bluuebunny/crossref_metadata_2025_split huggingface dataset:
Organised polarisation variability in radio pulsars and consequences for emission theory
Authors: Ilie Cristina-Diana , Weltevrede Patrick 
Published: June 2018

AbstractThe aim of this work is to explore the connection between variability in single pulse intensity and periodic switching of the position angle (PA) of the linear polarisation and how this relates to the radio emission mechanism. There are five pulsars reported in the literature for which the PA is seen to periodically change in tandem with the variability in their pulse shapes. This behaviour is seemingly incompatible with two well established models of the radio emission mechanism. The purpose of this study is to investigate in a systematic way whether this phenomenon is common or if only happens in special cases, using a high-quality sample of pulsar data observed with the Parkes telescope. We show that the connection between polarisation variability and intensity variability is more common than previously expected.
Multi-frequency scatter-broadening evolution of pulsars
Authors: Krishnakumar M. A. , Joshi Bhal Chandra , Manoharan P. K. 
Published: June 2018

AbstractIn this paper, we present our study on multi-frequency scatter-broadening observations of a large sample of pulsars, made using the Ooty Radio Telescope (ORT) and the Giant Metrewave Radio Telescope (GMRT). For each pulsar, the scatter-broadening time scales (τsc) have been estimated at different observing frequencies and the dependence of τsc with the observing frequency, i.e., the frequency scaling index (α) has been obtained. We report estimates of α for a set of 39 pulsars, of which 31 are completely new and provide the first-time measurement on about 50% of the sample. This enhanced sample suggests that almost 65% of the pulsars have an α much lower than the conventional value of 4.4 for a Kolmogorov type turbulence spectrum, and a considerably large scattering strength. An increase in scattering strength is observed with the distance to the pulsar in the Galaxy.
The Magnetoionic Universe: Timing, Bursts, and SETI
Authors: Cordes James M. 
Published: June 2018

AbstractPropagation effects have been central to pulsar research and indeed were an integral part of the pulsar discovery and its prologue. I will summarize the early deduction process for establishing pulsar distances and refinements to the distance scale and modeling of the Galaxy in electron density and magnetic field. This will lead to the analogous current situation of understanding distances and media for extragalactic radio bursts. The role of magnetoionic media in precision pulsar timing and surveys for transients will be summarized. Finally, going full circle, searches for extraterrestrial intelligence (LGMs) also require attention to propagation effects.
Scintillation Arcs Shed Light on Scattering from Planar Plasma Sheets
Authors: Stinebring Daniel R. 
Published: June 2018

AbstractScintillation arcs provide an unprecedented degree of detail into the scattering of radio waves from pulsars. We review evidence that has emerged over the last fifteen years that: a) the scattering of many nearby pulsars is dominated by one or several relatively thin “screens” of material, b) the resulting image on the sky is highly linear, with axial ratios at least as high as 10:1, and c) this arrangement is persistent for at least one source (B1133+16) for at least 25 years. We expand on the idea of Pen and Levin (2014) and previous authors that such scattering may be caused by linear sheets of plasma seen nearly edge-on. Further analysis of such scintillation arcs, including new work on multi-frequency, multi-epoch observations, should help elucidate the astrophysical nature of these ubiquitous scattering entities, which are currently not convincingly linked with any known structures.
X-Ray and Optical Properties of Black Widows and Redbacks
Authors: Roberts Mallory S.E. , Al Noori Hind , Torres Rodrigo A. , McLaughlin Maura A. , Gentile Peter A. , Hessels Jason W.T. , Ransom Scott M. , Ray Paul S. , Kerr Matthew , Breton Rene P. 
Published: June 2018

AbstractBlack widows and redbacks are binary systems consisting of a millisecond pulsar in a close binary with a companion having matter driven off of its surface by the pulsar wind. X-rays due to an intrabinary shock have been observed from many of these systems, as well as orbital variations in the optical emission from the companion due to heating and tidal distortion. We have been systematically studying these systems in radio, optical and X-rays. Here we will present an overview of X-ray and optical studies of these systems, including new XMM-Newton and NuStar data obtained from several of them, along with new optical photometry.
Effects of the Crustal Magnetic Fields and Changes in the IMF Orientation on the Magnetosphere of Mars: MAVEN Observations and LatHyS Results
Authors: Romanelli N. , Modolo R. , Leblanc F. , Chaufray J‐Y. , Hess S. , Brain D. , Connerney J. , Halekas J. , Mcfadden J. , Jakosky B. 
Published: June 2018

AbstractThe Mars Atmosphere and Volatile EvolutioN Mission (MAVEN) is currently probing the complex Martian environment. Although main structures arising from the interaction between the solar wind (SW) and the induced magnetosphere of Mars can be described using a steady state picture, time‐dependent physical processes modify the response of this obstacle. These processes result from temporal variabilities in the internal and/or external electromagnetic fields and plasma properties. Indeed, the crustal magnetic fields (CF) rotation constantly modifies the intrinsic magnetic field topology relative to the SW. Moreover, the magnetosphere's state is also modified by changes in the interplanetary magnetic field (IMF). In this work we analyze MAVEN magnetic field and plasma measurements obtained on 23 December 2014, between 06:00 UT and 14:15 UT. These measurements suggest that the external conditions remained approximately constant when MAVEN was inside the magnetosphere during the first orbit. In contrast, MAVEN observed changes in the IMF orientation before visiting the magnetosphere during the second orbit. To investigate the response of the Martian plasma environment to the CF rotation and IMF variability, we also perform hybrid simulations, using MAVEN observations to set SW external conditions. Simulation results are compared with the MAVEN measurements and show good agreement. Associated recovery timescales of different magnetospheric regions are found to range between ∼ 10 s and ∼ 10 min. Finally, we do not observe large variability in the total planetary H+ and O+ escape rates at different times during this event, although a correlation between the latter and the CF location is identified.
The Volume of Lava Erupted During the 2014 to 2015 Eruption at Holuhraun, Iceland: A Comparison Between Satellite‐ and Ground‐Based Measurements
Authors: Bonny E. , Thordarson T. , Wright R. , Höskuldsson A. , Jónsdóttir I. 
Published: June 2018

AbstractThe 31 August 2014 to 27 February 2015 eruption at Holuhraun created the largest lava flow field in Iceland since the 1783–1784 Laki eruption. Emplacement of a basaltic flow field of this magnitude onto an effectively flat surface (<0.1°) is a rare occurrence. Lava discharge rate, a fundamental variable that controls flow field emplacement, allows us to estimate the total volume of lava erupted when integrated over time. Thus, discharge rate data are important for volcano monitoring and lava flow modeling. Here we compare discharge rates estimated using data from National Aeronautics and Space Administration's MODerate Resolution Imaging Spectroradiometer (MODIS) and the method of Harris et al. (1997a, https://doi.org/10.1029/96JB03388; 1997b, https://doi.org/10.1007/s004450050174; 2007, https://doi.org/10.1007/s00445‐007‐0120‐y), with estimates of discharge rates derived from comparing intermittent ground‐based measurements of flow field volume. The time‐averaged discharge rates (TADR) reveal a pulsed increase in the first few days of the eruption. Although the trends of the satellite‐ and ground‐based discharge rates are similar, the ground‐based estimates are systematically higher than the satellite‐derived estimates (about 2 to 3 times higher) in the first 30 days of the eruption, and relatively close (within 30%) for the next 20 days. Conversely, during the final 130 days, the satellite‐based estimates are systematically higher than the ground‐based estimates (about 2 times higher). This difference likely arises from the assumption of the lava flow surface temperature used in the space‐based calculation, which may not be entirely representative of this uniquely large and intense basaltic eruption. However, the satellite‐based technique yields a total erupted volume of about 1.21 km3 in good agreement with the 1.2 km3 (84 km2) derived from field observations and mapping.
Ion Injection Triggered EMIC Waves in the Earth's Magnetosphere
Authors: Remya B. , Sibeck D. G. , Halford A. J. , Murphy K. R. , Reeves G. D. , Singer H. J. , Wygant J. R. , Farinas Perez G. , Thaller S. A. 
Published: June 2018

AbstractWe present Van Allen Probe observations of electromagnetic ion cyclotron (EMIC) waves triggered solely due to individual substorm‐injected ions in the absence of storms or compressions of the magnetosphere during 9 August 2015. The time at which the injected ions are observed directly corresponds to the onset of EMIC waves at the location of Van Allen Probe A (L = 5.5 and 18:06 magnetic local time). The injection was also seen at geosynchronous orbit by the Geostationary Operational Environmental Satellite and Los Alamos National Laboratory spacecraft, and the westward(eastward) drift of ions(electrons) was monitored by Los Alamos National Laboratory spacecraft at different local times. The azimuthal location of the injection was determined by tracing the injection signatures backward in time to their origin assuming a dipolar magnetic field of Earth. The center of this injection location was determined to be close to ∼20:00 magnetic local time. Geostationary Operational Environmental Satellite and ground magnetometer responses confirm substorm onset at approximately the same local time. The observed EMIC wave onsets at Van Allen Probe were also associated with a magnetic field decrease. The arrival of anisotropic ions along with the decrease in the magnetic field favors the growth of the EMIC wave instability based on linear theory analysis.
Adjusting urinary chemical biomarkers for hydration status during pregnancy
Authors: MacPherson Susan , Arbuckle Tye E. , Fisher Mandy 
Published: June 2018

AbstractOne way of assessing a population’s exposure to environmental chemicals is by measuring urinary biomarker concentrations, which can vary depending on the hydration status of the individual. The physiological changes that occur during pregnancy can impact the hydration adjustment approaches, such as calculating the individual’s urinary flow rate (UFR), or adjusting concentrations using specific gravity (SG) or creatinine. A total of 1260 serial spot urine samples were collected from 80 women, averaging 32.4 years of age, throughout and shortly after pregnancy. The relationship between each approach was examined and time of day and across pregnancy differences were tested using linear mixed models. The correlation between the calculated excretion rate and each of the adjustment techniques was examined on a selection of seven phthalate metabolites. Based on the linear mixed model results, we found that UFR and creatinine excretion rates differed systematically across the population, with respect to body mass index (BMI) and time. SG differed with respect to BMI, but there were no systematic time trends. SG had the highest within-person reproducibility, according to the intraclass correlation coefficient (ICC). The excretion rate of each of the phthalates was most strongly correlated with the SG-standardized concentration. This analysis showed that SG showed a slightly better within-person reproducibility and the least amount of systematic variation when compared to creatinine adjustment. Therefore, SG correction appears to be a favorable approach for correcting for the hydration status of the pregnant women from this cohort.
A randomised controlled trial to evaluate the plaque removal efficacy of sodium bicarbonate dentifrices in a single brushing clinical model
Authors: Bosma Mary-Lynn , Milleman Kimberly R , Akwagyiram Ivy , Targett Darren , Milleman Jeffery L 
Published: June 2018

Abstract
Objective
To evaluate plaque removal efficacy of dentifrices containing sodium bicarbonate (NaHCO3) compared with a non-NaHCO3 dentifrice after a single-timed brushing.

Materials and methods
A randomised, controlled, examiner-blinded, four-period, crossover study in 56 adults with a mean whole-mouth plaque index of ≥2.00 (six site modification of Turesky modification of Quigley-Hein Plaque Index [TPI]). Subjects brushed once for one timed minute with a 67% NaHCO3 dentifrice with herbs; a 67% NaHCO3 dentifrice without herbs; a 62% NaHCO3 dentifrice with herbs; or a non-NaHCO3 dentifrice without herbs. All contained 923 p.p.m. fluoride as sodium fluoride. Pre- and post-brushing plaque assessments were performed.

Results
Mean TPI score decreased from pre- to post-brushing with all treatments. There were statistically significantly greater reductions in plaque for NaHCO3 dentifrices compared to non-NaHCO3 (p < 0.0001 for all) with no significant differences between NaHCO3-containing dentifrices. A post hoc analysis of plaque removal from different oral areas showed statistically significant differences in favour of the NaHCO3 dentifrices over the non-NaHCO3 dentifrice for almost all surfaces. No adverse events were reported.

Discussion and conclusion
Plaque removal was significantly greater with NaHCO3-containing dentifrices compared with a non-NaHCO3 dentifrice after a single, timed brushing. There was no effect of herbal tinctures. This study was registered at ClincalTrials.org: NCT03285984.
Reduction of the ATPase inhibitory factor 1 (IF1) leads to visual impairment in vertebrates
Authors: Martín-Jiménez Rebeca , Faccenda Danilo , Allen Emma , Reichel Holly Beatrice , Arcos Laura , Ferraina Caterina , Strobbe Daniela , Russell Claire , Campanella Michelangelo 
Published: June 2018

AbstractIn vertebrates, mitochondria are tightly preserved energy producing organelles, which sustain nervous system development and function. The understanding of proteins that regulate their homoeostasis in complex animals is therefore critical and doing so via means of systemic analysis pivotal to inform pathophysiological conditions associated with mitochondrial deficiency. With the goal to decipher the role of the ATPase inhibitory factor 1 (IF1) in brain development, we employed the zebrafish as elected model reporting that the Atpif1a−/− zebrafish mutant, pinotage (pnt
tq209
), which lacks one of the two IF1 paralogous, exhibits visual impairment alongside increased apoptotic bodies and neuroinflammation in both brain and retina. This associates with increased processing of the dynamin-like GTPase optic atrophy 1 (OPA1), whose ablation is a direct cause of inherited optic atrophy. Defects in vision associated with the processing of OPA1 are specular in Atpif1−/− mice thus confirming a regulatory axis, which interlinks IF1 and OPA1 in the definition of mitochondrial fitness and specialised brain functions. This study unveils a functional relay between IF1 and OPA1 in central nervous system besides representing an example of how the zebrafish model could be harnessed to infer the activity of mitochondrial proteins during development.
Decreased expression of ARHGAP15 promotes the development of colorectal cancer through PTEN/AKT/FOXO1 axis
Authors: Pan Shengli , Deng Yingying , Fu Jun , Zhang Yuhao , Zhang Zhijin , Ru Xiaokun , Qin Xianju 
Published: June 2018

AbstractCopious evidence demonstrates the crucial role of Rho GTPase-activating proteins in human malignancies. The downregulation of Rho GTPase-activating protein 15 (ARHGAP15), a Rac1-specific GAP, has been observed in glioma and pancreatic ductal adenocarcinoma. The present study explored the expression in colorectal cancer (CRC) by quantitative real-time PCR and immunohistochemistry analysis. The possible function of ARHGAP15 in CRC was investegated in vitro and in vivo. We found that ARHGAP15 expression was obviously lower in CRC specimens than in normal colonic mucosa. ARHGAP15 expression was significantly correlated with clinical stage, tumor size metastasis, vital status, and overall survival of CRC patients. ARHGAP15 overexpression inhibited cell growth, migration, and invasion of HT29 and RKO cells in vitro, whereas opposite results were observed in ARHGAP15-silenced LoVo cells. Mechanically, we found that PTEN (phosphatase and tensin homology deleted on chromosome 10) signaling pathway was closely correlated with ARHGAP15 expression by Gene set enrichment analysis with The Cancer Genome Atlas CRC data set. Increased PTEN and Forkhead box protein O1 (FOXO1, a downstream transcription factor of AKT), and decreased phosphorylation of AKT were observed in ARHGAP15-overexpressed HT29 and RKO cells. In addition, ARHGAP15 overexpression increased p21, which was responsible for the accelerated cell growth and S phase arrest, but decreased the protein levels of MMP-2 and MMP-9, which were stimuli for cell metastasis. Notably, upregulating PTEN expression, FOXO1 overexpression and interdicting the activation of AKT pathway with MK2206 suppressed the proliferation and the metastatic ability of ARHGAP15-silenced LoVo cells. In addition, FOXO1 overexpression markedly enhanced the expression and the promoter activity of ARHGAP15. Furthermore, ARHGAP15 overexpression significantly decelerated the pace of tumor growth and metastasis in the lung in vivo. In summary, these results suggest that ARHGAP15 might serve as a tumor suppressor during CRC progression and metastasis through PTEN/AKT/FOXO1-signaling pathway.
Activation of neutral sphingomyelinase 2 by starvation induces cell-protective autophagy via an increase in Golgi-localized ceramide
Authors: Back Moon Jung , Ha Hae Chan , Fu Zhicheng , Choi Jong Min , Piao Yongwei , Won Jong Hoon , Jang Ji Min , Shin In Chul , Kim Dae Kyong 
Published: June 2018

AbstractAutophagy is essential for optimal cell function and survival, and the entire process accompanies membrane dynamics. Ceramides are produced by different enzymes at different cellular membrane sites and mediate differential signaling. However, it remains unclear which ceramide-producing pathways/enzymes participate in autophagy regulation under physiological conditions such as nutrient starvation, and what the underlying mechanisms are. In this study, we demonstrate that among ceramide-producing enzymes, neutral sphingomyelinase 2 (nSMase2) plays a key role in autophagy during nutrient starvation. nSMase2 was rapidly and stably activated upon starvation, and the enzymatic reaction in the Golgi apparatus facilitated autophagy through the activation of p38 MAPK and inhibition of mTOR. Moreover, nSMase2 played a protective role against cellular damage depending on autophagy. These findings suggest that nSMase2 is a novel regulator of autophagy and provide evidence that Golgi-localized ceramides participate in cytoprotective autophagy against starvation.
Neutrophils induce macrophage anti-inflammatory reprogramming by suppressing NF-κB activation
Authors: Marwick John A. , Mills Ross , Kay Oliver , Michail Kyriakos , Stephen Jillian , Rossi Adriano G. , Dransfield Ian , Hirani Nikhil 
Published: June 2018

AbstractApoptotic cells modulate the function of macrophages to control and resolve inflammation. Here, we show that neutrophils induce a rapid and sustained suppression of NF-κB signalling in the macrophage through a unique regulatory relationship which is independent of apoptosis. The reduction of macrophage NF-κB activation occurs through a blockade in transforming growth factor β-activated kinase 1 (TAK1) and IKKβ activation. As a consequence, NF-κB (p65) phosphorylation is reduced, its translocation to the nucleus is inhibited and NF-κB-mediated inflammatory cytokine transcription is suppressed. Gene Set Enrichment Analysis reveals that this suppression of NF-κB activation is not restricted to post-translational modifications of the canonical NF-κB pathway, but is also imprinted at the transcriptional level. Thus neutrophils exert a sustained anti-inflammatory phenotypic reprogramming of the macrophage, which is reflected by the sustained reduction in the release of pro- but not anti- inflammatory cytokines from the macrophage. Together, our findings identify a novel apoptosis-independent mechanism by which neutrophils regulate the mediator profile and reprogramming of monocytes/macrophages, representing an important nodal point for inflammatory control.
NHERF1 inhibits beta-catenin-mediated proliferation of cervical cancer cells through suppression of alpha-actinin-4 expression
Authors: Wang Qiqi , Qin Qiong , Song Ran , Zhao Chunjuan , Liu Hua , Yang Ying , Gu Siyu , Zhou Deshan , He Junqi 
Published: June 2018

AbstractCervical cancer is one of the most lethal types of cancer in female. Aberrant activation of Wnt/β-catenin signaling pathway has been found to be involved in cervical cancer development and progression, whereas the underlying molecular mechanisms remain poorly understood. The present study showed that NHERF1 was a novel gene associated with both cell proliferation and Wnt signaling pathway in cervical cancer by analysis of differential gene expression and gene cluster for the cervical cancer specimens from GEO data sets. It was further demonstrated in cellular study that NHERF1 inhibition of cervical cancer cell proliferation through Wnt/β-catenin signaling was dependent on α-actinin-4 (ACTN4) expression. A negative association between NHERF1 expression and levels of ACTN4 and β-catenin was found in mouse xenograft model and cervical cancer specimens. Low levels of NHERF1 in cervical cancer specimens were found to associate with activation of cell proliferation and Wnt/β-catenin signaling by gene set enrichment analysis, and also were an independent predictive factor for worse prognosis of cervical cancer patients by Cox regression analysis. These findings demonstrate that NHERF1 inhibits Wnt signaling-mediated proliferation of cervical cancer via suppression of ACTN4, and NHERF1 downregulation may contribute to the progression of cervical cancer. These findings may also shed some lights for understanding the underlying mechanisms of cisplatin resistance and worse prognosis of HPV-inactive cervical cancer patients.
Phylodynamic assessment of intervention strategies for the West African Ebola virus outbreak
Authors: Dellicour Simon , Baele Guy , Dudas Gytis , Faria Nuno R. , Pybus Oliver G. , Suchard Marc A. , Rambaut Andrew , Lemey Philippe 
Published: June 2018

AbstractGenetic analyses have provided important insights into Ebola virus spread during the recent West African outbreak, but their implications for specific intervention scenarios remain unclear. Here, we address this issue using a collection of phylodynamic approaches. We show that long-distance dispersal events were not crucial for epidemic expansion and that preventing viral lineage movement to any given administrative area would, in most cases, have had little impact. However, major urban areas were critical in attracting and disseminating the virus: preventing viral lineage movement to all three capitals simultaneously would have contained epidemic size to one-third. We also show that announcements of border closures were followed by a significant but transient effect on international virus dispersal. By quantifying the hypothetical impact of different intervention strategies, as well as the impact of barriers on dispersal frequency, our study illustrates how phylodynamic analyses can help to address specific epidemiological and outbreak control questions.