bluuebunny/crossref_metadata_2025_split huggingface dataset:
Shock aurora: Field‐aligned discrete structures moving along the dawnside oval
Authors: Zhou Xiaoyan , Haerendel Gerhard , Moen Jøran I. , Trondsen Espen , Clausen Lasse , Strangeway Robert J. , Lybekk Bjørn , Lorentzen Dag A. 
Published: February 2017

AbstractGenerated by interplanetary shocks or solar wind pressure pulses, shock aurora has transient, global, and dynamic significances and provides a direct manifestation of the solar wind‐magnetosphere‐ionosphere interaction. As a part of a series of studies of the shock aurora, this paper focuses on the interaction at the morning magnetopause and its auroral manifestation at ~06 magnetic local time, where the velocity and magnetic field shears dominate the interaction. Flow shears can generate wave‐like structures inside a viscous boundary layer or even larger‐scale vortices. These structures couple to the ionosphere via quasi‐static field‐aligned currents or via kinetic Alfvén waves. Potential drops along field‐aligned filaments may be generated accelerating electrons to form auroral manifestations of the structures. A shock aurora event at dawnside is used to test this scenario. The findings include moving auroral streaks/rays that have a vertical profile from red (at ~250 km altitude) to purple (at ~100 km). The streaks moved antisunward along the poleward boundary of the oval at an ionospheric speed of ~3 km s−1. It was mapped to the magnetopause flank at ~133 km s−1, which was consistent with the observed speed of the magnetopause surface waves generated by the Kelvin‐Helmholtz instability. The calculated field‐aligned potential drop using Haerendel's analytic model was ~5 kV that reasonably explained the observations. The results support the above scenario and reveal that magnetic and velocity shears at the flanks of the magnetospause may be the main cause of the fast moving shock aurora streaks.
Horizontal profile of a moving red line cusp aurora
Authors: Taguchi S. , Chiba Y. , Hosokawa K. , Ogawa Y. 
Published: February 2017

AbstractAuroral emission at a wavelength of 630.0 nm (red line) has a long radiative time. In this study, we show how this long radiative time controls the horizontal extent of a moving mesoscale aurora, which is typical of the cusp. Using high time resolution (4 s) observations by an all‐sky imager at Longyearbyen, Svalbard, and observations by the European Incoherent Scatter Svalbard Radar (ESR), we examined the auroral emission enhancements obtained in the cusp during an interval of southward interplanetary magnetic field on 27 November 2011. Simultaneous observations from the all‐sky imager and the ESR clearly show the manner in which auroral emission regions passed through the radar's field of view. When the front edge of the moving auroral structure intersected the radar's field of view, the ESR electron temperature was enhanced. A few minutes later, the ESR electron temperature dropped to the background level, indicating that the mesoscale electron precipitation region shifted away from the radar's field of view. At that time, the auroral emission in the radar's field of view decreased but still had adequate intensities. These results provide evidence demonstrating that moving cusp auroral emission occurs behind the electron precipitation region as well as inside that region. We interpreted this feature semiquantitatively by using the equation of continuity of the density of the excited atomic oxygen. Our model indicates that the maximum intensity in the moving auroral structure occurs at a point along the trailing edge of the electron precipitation region and that the velocity of that region is important for determining how the 630.0 nm aurora emissions extend horizontally.
The most intense current sheets in the high‐speed solar wind near 1 AU
Authors: Podesta John J. 
Published: February 2017

AbstractElectric currents in the solar wind plasma are investigated using 92 ms fluxgate magnetometer data acquired in a high‐speed stream near 1 AU. The minimum resolvable scale is roughly 0.18 s in the spacecraft frame or, using Taylor's “frozen turbulence” approximation, one proton inertial length di in the plasma frame. A new way of identifying current sheets is developed that utilizes a proxy for the current density J obtained from the derivatives of the three orthogonal components of the observed magnetic field B. The most intense currents are identified as 5σ events, where σ is the standard deviation of the current density. The observed 5σ events are characterized by an average scale size of approximately 3di along the flow direction of the solar wind, a median separation of around 50di or 100di along the flow direction of the solar wind, and a peak current density on the order of 0.5 pA/cm2. The associated current‐carrying structures are consistent with current sheets; however, the planar geometry of these structures cannot be confirmed using single‐point, single‐spacecraft measurements. If Taylor's hypothesis continues to hold for the energetically dominant fluctuations at kinetic scales
, then the results suggest that the most intense current‐carrying structures in high‐speed wind occur at electron scales, although the peak current densities at kinetic and electron scales are predicted to be nearly the same as those found in this study.
PFISR observation of intense ion upflow fluxes associated with an SED during the 1 June 2013 geomagnetic storm
Authors: Zou Shasha , Ridley Aaron , Jia Xianzhe , Boyd Emma , Nicolls Michael , Coster Anthea , Thomas Evan , Ruohoniemi J. M. 
Published: February 2017

AbstractThe Earth's ionosphere plays an important role in supplying plasma into the magnetosphere through ion upflow/outflow, particularly during periods of strong solar wind driving. An intense ion upflow flux event during the 1 June 2013 storm has been studied using observations from multiple instruments. When the open‐closed field line boundary (OCB) moved into the Poker Flat incoherent scatter radar (PFISR) field of view, divergent ion fluxes were observed by PFISR with intense upflow fluxes reaching ~1.9 × 1014 m−2 s−1 at ~600 km altitude. Both ion and electron temperatures increased significantly within the ion upflow, and thus, this event has been classified as a type 2 upflow. We discuss factors contributing to the high electron density and intense ion upflow fluxes, including plasma temperature effect and preconditioning by storm‐enhanced density (SED). Our analysis shows that the significantly enhanced electron temperature due to soft electron precipitation in the cusp can reduce the dissociative recombination rate of molecular ions above ~400 km and contributed to the density increase. In addition, this intense ion upflow flux event is preconditioned by the lifted F region ionosphere due to northwestward convection flows in the SED plume. During this event, the OCB and cusp were detected by DMSP between 15 and 16 magnetic local times, unusually duskward. Results from a global magnetohydrodynamics simulation using the Space Weather Modeling Framework have been used to provide a global context for this event. This case study provides a more comprehensive mechanism for the generation of intense ion upflow fluxes observed in association with SEDs.
Using radar‐derived parameters to forecast lightning cessation for nonisolated storms
Authors: Davey Matthew J. , Fuelberg Henry E. 
Published: February 2017

AbstractLightning impacts operations at the Kennedy Space Center (KSC) and other outdoor venues leading to injuries, inconvenience, and detrimental economic impacts. This research focuses on cases of “nonisolated” lightning which we define as one cell whose flashes have ceased although it is still embedded in weak composite reflectivity (Z ≥ 15 dBZ) with another cell that is still producing flashes. The objective is to determine if any radar‐derived parameters provide useful information about the occurrence of lightning cessation in remnant storms. The data set consists of 50 warm season (May–September) nonisolated storms near KSC during 2013. The research utilizes the National Lightning Detection Network, the second generation Lightning Detection and Ranging network, and polarized radar data. These data are merged and analyzed using the Warning Decision Support System‐Integrated Information at 1 min intervals. Our approach only considers 62 parameters, most of which are related to the noninductive charging mechanism. They included the presence of graupel at various thermal altitudes, maximum reflectivity of the decaying storm at thermal altitudes, maximum connecting composite reflectivity between the decaying cell and active cell, minutes since the previous flash, and several others. Results showed that none of the parameters reliably indicated lightning cessation for even our restrictive definition of nonisolated storms. Additional research is needed before cessation can be determined operationally with the high degree of accuracy required for safety.
Pulmonary function and airway inflammation among dairy parlor workers after exposure to inhalable aerosols
Authors: Nonnenmann Matthew W. , Gimeno Ruiz de Porras David , Levin Jeffrey , Douphrate David , Boggaram Vijay , Schaeffer Joshua , Gallagher Michael , Hornick Madeleine , Reynolds Stephen 
Published: February 2017

BackgroundInhalation exposure to organic dust causes lung inflammation among agricultural workers. Due to changes in production and work organization, task‐based inhalation exposure data, including novel lung inflammation biomarkers, will inform exposure recommendations for dairy farm workers.MethodsLinear regression was used to estimate the associations of airborne exposure to dust concentration, endotoxin, and muramic acid with pulmonary outcomes (i.e., FEV1, exhaled nitric oxide). Logistic regression was used to estimate associations with self‐reported pulmonary symptoms.ResultsMean exposure concentration to inhalable dust, endotoxin, and muramic acid were 0.55 mg/m3, 118 EU/m3, and 3.6 mg/m3, respectively. We found cross‐shift differences for exhaled nitric oxide (P = 0.005) and self‐reported pulmonary symptoms (P = 0.008) but no association of exposure with respiratory outcomes.ConclusionsInhalation exposures during parlor tasks, which were lower than previously reported and were not associated with cross‐shift measures of pulmonary health among dairy workers. Modern milking parlor designs may be contributing to lower inhalation exposure. Am. J. Ind. Med. 60:255–263, 2017. © 2017 Wiley Periodicals, Inc.
Testing biomechanical models of human lumbar lordosis variability
Authors: Castillo Eric R. , Hsu Connie , Mair Ross W. , Lieberman Daniel E. 
Published: February 2017

AbstractObjectivesLumbar lordosis (LL) is a key adaptation for bipedalism, but factors underlying curvature variations remain unclear. This study tests three biomechanical models to explain LL variability.Materials and methodsThirty adults (15 male, 15 female) were scanned using magnetic resonance imaging (MRI), a standing posture analysis was conducted, and lumbar range of motion (ROM) was assessed. Three measures of LL were compared. The trunk's center of mass was estimated from external markers to calculate hip moments (Mhip) and lumbar flexion moments. Cross‐sectional areas of lumbar vertebral bodies and trunk muscles were measured from scans. Regression models tested associations between LL and the Mhip moment arm, a beam bending model, and an interaction between relative trunk strength (RTS) and ROM.ResultsHip moments were not associated with LL. Beam bending was moderately predictive of standing but not supine LL (R2 = 0.25). Stronger backs and increased ROM were associated with greater LL, especially when standing (R2 = 0.65). The strength‐flexibility model demonstrates the differential influence of RTS depending on ROM: individuals with high ROM exhibited the most LL variation with RTS, while those with low ROM showed reduced LL regardless of RTS.DiscussionHip moments appear constrained suggesting the possibility of selection, and the beam model explains some LL variability due to variations in trunk geometry. The strength‐flexibility interaction best predicted LL, suggesting a tradeoff in which ROM limits the effects of back strength on LL. The strength‐flexibility model may have clinical relevance for spinal alignment and pathology. This model may also suggest that straight‐backed Neanderthals had reduced lumbar mobility.
A Two‐Tailed Phosphopeptide Crystallizes to Form a Lamellar Structure
Authors: Pellach Michal , Mondal Sudipta , Harlos Karl , Mance Deni , Baldus Marc , Gazit Ehud , Shimon Linda J. W. 
Published: February 2017

AbstractThe crystal structure of a designed phospholipid‐inspired amphiphilic phosphopeptide at 0.8 Å resolution is presented. The phosphorylated β‐hairpin peptide crystallizes to form a lamellar structure that is stabilized by intra‐ and intermolecular hydrogen bonding, including an extended β‐sheet structure, as well as aromatic interactions. This first reported crystal structure of a two‐tailed peptidic bilayer reveals similarities in thickness to a typical phospholipid bilayer. However, water molecules interact with the phosphopeptide in the hydrophilic region of the lattice. Additionally, solid‐state NMR was used to demonstrate correlation between the crystal structure and supramolecular nanostructures. The phosphopeptide was shown to self‐assemble into semi‐elliptical nanosheets, and solid‐state NMR provides insight into the self‐assembly mechanisms. This work brings a new dimension to the structural study of biomimetic amphiphilic peptides with determination of molecular organization at the atomic level.
Ultrasensitive Fluorogenic Reagents for Neuraminidase Titration
Authors: Gao Zhizeng , Niikura Masahiro , Withers Stephen G. 
Published: February 2017

AbstractInfluenza viral neuraminidase plays a crucial role during infections. It is a major target for the development of anti‐influenza drugs and is also attracting increasing attention as a vaccine target as evidence accumulates that neuraminidase‐neutralizing antibodies contribute to protection. However, no method currently exists to accurately and efficiently measure concentrations of active neuraminidase in virus samples or other crude mixtures, which hampers development on both fronts. In this report, we describe the development of a selective and sensitive active‐site titration reagent for neuraminidase that can quantify viral neuraminidases down to sub‐nanomolar levels in crude samples, with no background from non‐viral neuraminidases. By using this reagent, we determined accurate kcat values for six influenza A and two influenza B neuraminidases for the first time. We also quantified the neuraminidase content in a commercial influenza vaccine, thus demonstrating that this titration reagent opens the possibility for better vaccine analysis.
Sustainability assessment of glucose production technologies from highly recalcitrant softwood including scavengers
Authors: Morales Merten , Pielhop Thomas , Saliba Philippe , Hungerbühler Konrad , Rudolf von Rohr Philipp , Papadokonstantakis Stavros 
Published: February 2017

AbstractThe utilization of abandoned lignocellulosic residues for chemical production has a strong potential to partially substitute chemicals, which are traditionally produced from non‐renewable resources. Softwood especially, with its high availability, presents a sustainable resource for the conversion to higher value‐added products such as biofuels and bioplastics. In this study, we investigate mature and innovative technologies for the conversion of softwood to the platform chemical sugar from an economic and environmental perspective. We show that the conventional enzymatic hydrolysis has high economic as well as environmental burdens and that the increase of enzyme availability via a carbocation scavenger process is the key solution to overcome them. Furthermore, we present a process design based on concentrated acid hydrolysis, which is both environmentally and economically competitive compared to conventional production from sugarbeet. The low energy and raw material requirements combined with heat integration and moderate capital costs makes this technology attractive for utilization of softwood residues. This proves that lignocellulosic residues have the potential to become an important raw material in the future bioeconomy. © 2017 Society of Chemical Industry and John Wiley & Sons, Ltd
Costs, mortality, and hospital usage in relation to prenatal diagnosis in d‐transposition of the great arteries
Authors: Pinto Nelangi M. , Nelson Richard , Botto Lorenzo , Puchalski Michael D. , Krikov Sergey , Kim Jaewhan , Waitzman Norman J. 
Published: February 2017

BackgroundThe impact of prenatal diagnosis of d‐transposition of the great arteries (dTGA) on health‐care usage is largely unknown. We evaluated a population‐based cohort to assess costs, mortality and inpatient encounters by whether dTGA was prenatally diagnosed or not.MethodsThe dTGA cases (born 1997–2011) identified at the Utah Birth Defect Network, which includes data on timing of diagnosis, were linked to statewide inpatient discharge data. We excluded preterm cases or cases with additional major heart defects. We evaluated hospitalizations and costs for infants (first year of life) and mothers (10 months before birth) using multivariable models adjusted for demographic and clinical risk factors.ResultsOf 119 cases, 14 (12%) were prenatally diagnosed. Birth weight, surgical complexity and extracardiac defects/syndromes were similar between groups. Of 7 deaths (6%), two occurred pre‐intervention in postnatally diagnosed infants. Prenatal diagnosis was associated with more in‐hospital days (estimate 13 additional days, p = 0.03) and higher mean costs for mothers ($4,141 vs $12,148) and infants (90,419 vs $49,576). Prenatal diagnosis independently predicted higher adjusted costs for the overall cohort ($22,570, p = 0.045). After excluding deaths, total costs were no longer significantly different.ConclusionMothers of prenatally diagnosed infants with dTGA had higher inpatient costs compared with those postnatally diagnosed. Costs trended higher for their infants, although were not significantly different. Linkage of population‐based surveillance systems and outcome databases can be a powerful tool to further explore the complex relationship of prenatal diagnosis to costs and outcomes in other types of congenital heart diseases. Birth Defects Research 109:262–270, 2017. © 2017 Wiley Periodicals, Inc.
Functional mucous layer and healing of proximal colonic anastomoses in an experimental model
Authors: Bosmans J W A M , Jongen A C H M , Birchenough G M H , Nyström E E L , Gijbels M J J , Derikx J P M , Bouvy N D , Hansson G C 
Published: February 2017

Abstract

Background
Anastomotic leakage (AL) is the most dreaded complication after colorectal surgery, causing high morbidity and mortality. Mucus is a first line of defence against external factors in the gastrointestinal tract. In this study, the structural mucus protein Muc2 was depleted in genetically engineered mice and the effect on healing of colonic anastomoses studied in an experimental model.

Methods
Mice of different Muc2 genotypes were used in a proximal colonic AL model. Tissues were scored histologically for inflammation, bacterial translocation was determined by quantitative PCR of bacterial 16S ribosomal DNA, and epithelial cell damage was determined by assessing serum levels of intestinal fatty acid-binding protein.

Results
Of 22 Muc2-deficient (Muc2−/−) mice, 20 developed AL, compared with seven of 22 control animals (P &lt; 0·001). Control mice showed normal healing, whereas Muc2−/− mice had more inflammation with less collagen deposition and neoangiogenesis. A tendency towards higher bacterial translocation was seen in mesenteric lymph nodes and spleen in Muc2−/− mice. Intestinal fatty acid-binding protein levels were significantly higher in Muc2−/− mice compared with controls (P = 0·011).

Conclusion
A functional mucous layer facilitates the healing of colonic anastomoses.
Effect of obeticholic acid on liver regeneration following portal vein embolization in an experimental model
Authors: Olthof P B , Huisman F , Schaap F G , van Lienden K P , Bennink R J , van Golen R F , Heger M , Verheij J , Jansen P L , Olde Damink S W , van Gulik T M 
Published: February 2017

Abstract

Background
The bile salt-activated transcription factor farnesoid X receptor (FXR) is a key mediator of proliferative bile salt signalling, which is assumed to play a role in the early phase of compensatory liver growth. The aim of this study was to evaluate the effect of a potent FXR agonist (obeticholic acid, OCA) on liver growth following portal vein embolization (PVE).

Methods
Rabbits were allocated to receive daily oral gavage with OCA (10 mg/kg) or vehicle (control group) starting 7 days before PVE (n = 18 per group), and continued until 7 days after PVE. PVE of the cranial liver lobes was performed using polyvinyl alcohol particles and coils on day 0. Caudal liver volume (CLV) was analysed by CT volumetry on days –7, –1, +3 and +7. Liver function was determined by measuring mebrofenin uptake using hepatobiliary scintigraphy. Additional parameters analysed were plasma aminotransferase levels, and histological scoring of haematoxylin and eosin- and Ki-67-stained liver sections.

Results
Three days after PVE of the cranial lobes, the increase in CLV was 2·2-fold greater in the OCA group than in controls (mean(s.d.) 56·1(20·3) versus 26·1(15·4) per cent respectively; P &lt; 0·001). This increase remained greater 7 days after PVE (+1·5-fold; P = 0·020). The increase in caudal liver function at day +3 was greater in OCA-treated animals (+1·2-fold; P = 0·017). The number of Ki-67-positive hepatocytes was 1·6-fold higher in OCA-treated animals 3 days after PVE (P = 0·045). Plasma aminotransferase levels and histology did not differ significantly between groups.

Conclusion
OCA accelerated liver regeneration after PVE in a rabbit model. OCA treatment might increase the efficacy of PVE and, thereby, resectability.