bluuebunny/crossref_metadata_2025 huggingface dataset:
Intumescent polypropylene: Interactions between physical and chemical expansion
Authors: Bensabath Tsilla , Sarazin Johan , Jimenez Maude , Samyn Fabienne , Bourbigot Serge
Published: November 2019

To decrease the reaction to fire of a highly flammable plastic, polypropylene (PP), the concept of intumescence was applied. Two intumescent systems were designed on the basis of different mechanisms: physical expansion with expandable graphite (EG) and chemical expansion with modified ammonium polyphosphate (AP). Fire behavior of PP containing EG, AP, or an AP/EG mixture with a total loading of 10 wt% was evaluated by cone calorimetry at 35 kW·m−2. Thermocouples allowed measuring the temperature at the backside or inside samples over time and evaluating the thermal barrier of these intumescent materials. Two grades of AP (difference in composition) and several grades of EG (difference in expansion characteristics) were compared. Mixing AP and EG does not create a synergistic effect in studied conditions. Contrarily, the incorporation of small amount of EG in PP‐AP modifies heat transfer in the coating, creating a strong anisotropy. Graphite worms are trapped vertically into the expanded AP, which increases the transverse heat conductivity (lower efficiency of the thermal barrier) and decreases the fire performance. This phenomenon disappears in thicker specimens. While a higher expansion volume of graphite worms improves fire performances of PP with only small amount of EG (1 wt%), this effect is not noticeable with AP/EG mixtures.
Horizon Scanning in Foresight – Why Horizon Scanning is only a part of the game
Authors: Cuhls Kerstin E.
Published: November 2019

Foresight and Horizon Scanning are often regarded as identical concepts with identical models and purposes. But they can be completely different activities, both in and for any kind of prospective activity as well as for strategy purposes. Scanning is no debate and no strategy building. Whereas Foresight is more process‐oriented and always includes a Horizon Scanning phase, Horizon Scanning is rather found at the beginning of any forward‐looking activity and can be an automatized stand‐alone approach for identifying “things to come” ‐ which often means the identification of new science and technology and providing information about them. This paper wants to shed light on some of the confusions in Foresight and Horizon Scanning (HS) that often occur in organizations, among researchers and practitioners being thus of practical and scientific relevance for using an integrated model. The contribution is backed up by a study conducted for the European Commission (Cuhls et al., 2015) conducted to clarify for the Commission’s Foresight department (A6) how the strategic intelligence part of a foresight, the Horizon Scanning, is intertwined with the sense‐making part in similar projects in other parts of the world. The contribution thus starts with a broad definition of Foresight and of Horizon Scanning, explains findings from the study on objectives, methods used and relates the discussion to the EU standard “Foresight Cycle” derived from EFFLA. The conclusions are relevant for decision‐making and strategy processes in the European Commission, for national foresight processes but also for company's and other users.
Mapping the University of Washington Quality of life questionnaire onto EQ‐5D and HUI‐3 indices in patients with head and neck cancer
Authors: Stephens Robert F. , Noel Christopher W. , Su Jie (Susie) , Xu Wei , Krahn Murray , Monteiro Eric , Goldstein David P. , Giuliani Meredith , Hansen Aaron R. , de Almeida John R.
Published: November 2019

Background

There is no mechanism to predict health utility (HU) values from the University of Washington Quality of Life Questionnaire (UWQoL) scores. We sought to develop a mapping algorithm capable of using UWQoL data to approximate HU scores.

Methods

Outpatients with head and neck cancer completed the UWQoL, EQ‐5D, and the Health Utilities Index‐Mark 3 (HUI‐3). Results of the UWQoL were mapped onto both EQ‐5D and HUI‐3 scores using ordinary least‐squares regression models. Two‐part models were explored. The predictive power of the model was assessed using 10‐fold cross‐validation.

Results

A total of 209 patients were recruited. The reduced model converting UWQoL data into EQ‐5D scores performed best (adjusted R2 = 0.628, root mean square error = 0.076). Both models demonstrated construct validity by discriminating between clinical indices of disease severity.

Conclusions

The abovementioned algorithms enable researchers to perform health economic evaluations with existing UWQoL data in cases where prospectively collected HU values are not available.
Pelvic inflammatory disease and risk of cancer: A nationwide cohort study
Authors: Søgaard Kirstine K. , Leisner Michelle Z. , Laugesen Kristina , Farkas Dóra K. , Karagas Margaret R. , Sørensen Henrik T.
Published: November 2019

≥1 year after PID diagnosis, an elevated risk persists for female genital cancers and smoking‐related cancers.
Nonresponse Bias in Sample Surveys
Authors: Kinney Satkartar K. , Cooney Darryl A.
Published: November 2019

Nonresponse is an increasing problem in sample surveys and student surveys are no exception. When nonrespondents differ from respondents in meaningful ways, respondents may not be representative of the population. Hence, analyses of survey data may be biased and not generalizable to the population. In this chapter we provide an overview of nonresponse bias and discuss how to assess the potential for bias in survey results and steps that can be taken to address bias during and after data collection. An example bias analysis is provided.
The National Student Clearinghouse: Leveraging Administrative Data for Postsecondary Improvement
Authors: Shapiro Douglas T. , Tang Zun
Published: November 2019

We provide an overview of existing and emerging ways that institutional researchers can leverage National Student Clearinghouse data to expand a culture of data‐driven decision‐making across campus, with a focus on examples from the field.
Martini Force Field for Protonated Polyethyleneimine
Authors: Beu Titus Adrian , Ailenei Andrada‐Elena , Costinaş Răzvan‐Ioan
Published: November 2019

Polyethyleneimine (PEI), one of the most widely used nonviral gene carriers, was investigated in the presented work at coarse‐grained (CG) level. The main focus was on elaborating a realistic CG force field (FF) aimed to reproduce dynamic structural features of protonated PEI chains and, furthermore, to enable massive simulations of DNA–PEI complex formation and condensation. We parametrized CG Martini FF models for PEI in polarizable and nonpolarizable water by applying Boltzmann inversion techniques to all‐atom (AA) probability distributions for distances, angles, and dihedrals of entire monomers. The fine‐tuning of the FFs was achieved by fitting simulated CG gyration radii and end‐to‐end distances to their AA counterparts. The developed Martini FF models are shown to be well suited for realistic large‐scale simulations of size/protonation‐dependent behavior of solvated PEI chains, either individually or as part of DNA–PEI systems. © 2019 Wiley Periodicals, Inc.
Benzoylquinazolinone derivatives as new potential antidiabetic agents: α‐Glucosidase inhibition, kinetic, and docking studies
Authors: Mohammadi‐Khanaposhtani Maryam , Yahyavi Hoda , Imanparast Somaye , Harandi Fereshte Nazemi , Faramarzi Mohammad Ali , Foroumadi Alireza , Larijani Bagher , Biglar Mahmood , Mahdavi Mohammad
Published: November 2019

Benzoylquinazolinone derivatives 3a–n were synthesized via a simple one‐step reaction, and evaluated for in vitro α‐glucosidase inhibitory activity. Compounds 3d, 3f–g, 3i, and 3m–n showed more inhibitory activity than standard drug acarbose (IC50 = 750.0 ± 1.5 μM), and among them, compound 3d displayed the highest α‐glucosidase inhibitory activity (IC50 = 261.6 ± 0.1 μM). The kinetic analysis of the compound 3d revealed that this compound inhibited α‐glucosidase in a competitive manner (Ki = 255 μM). The docking studies were applied to predict binding modes of the synthesized compounds in active site of α‐glucosidase.
Pd(OAc)2 promoted bis‐N‐heterocyclic carbene‐catalyzed oxidative transformation of aldehydes
Authors: Yu Ya‐Han , Wang Tsui , Chiu Chien‐Cheng , Lu Ta‐Jung , Lee Dong‐Sheng
Published: November 2019

The bis‐N‐heterocyclic carbene‐catalyzed (bis‐NHC‐catalyzed) oxidative transformation of aldehydes was successfully studied in water under air. The reaction rate increased through the use of Pd(OAc)2 as an additive. Notably, the catalytic system exhibited good tolerance toward aliphatic and aromatic aldehydes bearing halide and alkyl functional groups. In addition, gram‐scale reaction was also tested in this study. The use of water and operational simplicity make this methodology environmentally benign and cost‐effective.
Parametric study of modified dipole nano‐antennas printed on thick substrates for infrared energy harvesting
Authors: Amara Wided , Oueslati Donia , Eltresy Nermeen , Alghamdi Abdulsalam , Sedraoui Khaled , Aguili Taoufik , Rmili Hatem , Mittra Raj
Published: November 2019

Three efficient infrared‐printed dipole nano‐antennas are designed on a dielectric substrate for infrared energy harvesting. The three printed dipoles have different shapes, namely, rectangular, curved bowtie, and elliptical. These antennas are designed in to collect maximum electric field in the gap between the two poles in the frequency band of 28to 29THz, which is chosen because the received infrared power is maximum at 28.3 THz. A parametric study of the three proposed dipole shapes is performed to increase the localized electric field as well as modify to achieve resonance frequency at 28.3 THz. A parametric study is carried out to determine the dipole length, width, gap size, substrate thickness, and ground plane thickness. Next, the three dipoles are exposed to different polarizations incident plane waves in order to study the effect of the polarization of the incident wave on the electric field induced in the gap and to compare the performances of the three designs. The comparison study shows that at 28.3 THz, the curved bowtie dipole shape collects a larger electric field than the rectangular and elliptical shapesdo.
Phosphorus uptake from struvite is modulated by the nitrogen form applied
Authors: Robles-Aguilar Ana A. , Schrey Silvia D. , Postma Johannes A. , Temperton Vicky M. , Jablonowski Nicolai D.
Published: November 2019

Next to nitrogen, phosphorus (P) is the most limiting nutrient for plant production worldwide. To secure food production, new nutrient management strategies using alternative P sources instead of mined P fertilizers need to be implemented. Struvite (MgNH4PO4 · 6 H2O) is a promising example of a recycled mineral P fertilizer. Besides positive agronomic results regarding crop yields, further investigations are required to improve the use efficiency of the product and thereby increase its value. Using an automated plant phenotyping platform, we investigated the dynamic response to struvite by two plant species (lupine and maize) with diverse P acquisition strategies in an acidic sandy substrate. Although at three weeks after germination both maize and lupine had reduced leaf area in the struvite treatments compared to the commercial triple superphosphate (TSP), from week four onwards struvite plants grew larger than the TSP‐treated plants, indicating a slow release fertilizing effect. Greater P uptake efficiency (g / root length), but reduced root length were observed in the combined treatment of struvite and ammonium, in comparison to struvite and nitrate. We propose that rhizosphere acidification in response to ammonium uptake may enhance P recovery from struvite. A possible additional acidification effect by lupine root exudation might explain the higher P uptake efficiency in this species compared to maize. We conclude that struvite combined with ammonium can be used as a sustainable slow‐release P fertilizer on acidic sandy soils.
Predicting and Controlling the Effect of Solubilized Flavor Oil on Foam Properties of Surfactant through Study of the Adsorption Activity and Configuration
Authors: Qi Na , Chen Ziyun , Zhao Hui , Wang Qiaozhi , Chen Heng , Yuan Hao , Li Ying
Published: November 2019

In the wide application of foam products, the effect of oil additive on foam property is a critical issue that has gained increasing attention; the effect on foam induced by various flavor oils is still a puzzling question, and relative study is rare. In this article, a series of typical flavor oils were studied for their effects on the foam properties of sodium dodecylsulfate. Measurements of foamability, foam stability, foam elasticity, and surface activity were taken; meanwhile, molecular dispersion and interfacial arrangement behavior of surfactant and oil molecules were explored by molecular dynamics simulation. Through a combination of macroscopic phenomenon and microscopic information, how flavor oils with different chemical structures affected the foaming properties of surfactants was demonstrated, and an evaluation scheme for predicting the level of influence on foam properties by different flavor oils was constructed. This investigation may help better understand the role of flavor oils in foam systems and provide a theoretical foundation for optimizing the application of flavor oils in relevant industries.
Assessing Step Count–Dependent Changes in Femoral Articular Cartilage Using Ultrasound
Authors: Pfeiffer Steven J. , Davis‐Wilson Hope C. , Pexa Brett , Szymczak Jessica , Wistreich Catherine , Sorensen Rachel , Wikstrom Erik A. , Blackburn J. Troy , Pietrosimone Brian
Published: November 2019

Objectives

To evaluate changes in the femoral cartilage cross‐sectional area (CSA) measured with ultrasound (US) between baseline and 1000, 2000, 3000, 4000, and 5000 steps of walking on a treadmill.

Methods

Forty‐one healthy individuals completed a single testing session. Participants rested with their knees extended on a plinth for 45 minutes to unload the femoral cartilage. Ultrasound was used to acquire images of the femoral cartilage before the treadmill‐walking protocol. After the baseline US acquisition, participants walked on a treadmill at their preferred overground walking speed for 1000 steps, after which additional US images of the femoral cartilage were acquired. This process was repeated after 2000, 3000, 4000, and 5000 steps. A 1‐way repeated‐measures analysis of variance compared the CSA across the 6 step counts. An analysis of variance with repeated measures on time and Bonferroni corrected planned comparisons (.05/5) were used to evaluate differences in the femoral cartilage at each step count compared to baseline.

Results

The study included 20 male and 21 female participants (mean age ± SD, 21.5 ± 2.8 years; mean body mass index, 24.3 ± 3.4 kg/m
2
). The CSAs were significantly greater at the 2000‐step (1.27 ± 1.75 mm
2
; P < .001), 4000‐step (0.89 ± 1.17 mm2; P < .001), and 5000‐step (2.10 ± 1.73 mm
2
; P < .001) points compared to baseline. The CSA was significantly less at the 3000‐step point (1.05 ± 1.29 mm
2
; P < .001) compared to baseline.

Conclusions

Changes in the CSA after walking may be dependent on the number of steps. The participants had a significant decrease in the CSA after 3000 steps of normal walking and a significant increase in the CSA after 2000, 4000, and 5000 steps of normal walking.
Risk Factors Affecting Length of Stay in Patients with Deep Neck Space Infection
Authors: O'Brien Kaitlin July , Snapp Kaitlin R. , Dugan Adam J. , Westgate Philip M. , Gupta Nikita
Published: November 2019

Objectives

Analyze risk factors affecting length of stay (LOS) for patients presenting with deep neck space infections including care by medical versus surgical team.

Methods

This is a retrospective chart review from January 2005 through May 2018 at the University of Kentucky analyzing factors related to deep neck space abscesses. Patients included adults >18 years old admitted for deep neck space infections undergoing surgical intervention. This study compared effects of treatment on a medical versus surgical service on LOS while accounting for patient confounders. Independent variables included age, gender, tobacco use, medical comorbidities, Charlson comorbidity index, American Society of Anesthesiology (ASA) classification, presence of drain, readmissions, and repeat surgical interventions. Univariate and multivariate analysis were performed.

Results

One hundred sixty‐three patients were included in the analysis. LOS was significantly longer for those on medicine services (P < .001). Patients on medicine services had a higher incidence of diabetes (P = .011), higher Charlson comorbidity score (P = .001), and higher incidence of repeat interventions (P = .005). Postoperative LOS remained lower for patients on a surgical service (P = .009) after adjusting for Charlson comorbidity scores. Presence of a drain or tobacco use was not significant between service management (P = .89; P = .63) or LOS (P = .366; P = .225).

Conclusion

Increased postoperative LOS was associated with age, diabetes, ASA class, Charlson comorbidity index, and repeat procedures. Patients on a medicine service had longer LOS and higher comorbidity indices. Patients had shorter hospital stays on surgical services after adjusting for comorbidity indices. Use of a drain or presence of tobacco use did not affect LOS.

Level of Evidence

3 Laryngoscope, 130:2133–2137, 2020
Opioid sparing multimodal analgesia treats pain after head and neck microvascular reconstruction
Authors: Lee Thomas S. , Wang Lexie L. , Yi Dae Ik , Prasanna Praveen D. , Kandl Christopher
Published: November 2019

Objective

To compare pain control (opioid consumption and postsurgical pain scores) in head and neck (H&N) free flap reconstruction patients who undergo traditional means of postoperative analgesia including use of opioids versus a novel protocol that includes ketamine and gabapentin.

Methods

Single‐institution retrospective cohort study.

Results

Eighty‐six patients who underwent H&N free flap reconstruction from 2015 to 2018 were included. Forty‐three patients were in the control cohort treated with opioids only, and 43 patients were in the treatment group. There was a statistically significant decrease in opioid consumption in each of the first 5 postoperative days ranging from 80% to 83% in the treatment group. The daily pain scores were significantly lower in the treatment group in the first 2 postoperative days. At the 1‐month postoperative visit, there was no significant difference in pain scores between the groups; however, by the 2‐month visit, the treatment group reported significantly lower pain scores than the control group (P = 0.001). No adverse outcomes of ketamine or gabapentin were experienced.

Conclusion

Ketamine and gabapentin are safe and effective analgesics in H&N free flap surgery that significantly decrease opioid use in the acute postoperative setting and may improve pain control.

Level of Evidence

3a

Laryngoscope, 130:1686–1691, 2020
Does damming streams alter the water use strategies of riparian trees? A case study in a subtropic climate
Authors: Zhao Pei , Cornelis Wim , Tang Xiangyu , Zhao Peng , Tang Jialiang
Published: November 2019

Understand the mechanism governing degradation of riparian forests in response to damming streams is needed for a comprehensive impact assessment of dams in relation to protection of river ecosystems. However, the ascription of riparian forest degradation to the hydrological changes induced by dams lacks of direct proof and the hypothesis that dam construction alters the water use strategy of riparian trees is yet to be tested. In this study, the water sources of riparian trees grown upstream and downstream of dams at SW China, were investigated by dual isotopes and a Bayesian model. We observed that xylem water in downstream Populus adenopoda had significantly lower line‐conditioned excess values than upstream trees. The water source of upstream trees was barely subjected to evaporation. Upstream mature and young P. adenopoda trees both acquired more streamwater (47.2 ± 9.8% and 44.8 ± 7.9%) than groundwater (28.2 ± 4.4% and 29.2 ± 3.5%) or soil water (24.5 ± 5.6% and 26.0 ± 4.9%). Downstream mature and young P. adenopoda trees both largely used soil water (49.0 ± 11.6% and 53.0 ± 6.2%) as main water source. In contrast, Pterocarya stenoptera highly depended on streamwater, regardless of size and location, implying that damming had little effect on this species. Damming streams may increase water competition among downstream riparian trees, which could explain declines in growth rate, canopy dieback, tree death, and eventually downstream land degradation. We believe that this study is of significant value for research into riparian forest degradation resulting from hydrological changes, and in particular to apprehend the impact of small dams, which has barely been studied.
The Effects of Enhancing the Crosslinking Degree in High Internal Phase Emulsion Templated Poly(dicyclopentadiene)
Authors: Vakalopoulou Efthymia , Slugovc Christian
Published: November 2019

The 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.
Continuing resolution passage extends CCBHC demonstration
Authors: Canady Valerie A.
Published: November 2019

Congress on Nov. 21 voted to approve a continuing resolution that would extend the federal government through Dec. 20 and includes a short‐term extension for the Certified Community Behavioral Health Clinic (CCBHC) demonstration program.
Stigma prevention program encourages students to discuss MH
Authors: Canady Valerie A.
Published: November 2019

A New York–based stigma prevention program that began as an online public awareness campaign for young people three years ago is evolving into a community outreach plan for educators and school staff members who will be trained on how to encourage students to converse with a trusted person about their mental health.
New exact solutions of (3 + 1)‐dimensional generalized Kadomtsev‐Petviashvili equation using a combination of lie symmetry and singular manifold methods
Authors: Saleh Rasha , Rashed Ahmed S.
Published: November 2019

A new combination of Lie symmetry and Singular Manifold methods has been employed to study (3 + 1)‐dimensional generalized Kadomtsev‐Petviashvili (KP). Infinite‐dimensional space of Lie vectors has been established. Single and dual linear combinations of Lie vectors are used after appropriate calculations of the arbitrary functions to reduce the equation to an ordinary differential equation (ODE). The resulting ODE is then analytically solved through the singular manifold method which resulted in a Bäcklund truncated series with seminal analysis leading to a Schwarzian differential equation in the Eigenfunction φ (η). Solving this differential equation leads to new analytical solutions.
On the discrete symmetry analysis of some classical and fractional differential equations
Authors: Chatibi Youness , El Kinani El Hassan , Ouhadan Abdelaziz
Published: November 2019

In this paper, the Hydon method to determine discrete symmetries for a differential equation is employed to construct discrete symmetries for a family of ordinary, partial, and fractional differential equations. An application of those discrete symmetries to construct other solutions from known ones is illustrated.
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

Purpose

Oscillating 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 Methods

Multiple 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.

Results

For 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.

Conclusions

This 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

Purpose

To 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.

Methods

A 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.

Results

This 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.

Conclusions

Ultra‐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

This 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

Chloramphenicol 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

In 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.
Low‐temperature formation and characterization of Cu2O nanoparticles in the binary gold alloys
Authors: Hamana Djamel , Lamiri Imene , Chetibi Loubna , Achour Slimane
Published: November 2019

Thermal analyses, using differential scanning calorimetry (DSC) and dilatometry, reveal an important anomaly at low temperature for Au‐25 wt.% Cu composition after homogenization at 700°C during 2 hours under vacuum followed by heating up to 160°C before water quenching. This anomaly has been already observed and not explained. Surface characterization, using scanning electron microscopy (SEM), atomic force microscopy (AFM), and scanning tunneling microscopy (STM), exhibits a specific topography, consisting of a nanostructured surface. The precipitates of nanostructured particles are homogeneously scattered all over the surface for this 18‐carat gold alloy. Moreover, X‐ray photoelectron spectroscopy (XPS) shows that the composition of the observed particles corresponds to cuprous oxide phase (Cu2O). The formation of such material can be explained by the diffusion of copper atoms from the lattice to the surface at 160°C. Pulsed radio‐frequency glow discharge optical emission spectroscopy (RF GD‐OES) further proves the proposed Cu2O formation through a diffusion process. The appearance of such cuprous oxide nanoparticles on the Au‐Cu alloy surface explains the low‐temperature DSC and dilatometry anomaly and affects directly the surface electrical resistance at low temperature. These results might open a large gate for new ideas to investigate in catalytic, electronic, and antimicrobial activities.
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

Although 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

We 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

As 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

The 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

Honey 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

Recognizing 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

Noninvasive 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

In 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.
Correction to: Molecular characterization of Ecuadorian quinoa (Chenopodium quinoa Willd.) diversity: implications for conservation and breeding
Authors: Salazar Juan , Roman Viviana Jaramillo , Gutierrez Bernardo , van Loo Eibertus Nicolaas , de Lourdes Torres María , Torres Andrés Francisco
Published: November 2019

Due to an unfortunate error of miscommunication, two of the co-authors of this manuscript were omitted from the original publication. The correct representation of the authors and their affiliations are listed here and should be treated as definitive.
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

Self-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.