bluuebunny/crossref_metadata_2025_split huggingface dataset:
Studying dynamics without explicit dynamics: A structure‐based study of the export mechanism by AcrB
Authors: Simsir Méliné , Broutin Isabelle , Mus‐Veteau Isabelle , Cazals Frédéric 
Published: September 2020

AbstractResistance‐nodulation‐cell division family proteins are transmembrane proteins identified as large spectrum drug transporters involved in multidrug resistance. A prototypical case in this superfamily, responsible for antibiotic resistance in selected gram‐negative bacteria, is AcrB. AcrB forms a trimer using the proton motive force to efflux drugs, implementing a functional rotation mechanism. Unfortunately, the size of the system (1049 amino acid per monomer and membrane) has prevented a systematic dynamical exploration, so that the mild understanding of this coupled transport jeopardizes our ability to counter it. The large number of crystal structures of AcrB prompts studies to further our understanding of the mechanism. To this end, we present a novel strategy based on two key ingredients, which are to study dynamics by exploiting information embodied in the numerous crystal structures obtained to date, and to systematically consider subdomains, their dynamics, and their interactions. Along the way, we identify the subdomains responsible for dynamic events, refine the states (A, B, E) of the functional rotation mechanism, and analyze the evolution of intramonomer and intermonomer interfaces along the functional cycle. Our analysis shows the relevance of AcrB's efflux mechanism as a template within the HAE1 family but not beyond. It also paves the way to targeted simulations exploiting the most relevant degrees of freedom at certain steps, and to a targeting of specific interfaces to block the drug efflux. Our work shows that complex dynamics can be unveiled from static snapshots, a strategy that may be used on a variety of molecular machines of large size.
Cross‐resistance between myclobutanil and tebuconazole and the genetic basis of tebuconazole resistance in Venturia inaequalis
Authors: Cordero‐Limon Laura , Shaw Michael W , Passey Thomas AJ , Robinson Joyce D , Xu Xiangming 
Published: September 2020

AbstractBACKGROUNDMyclobutanil is one of the most widely used demethylation inhibitor (DMI) fungicides for the management of apple scab, caused by Venturia inaequalis. Strains of V. inaequalis resistant to myclobutanil have been reported across the world. Tebuconazole, another DMI fungicide, has been proposed as an alternative to myclobutanil, and the extent of cross‐resistance with myclobutanil therefore needs to be evaluated. The sensitivity to tebuconazole and myclobutanil of a total of 40 isolates was determined. Half the isolates came from an isolated orchard which had never been sprayed with fungicides and half from orchards sprayed regularly with myclobutanil, but still with disease control problems. The progeny of a tebuconazole resistant (R) × sensitive (S) V. inaequalis cross were analyzed in order to improve understanding of the genetic control of tebuconazole sensitivity.RESULTSThere is cross‐resistance between myclobutanil and tebuconazole (r = 0.91; P < 0.001). Sensitivity to tebuconazole of the progeny of a R × S cross varied quantitatively in a pattern which implied at least two gene loci differing between the parental strains. In addition, the asymmetric distribution of the sensitivity in the progeny implied possible epistatic effects.CONCLUSIONResistance to myclobutanil and tebuconazole is strongly correlated. At least two genes are involved in the control of tebuconazole resistance in V. inaequalis.
A novel adaptive event‐triggering scheme for network descriptor systems with time‐delay
Authors: Wang Yuzhong , Zhang Tie , Ren Junchao 
Published: September 2020

SummaryThis article is concerned with the problem of the event‐triggered H∞ control for network descriptor systems with time‐delay under a novel adaptive event‐triggering scheme. First, to save more limited communication resource, a novel adaptive event‐triggering scheme is introduced to adaptively adjust the communication threshold. Second, by considering the network‐induced delay, the system's time‐varying delay, and the transmission scheme, a delay system method is used to build a novel time‐varying delay system model. Based on this model and Lyapunov function technology, sufficient stability conditions with the H∞ disturbance performance to verdict admissible and stabilization conditions to codesign the controller gain are obtained in terms of linear matrix inequalities. Then, an event‐triggered H∞ controller is proposed to stabilize descriptor systems with time‐delay. Finally, a numerical simulation example and a comparing example are employed to illustrate the effectiveness and the advantageous performances of the proposed adaptive event‐triggering scheme.
Robust stabilization of differential‐algebraic systems
Authors: Tudor Sebastian Florin , Sperilă Andrei , Oară Cristian 
Published: September 2020

SummaryFor an uncertain differential‐algebraic system subject to perturbations acting additively on coprime factors of its transfer function matrix, we construct a robust stabilizing controller and give a formula for the maximum stability margin in terms of realizations and solutions to appropriate Riccati equations.
Pregnancy and COVID‐19: pharmacologic considerations
Authors: D'Souza R. , Ashraf R. , Rowe H. , Zipursky J. , Clarfield L. , Maxwell C. , Arzola C. , Lapinsky S. , Paquette K. , Murthy S. , Cheng M. P. , Malhamé I. 
Published: September 2020

ABSTRACTIn this review, we summarize evidence regarding the use of routine and investigational pharmacologic interventions for pregnant and lactating patients with coronavirus disease 2019 (COVID‐19). Antenatal corticosteroids may be used routinely for fetal lung maturation between 24 and 34 weeks' gestation, but decisions in those with critical illness and those < 24 or > 34 weeks' gestation should be made on a case‐by‐case basis. Magnesium sulfate may be used for seizure prophylaxis and fetal neuroprotection, albeit cautiously in those with hypoxia and renal compromise. There are no contraindications to using low‐dose aspirin to prevent placenta‐mediated pregnancy complications when indicated. An algorithm for thromboprophylaxis in pregnant patients with COVID‐19 is presented, which considers disease severity, timing of delivery in relation to disease onset, inpatient vs outpatient status, underlying comorbidities and contraindications to the use of anticoagulation. Nitrous oxide may be administered for labor analgesia while using appropriate personal protective equipment. Intravenous remifentanil patient‐controlled analgesia should be used with caution in patients with respiratory depression. Liberal use of neuraxial labor analgesia may reduce the need for emergency general anesthesia which results in aerosolization. Short courses of non‐steroidal anti‐inflammatory drugs can be administered for postpartum analgesia, but opioids should be used with caution due to the risk of respiratory depression. For mechanically ventilated pregnant patients, neuromuscular blockade should be used for the shortest duration possible and reversal agents should be available on hand if delivery is imminent. To date, dexamethasone is the only proven and recommended experimental treatment for pregnant patients with COVID‐19 who are mechanically ventilated or who require supplemental oxygen. Although hydroxycholoroquine, lopinavir/ritonavir and remdesivir may be used during pregnancy and lactation within the context of clinical trials, data from non‐pregnant populations have not shown benefit. The role of monoclonal antibodies (tocilizumab), immunomodulators (tacrolimus), interferon, inhaled nitric oxide and convalescent plasma in pregnancy and lactation needs further evaluation. © 2020 The Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of International Society of Ultrasound in Obstetrics and Gynecology.
Progesterone for prevention of preterm birth in women with short cervical length: 2‐year infant outcomes
Authors: Cuijpers C. J. J. , Van't Hooft J. , Schneeberger C. , Van Der Lee J. H. , Simons N. E. , Van Os M. A. , Van Der Ven J. , De Groot C. J. M. , Mol B. W. J. , Van Wassenaer‐leemhuis A. G. 
Published: September 2020

ABSTRACTObjectiveTo evaluate the long‐term outcomes of children born to women with a short cervix and otherwise low risk for preterm birth, after antenatal exposure to vaginal progesterone vs placebo.MethodsThis was a follow‐up study of the Triple P trial, which randomized 80 low‐risk women with a short cervix (≤ 30 mm) at 18–22 weeks' gestation to progesterone (n = 41) or placebo (n = 39). At 2 years of corrected age, children were invited for a neurodevelopmental assessment, using the Bayley Scales of Infant and Toddler Development, third edition (BSID‐III), and a neurological and physical examination by an assessor blinded to the allocated treatment. Parents filled out the Ages and Stages Questionnaire, the Child Behavior Checklist (CBCL) and a general‐health questionnaire. The main outcome of interest was mean BSID‐III cognitive and motor scores. Additionally, a composite score of mortality and abnormal developmental outcome, including BSID‐III ≤–1 SD, CBCL score in the clinical range and/or parental reported physical problems (at least two operations or at least two hospital admissions in the previous 2 years), was evaluated. Our sample size, dictated by the original sample of the Triple P trial, provided 80% power to detect a mean difference (MD) of 15 points (1 SD) between groups for the BSID‐III tests.ResultsOf the 80 children born to the randomized women, one in the progesterone group and two in the placebo group died in the neonatal period. Follow‐up data were obtained for 59/77 (77%) children and BSID‐III outcomes in 57 children (n = 28 in the progesterone group and n = 29 in the placebo group) born at a median gestational age of 38 + 6 weeks (interquartile range (IQR), 37 + 3 to 40 + 1 weeks) with a median birth weight of 3240 g (IQR, 2785–3620 g). In the progesterone vs placebo groups, mean BSID‐III cognitive development scores were 101.6 vs 105.0 (MD, –3.4 (95% CI, –9.3 to 2.6); P = 0.29) while mean motor scores were 102.4 vs 107.3 (MD, –4.9 (95% CI, –11.2 to 1.4); P = 0.13). No differences were seen between the two groups in physical (including genital and neurological examination), behavioral and health‐related outcomes.ConclusionIn this sample of children born to low‐risk women with a short cervix at screening, no relevant differences in neurodevelopmental, behavioral, health‐related and physical outcomes were found between offspring exposed to vaginal progesterone and those exposed to placebo. © 2020 The Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of International Society of Ultrasound in Obstetrics and Gynecology.
Association between 3D endovaginal and 2D perineal pelvic floor ultrasound findings and symptoms in women presenting with mid‐urethral sling complications
Authors: Taithongchai A. , Pandeva I. , Sultan A. H. , Thakar R. 
Published: September 2020

ABSTRACTObjectivesTo present the characteristics of women attending a tertiary urogynecology pelvic floor scan clinic with mid‐urethral sling (MUS) complications and examine the association between patient symptoms and findings on two‐dimensional (2D) perineal and three‐dimensional (3D) endovaginal ultrasound.MethodsThis was a cross‐sectional study of all women with MUS complications referred to a specialist pelvic floor ultrasound clinic between October 2016 and October 2018. Detailed history was obtained regarding their symptoms and time of onset. All patients underwent 2D perineal and 3D endovaginal ultrasound assessment. The association between patient symptoms and ultrasound findings was evaluated using logistic regression analysis. Only symptomatic women with a single MUS, without other pelvic floor mesh, prior mesh excision or bulking agents, were included in the regression analysis.ResultsA total of 311 women with a history of MUS surgery were seen during the study period. Vaginal and/or non‐vaginal pain was reported by 80% of patients and this was the primary presenting complaint in 59% of the patients. One‐third of the patients reported symptoms starting within 4 weeks after surgery. The data of 172 patients were included in the regression analysis. MUS position within the rhabdosphincter was significantly associated with voiding dysfunction (odds ratio (OR), 10.6 (95% CI, 2.2–50.9); P = 0.003). Voiding dysfunction was highest in those with C‐shaped MUS both at rest and on Valsalva maneuver (OR, 3.2 (95% CI, 1.3–7.6); P < 0.001). MUS position in the distal third of the urethra was significantly associated with a higher rate of recurrent urinary tract infection (OR, 2.9 (95% CI, 1.3–6.3); P = 0.01).ConclusionsPelvic floor ultrasound can provide insight into the position and shape of the MUS, which could explain some patient symptoms and guide management or surgical planning. © 2020 The Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of International Society of Ultrasound in Obstetrics and Gynecology.
Indigenous microbial communities in Albertan sediments are capable of anaerobic benzene biodegradation under methanogenic, sulfate‐reducing, nitrate‐reducing, and iron‐reducing redox conditions
Authors: Lee Korris , Ulrich Ania 
Published: September 2020

AbstractAlberta is a major center for oil and gas production, and correspondingly harbors hundreds of unresolved contamination sites by environmental hazards such as benzene (C6H6). Due to its cost‐effectiveness, bioremediation has become a promising strategy for C6H6 removal. Contamination sites typically take on an anaerobic context, which complicates the energetics of contamination sites and is a subject that is scarcely broached in studies of Albertan sediments. This study examines the innate potential for indigenous microbial communities in Albertan sediments to remove C6H6 in a multitude of reduced conditions. Community profiles of these sediments were analyzed by 16S rRNA gene amplicon sequencing, and removal rates and reaction stoichiometries were observed by gas chromatography and ion chromatography. Organisms belonging to known primary degrader taxa were identified, including Geobacter (iron‐reducing), and Peptococcaceae (nitrate‐reducing). Furthermore, benzene removal patterns of the cultures were similar to those observed in previously reported microcosms, with lag times between 70 and 168 days and removal rates between 3.27 and 12.70 µM/day. Such information could support a more comprehensive survey of Albertan sediment consortia, which may eventually be utilized in informing future remediation efforts in the province.Practitioner points

Clay and sand sediments originating from Northern Alberta could remove benzene under methanogenic, sulfate‐reducing, iron‐reducing, and nitrate‐reducing conditions.

Degradation profiles were broadly comparable to those of reported cultures from other geographical locales.

Key degrader taxa observed included Geobacter (Fe3+‐reducing) and Peptococcaceae (‐reducing).

Knowledge gained can be the start of a more extensive survey of Albertan sediments. Eventually, this collection of information can be used to generate robust C6H6‐degrading cultures that can be implemented for bioaugmentation and be implemented in informing remediation strategies in soil and water matrices for priority contamination cases such as leaking underground storage tanks and orphan wells.
On Sugawara construction on celestial sphere
Authors: Fan Wei , Fotopoulos Angelos , Stieberger Stephan , Taylor Tomasz R. 
Published: September 2020

Abstract
Conformally soft gluons are conserved currents of the Celestial Conformal Field Theory (CCFT) and generate a Kac-Moody algebra. We study celestial amplitudes of Yang-Mills theory, which are Mellin transforms of gluon amplitudes and take the double soft limit of a pair of gluons. In this manner we construct the Sugawara energy-momentum tensor of the CCFT. We verify that conformally soft gauge bosons are Virasoro primaries of the CCFT under the Sugawara energy-momentum tensor. The Sugawara tensor though does not generate the correct conformal transformations for hard states. In Einstein-Yang- Mills theory, we consider an alternative construction of the energy-momentum tensor, similar to the double copy construction which relates gauge theory amplitudes with gravity ones. This energy momentum tensor has the correct properties to generate conformal transformations for both soft and hard states. We extend this construction to supertranslations.
Chern-Simons invariants and heterotic superpotentials
Authors: Anderson Lara B. , Gray James , Lukas Andre , Wang Juntao 
Published: September 2020

Abstract
The superpotential in four-dimensional heterotic effective theories contains terms arising from holomorphic Chern-Simons invariants associated to the gauge and tangent bundles of the compactification geometry. These effects are crucial for a number of key features of the theory, including vacuum stability and moduli stabilization. Despite their importance, few tools exist in the literature to compute such effects in a given heterotic vacuum. In this work we present new techniques to explicitly determine holomorphic Chern-Simons invariants in heterotic string compactifications. The key technical ingredient in our computations are real bundle morphisms between the gauge and tangent bundles. We find that there are large classes of examples, beyond the standard embedding, where the Chern-Simons superpotential vanishes. We also provide explicit examples for non-flat bundles where it is non-vanishing and non-integer quantized, generalizing previous results for Wilson lines.
Intestinal Nematode Infection Affects Metastasis of EL4 Lymphoma Cells
Authors: Donskow-Łysoniewska Katarzyna , Krawczak Katarzyna , Machcińska Maja , Brodaczewska Klaudia 
Published: September 2020

AbstractAn effective host immune system prevents the growth of most cancer cells. However, as intestinal nematodes are able to induce both immunotolerance and immunosuppression in the host, it is possible that their presence could allow co-occurring cancer cells to proliferate and metastasize. Our findings indicate that previous, subsequent or concurrent intestinal nematode infection affects the formation of lung metastatic nodules in mice experimentally infected with Heligmosomoides polygyrus. In addition, pre-infection with nematodes renders mice resistant to metastasis development in lungs, with the inoculated EL4 cancer cells being located mainly in mesenteric lymph nodes. The present paper discusses the nematode-induced mechanisms which may influence the metastatic process.
Fractures of the acetabulum: from yesterday to tomorrow
Authors: Cimerman Matej , Kristan Anže , Jug Marko , Tomaževič Matevž 
Published: September 2020

Abstract
Purpose
The aim of this article is to present history, state of the art, and future trends in the treatment of acetabular fractures.

Methods
Review of recent and historical literature.

Results
Acetabular fractures are difficult to treat. The first descriptions of this injury already appeared in ancient Greek history, but intensive development started in the second half of the twentieth century after Judet and Letournel’s seminal work. Their classification is still the gold standard today. It is actually a pre-operative planning system and is used to determine the most appropriate surgical approach. The therapy of choice for dislocated fractures is open reduction and internal fixation. Recent modern techniques based on high-tech computerized planning systems and 3D printing have been successfully integrated into orthopaedic trauma practice.

Conclusion
There is no ideal surgical approach for acetabulum fracture treatment, so new approaches have been developed in recent decades. The best outcome series have shown good or excellent results, between 70 and 80%.
The Intricate Determination of Magnetic Anisotropy in Quasi-octahedral Vanadium(III): An HF-EPR and Magnetic Study
Authors: Westrup Kátia Cristina Molgero , Santana Francielli Sousa , Hughes David Lewis , Nunes Giovana Gioppo , Soares Jaísa Fernandes , Barra Anne-Laure , Sessoli Roberta , Sorace Lorenzo 
Published: September 2020

AbstractWe report here the synthesis and a preliminary characterization of the tetranuclear complex of formula [Ga3V(LEt)2(dpm)6],Ga3VEt, in whichH3LEt = 2-Ethyl-2-(hydroxymethyl)-propane-1,3-diol and Hdpm = dipivaloylmethane,containing a single paramagnetic vanadium(III) center, from a structural, magnetic, and spectroscopic point of view. Structural characterization by X-ray diffraction evidenced that this derivative is isostructural with the star-shaped Single-Molecule Magnet [Fe3V(LEt)2(dpm)6],Fe3VEt, and can, thus, be considered a model to analyze the magnetic anisotropy of the vanadium(III) ion in that system. The observed results confirm the complexity in obtaining a rationalization of the magnetic behavior of this metal ion, with magnetization data and High Field Electron Paramagnetic Resonance (HF-EPR) spectroscopy providing apparently conflicting results. Indeed, the former were rationalized assuming a rhombic distortion of the ligand field and a dominant easy-axis type anisotropy (equivalent toD≈ −14.1 cm−1,E≈ 1.2 cm−1), while a simple axial Spin Hamiltonian approach could explain HF-EPR data (|D| ≈ 6.98 cm−1).
Understanding National Preferences in EU Consumer Policy: A Regime Approach
Authors: Austgulen M. H. 
Published: September 2020

AbstractEU consumer policy is a policy area that is receiving increased attention and is considered important for the proper functioning of the internal market. Yet, as with many other supranational policy areas, conflicting positions of the Member States have led to many compromises and rejections of EU-initiated proposals. By building on regime theory and previous research identifying consumer policy regimes, the aim with this article is to investigate potential patterns in countries’ preferences in EU consumer policy. With this, the article seeks both to contribute to the theoretical understanding of factors influencing Member States’ positions to EU consumer policy and to the debate on how future EU consumer policies should be designed and put into power. Differences in country and regime preferences are analysed using data collected through an open public consultation as part of the European Commission’s Fitness Check of European consumer and marketing law in 2016 and through interviews with key stakeholders in 2018. The results show that there are substantial differences between the regimes and that the level of harmonization of consumer and marketing law seems to be the most contested issue. Furthermore, the article points to several potential reasons for these differences between countries and regimes and recommends that future studies should be undertaken to generate deeper knowledge about the effects of these explanatory factors.