861 research outputs found

    Early amniotomy after cervical ripening for induction of labor: a systematic review and meta-analysis of randomized controlled trials

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    OBJECTIVE DATA: Timing of artificial rupture of membranes (ie, amniotomy) in induction of labor is controversial, because it has been associated not only with shorter labors, but also with fetal nonreassuring testing, at times necessitating cesarean delivery. The aim of this systematic review and metaanalysis of randomized trials was to evaluate the effectiveness of early amniotomy vs late amniotomy or spontaneous rupture of membranes after cervical ripening. STUDY: The search was conducted with the use of electronic databases from inception of each database through February 2019. Review of articles included the abstracts of all references that were retrieved from the search. STUDY APPRAISAL AND SYNTHESIS METHODS: Selection criteria included randomized clinical trials that compared early amniotomy vs control (ie, late amniotomy or spontaneous rupture of membranes) after cervical ripening with either Foley catheter or prostaglandins at any dose. The primary outcome was the incidence of cesarean delivery. The summary measures were reported as summary relative risk with 95% of confidence interval with the use of the random effects model of DerSimonian and Laird. RESULTS: Four trials that included 1273 women who underwent cervical ripening with either Foley catheter or prostaglandins and then were assigned randomly to either early amniotomy, late amniotomy, or spontaneous rupture of membranes (control subjects) were included in the review. Women who were assigned randomly to early amniotomy had a similar risk of cesarean delivery (31.1% vs 30.9%; relative risk, 1.05; 95% confidence interval, 0.71-1.56) compared with control subjects and had a shorter interval from induction to delivery of approximately 5 hours (mean difference, -4.95 hours; 95% confidence interval, -8.12 to -1.78). Spontaneous vaginal delivery was also reduced in the early amniotomy group, but only 1 of the included trials reported this outcome (67.5% vs 69.1%; relative risk, 0.78; 95% confidence interval, 0.66-0.93). No between-group differences were reported in the other obstetrics or perinatal outcomes. CONCLUSION: After cervical ripening, routine early amniotomy does not increase the risk of cesarean delivery and reduces the interval from induction to delivery

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    Optimization of graphene-based materials outperforming host epoxy matrices

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    The degree of graphite exfoliation and edge-carboxylated layers can be controlled and balanced to design lightweight materials characterized by both low electrical percolation thresholds (EPT) and improved mechanical properties. So far, this challenging task has been undoubtedly very hard to achieve. The results presented in this paper highlight the effect of exfoliation degree and the role of edge-carboxylated graphite layers to give self-assembled structures embedded in the polymeric matrix. Graphene layers inside the matrix may serve as building blocks of complex systems that could outperform the host matrix. Improvements in electrical percolation and mechanical performance have been obtained by a synergic effect due to finely balancing the degree of exfoliation and the chemistry of graphene edges which favors the interfacial interaction between polymer and carbon layers. In particular, for epoxy-based resins including two partially exfoliated graphite samples, differing essentially in the content of carboxylated groups, the percolation threshold reduces from 3 wt% down to 0.3 wt%, as the carboxylated group content increases up to 10 wt%. Edge-carboxylated nanosheets also increase the nanofiller/epoxy matrix interaction, determining a relevant reinforcement in the elastic modulus

    Number statistics for β\beta-ensembles of random matrices: applications to trapped fermions at zero temperature

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    Let Pβ(V)(NI)\mathcal{P}_{\beta}^{(V)} (N_{\cal I}) be the probability that a N×NN\times N β\beta-ensemble of random matrices with confining potential V(x)V(x) has NIN_{\cal I} eigenvalues inside an interval I=[a,b]{\cal I}=[a,b] of the real line. We introduce a general formalism, based on the Coulomb gas technique and the resolvent method, to compute analytically Pβ(V)(NI)\mathcal{P}_{\beta}^{(V)} (N_{\cal I}) for large NN. We show that this probability scales for large NN as Pβ(V)(NI)exp(βN2ψ(V)(NI/N))\mathcal{P}_{\beta}^{(V)} (N_{\cal I})\approx \exp\left(-\beta N^2 \psi^{(V)}(N_{\cal I} /N)\right), where β\beta is the Dyson index of the ensemble. The rate function ψ(V)(kI)\psi^{(V)}(k_{\cal I}), independent of β\beta, is computed in terms of single integrals that can be easily evaluated numerically. The general formalism is then applied to the classical β\beta-Gaussian (I=[L,L]{\cal I}=[-L,L]), β\beta-Wishart (I=[1,L]{\cal I}=[1,L]) and β\beta-Cauchy (I=[L,L]{\cal I}=[-L,L]) ensembles. Expanding the rate function around its minimum, we find that generically the number variance Var(NI){\rm Var}(N_{\cal I}) exhibits a non-monotonic behavior as a function of the size of the interval, with a maximum that can be precisely characterized. These analytical results, corroborated by numerical simulations, provide the full counting statistics of many systems where random matrix models apply. In particular, we present results for the full counting statistics of zero temperature one-dimensional spinless fermions in a harmonic trap.Comment: 34 pages, 19 figure

    Spectra of Empirical Auto-Covariance Matrices

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    We compute spectra of sample auto-covariance matrices of second order stationary stochastic processes. We look at a limit in which both the matrix dimension NN and the sample size MM used to define empirical averages diverge, with their ratio α=N/M\alpha=N/M kept fixed. We find a remarkable scaling relation which expresses the spectral density ρ(λ)\rho(\lambda) of sample auto-covariance matrices for processes with dynamical correlations as a continuous superposition of appropriately rescaled copies of the spectral density ρα(0)(λ)\rho^{(0)}_\alpha(\lambda) for a sequence of uncorrelated random variables. The rescaling factors are given by the Fourier transform C^(q)\hat C(q) of the auto-covariance function of the stochastic process. We also obtain a closed-form approximation for the scaling function ρα(0)(λ)\rho^{(0)}_\alpha(\lambda). This depends on the shape parameter α\alpha, but is otherwise universal: it is independent of the details of the underlying random variables, provided only they have finite variance. Our results are corroborated by numerical simulations using auto-regressive processes.Comment: 4 pages, 2 figure

    Compact smallest eigenvalue expressions in Wishart-Laguerre ensembles with or without fixed-trace

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    The degree of entanglement of random pure states in bipartite quantum systems can be estimated from the distribution of the extreme Schmidt eigenvalues. For a bipartition of size M\geq N, these are distributed according to a Wishart-Laguerre ensemble (WL) of random matrices of size N x M, with a fixed-trace constraint. We first compute the distribution and moments of the smallest eigenvalue in the fixed trace orthogonal WL ensemble for arbitrary M\geq N. Our method is based on a Laplace inversion of the recursive results for the corresponding orthogonal WL ensemble by Edelman. Explicit examples are given for fixed N and M, generalizing and simplifying earlier results. In the microscopic large-N limit with M-N fixed, the orthogonal and unitary WL distributions exhibit universality after a suitable rescaling and are therefore independent of the constraint. We prove that very recent results given in terms of hypergeometric functions of matrix argument are equivalent to more explicit expressions in terms of a Pfaffian or determinant of Bessel functions. While the latter were mostly known from the random matrix literature on the QCD Dirac operator spectrum, we also derive some new results in the orthogonal symmetry class.Comment: 25 pag., 4 fig - minor changes, typos fixed. To appear in JSTA

    Identification of Cdk8 and Cdkn2d as New Prame-Target Genes in 2C-like Embryonic Stem Cells

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    Embryonic stem cells (ESCs) present a characteristic pluripotency heterogeneity correspondent to specific metastates. We recently demonstrated that retinoic acid (RA) induces an increase in a specific 2C-like metastate marked by target genes specific to the two-cell embryo stage in preimplantation. Prame (Preferentially expressed antigen in melanoma) is one of the principal actors of the pluripotency stage with a specific role in RA responsiveness. Additionally, PRAME is overexpressed in a variety of cancers, but its molecular functions are poorly understood. To further investigate Prame’s downstream targets, we used a chromatin immunoprecipitation sequencing (ChIP-seq) assay in RA-enriched 2C-like metastates and identified two specific target genes, Cdk8 and Cdkn2d, bound by Prame. These two targets, involved in cancer dedifferentiation and pluripotency, have been further validated in RA-resistant ESCs. Here, we observed for the first time that Prame controls the Cdk8 and Cdkn2d genes in ESCs after RA treatment, shedding light on the regulatory network behind the establishment of naïve pluripotency

    A dominant mutation etiologic for human tricho-dento-osseous syndrome impairs the ability of DLX3 to downregulate ΔNp63α.

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    The homeodomain transcription factors play crucial roles in many developmental processes ranging from organization of the body plan to differentiation of individual tissues. The homeodomain protein Distal-less-3 (DLX3) has an essential role in epidermal stratification and development of ectodermal appendages, placenta and bones. A four-nucleotide deletion in the human DLX3 gene is etiologic for the human hereditary tricho-dento-osseous (TDO) ectodermal dysplasia, a dominant syndrome characterized by abnormalities in hair, nails, teeth, and bones. We have previously demonstrated that DLX3 gene expression induces degradation of ΔNp63α, a specific product of the TP63 gene, a master regulator of multi-layered epithelia. Here we show that the DLX3(TDO) mutant protein is unable to promote ΔNp63α protein degradation and impairs the expression of cell cycle regulatory proteins and skin differentiation markers. However, we found that in cell expressing equal amounts of mutant and wild-type DLX3, ΔNp63α protein level is efficiently regulated implying that genetic heterozygosity at the DLX3 locus protects TDO patients from developing severe p63-associated skin defects

    Carbon nanofiber-supported tantalum oxides as durable catalyst for the oxygen evolution reaction in alkaline media

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    Active and durable electrocatalysts for the oxygen evolution reaction (OER), capable of replacing noble metal catalysts, are required to develop efficient and competitive devices within the frame of the water electrolysis technology for hydrogen production. In this work, we have investigated tantalum based catalysts supported on carbon nanofibers (CNF) for the first time. The effect of CNF characteristics and the catalyst annealing temperature on the electrochemical response for the OER have been analyzed in alkaline environment using a rotating ring disc electrode (RRDE). The best OER activity and oxygen efficiency were found with a highly graphitic CNF, despite its lower surface area, synthesized at 700 °C, and upon a catalyst annealing temperature of 800 °C. The ordering degree of carbon nanofibers favors the production of oxygen in combination with a low oxygen content in tantalum oxides. The most active catalyst exhibited also an excellent durability.The authors want to thank the Ministerio de Economía, Industria y Competitividad (MICINN) and FEDER for the received funding in the project of reference ENE2017-83976-C2-1-R, and to the Gobierno de Aragón (DGA) for the funding to Grupo de Investigación Conversión de Combustibles ( T06_17R ). J.C. Ruiz-Cornejo acknowledges DGA for his PhD grant. D. Sebastián acknowledges the MICINN for the Ramón y Cajal research contract (RyC-2016-20944
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