bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Effects of Enhancing the Crosslinking Degree in High Internal Phase Emulsion Templated Poly(dicyclopentadiene)
Authors: Vakalopoulou Efthymia , Slugovc Christian 
Published: November 2019

AbstractThe effect of enhancing the crosslinking degree in polyHIPEs made from dicyclopentadiene by additionally using a crosslinking comonomer is described. Foams of 80% porosity with 10–40 wt% comonomer content in the continuous phase are prepared and show similar porosities and morphological characteristics as foams prepared with dicyclopentadiene alone. Assessing the mechanical properties reveals that the ductility is decreasing while the stiffness of the samples is increasing with increasing comonomer content. The foams containing the crosslinking comonomer take up at least five times their mass of toluene thereby swelling to at least 30 vol%. Upon drying of the swollen specimens, their initial shape and porosity are recovered. This feature distinguishes them from polyHIPEs made from dicyclopentadiene only.
Diffusion dispersion imaging: Mapping oscillating gradient spin‐echo frequency dependence in the human brain
Authors: Arbabi Aidin , Kai Jason , Khan Ali R. , Baron Corey A. 
Published: November 2019

PurposeOscillating gradient spin‐echo (OGSE) diffusion MRI provides information about the microstructure of biological tissues by means of the frequency dependence of the apparent diffusion coefficient (ADC). ADC dependence on OGSE frequency has been explored in numerous rodent studies, but applications in the human brain have been limited and have suffered from low contrast between different frequencies, long scan times, and a limited exploration of the nature of the ADC dependence on frequency.Theory and MethodsMultiple frequency OGSE acquisitions were acquired in healthy subjects at 7T to explore the power‐law frequency dependence of ADC, the “diffusion dispersion.” Furthermore, a method for optimizing the estimation of the ADC difference between different OGSE frequencies was developed, which enabled the design of a highly efficient protocol for mapping diffusion dispersion.ResultsFor the first time, evidence of a linear dependence of ADC on the square root of frequency in healthy human white matter was obtained. Using the optimized protocol, high‐quality, full‐brain maps of apparent diffusion dispersion rate were also demonstrated at an isotropic resolution of 2 mm in a scan time of 6 min.ConclusionsThis work sheds light on the nature of diffusion dispersion in the healthy human brain and introduces full‐brain diffusion dispersion mapping at clinically relevant scan times. These advances may lead to new biomarkers of pathology or improved microstructural modeling.
Highly efficient head‐only magnetic field insert gradient coil for achieving simultaneous high gradient amplitude and slew rate at 3.0T (MAGNUS) for brain microstructure imaging
Authors: Foo Thomas K. F. , Tan Ek Tsoon , Vermilyea Mark E. , Hua Yihe , Fiveland Eric W. , Piel Joseph E. , Park Keith , Ricci Justin , Thompson Paul S. , Graziani Dominic , Conte Gene , Kagan Alex , Bai Ye , Vasil Christina , Tarasek Matthew , Yeo Desmond T.B. , Snell Franklyn , Lee David , Dean Aaron , DeMarco J. Kevin , Shih Robert Y. , Hood Maureen N. , Chae Heechin , Ho Vincent B. 
Published: November 2019

PurposeTo develop a highly efficient magnetic field gradient coil for head imaging that achieves 200 mT/m and 500 T/m/s on each axis using a standard 1 MVA gradient driver in clinical whole‐body 3.0T MR magnet.MethodsA 42‐cm inner diameter head‐gradient used the available 89‐ to 91‐cm warm bore space in a whole‐body 3.0T magnet by increasing the radial separation between the primary and the shield coil windings to 18.6 cm. This required the removal of the standard whole‐body gradient and radiofrequency coils. To achieve a coil efficiency ~4× that of whole‐body gradients, a double‐layer primary coil design with asymmetric x‐y axes, and symmetric z‐axis was used. The use of all‐hollow conductor with direct fluid cooling of the gradient coil enabled ≥50 kW of total heat dissipation.ResultsThis design achieved a coil efficiency of 0.32 mT/m/A, allowing 200 mT/m and 500 T/m/s for a 620 A/1500 V driver. The gradient coil yielded substantially reduced echo spacing, and minimum repetition time and echo time. In high b = 10,000 s/mm2 diffusion, echo time (TE) < 50 ms was achieved (>50% reduction compared with whole‐body gradients). The gradient coil passed the American College of Radiology tests for gradient linearity and distortion, and met acoustic requirements for nonsignificant risk operation.ConclusionsUltra‐high gradient coil performance was achieved for head imaging without substantial increases in gradient driver power in a whole‐body 3.0T magnet after removing the standard gradient coil. As such, any clinical whole‐body 3.0T MR system could be upgraded with 3‐4× improvement in gradient performance for brain imaging.
Nonlinear shear of entangled polymers from nonequilibrium molecular dynamics
Authors: Anwar Muhammad , Graham Richard S. 
Published: November 2019

ABSTRACTThis study aims to use molecular dynamics (MD) simulations of Kremer–Grest (KG) chains to inform future developments of models of entangled polymer dynamics. We perform nonequilibrium MD simulations, under shear flow, for well‐entangled KG chains. We study chains of 512 and 1000 KG beads, corresponding to 8 and 15 entanglements, respectively. We compute the linear rheological properties from equilibrium simulations of the stress autocorrelation and obtain from these data the tube model parameters. Under nonlinear shear flow, we compute the shear viscosity, the first and second normal stress differences, and chain contour length. For chains of 512 monomers, we obtain agreement with the results of Cao and Likhtman (ACS Macro. Lett. 2015, 4, 1376). We also compare our nonlinear results with the Graham, Likhtman and Milner‐McLeish (GLaMM) model. We identify some systematic disagreement that becomes larger for the longer chains. We made a comparison of the transient shear stress maximum from our simulations, two nonlinear models and experiments on a wide range of melts and solutions, including polystyrene (PS), polybutadiene, and styrene–butadiene rubber. This comparison establishes that the PS melt data show markedly different behavior to all other melts and solutions and KG simulations reproduce the PS data more closely than either the GLaMM or Xie and Schweizer models. We discuss the performance of these models against the data and simulations. Finally, by imposing a rapid reversing flow, we produce a method to extract the recoverable strain from MD simulations, valid for sufficiently entangled monodisperse polymers. We explore how the resulting data can probe the melt state just before the reversing flow. © 2019 The Authors. Journal of Polymer Science Part B: Polymer Physics published by Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2019, 57, 1692–1704
Structural and functional characterization of three Type B and C chloramphenicol acetyltransferases from Vibrio species
Authors: Alcala Ashley , Ramirez Guadalupe , Solis Allan , Kim Youngchang , Tan Kemin , Luna Oscar , Nguyen Karen , Vazquez Daniel , Ward Michael , Zhou Min , Mulligan Rory , Maltseva Natalia , Kuhn Misty L. 
Published: November 2019

AbstractChloramphenicol acetyltransferases (CATs) were among the first antibiotic resistance enzymes identified and have long been studied as model enzymes for examining plasmid‐mediated antibiotic resistance. These enzymes acetylate the antibiotic chloramphenicol, which renders it incapable of inhibiting bacterial protein synthesis. CATs can be classified into different types: Type A CATs are known to be important for antibiotic resistance to chloramphenicol and fusidic acid. Type B CATs are often called xenobiotic acetyltransferases and adopt a similar structural fold to streptogramin acetyltransferases, which are known to be critical for streptogramin antibiotic resistance. Type C CATs have recently been identified and can also acetylate chloramphenicol, but their roles in antibiotic resistance are largely unknown. Here, we structurally and kinetically characterized three Vibrio CAT proteins from a nonpathogenic species (Aliivibrio fisheri) and two important human pathogens (Vibrio cholerae and Vibrio vulnificus). We found all three proteins, including one in a superintegron (V. cholerae), acetylated chloramphenicol, but did not acetylate aminoglycosides or dalfopristin. We also determined the 3D crystal structures of these CATs alone and in complex with crystal violet and taurocholate. These compounds are known inhibitors of Type A CATs, but have not been explored in Type B and Type C CATs. Based on sequence, structure, and kinetic analysis, we concluded that the V. cholerae and V. vulnificus CATs belong to the Type B class and the A. fisheri CAT belongs to the Type C class. Ultimately, our results provide a framework for studying the evolution of antibiotic resistance gene acquisition and chloramphenicol acetylation in Vibrio and other species.
A direct NN‐approximation control for uncertain nonaffine systems with unknown control direction
Authors: Zhang Yao , Chen Shengyong , Diao Chen , Xian Bin 
Published: November 2019

SummaryIn this paper, we present an adaptive neural network (NN) controller for uncertain nonaffine systems with unknown control direction. Most of the previous NN‐based controllers included a damping term in the adaptive law of NN weights to ensure the closed‐loop stability. The estimated error of the NN weights as well as the tracking error were therefore increased, relying not only on the size of the NN approximation error but also on the ideal NN weights. Compared with those, the proposed controller evades using the damping term through combining a novel adaptive algorithm and a switching mechanism to update the weights. The NN thus can directly approach a target controller with satisfactory accuracy even if the control direction is unknown. Stability analysis shows that the tracking error and the estimated error of NN weights both converge to small neighbors of 0 which solely depend on the NN approximation error. At last, simulations on a Duffing‐Holmes chaotic model show the effectiveness of the proposed controller in comparison to another NN‐based method.
The effect of FRP prestressing on the fatigue performance of strengthened RC beams
Authors: Garcez Mônica Regina , Meneghetti Leila Cristina , Teixeira Ritermayer Monteiro 
Published: November 2019

AbstractAlthough Fiber Reinforced Polymer (FRP) prestressing is widely recognized for enhancing the serviceability conditions of strengthened structural elements, there are no available fatigue prediction models encompassing the specificities and advantages of FRP prestressing. In this context, this paper addresses the effect of FRP prestressing on the fatigue performance of strengthened reinforced concrete (RC) beams through the assessment of experimental data, constant life diagrams, and the adjustment of specific stress versus number of cycle (S‐N) curves for RC strengthened with prestressed FRP. First, data obtained through the development of an experimental program give an insight into the long‐term behavior of full‐scale beams subjected to in‐service and severe fatigue loading conditions. Fatigue life prediction models based on the adjustment of S‐N curves are developed using an extensive database of failure data and runouts of fatigue tests. Finally, data of fatigue tests plotted in a constant life diagram evidence the combined effects of stress range, mean stress, R ratio, and reinforcing steel properties on the fatigue life of RC beams strengthened with prestressed FRP. Results highlight the positive effects of FRP prestressing by the improvement of serviceability condition under static loading and the increasing of endurance limit under cyclic loading.
A novel phylogenetic infrageneric classification of Baccharis (Asteraceae: Astereae), a highly diversified American genus
Authors: Heiden Gustavo , Antonelli Alexandre , Pirani José Rubens 
Published: November 2019

AbstractWe present the hitherto most comprehensive phylogenetic hypothesis for Baccharis. Our results confirm that subtribe Baccharidinae is a monogeneric group and support a broad circumscription of Baccharis as monophyletic with the inclusion of all genera that have been previously segregated from it (Baccharidastrum, Baccharidiopsis, Heterothalamulopsis, Heterothalamus, Lanugothamnus). We provide comprehensive lists of accepted and synonymized infrageneric taxa. Seven main lineages are recognized, which we treat as subgenera. Subgenera Baccharis and Molina roughly match previous circumscriptions, while subgenera Pteronioides and Stephananthus are merged with Molina. In total, we propose that Baccharis comprises 440 species classified into 7 subgenera and 47 sections, while 22 sections are considered synonyms. The phylogeny provided constitutes the basis for further exploration of the evolutionary processes that have allowed the group to attain its wide geographic distribution, morphological variation, variable sexual reproductive strategies, and complex chemical contents.
Realizing the Promise of Project‐Based Learning
Authors: Revelle Katie Z. , Wise Crystal N. , Duke Nell K. , Halvorsen Anne‐Lise 
Published: November 2019

AbstractAs the popularity of project‐based learning grows, so does the importance of understanding how this instructional approach can support students’ learning and development. The authors describe a project‐based approach to literacy and social studies instruction that research has shown to be effective. Key characteristics of the approach and illustrations of how those characteristics are enacted in a project‐based learning geography unit are identified. In the unit, students develop informational reading and persuasive writing skills and learn key social studies content and skills by engaging in the development of brochures about their local community for an authentic audience. The authors also describe how educators can navigate common challenges that can arise when transitioning to a project‐based approach.
Mapping Exosome–Substrate Interactions In Vivo by UV Cross-Linking
Authors: Delan-Forino Clémentine , Tollervey David 
Published: November 2019

AbstractThe RNA exosome complex functions in both the accurate processing and rapid degradation of many classes of RNA in eukaryotes and Archaea. Functional and structural analyses indicate that RNA can either be threaded through the central channel of the exosome or more directly access the active sites of the ribonucleases Rrp44 and Rrp6, but in most cases, it remains unclear how many substrates follow each pathway in vivo. Here we describe the method for using an UV cross-linking technique termed CRAC to generate stringent, transcriptome-wide mapping of exosome–substrate interaction sites in vivo and at base-pair resolution.
Use of energy-dispersive X-ray fluorescence combined with chemometric modelling to classify honey according to botanical variety and geographical origin
Authors: Fiamegos Yiannis , Dumitrascu Catalina , Ghidotti Michele , de la Calle Guntiñas Maria Beatriz 
Published: November 2019

AbstractHoney is one of the food commodities most frequently affected by fraud. Although addition of extraneous sugars is the most common type of fraud, analytical methods are also needed to detect origin masking and misdescription of botanical variety. In this work, multivariate analysis of the content of certain macro- and trace elements, determined by energy-dispersive X-ray fluorescence (ED-XRF) without any type of sample treatment, were used to classify honeys according to botanical variety and geographical origin. Principal component analysis (PCA) and partial least squares-discriminant analysis (PLS-DA) were used to create classification models for nine different botanical varieties—orange, robinia, lavender, rosemary, thyme, lime, chestnut, eucalyptus and manuka—and seven different geographical origins—Italy, Romania, Spain, Portugal, France, Hungary and New Zealand. Although characterised by 100% sensitivity, PCA models lacked specificity. The PLS-DA models constructed for specific combinations of botanical variety-country (BV-C) allowed the successful classification of honey samples, which was verified by external validation samples.
Hierarchical syntactic models for human activity recognition through mobility traces
Authors: Casella Enrico , Ortolani Marco , Silvestri Simone , Das Sajal K. 
Published: November 2019

AbstractRecognizing users’ daily life activities without disrupting their lifestyle is a key functionality to enable a broad variety of advanced services for a Smart City, from energy-efficient management of urban spaces to mobility optimization. In this paper, we propose a novel method for human activity recognition from a collection of outdoor mobility traces acquired through wearable devices. Our method exploits the regularities naturally present in human mobility patterns to construct syntactic models in the form of finite state automata, thanks to an approach known asgrammatical inference. We also introduce a measure ofsimilaritythat accounts for the intrinsic hierarchical nature of such models, and allows to identify the common traits in the paths induced by different activities at various granularity levels. Our method has been validated on a dataset of real traces representing movements of users in a large metropolitan area. The experimental results show the effectiveness of our similarity measure to correctly identify a set of common coarse-grained activities, as well as their refinement at a finer level of granularity.
Noninvasive population assessment of moose (Alces alces) by SNP genotyping of fecal pellets
Authors: Blåhed Ida-Maria , Ericsson Göran , Spong Göran 
Published: November 2019

AbstractNoninvasive genetic studies of wild animals enable the recovery of information infeasible to obtain using other means. However, the low quantity and quality of noninvasively collected DNA often challenge the retrieval of reliable genotypes, which may cause biases in downstream analyses. In this study, we optimized SNP (single nucleotide polymorphism) genotyping of fecal samples from moose (Alces alces) with the main purpose of exploring the potential of using noninvasively retrieved genotypes for individual- and sex identification. Fecal pellets were collected during the late winter of 2016 on the Swedish island of Öland in the Baltic Sea and DNA was extracted and genotyped using 86 autosomal, six sex-specific and five species diagnostic SNPs. The SNP error rate of the quality filtered dataset was 0.06 and the probability of identity for siblings below 0.001. Following a thorough quality filtering process, 182 reliable genotypes were obtained, corresponding to 100 unique individuals (37 males, 63 females), with an estimated male proportion of 37% (± 9%). The population size, estimated using two different capture-mark-recapture approaches, was found to be in the range of 115–156 individuals (95% CI). Furthermore, moose on Öland showed significantly lower heterozygosity levels (zHexp = −5.51, N = 69, pHexp = 3.56·10−8, zHobs = −3.58, N = 69, pHobs = 3.38·10−4) and appeared genetically differentiated from moose on the Swedish mainland. Thus, we show that quality controlled noninvasively derived SNP genotypes can be highly informative for individual and population monitoring in a large ungulate.
Entropy stable numerical approximations for the isothermal and polytropic Euler equations
Authors: Winters Andrew R. , Czernik Christof , Schily Moritz B. , Gassner Gregor J. 
Published: November 2019

AbstractIn this work we analyze the entropic properties of the Euler equations when the system is closed with the assumption of a polytropic gas. In this case, the pressure solely depends upon the density of the fluid and the energy equation is not necessary anymore as the mass conservation and momentum conservation then form a closed system. Further, the total energy acts as a convex mathematical entropy function for the polytropic Euler equations. The polytropic equation of state gives the pressure as a scaled power law of the density in terms of the adiabatic index $$\gamma $$
γ
. As such, there are important limiting cases contained within the polytropic model like the isothermal Euler equations ($$\gamma {=}1$$

γ
=
1

) and the shallow water equations ($$\gamma {=}2$$

γ
=
2

). We first mimic the continuous entropy analysis on the discrete level in a finite volume context to get special numerical flux functions. Next, these numerical fluxes are incorporated into a particular discontinuous Galerkin (DG) spectral element framework where derivatives are approximated with summation-by-parts operators. This guarantees a high-order accurate DG numerical approximation to the polytropic Euler equations that is also consistent to its auxiliary total energy behavior. Numerical examples are provided to verify the theoretical derivations, i.e., the entropic properties of the high order DG scheme.
Capturing the dynamic and cyclical nature of regulation: Methodological Progress in understanding socially shared regulation in learning
Authors: Järvelä Sanna , Järvenoja Hanna , Malmberg Jonna 
Published: November 2019

AbstractSelf-regulation is critical for successful learning, and socially shared regulation contributes to productive collaborative learning. The problem is that the psychological processes at the foundation of regulation are invisible and, thus, very challenging to understand, support, and influence. The aim of this paper is to review the progress in socially shared regulation research data collection methods for trying to understand the complex process of regulation in the social learning context, for example, collaborative learning and computer-supported collaborative learning. We highlight the importance of tracing the sequential and temporal characteristics of regulation in learning by focusing on data for individual- and group-level shared regulatory activities that use technological research tools and by gathering in-situ data about students’ challenges that provoke regulation of learning. We explain how we understand regulation in a social context, argue why methodological progress is needed, and review the progress made in researching regulation of learning.
Personality, Luck Beliefs, and (Non-?) Problem Lottery Gambling
Authors: Thompson Edmund R. , Prendergast Gerard P. , Dericks Gerard H. 
Published: November 2019

AbstractThis study offers both the first systematic investigation of the relationship between the five-factor personality model and general (ostensibly non-problem) lottery gambling, and the first application of Thompson and Prendergast’s (2013) bidimensional model of luck beliefs to gambling behavior. Cross-sectional analyses (N = 844) indicate the bidimensional model of luck beliefs significantly accounts for variance in lottery gambling that is discrete from and greater than that of the five-factor personality model. Moreover, the broad pattern of relationships we find between presumably harmless state-sponsored lottery gambling and both personality and luck beliefs tend to parallel those found in studies of problem gambling, suggesting implications for quality of life and public policy in relation to lottery gambling.