guidelines on labor management, training on the correct interpretation of cardiotocography, and dealing with emergencies in vaginal deliveries, while the steering committee members will be available to discuss and implement organizational and behavioral changes, answer questions, clarify relevant issues, and provide practical instructions to the participating healthcare professionals during regular visits or video conferences. Furthermore, during the study, the results will be available for the participating units in order for them to monitor their own performance while also receiving feedback regarding their rates. Τhe final 2-month phase of the study will be devoted to completing follow-up questionnaires with data concerning maternal and neonatal morbidities that occurred after the completion of the intervention period. The total duration of the study is estimated at 28 months. The primary outcome assessed will be the cesarean section rate change and the secondary outcomes will be maternal and neonatal morbidity and mortality. Discussion The study is expected to yield new information on the effects, advantages, possibilities, and challenges of consistent clinical engagement and implementation of behavioral, educational, and organizational interventions described in detail in the protocol on cesarean section practice in Greece. The results may lead to new insights into means of improving the quality of maternal and neonatal care, particularly since this represents a shared effort to reduce the high cesarean section rates in Greece and, moreover, points the way to their reduction in other countries. Trial registration NCT 04504500 (ClinicalTrials.gov). The trial was prospectively registered. Ethics Reference No: 320/23.6.2020, Bioethics and Conduct Committee, School of Medicine, National and Kapodistrian University of Athens, Athens, Greece

An escalating challenge in condensed-matter research is the characterization of emergent order-parameter nanostructures such as ferroelectric and ferromagnetic skyrmions. Their small length scales coupled with complex, three-dimensional polarization or spin structures makes them demanding to trace out fully. Resonant elastic x-ray scattering (REXS) has emerged as a technique to study chirality in spin textures such as skyrmions and domain walls. It has, however, been used to a considerably lesser extent to study analogous features in ferroelectrics. Here, we present a framework for modeling REXS from an arbitrary arrangement of charge quadrupole moments, which can be applied to nanostructures in materials such as ferroelectrics. With this, we demonstrate how extended reciprocal space scans using REXS with circularly polarized x rays can probe the three-dimensional structure and chirality of polar skyrmions. Measurements, bolstered by quantitative scattering calculations, show that polar skyrmions of mixed chirality coexist, and that REXS allows valuation of relative fractions of right- and left-handed skyrmions. Our quantitative analysis of the structure and chirality of polar skyrmions highlights the capability of REXS for establishing complex topological structures toward future application exploits.

Abstract The mechanism of unconventional superconductivity in correlated materials remains a great challenge in condensed matter physics. The recent discovery of superconductivity in infinite-layer nickelates, as an analog to high-T c cuprates, has opened a new route to tackle this challenge. By growing 8 nm Pr0.8Sr0.2NiO2 films on the (LaAlO3)0.3(Sr2AlTaO6)0.7 substrate, we successfully raise the superconducting onset transition temperature T c in the widely studied SrTiO3-substrated nickelates from 9 K into 15 K, which indicates compressive strain is an efficient protocol to further enhance superconductivity in infinite-layer nickelates. Additionally, the x-ray absorption spectroscopy, combined with the first-principles and many-body simulations, suggest a crucial role of the hybridization between Ni and O orbitals in the unconventional pairing. These results also suggest the increase of T c be driven by the change of charge-transfer nature that would narrow the origin of general unconventional superconductivity in correlated materials to the covalence of transition metals and ligands.

The discovery of infinite-layer nickelate superconductors has spurred enormous interest. While the Ni1+ cations possess nominally the same 3d9 configuration as Cu2+ in cuprates, the electronic structure variances remain elusive. Here, we present a soft X-ray photoemission spectroscopy study on parent and doped infinite-layer Pr-nickelate thin films with a doped perovskite reference. By identifying the Ni character with resonant photoemission and comparison with density functional theory + U (on-site Coulomb repulsion energy) calculations, we estimate U ∼5 eV, smaller than the charge transfer energy Δ ∼8 eV, confirming the Mott-Hubbard electronic structure in contrast to charge-transfer cuprates. Near the Fermi level (EF), we observe a signature of occupied rare-earth states in the parent compound, which is consistent with a self-doping picture. Our results demonstrate a correlation between the superconducting transition temperature and the oxygen 2p hybridization near EF when comparing hole-doped nickelates and cuprates.

Resonant elastic X-ray scattering (REXS) offers a unique tool to investigate solid-state systems providing spatial knowledge from diffraction combined with electronic information through the enhanced absorption process, allowing the probing of magnetic, charge, spin, and orbital degrees of spatial order together with electronic structure. A new promising application of REXS is to elucidate the chiral structure of electrical polarization emergent in a ferroelectric oxide superlattice in which the polarization vectors in the REXS amplitude are implicitly described through an anisotropic tensor corresponding to the quadrupole moment. Here, we present a detailed theoretical framework and analysis to quantitatively analyze the experimental results of Ti L-edge REXS of a polar vortex array formed in a PbTiO3/SrTiO3 superlattice. Based on this theoretical framework, REXS for polar chiral structures can become a useful tool similar to x-ray resonant magnetic scattering (XRMS), enabling a comprehensive study of both electric and magnetic REXS on the chiral structures.

Identifying what broken symmetries are present in the cuprates has become a major area of research. Many authors have reported evidence for so-called "Q ∼ 0"order that involves broken inversion, mirror, chiral, or time-reversal symmetry that is uniform in space. Not all these observations are well understood and new experimental probes are needed. Here we use resonant soft x-ray scattering (RSXS) to search for Q ∼ 0 order in Bi2.1Sr1.9CaCu2O8+x (Bi-2212) by measuring the region of a forbidden Bragg peak, 0; 0; 3 , which is normally extinguished by symmetry but may become allowed on resonance if valence band order is present. Using circularly polarized light, we found that this reflection becomes allowed on the Cu L3 resonance for temperatures Tc < T < T+, though remains absent in linear polarization and at other temperatures. This observation suggests the existence of spatially uniform valence band order near the pseudogap temperature. In addition, we observed periodic oscillations in the specular reflectivity from the sample surface that resemble thin film interference fringes, though no known film is present. These fringes are highly resonant, appear in all polarizations, and exhibit a period that depends on the location where the beam strikes the sample surface. We speculate that these fringes arise from interaction between some intrinsic valence band instability and extrinsic structural surface morphologies of the material. Our study supports the existence of some kind of Q ∼ 0 broken symmetry state in Bi-2212 at intermediate temperatures. Further studies using a microfocused beam, which could disentangle microscopic effects from macroscopic heterogeneities, are needed to ascertain the universality of the effect.

Sensitivity to the "bulk" oxygen core orbital makes hard X-ray photoelectron spectroscopy (HAXPES) an appealing technique for studying oxygen redox candidates. Various studies have reported an additional O 1s peak (530-531 eV) at high voltages, which has been considered a direct signature of the bulk oxygen redox process. Here, we find the emergence of a 530.4 eV O 1s HAXPES peak for three model cathodes-Li2MnO3, Li-rich NMC, and NMC 442-that shows no clear link to oxygen redox. Instead, the 530.4 eV peak for these three systems is attributed to transition metal reduction and electrolyte decomposition in the near-surface region. Claims of oxygen redox relying on photoelectron spectroscopy must explicitly account for the surface sensitivity of this technique and the extent of the cathode degradation layer.

External perturbations can induce 3D charge order in cuprates, but the 3D correlation length is limited and the mechanism is not well understood. Ruiz et al. show that Pr substitution in YBa2Cu3O7 enhances interplanar orbital coupling and stabilizes coherent 3D charge order that coexists with superconductivity.

The purpose of the present systematic review is to clarify whether adjuvant chemotherapy improves survival rates in women with stage IC1 ovarian cancer. We searched Medline, Scopus, Clinicaltrials.gov, EMBASE, Cochrane Central Register of Controlled Trials CENTRAL and Google Scholar. We considered comparative observational studies and randomized trials that investigated survival outcomes (progression-free (PFS) and overall survival (OS)) among women with intraoperative rupture of early-stage epithelial ovarian cancer who received adjuvant chemotherapy and those that did not. Eleven studies, which recruited 7556 patients, were included. The risk of bias was defined as moderate after assessment with the Risk of Bias in non-Randomized Trials tool. Meta-analysis was performed with RStudio. Seven studies investigated the impact of adjuvant chemotherapy on recurrence-free survival of patients experiencing intraoperative cyst rupture for otherwise stage I ovarian cancer. The outcome was not affected by the use of adjuvant chemotherapy as the effect estimate was not significant (HR 1.24, 95% CI 0.74, 2.04). The analysis of data from 5 studies similarly revealed that overall survival rates were comparable among the two groups (HR 0.75, 95% CI 0.54, 1.05). This meta-analysis did not detect any benefit from adjuvant chemotherapy for stage IC ovarian cancer patients with cyst rupture. However, conclusions from this investigation are limited by a study population which included multiple histologic subtypes, high and low grade tumors and incompletely staged patients.

The metal-insulator transition of NbO2 is thought to be important for the functioning of recent niobium oxide-based memristor devices, and is often described as a Mott transition in these contexts. However, the actual transition mechanism remains unclear, as current devices actually employ electroformed NbOx that may be inherently different to crystalline NbO2. We report on our synchrotron x-ray spectroscopy and density-functional-theory study of crystalline, epitaxial NbO2 thin films grown by pulsed laser deposition and molecular beam epitaxy across the metal-insulator transition at ∼810°C. The observed spectral changes reveal a second-order Peierls transition driven by a weakening of Nb dimerization without significant electron correlations, further supported by our density-functional-theory modeling. Our findings indicate that employing crystalline NbO2 as an active layer in memristor devices may facilitate analog control of the resistivity, whereby Joule-heating can modulate Nb-Nb dimer distance and consequently control the opening of a pseudogap.

The discovery of analog LixNbO2 memristors revealed a promising new memristive mechanism wherein the diffusion of Li+ rather than O2- ions enables precise control of the resistive states. However, directly correlating lithium concentration with changes to the electronic structure in active layers remains a challenge and is required to truly understand the underlying physics. Chemically delithiated single crystals of LiNbO2 present a model system for correlating lithium variation with spectroscopic signatures from operando soft x-ray spectroscopy studies of device active layers. Using electronic structure modeling of the x-ray spectroscopy of LixNbO2 single crystals, we demonstrate that the intrinsic memristive behavior in LixNbO2 active layers results from field-induced degenerate p-type doping. We show that electrical operation of LixNbO2-based memristors is viable even at marginal Li deficiency and that the analog memristive switching occurs well before the system is fully metallic. This study serves as a benchmark for material synthesis and characterization of future LixNbO2-based memristor devices and suggests that valence change switching is a scalable alternative that circumvents the electroforming typically required for filamentary-based memristors.

The polar chiral texture of the vortex or skyrmion structure in ferroelectric oxide PbTiO3/SrTiO3 superlattice attracts attention. Here, the authors report a theoretical framework to probe emergent chirality of electrical polarization textures.

The authors attempt to address the importance of timely detection and management of cervical intraepithelial neoplasia (CIN) to prevent cervical cancer. The study focused on the potential of electrical impedance spectroscopy (EIS) as an adjunct to colposcopy, aiming to enhance the accuracy of identifying high-grade cervical lesions. Colposcopy, a widely used technique, exhibited variable sensitivity in detecting high-grade lesions, which relies on the expertise of the operator. The study’s primary objective is to evaluate the effectiveness of combining colposcopy with EIS in detecting high-grade cervical lesions among patients initially diagnosed with low-grade CIN based on cytology. We employed a cross-sectional observational design, recruiting 101 women with abnormal cervical cytology results. The participants underwent colposcopy with acetic acid and subsequent EIS using the ZedScan device. The ZedScan results are categorized into color-coded probability levels, with red indicating the highest likelihood of high-grade squamous intraepithelial lesions (HSIL) occurrence. Results revealed that ZedScan exhibits a sensitivity rate of 89.5% and a specificity rate of 84% for detecting high-grade lesions. Colposcopy, on the other hand, recorded a sensitivity rate of 85.5% and a specificity rate of 92%. The agreement rate between ZedScan and biopsy is 79.2%, as indicated by a kappa coefficient of 0.71, while the agreement rate between colposcopy and biopsy is 74.3%, with a kappa coefficient of 0.71.

Research highlights Biomarkers that would predict response to neoadjuvant chemotherapy in advanced ovarian cancer patients are eagerly needed: • Neutrophil to Lymphocyte Ratio (NLR) is an indicator of systemic inflammatory response to the malignancy. • NLR was evaluated in 132 patients undergoing Neoadjuvant Chemotherapy for advanced ovarian cancer. • Elevated NLR was associated with worse prognosis. • No association between NLR and response to chemotherapy was noted.

Background: High grade serous ovarian carcinoma (HGSOC) is the most lethal type of epithelial ovarian cancer, with a prevalence of germline BRCA1/2 mutations as high as 20%. Our objective is to determine whether the location of mutations in the different domains of the BRCA1/2 genes affects the clinical outcome of HGSOC patients. Methods: A total of 51 women with BRCA1 or BRCA2 mutated ovarian cancer were identified. Progression-free survival (PFS) and overall survival (OS) were analyzed. Results: In our study cohort, 35 patients were carriers of germline mutations in BRCA1 and 16 in BRCA2. The median PFS time following completion of the primary therapy was 23.8 months (95% CI 20.1–27.5) and the median OS was 92.9 months (95% CI 69.8–116.1) in all BRCA carriers. After multivariate analysis, no significant association among the location or type of BRCA1/2 mutation with PFS or OS was identified. Notably, significant differences in PFS between carriers of identical mutations in the same BRCA gene were detected. Conclusions: Among HGSOC patients, BRCA1/2 carriers with mutations in different locations of the genes show no significant difference in survival outcomes, in terms of PFS and OS, suggesting the potential effect of other genetic abnormalities and co-contributing risk factors.

Uterine serous carcinoma accounts for 3–10% of endometrial cancers, but it is the most lethal histopathological subtype. The molecular characterization of endometrial carcinomas has allowed novel therapeutic approaches for these patients. We undertook a retrospective analysis of patients with uterine serous carcinomas treated in our hospital within the last two decades to identify possible changes in their management. The patients and their characteristics were evenly distributed across the two decades. Treatment modalities did not change significantly throughout this period. After adjuvant treatment, patients’ median disease-free survival was 42.07 months (95% CI: 20.28–63.85), and it did not differ significantly between the two decades (p = 0.059). The median overall survival was 47.51 months (95% Cl: 32.18–62.83), and it significantly favored the first decade’s patients (p = 0.024). In patients with de novo metastatic or recurrent disease, median progression-free survival was 7.8 months (95% Cl: 5.81–9.93), whereas both the median progression-free survival and the median overall survival of these patients did not show any significant improvement during the examined time period. Overall, the results of our study explore the minor changes in respect of uterine serous carcinoma’s treatment over the last two decades, which are reflected in the survival outcomes of these patients and consequently underline the critical need for therapeutic advances in the near future.

Subarachnoid hemorrhage, a potentially lethal medical emergency, represents an atypical clinical manifestation of gestational choriocarcinoma. We present the uncommon case of a 31-year-old primigravid female who presented with cerebral oncotic aneurysmal rupture, five weeks after vaginal delivery. Albeit the absence of neurological deficits after endovascular embolization, the patient was soon readmitted, complaining of fever, abdominal pain, and fetid lochia, all suggestive of puerperal endometritis. Upon a comprehensive diagnostic work-up, she was subsequently diagnosed with metastatic choriocarcinoma. Early initiation of multiagent chemotherapy, despite being in septic shock associated with Escherichia coli bacteremia, resulted in favorable prognosis.

Pregnant women and young infants are at increased risk for severe influenza and its complications. Influenza vaccination during pregnancy is increasingly implemented as a strategy aiming to protect the pregnant woman, the fetus and the young infant. In clinical practice, the achievement of satisfactory protection for the pregnant woman without compromising the protection of her infant during the first months of life remains a challenge. Determinants that are implicated in the optimal timing of influenza vaccination in pregnancy include influenza season, trimester of pregnancy, maternal host factors and infant factors. This article addresses influenza vaccination in pregnancy and presents recent published evidence on issues that affect the optimization of the timing of maternal vaccination.

Habituation and sensitization represent nonassociative learning mechanisms in both non‐neural and neural organisms. They are essential for a range of functions from survival to adaptation in dynamic environments. Design of hardware for neuroinspired computing strives to emulate such features driven by electric bias and can also be incorporated into neural network algorithms. Herein, cellular‐like learning in oxygen‐deficient NiOx devices is demonstrated. Both habituation learning and sensitization response can be achieved in a single device by simply controlling the magnitude of the electric field. Spontaneous memory relaxations and dynamic redistribution of oxygen vacancies under electric bias enable such learning behavior of NiOx under sequential training. These characteristics in simple device arrays are implemented to learn alphabets as well as demonstrate simulated algorithmic use cases in digit recognition. Transition metal oxides with carefully prepared defect concentrations can be highly sensitive to electronic structure perturbations under moderate electrical stimulus and serve as building blocks for next‐generation neuroinspired computing hardware.

Twin pregnancies demonstrate a 2–3-fold higher chance of developing PE compared to singletons, and recent evidence has demonstrated that the sFLT1/PIGF ratio is strongly associated with PE, adverse pregnancy outcomes, as well as imminent deliveries due to PE complications. The primary objective of this systematic review was to summarise the available data on the levels of sFLT1, PlGF and their ratios in twin pregnancies and to investigate their association with the development of PE, adverse pregnancy outcomes and the timing of the delivery. A systematic search of Ovid Embase, Web of Science, Science Direct, PubMed, Ovid Medline, Google Scholar and CINAHL was carried out. sFLT1 levels and the sFLT1/PIGF ratio appeared higher in twins compared to singleton pregnancies, especially in the third trimester, while PlGF levels appeared higher up until the third trimester, with their values showing no difference or being even lower than in singletons thereafter. The sFLT1/PIGF ratio has been reported to be an independent marker of adverse outcomes related to pre-eclampsia and is associated with the mean time until delivery in an inverse manner. Further research is required in order to establish the optimal sFLT1/PIGF cut-off values and to stratify the risk of adverse outcomes in twin pregnancies.