bluuebunny/crossref_metadata_2025 huggingface dataset:
Assessment of Disease Activity in Takayasu Arteritis: Potential Role of Contrast-Enhanced Ultrasound
Authors: Lottspeich Christian , Dechant Claudia , Köhler Anton , Tischler Maximilian , Treitl Karla Maria , Treitl Marcus , Schulze-Koops Hendrik , Hoffmann Ulrich , Czihal Michael
Published: January 2019

Purpose To assess the diagnostic value of intima media thickness measurements and contrast-enhanced ultrasound (CEUS) of the supraaortic arteries in the assessment of disease activity in Takayasu arteritis (TA).

Materials and Methods Patients with TA and involvement of the carotid and/or subclavian/axillary arteries underwent CEUS imaging in addition to B-mode and color duplex ultrasound. The maximum IMT (mIMT) was measured and high-resolution CEUS of the most prominently thickened vessel segment was performed. Two blinded readers reviewed the CEUS movies, with semiquantitative assessment of microbubble enhancement of the arterial wall (grade 0: no or minimal; grade 1: moderate; grade 2: pronounced). Clinical symptoms, acute phase reactants, and established indices of clinical disease activity (NIH criteria, ITAS score) were recorded.

Results 40 examinations in 17 patients were analyzed. According to clinical judgement, 27 and 13 cases were classified as clinically inactive and active, respectively. An mIMT-cutoff of > 2.7 mm identified active disease with a sensitivity and specificity of 69.2 % and 88.9 %, respectively (area under the curve 0.83). The interobserver agreement of CEUS analysis was substantial (Cohen’s kappa 0.76). By consensus reading, 17, 15, and 8 cases were classified as uptake grade 0, grade 1 and grade 2, respectively. Grade 0 uptake was exclusively present in 17 clinically inactive patients. Grade 1 uptake was seen in 10 patients with clinically inactive disease and 5 patients with clinically active disease. Grade 2 uptake was exclusively present in 8 patients with active disease.

Conclusion Both sonographic IMT measurements and high-resolution CEUS are promising in the ad-hoc assessment of disease activity in patients with TA.
Synthetic Phosphonic Acids as Potent Tools to Study Phosphonate Enzymology
Authors: Pallitsch K. , Kalina T. , Stanković T.
Published: January 2019

Phosphonic acids are highly stable phosphorus-containing compounds, which have been proposed as important intermediates in the global phosphorus cycle. Biogenic phosphonates as well as their synthetic analogues play an important role as potential enzyme inhibitor drugs and as alternative phosphorus source for microbes. Despite these properties, their metabolism is still poorly understood. New degradative pathways and unknown compounds are identified at fast pace. However, most of these pathways include a variety of unique enzymatic transformations, which are difficult to characterize – especially without sufficient amounts of the potential substrates and intermediates of the postulated transformations in hands. Thus, there is a great need for the development of synthetic methodologies to access phosphonic acids in high yields and in enantiomerically pure form for the use in enzymatic studies and in studies on the biological activity of newly isolated natural products, which are often only obtained in low yields. In this Synpacts article we aim at highlighting our recent contributions to this field.

1 Introduction2 Phosphonates as Alternative Phosphorus Source

3 The Application of Phosphonates in Enzymatic Studies

4 Conclusion
A Genome-Wide Analysis of Clinical Chorioamnionitis among Preterm Infants
Authors: Spiegel Ariana M. , Li Jingjing , Oehlert John W. , Mayo Jonathan A. , Quaintance Cecele C. , Girsen Anna I. , Druzin Maurice L. , El-Sayed Yasser Y. , Shaw Gary M. , Stevenson David K. , Gibbs Ronald S.
Published: January 2019

Objective To identify single nucleotide polymorphisms (SNPs) associated with clinical chorioamnionitis among preterm infants.

Study Design We reanalyzed a genome-wide association study (GWAS) from preterm newborns at less than 30 weeks' gestation. Cases and control definitions were determined using administrative records. There were 213 clinical chorioamnionitis cases and 707 clinically uninfected controls. We compared demographic and clinical outcomes of cases and controls. We performed a GWAS and compared the distribution of SNPs from the background genes and from the immunome genes. We used a Wilcoxon's rank-sum test to compare the SNPs normalized odds ratio and used odds ratios and p-values to determine candidate genes.

Results Infants affected by clinical chorioamnionitis were more likely to have periventricular leukomalacia, high-grade retinopathy, and high-grade intraventricular hemorrhage (IVH). Although a GWAS did not identify SNPs associated with clinical chorioamnionitis at the genome-wide significance level, a direct test on the exonic variants in the human immunome revealed their significant increase of risk in clinical chorioamnionitis.

Conclusion Among very preterm infants, clinical chorioamnionitis was associated with periventricular leukomalacia, high-grade retinopathy, and IVH. Our analysis of variants in the human immunome indicates an association with clinical chorioamnionitis in very preterm pregnancies.
Serum Neuron-Specific Enolase Level as Predictor of Neurologic Outcome after Aortic Surgery
Authors: Kimura Fumiaki , Kadohama Takayuki , Kitahara Hiroto , Ise Hayato , Nakanishi Sentaro , Akasaka Nobuyuki , Kamiya Hiroyuki
Published: January 2019

Background This study aimed to evaluate the significance of serum neuron-specific enolase (NSE) level as a predictor of neurologic injury in thoracic aortic surgery.

Methods We neurologically assessed 60 consecutive patients who underwent thoracic aortic surgery for thoracic aortic aneurysm (n = 26) and aortic dissection (n = 34). Using moderate hypothermic circulatory arrest with antegrade cerebral perfusion, total arch replacement and hemiarch replacement were performed in 37 and 23 patients, respectively. Serum NSE levels in venous blood samples drawn before surgery and at 1 day after surgery were measured. Severity of neurologic injury was categorized as either uncomplicated (n = 48), temporary neurologic dysfunction (TND, n = 5), or permanent neurologic dysfunction (PND, n = 7). The extent of stroke was estimated on computed tomography or magnetic resonance imaging.

Results The NSE level significantly differed among the three groups (PND > TND > uncomplicated) on the first postoperative day. Receiver-operating characteristic curve analysis showed that the cutoff value of NSE level was 34.14 ng/mL for neurologic injury (sensitivity, 0.769; specificity, 0.851) and 43.56 ng/mL for PND (sensitivity, 1.000; specificity, 0.963). The NSE level significantly correlated with the extent of stroke (r = 0.61, p < 0.001).

Conclusion Serum NSE level is a significant predictor of adverse neurologic outcomes and extent of stroke after thoracic aortic surgery.
Birth Size and Gestational Age Specific Outcomes of Inhaled Nitric Oxide Therapy in Preterm Neonates with Clinically Diagnosed Pulmonary Hypertension
Authors: Udland Carley J. , Carey William A. , Weaver Amy L. , Mara Kristin C. , Clark Reese H. , Ellsworth Kevin R.
Published: January 2019

Objective Among neonates of 22 to 29 weeks' gestational age (GA) who required mechanical ventilation for the treatment of respiratory distress syndrome (RDS) and clinically diagnosed pulmonary hypertension (PH), we tested our hypothesis that the association between early treatment with inhaled nitric oxide (iNO) and survival would vary according to birth size and GA.

Study Design Because iNO was not randomly prescribed to patients in this cohort, we used propensity score matching to pair a neonate who received iNO at a chronological age of ≤7 days with an unexposed neonate with similar baseline characteristics. The primary outcome was inhospital mortality, which we evaluated based on size for GA and GA strata using the Cox proportional hazards regression model.

Results Among 1,531 neonates who met study criteria, we created a propensity score matched cohort of 615 pairs of neonates (iNO-exposed and unexposed). The risk of inhospital mortality for iNO-exposed neonates was observed only in the minority (<10%) who were large for GA, though this finding did not persist when matching for illness severity.

Conclusion Early treatment with iNO is not associated with survival in most extremely premature neonates with RDS and clinically diagnosed PH when stratified for birth size or GA.
On the nonreflecting boundary operators for the general two dimensional Schrödinger equation
Authors: Vaibhav Vishal
Published: January 2019

Of the two main objectives we pursue in this paper, the first one consists in the studying operators of the form (∂t−i△Γ)α,  α=1/2,−1/2,−1,…, where △Γ is the Laplace-Beltrami operator. These operators arise in the context of nonreflecting boundary conditions in the pseudo-differential approach for the general Schrödinger equation. The definition of such operators is discussed in various settings, and a formulation in terms of fractional operators is provided. The second objective consists in deriving corner conditions for a rectangular domain in order to make such domains amenable to the pseudo-differential approach. The stability and uniqueness of the solution is investigated for each of these novel boundary conditions.
Chaotic genetic algorithm and the effects of entropy in performance optimization
Authors: Fuertes Guillermo , Vargas Manuel , Alfaro Miguel , Soto-Garrido Rodrigo , Sabattin Jorge , Peralta María Alejandra
Published: January 2019

This work proposes a new edge about the Chaotic Genetic Algorithm (CGA) and the importance of the entropy in the initial population. Inspired by chaos theory, the CGA uses chaotic maps to modify the stochastic parameters of Genetic Algorithm. The algorithm modifies the parameters of the initial population using chaotic series and then analyzes the entropy of such population. This strategy exhibits the relationship between entropy and performance optimization in complex search spaces. Our study includes the optimization of nine benchmark functions using eight different chaotic maps for each of the benchmark functions. The numerical experiment demonstrates a direct relation between entropy and performance of the algorithm.
An electro-gravitational induction effect
Authors: Kremer Attay
Published: January 2019

In this paper, we show that in general relativity the gravitational field induces an electromagnetic field. This is performed by considering the general solution of the homogeneous Maxwell equations in a gravitational field. The solution of these equations involves an ambiguity in the choice of path. This ambiguity is resolved by the derivation and solution of the path of a particle in curved spacetime under the impression of the force of the induced field. This induction effect shows that in the context of general relativity the gravitational and electromagnetic forces are dynamically linked.
Lower bound on entanglement in subspaces defined by Young diagrams
Authors: Reuvers Robin
Published: January 2019

Eigenvalues of 1-particle reduced density matrices of N-fermion states are upper bounded by 1/N, resulting in a lower bound on entanglement entropy. We generalize these bounds to all other subspaces defined by Young diagrams in the Schur–Weyl decomposition of ⊗NCd.
Crystal structures, dielectric properties, and phase transition in hybrid improper ferroelectric Sr3Sn2O7-based ceramics
Authors: Lu J. J. , Liu X. Q. , Ma X. , Fu M. S. , Yuan A. , Wu Y. J. , Chen X. M.
Published: January 2019

Hybrid improper ferroelectricity is induced by the coupling of oxygen octahedral rotation and tilt, and it may provide a promising way to develop new room-temperature single-phase multiferroic materials with a strong magnetoelectric effect. Though ferroelectric polarizations are confirmed by the electric hysteresis loops at room temperature, the ferroelectric-paraelectric phase transition has not been well understood. In the present work, the crystal structures, dielectric properties, and phase transition behaviors of Ruddlesden-Popper Sr3–xCaxSn2O7 ceramics are thoroughly determined. Ferroelectricity is confirmed through the polarization-electric field hysteresis loops at room temperature, and the Curie temperature is identified by the variable-temperature differential scanning calorimetric analysis and dielectric characterization. The polarizations and Curie temperatures of the present ceramics increase with increasing the calcium content. An improper ferroelectric transition is experimentally evidenced by a small dielectric constant and a step variation of dielectric constant around the Curie temperature, and the thermal hysteresis of dielectric constant confirms the first order transition nature. Moreover, the fitting result of Landau phase transition theory also suggests the first-order improper ferroelectric transition nature. The variable-temperature Raman result implies a tetragonal paraelectric phase above TC. The present work confidently confirms the first-order hybrid improper ferroelectric transitions in the present ceramics, and ferroelectric properties can be readily tuned by substituting the cations at the A-site.
On nonlinear Dirac equations
Authors: Benhassine Abderrazek
Published: January 2019

This paper is concerned with the multiplicity of solutions for the nonlinear Dirac equation −i∑k=13αk∂ku+(V(x)+a)βu+ωu=Fu(x,u), where V (x) is a potential function and F(x, u) is a nonlinear function modeling various types of interactions. Under suitable assumptions on V (x) and F(x, u), we prove the existence of infinitely many geometrically distinct solutions for superquadratic as asymptotically quadratic nonlinearities via variational approach. Some recent results in the literature are generalized and significantly improved. Some examples are also given to illustrate our main theoretical results.
On the stability of multilayer Boolean networks under targeted immunization
Authors: Wang Jiannan , Zhang Renquan , Wei Wei , Pei Sen , Zheng Zhiming
Published: January 2019

In this paper, we study targeted immunization in a multilayer Boolean network model for genetic regulatory networks. Given a specific set of nodes immune to perturbations, we find that the stability of a multilayer Boolean network is determined by the largest eigenvalue of the weighted non-backtracking matrix of corresponding aggregated network. Aimed to minimize this largest eigenvalue, we developed the metric of multilayer collective influence (MCI) to quantify the impact of immunizing individual nodes on the stability of the system. Compared with other competing heuristics, immunizing nodes with high MCI scores can stabilize an unstable multilayer network with higher efficiency on both synthetic and real-world networks. Moreover, despite that coupling nodes can exert direct influence across multiple layers, they are found to exhibit less importance as measured by the MCI score. Our work reveals the mechanism of maintaining the stability of multilayer Boolean networks and provides an efficient targeted immunization strategy, which can be potentially applied to the location of pathogenesis of diseases and the development of targeted therapy.
Measurement of the sound speed in dense fluid deuterium along the cryogenic liquid Hugoniot
Authors: Fratanduono D. E. , Millot M. , Fernandez Pañella A. , Sterne P. A. , Collins G. W. , Hicks D. G. , Eggert J. H. , Boehly T. R. , Celliers P. M.
Published: January 2019

Many experimental studies, spanning several decades of research and using various dynamic compression schemes, have been conducted to investigate cryogenic liquid deuterium under strong shock compression. The consensus emerging from these studies is that of a progressive dissociation of the D2 molecules into an electrically conducting, atomic plasma, when subjected to shock pressures exceeding ∼50 GPa. While state-of-the-art numerical simulations based on density-functional-theory or quantum Monte-Carlo techniques capture this behavior quite well, subtle differences subsist between these simulations and the available experimental data regarding the pressure-density compressibility. Here, leveraging a recently developed analysis method for high-resolution Doppler interferometric velocity data, we present Eulerian sound speed measurements in compressed deuterium to shock pressures between 50 and 200 GPa. These results, extracted from laser-driven shockwave experiments, are found to agree with several of the most accurate equation of state models for deuterium at those conditions up to ∼150 GPa. However, the data indicate that these models fail to reproduce the experimentally observed sound speed at higher pressures, approaching 200 GPa. In particular, we unveil a discrepancy between the experimental results and the equation of state model that is most commonly used in inertial confinement fusion at the National Ignition Facility.
Near-field imaging of spin-locked edge states in all-dielectric topological metasurfaces
Authors: Slobozhanyuk Alexey , Shchelokova Alena V. , Ni Xiang , Hossein Mousavi S. , Smirnova Daria A. , Belov Pavel A. , Alù Andrea , Kivshar Yuri S. , Khanikaev Alexander B.
Published: January 2019

A new class of phenomena stemming from topological states of quantum matter has recently found a variety of analogies in classical systems. Spin-locking and one-way propagation have been shown to drastically alter scattering of electromagnetic waves, thus offering an unprecedented robustness to defects and disorder. Despite these successes, bringing these new ideas to practical grounds meets a number of serious limitations. In photonics, when it is crucial to implement topological photonic devices on a chip, two major challenges are associated with electromagnetic dissipation into heat and out-of-plane radiation into free space. Both these mechanisms may destroy the topological state and seriously affect the device performance. Here, we demonstrate experimentally that the topological order for light can be implemented in all-dielectric on-chip prototype metasurfaces, which mitigate the effect of Ohmic losses by using exclusively structured dielectric materials, and we reveal that coupling of the system to the radiative continuum does not affect topological properties. We demonstrate the spin-Hall effect of light for spin-polarized topological edge states through near-field spectroscopy measurements.
Magnetic-field tailoring of the terahertz polarization emitted from a spintronic source
Authors: Hibberd M. T. , Lake D. S. , Johansson N. A. B. , Thomson T. , Jamison S. P. , Graham D. M.
Published: January 2019

We demonstrate a method to create arbitrary terahertz (THz) polarization profiles by exploiting the magnetic field-dependent emission process of a spintronic source. As a proof-of-concept, we show that by applying a specific magnetic field pattern to the source, it is possible to generate a quadrupole-like THz polarization profile. Experimental measurements of the electric field at the focus of the THz beam revealed a polarity flip in the transverse profile of the quadrupole-like mode with a resulting strong, on-axis longitudinal component of 17.7 kV cm−1. This represents an order of magnitude increase in the longitudinal component for the quadrupole-like profile compared to a linear polarization, showing an example of how the magnetic field patterning of a spintronic source can be exploited to obtain desirable THz polarization properties. This unique ability to generate any desired THz polarization profile opens up possibilities for schemes such as rotatable polarization spectroscopy and for efficient mode coupling in various waveguide designs. Furthermore, the strong longitudinal fields that can be generated have applications in areas including intra-subband spectroscopy of semiconductors, non-diffraction limited THz imaging, and particle-beam acceleration.
Dynamic analysis of a nonlinear nanobeam with flexoelectric actuation
Authors: Baroudi S. , Najar F.
Published: January 2019

Over the past few years, several researchers have been increasingly attracted to flexoelectric transduction because of its potential application for sensing and actuation in NanoElectroMechanical Systems. The flexoelectric effect refers to coupling between polarization and strain gradient in centrosymmetric and non-centrosymmetric dielectrics. Consequently, not only piezoelectric dielectrics with an initial polarization are of interest, but also a larger range of dielectric materials. In contrast to piezoelectricity, the flexoelectric effect is scale-dependent and can exhibit large electromechanical coefficients only at small scales. This paper focuses on the effects of geometric nonlinearity, resulting from relatively large displacements and restrictive boundary conditions, on the static and dynamic responses of piezoelectric flexoelectric nanobeams. The derived equations of motion for the transverse displacement and variation of the internal electric potential are discretized using a Galerkin procedure. A closed-form solution for the nonlinear static response is proposed. The results are compared and validated with those found in the literature. For the dynamic response, a perturbation technique is used to solve analytically the nonlinear equations of motion for the primary and parametric resonances of the first mode. The analytical perturbation solution is validated using a numerical technique. The results show that a general hardening-type behavior is obtained and, therefore, several jumps are observed for the dynamic solution. High sensitivity of the solution to an applied AC voltage is also demonstrated for the principal resonance of the first mode.
The smallest chimera: Periodicity and chaos in a pair of coupled chemical oscillators
Authors: Awal Naziru M. , Bullara Domenico , Epstein Irving R.
Published: January 2019

Symmetrically coupled identical oscillators were once believed to support only totally synchronous or totally asynchronous states. More recently, chimera states, in which a subset of oscillators behaves coherently while the other subset exhibits disorder, have been found in large arrays of oscillators, coupled either locally or globally. We demonstrate for the first time the existence of a chimera state with only two diffusively coupled identical oscillators, one behaving nearly periodically (coherently) and the other chaotically (incoherently). We attribute this behavior to a “master-slave” interaction, which arises via a symmetry-breaking canard explosion.
Experimental and analytical investigation into lift prediction on large trailing edge flaps
Authors: Mancini Peter , Medina Albert , Jones Anya R.
Published: January 2019

The present work aims to demonstrate the relationship between circulation production and force production on rapidly maneuvering wings using experimental measurements and two forms of low order modeling: an empirical model based on Lamb’s point vortex impulse theory and an analytical model stemming from classical airfoil theory. Experiments were performed on a 50%-chord trailing-edge flap deflecting with a linear motion profile. Both flap-down (0° − δf) and flap-up (δf − 0°) motions were examined, where δf = 20° or 40°. All cases were run at a Reynolds number of Re ∼ O(104), corresponding to convective times on the order of the free stream or faster, with the fore element of the wing fixed at zero incidence. Time-resolved circulation measurements confirmed that bound circulation on the wing equated to circulation shed into the wake from the trailing edge for the duration of flap deflection. A two-vortex model matched well with the experimental results, regardless of whether the plate experienced fully attached or massively separated flow. An analytical model based only on flap kinematics showed an equivalence between its time-dependent quantities proportional to the motion rate (δ̇,δ̈) and those proportional to the circulation rate (Γ̇) in the empirical model. Agreement between force measurements and both low order models emphasizes the need for future investigation into the direct relationship between force and circulation production.
The role of transient surface morphology on composition control in AlGaN layers and wells
Authors: Houston Dycus J. , Washiyama Shun , Eldred Tim B. , Guan Yan , Kirste Ronny , Mita Seiji , Sitar Zlatko , Collazo Ramon , LeBeau James M.
Published: January 2019

The mechanisms governing “compositional pulling” during the growth of AlxGa1−xN wells are investigated. Gallium-rich AlxGa1−xN wells grown on high dislocation density AlN/sapphire templates exhibit asymmetric and diffuse composition profiles, while those grown on low dislocation density native AlN substrates do not. Furthermore, strain in all AlxGa1−xN wells is found to be pseudomorphic, ruling it out as the dominating driving force. Rather, the high threading dislocation density of the AlN template is considered to play the defining role. We propose that a transient surface morphology is introduced during dislocation mediated spiral growth, which, in conjunction with process supersaturation, determines the Ga incorporation. These findings provide insights into compositional pulling in high Ga content AlxGa1−xN grown on AlN and provide a route to grow thicker wells with very abrupt interfaces on native AlN substrates.
Vibration isolation with high thermal conductance for a cryogen-free dilution refrigerator
Authors: de Wit Martin , Welker Gesa , Heeck Kier , Buters Frank M. , Eerkens Hedwig J. , Koning Gert , van der Meer Harmen , Bouwmeester Dirk , Oosterkamp Tjerk H.
Published: January 2019

We present the design and implementation of a mechanical low-pass filter vibration isolation used to reduce the vibrational noise in a cryogen-free dilution refrigerator operated at 10 mK, intended for scanning probe techniques. We discuss the design guidelines necessary to meet the competing requirements of having a low mechanical stiffness in combination with a high thermal conductance. We demonstrate the effectiveness of our approach by measuring the vibrational noise levels of an ultrasoft mechanical resonator positioned above a superconducting quantum interference device. Starting from a cryostat base temperature of 8 mK, the vibration isolation can be cooled to 10.5 mK, with a cooling power of 113 µW at 100 mK. We use the low vibrations and low temperature to demonstrate an effective cantilever temperature of less than 20 mK. This results in a force sensitivity of less than 500 zN/Hz and an integrated frequency noise as low as 0.4 mHz in a 1 Hz measurement bandwidth.
New homogenization approaches for stochastic transport through heterogeneous media
Authors: Carr Elliot J. , Simpson Matthew J.
Published: January 2019

The diffusion of molecules in complex intracellular environments can be strongly influenced by spatial heterogeneity and stochasticity. A key challenge when modelling such processes using stochastic random walk frameworks is that negative jump coefficients can arise when transport operators are discretized on heterogeneous domains. Often this is dealt with through homogenization approximations by replacing the heterogeneous medium with an effective homogeneous medium. In this work, we present a new class of homogenization approximations by considering a stochastic diffusive transport model on a one-dimensional domain containing an arbitrary number of layers with different jump rates. We derive closed form solutions for the kth moment of particle lifetime, carefully explaining how to deal with the internal interfaces between layers. These general tools allow us to derive simple formulae for the effective transport coefficients, leading to significant generalisations of previous homogenization approaches. Here, we find that different jump rates in the layers give rise to a net bias, leading to a non-zero advection, for the entire homogenized system. Example calculations show that our generalized approach can lead to very different outcomes than traditional approaches, thereby having the potential to significantly affect simulation studies that use homogenization approximations.
Decomposing magnetic field measurements into internally and externally sourced components in toroidal plasma devices
Authors: Sweeney R. M. , Strait E. J.
Published: January 2019

The magnetic field on any closed surface can be separated into the component produced by currents in the volume enclosed by the surface and the component produced by currents external to the surface. This decomposition was first discovered by Gauss in 1839, and “Gauss' Algorithm” was used to show that the terrestrial field is sourced from inside the Earth. This magnetic source-decomposition can be used in magnetic confinement fusion to distinguish plasma fields from the fields of external sources using standard magnetic measurements, when no conductors reside in the region between the plasma and the magnetic sensors (otherwise, the internal source is not the plasma alone). Here, Gauss' Algorithm is extended from spherical geometry to cylindrical geometry to decompose fields in the cylindrical tokamak. Demonstrations of the decomposition on DIII-D discharges include the measurement of a rotating tearing mode separate from the induced wall eddy currents and the recovery of a vacuum measurement in the presence of an externally applied 3D field. Anticipated axisymmetric and non-axisymmetric applications, and the requisite diagnostics, are discussed. It is concluded that the ITER magnetic diagnostic design is well suited for many important axisymmetric and non-axisymmetric applications. Future work will extend this decomposition to include fields from halo currents and to generalize it to arbitrary toroidal geometries.
Quantum coherent control of H3+ formation in strong fields
Authors: Michie Matthew J. , Ekanayake Nagitha , Weingartz Nicholas P. , Stamm Jacob , Dantus Marcos
Published: January 2019

Quantum coherent control (QCC) has been successfully demonstrated experimentally and theoretically for two- and three-photon optical excitation of atoms and molecules. Here, we explore QCC using spectral phase functions with a single spectral phase step for controlling the yield of H3+ from methanol under strong laser field excitation. We observe a significant and systematic enhanced production of H3+ when a negative 34 π phase step is applied near the low energy region of the laser spectrum and when a positive 34 π phase step is applied near the high energy region of the laser spectrum. In some cases, most notably the HCO+ fragment, we found the enhancement exceeded the yield measured for transform limited pulses. The observation of enhanced yield is surprising and far from the QCC prediction of yield suppression. The observed QCC enhancement implies an underlying strong field process responsible for polyatomic fragmentation controllable by easy to reproduce shaped pulses.
Stimulated backscatter of laser light from BigFoot hohlraums on the National Ignition Facility
Authors: Berger R. L. , Thomas C. A. , Baker K. L. , Casey D. T. , Goyon C. S. , Park J. , Lemos N. , Khan S. F. , Hohenberger M. , Milovich J. L. , Strozzi D. J. , Belyaev M. A. , Chapman T. , Langdon A. B
Published: January 2019

The high implosion velocity, high adiabat BigFoot design [Casey et al., Phys. Plasmas 25, 056308 (2018)] has produced the highest neutron yield to date in an ignition hohlraum on the National Ignition Facility. It has used up to 500 TW of peak power and nearly 2 MJ of laser energy in pulses up to 8 ns in duration, with the goal of fielding controlled implosions with high coupled energy, which can suppress deleterious hydrodynamic instabilities. However, when the laser pulse exceeds 6 ns with the laser energy greater than 1.6 MJ, stimulated Brillouin scattering (SBS) reaches levels that may damage optical components in the laser. Pending development of techniques to reduce SBS, limitation of laser power, and energy to avoid damage prevents the full exploitation of this approach to ignition. In this manuscript, we present three-dimensional simulations that match the experimentally measured SBS energy, in particular, reproducing quantitatively the time in the pulse when maximum backscatter occurs, and its magnitude across ∼10 BigFoot experiments. The demonstrated robustness of the modeling, which combines LASNEX and pF3D simulations, motivates us to explore and recommend several feasible SBS mitigation strategies: modified laser pointing, different laser frequencies for each cone of beams, increased laser bandwidth on all or some of the cones, and materials with a mixture of light and heavy atoms lining the inside of the hohlraum walls.
Electron injection-induced effects in Si-doped β-Ga2O3
Authors: Modak Sushrut , Lee Jonathan , Chernyak Leonid , Yang Jiancheng , Ren Fan , Pearton Stephen J. , Khodorov Sergey , Lubomirsky Igor
Published: January 2019

The impact of electron injection, using 10 keV beam of a Scanning Electron Microscope, on minority carrier transport in Si-doped β-Ga2O3 was studied for temperatures ranging from room to 120°C. In-situ Electron Beam-Induced Current technique was employed to determine the diffusion length of minority holes as a function of temperature and duration of electron injection. The experiments revealed a pronounced elongation of hole diffusion length with increasing duration of injection. The activation energy, associated with the electron injection-induced elongation of the diffusion length, was determined at ∼ 74 meV and matches the previous independent studies. It was additionally discovered that an increase of the diffusion length in the regions affected by electron injection is accompanied by a simultaneous decrease of cathodoluminescence intensity. Both effects were attributed to increasing non-equilibrium hole lifetime in the valence band of β-Ga2O3 semiconductor.
Bargmann and Barut-Girardello models for the Racah algebra
Authors: De Bie Hendrik , Iliev Plamen , Vinet Luc
Published: January 2019

The Racah algebra and its higher rank extension are the algebras underlying the univariate and multivariate Racah polynomials. In this paper, we develop two new models in which the Racah algebra naturally arises as symmetry algebra, namely, the Bargmann model and the Barut-Girardello model. We show how both models are connected with the superintegrable model of Miller et al. The Bargmann model moreover leads to a new realization of the Racah algebra of rank n as n-variable differential operators. Our conceptual approach also allows us to rederive the basis functions of the superintegrable model without resorting to separation of variables.
Room temperature surface emission on large-area photonic crystal quantum cascade lasers
Authors: Liang Y. , Wang Z. , Wolf J. , Gini E. , Beck M. , Meng B. , Faist J. , Scalari G.
Published: January 2019

We design and fabricate large-area (1.1 mm × 1.1 mm) photonic crystal quantum cascade lasers, enabling single-mode (wavelength ∼ 8.5 µm) surface emission at room temperature, with a maximum peak power up to 176 mW. The beam divergence is <1∘ and with no side-lobes. Moreover, by introducing asymmetry into the photonic crystal pillar shape, a single-lobed far-field pattern is realized. The photonic band structure is measured with high spectral (0.72 cm−1) and angular (0.1°) resolution by using the photonic crystal quantum cascade laser itself as a detector.
Phase diagram of ice polymorphs under negative pressure considering the limits of mechanical stability
Authors: Matsui Takahiro , Yagasaki Takuma , Matsumoto Masakazu , Tanaka Hideki
Published: January 2019

Thermodynamic and mechanical stabilities of various ultralow-density ices are examined using computer simulations to construct the phase diagram of ice under negative pressure. Some ultralow-density ices, which were predicted to be thermodynamically metastable under negative pressures on the basis of the quasi-harmonic approximation, can exist only in a narrow pressure range at very low temperatures because they are mechanically fragile due to the large distortion in the hydrogen bonding network. By contrast, relatively dense ices such as ice Ih and ice XVI withstand large negative pressure. Consequently, various ices appear one after another in the phase diagram. The phase diagram of ice under negative pressure exhibits a different complexity from that of positive pressure because of the mechanical instability.
Various synchronous states due to coupling strength inhomogeneity and coupling functions in systems of coupled identical oscillators
Authors: Kim Junhyeok , Moon Joon-Young , Lee Uncheol , Kim Seunghwan , Ko Tae-Wook
Published: January 2019

We study the effects of coupling strength inhomogeneity and coupling functions on locking behaviors of coupled identical oscillators, some of which are relatively weakly coupled to others while some are relatively strongly coupled. Through the stability analysis and numerical simulations, we show that several categories of fully locked or partially locked states can emerge and obtain the conditions for these categories. In this system with coupling strength inhomogeneity, locked and drifting subpopulations are determined by the coupling strength distribution and the shape of the coupling functions. Even the strongly coupled oscillators can drift while weakly coupled oscillators can be locked. The simulation results with Gaussian and power-law distributions for coupling strengths are compared and discussed.
Direct quantum dynamics using variational Gaussian wavepackets and Gaussian process regression
Authors: Polyak Iakov , Richings Gareth W. , Habershon Scott , Knowles Peter J.
Published: January 2019

The method of direct variational quantum nuclear dynamics in a basis of Gaussian wavepackets, combined with the potential energy surfaces fitted on-the-fly using Gaussian process regression, is described together with its implementation. Enabling exact and efficient analytic evaluation of Hamiltonian matrix elements, this approach allows for black-box quantum dynamics of multidimensional anharmonic molecular systems. Example calculations of intra-molecular proton transfer on the electronic ground state of salicylaldimine are provided, and future algorithmic improvements as well as the potential for multiple-state non-adiabatic dynamics are discussed.
Spectral dynamics of shift current in ferroelectric semiconductor SbSI
Authors: Sotome M. , Nakamura M. , Fujioka J. , Ogino M. , Kaneko Y. , Morimoto T. , Zhang Y. , Kawasaki M. , Nagaosa N. , Tokura Y. , Ogawa N.
Published: January 2019

Significance

Shift current is one of the bulk photovoltaic phenomena in the materials without inversion symmetry, originating from the geometric Berry phase of the constituting electron bands. This concept of photocurrent generation based on the real-space shift of the electron cloud on the short timescale of optical transition is distinct from that of conventional
p–n
junction photovoltaics, where the carriers are driven by the built-in Coulomb potential. We experimentally demonstrate for a ferroelectric polar semiconductor how the subpicosecond charge swing on the relevant chemical bond changes its dynamics while scanning the excitation photon energy across the bandgap. On the interband photoexcitation above the bandgap, a finite net charge flow is produced along the electrically polar direction.
The RNA degradosome promotes tRNA quality control through clearance of hypomodified tRNA
Authors: Kimura Satoshi , Waldor Matthew K.
Published: January 2019

The factors and mechanisms that govern tRNA stability in bacteria are not well understood. Here, we investigated the influence of posttranscriptional modification of bacterial tRNAs (tRNA modification) on tRNA stability. We focused on ThiI-generated 4-thiouridine (s
4
U), a modification found in bacterial and archaeal tRNAs. Comprehensive quantification of
Vibrio cholerae
tRNAs revealed that the abundance of some tRNAs is decreased in a Δ
thiI
strain in a stationary phase-specific manner. Multiple mechanisms, including rapid degradation of a subset of hypomodified tRNAs, account for the reduced abundance of tRNAs in the absence of
thiI
. Through transposon insertion sequencing, we identified additional tRNA modifications that promote tRNA stability and bacterial viability. Genetic analysis of suppressor mutants as well as biochemical analyses revealed that rapid degradation of hypomodified tRNA is mediated by the RNA degradosome. Elongation factor Tu seems to compete with the RNA degradosome, protecting aminoacyl tRNAs from decay. Together, our observations describe a previously unrecognized bacterial tRNA quality control system in which hypomodification sensitizes tRNAs to decay mediated by the RNA degradosome.
Viscoelastic shear stress relaxation in two-dimensional glass-forming liquids
Authors: Flenner Elijah , Szamel Grzegorz
Published: January 2019

Significance

A phase transition from a liquid to an ordered solid state in two dimensions is different from that in three dimensions. In two dimensions, the appearance of quasi–long-range orientational correlations is decoupled from the that of quasi–long-range translational correlations, which is correlated with the emergence of a nonzero shear modulus. Here, we show that a similar decoupling also exists in 2D glassy phenomena, albeit with transitions replaced by crossovers. The onset of slow dynamics is signaled by the appearance of a two-step decay in orientational correlations, but a glassy viscoelastic response develops at a lower temperature.
Reconnection scaling in quantum fluids
Authors: Fonda Enrico , Sreenivasan Katepalli R. , Lathrop Daniel P.
Published: January 2019

Fundamental to classical and quantum vortices, superconductors, magnetic flux tubes, liquid crystals, cosmic strings, and DNA is the phenomenon of reconnection of line-like singularities. We visualize reconnection of quantum vortices in superfluid
4
He, using submicrometer frozen air tracers. Compared with previous work, the fluid was almost at rest, leading to fewer, straighter, and slower-moving vortices. For distances that are large compared with vortex diameter but small compared with those from other nonparticipating vortices and solid boundaries (called here the intermediate asymptotic region), we find a robust 1/2-power scaling of the intervortex separation with time and characterize the influence of the intervortex angle on the evolution of the recoiling vortices. The agreement of the experimental data with the analytical and numerical models suggests that the dynamics of reconnection of long straight vortices can be described by self-similar solutions of the local induction approximation or Biot–Savart equations. Reconnection dynamics for straight vortices in the intermediate asymptotic region are substantially different from those in a vortex tangle or on distances of the order of the vortex diameter.
Apobec3A maintains HIV-1 latency through recruitment of epigenetic silencing machinery to the long terminal repeat
Authors: Taura Manabu , Song Eric , Ho Ya-Chi , Iwasaki Akiko
Published: January 2019

Significance

Human immunodeficiency virus 1 (HIV-1) infection causes a life-long disease, due to the ability of the virus to integrate into the host genome and establish latent infection. While research has revealed a number of host restriction factors that block primary infection, much less is understood with regard to the host factors that promote or block reactivation of the integrated proviral HIV-1. In this study, we show that a member of the Apobec3A (apolipoprotein B MRNA editing enzyme catalytic subunit 3A) family, A3A, suppresses HIV-1 reactivation by recruiting chromatin-modifying enzymes to impose repressive marks around the long terminal repeat promoter region. Identification of host factors that control HIV-1 latency may provide clues for therapeutic interventions needed to remove the viral reservoir from the infected individual.
Stromal-derived interleukin 6 drives epithelial-to-mesenchymal transition and therapy resistance in esophageal adenocarcinoma
Authors: Ebbing Eva A. , van der Zalm Amber P. , Steins Anne , Creemers Aafke , Hermsen Simone , Rentenaar Rosa , Klein Michelle , Waasdorp Cynthia , Hooijer Gerrit K. J. , Meijer Sybren L. , Krishnadath Kausilia K. , Punt Cornelis J. A. , van Berge Henegouwen Mark I. , Gisbertz Suzanne S. , van Delden Otto M. , Hulshof Maarten C. C. M. , Medema Jan Paul , van Laarhoven Hanneke W. M. , Bijlsma Maarten F.
Published: January 2019

Significance

We found that cancer-associated fibroblasts, the most abundant noncancer cell type in esophageal cancer tissue, contribute to the resistance of tumors against currently applicable treatments. These cancer-associated fibroblasts do so by producing and secreting IL-6. IL-6 induces a mesenchymal, resistant tumor cell state. Inhibition of IL-6 reverted the mesenchymal cell state and resensitized tumor cells to therapy. Serum-borne proxies for the presence of IL-6–producing fibroblasts were identified and found to be predictive for the response to neoadjuvant therapy.
Los verbos de percepción en el discurso turístico promocional
Authors: Almela Jorge Soto , Coy Marta Navarro
Published: January 2019

Persuasion is the dominant function of tourist promotional texts and is fostered through the use of certain lexical devices such as verbs of perception, which engage readers and arouse in them pleasant feelings. This paper aims to compare verbs of perception in English and Spanish through the exploitation of a bilingual comparable corpus of five British and five Spanish institutional websites. In particular, the analysis conducted seeks to (1) determine which language expresses more perceptions through verbal forms, (2) analyse to what extent each language uses verbs of sensory and intellectual perception, and (3) identify equivalent verbs in both corpora. In general terms, the results show that the English corpus includes a higher frequency of verbs of perception, cognitive verbs prevail over sensory ones in both corpora, and there exist equivalent verbs which are more used in one language than in the other.
COMMD1 regulates cell proliferation and cell cycle progression by modulating p21 Cip1 levels
Authors: Jiang Zhiwen , Yuan Yuan , Zheng Huiling , Cui Hongjing , Sun Xuerong , Zhao Wei , Liu Xinguang
Published: January 2019

Copper metabolism MURR1 domain-containing 1 (COMMD1) is a protein that participates in multiple cellular processes, including copper homeostasis and nuclear factor kappa B (NF-κB) and hypoxia-inducible factor 1α (HIF-1α) signaling. The COMMD1 upstream regulators X-linked inhibitor of apoptosis protein (XIAP) and p300 and downstream targets such as NF-κB and HIF-1α are involved in the regulation of cell proliferation and cell cycle progression. However, whether COMMD1 regulates cell proliferation and the cell cycle remains unclear. In the present study, we demonstrated that both overexpression and knockdown of COMMD1 affected the proliferation of HEK293 cells, and the cell cycle assay revealed that ectopic expression of COMMD1 arrested the cell cycle at the G1 phase. Furthermore, western blot analysis showed that COMMD1 affected p21 Cip1 levels. Taken together, these results suggest that COMMD1 regulates cell proliferation and cell cycle progression by modulating p21 Cip1 levels.

Abbreviations COMMD1: Copper metabolism MURR1 domain containing 1; XIAP: X chromosome-linked inhibitor of apoptosis protein; FCS: Fetal calf serum; WCE: Whole cell extracts; RT-PCR: Reverse transcription-polymerase chain reaction; HEK293: Human embryonic kidney 293; ShRNA: Short hairpin RNA; NF-κB: Nuclear factor kappa-light-chain-enhancer of activated B cells; ARF: Alternate reading frame protein product of the CDKN2A locus.