bluuebunny/crossref_metadata_2025 huggingface dataset:
Doppler images of V1358 Ori
Authors: Kriskovics Levente , Kövári Zsolt , Vida Krisztián , Oláh Katalin , Carroll Thorsten A.
Published: March 2020

We present Doppler images of the active dwarf star V1358 Ori using high-resolution spectra from the NARVAL spectropolarimeter mounted on the Bernard Lyot Telescope. The spectra were taken between 09-20 Dec, 2013 with a resolution of R=80000. Doppler imaging was carried out with our new generation multi-line Dopper imaging code iMap (Carroll et al. 2012). 40 individual photospheric lines were selected by line depth, temperature sensitivity and blends. Two data subsets were formed to get two consecutive Doppler images. Prominent cool spots at lower latitudes are found on both maps. At 0.5 phase there is a prominent equatorial feature on both maps. Weaker polar features can be seen on the first map, which somewhat diminishes for the second map. On the first image there is a cool surface feature at 30 degrees latitude which seems to fade greatly on the second map. Around 0.75 phase, a new spot seems to form. These changes suggest a rapid surface evolution. Spot displacements may also indicate surface differential rotation, which was derived by cross-correlating the two subsequent Doppler images (see e.g. Kővári et al. 2012). We fit the latitudinal correlation peaks with a sine-squared law. The fit suggests solar-type surface differential rotation with a shear parameter of α=0.02±0.02. The shear parameter fits the
${P_{{\rm{rot}}}} - |\alpha | $
diagram in Kővári et al. (2017) quite well.
Applying Historical Observations to Study Transient Phenomena
Authors: Griffin Elizabeth
Published: March 2020

Astronomy has an enviable wealth of historical observations. Some verge on the archaeological, and display rare events such as novæ and supernovæ; others range up to 100 or more years in age, and bear unique information about events that will never repeat in detail. Yet most astronomers today know little of those resources and the scientific potential which they harbour, so rather infrequent use is made today of those historical data. The problem is that historical data were perforce obtained in analogue formats, and because of those formats the data too tend to be regarded as hailing from a culture whose scientific significance is passé. But the medium is not the message! Astronomy’s archives of photographic observations constitute an irreplaceable resource. The change in technology from analogue to electronic recording in the late 20th Century was abrupt, and it left most of today’s astronomers unable to handle and use photographic data, and led to a general skepticism of the value of photographic observations for present-day studies of variability in the cosmos. But that is precisely what older data can do; in particular, the older the data the more reliable the base-line against which one can measure new trends, refine orbital parameters, discern period modulations, etc.
The present-time Milky Way stellar Metallicity Gradient
Authors: Inno Laura
Published: March 2020

The present-time Milky Way (MW) radial metallicity gradient is a prime observable for galaxy evolution studies. Yet, a large diversity of measured gradients can be found in the literature, with values ranging from -0.01 to -0.09 dex kpc−1, depending on the tracers used. In order to understand if this diversity comes from Galactic evolution processes or observational biases, stellar probes uniformly distributed across the disc and with accurately known ages and distances are needed. Classical Cepheids fulfil all these requirements and have been used to measure accurate abundance gradients in the MW. Here, I summarise some of the recent results based on Cepheids and on other stellar probes of similar age, and briefly discuss their implication for Galactic evolution.
The radial distribution in nearby galaxies of the ionizing field of radiation of hii regions using photoionization models
Authors: Pérez-Montero Enrique , García-Benito Rubén , Vílchez José M.
Published: March 2020

Hii regions in galaxy disks can be used as a powerful tool to trace the radial distribution of several of their properties and shed some light on the different relevant processes on galaxy formation and evolution. Among the properties that can be extracted from the study of the ionized gas are the metallicity, the excitation and the hardness of the ionizing field of radiation. In this contribution we focus on the determination of both the ionization parameter (U) and the effective temperature of the ionizing clusters (T) by means of a bayesian-like comparison between the observed relative fluxes of several emission-lines with the predictions from a set of photoionization models. We also show the implications that the use of our method has for the study of the radial variation of both U and T in some very well-studied disk galaxies of the Local Universe.
Metallicity gradients in high-z galaxies: insights from the KLEVER Survey
Authors: Curti Mirko
Published: March 2020

We present reconstructed source plane metallicity maps for a sample of ~30 gravitationally lensed galaxies between 1.2 < z < 2.5, observed in the framework of the KLEVER Survey. Oxygen abundance is derived exploiting a variety of different emission line diagnostics, as provided by the full coverage of the near-infrared bands. The majority of galaxies in our sample present flat radial metallicity gradients, in agreement with galaxy evolution models predicting strong feedback mechanisms in place at these epochs. However, complex patterns as seen in some of our metallicity maps warn against the use of azimuthally-averaged radial gradients as the only observable to constrain chemical evolution models.
Radial elemental abundance gradients in galaxies from cosmological chemodynamical simulations
Authors: Vincenzo Fiorenzo , Kobayashi Chiaki
Published: March 2020

Cosmological chemodynamical simulations are nowadays among the best tools to study how chemical elements are produced within galaxies, to reconstruct also the spatial distribution of the chemical elements as a function of time within different galaxy environments. Our simulation code includes the main stellar nucleosynthetic sources in the cosmos (core-collapse and Type Ia supernovae, hypernovae, asymptotic giant branch stars, and stellar winds from stars of all masses and metallicities). We present the predictions of our simulation for the evolution of the radial gradients of O/H, N/O and C/N in the gas-phase of a sample of ten star-forming disc galaxies, all characterised by very different star formation histories at the present time (see Figure 1.). On average, our simulated disc galaxies show a clear inside-out growth of the stellar mass as a function of time, and more negative slopes of the radial gas-phase O/H versus radius at earlier epochs of the galaxy evolution; we predict negative slopes of N/O and positive slopes of C/N at almost all redshifts, because of the main secondary origin of N in stars, even though the high-redshift simulation data are highly scattered because of the more turbulent conditions of the interstellar medium. Finally, we show that similar results are found with zoom-in simulations, where a spiral galaxy is re-simulated with a larger number of resolution elements. With zoom-in simulations, we study how stellar migrations (particularly old and metal-poor stellar populations migrating outwards) and radial gas flows are capable of influencing the galaxy chemical evolution at different galactic radii.
Statistical properties of starspots on solar-type stars and their correlation with flare activity
Authors: Maehara Hiroyuki
Published: March 2020

We analyzed the statistical properties of starspots on solar-type stars and the correlation between properties of starspots and flare activity using observations from the Kepler mission. We found the size distribution of starspots on solar-type stars shows the power-law distribution and both size distributions of starspots on slowly-rotating solar-type stars and of relatively large sunspots are roughly lie on the same power-law line. We also found that the frequency-energy distributions for superflares and solar flares from spots with different sizes are the same for solar-type stars and the Sun. These results suggest that the magnetic activity on solar-type stars and that on the Sun are caused by the same physical processes
CALSPEC: HST Spectrophotometric Standards at 0.115 to 32 μm with a 1% Accuracy Goal
Authors: Bohlin Ralph C.
Published: March 2020

The flux distributions of spectrophotometric standard stars were initially derived from the comparison of stars to laboratory sources of known flux but are now based on calculated model atmospheres. For example, pure hydrogen white dwarf (WD) models provide the basis for the HST CALSPEC archive of flux standards. There is good evidence that relative fluxes from the visible to the near-IR wavelength of ∼2.5 μm are currently accurate to ∼1% for the primary reference standards.
Testing of the LSST’s photometric calibration strategy at the CTIO 0.9 meter telescope
Authors: Coughlin Michael W. , Deustua Susana , Guyonnet Augustin , Mondrik Nicholas , Rice Joseph P. , Stubbs Christopher W. , Woodward John T.
Published: March 2020

The calibration hardware system of the Large Synoptic Survey Telescope (LSST) is designed to measure two quantities: a telescope’s instrumental response and atmospheric transmission, both as a function of wavelength. First of all, a “collimated beam projector” is designed to measure the instrumental response function by projecting monochromatic light through a mask and a collimating optic onto the telescope. During the measurement, the light level is monitored with a NIST-traceable photodiode. This method does not suffer from stray light effects or the reflections (known as ghosting) present when using a flat-field screen illumination, which has a systematic source of uncertainty from uncontrolled reflections. It allows for an independent measurement of the throughput of the telescope’s optical train as well as each filter’s transmission as a function of position on the primary mirror. Second, CALSPEC stars can be used as calibrated light sources to illuminate the atmosphere and measure its transmission. To measure the atmosphere’s transfer function, we use the telescope’s imager with a Ronchi grating in place of a filter to configure it as a low resolution slitless spectrograph. In this paper, we describe this calibration strategy, focusing on results from a prototype system at the Cerro Tololo Inter-American Observatory (CTIO) 0.9 meter telescope. We compare the instrumental throughput measurements to nominal values measured using a laboratory spectrophotometer, and we describe measurements of the atmosphere made via CALSPEC standard stars during the same run.
New calibration of the Vilnius photometric system
Authors: Maskoliunas M. , Zdanavičius J. , Čepas V. , Kazlauskas A. , Boyle R. P. , Zdanavičius K. , Černis K. , Milašius K. , Macijauskas M.
Published: March 2020

The medium-band Vilnius photometric system with the mean wavelengths at 345 (U), 374 (P), 405 (X), 466 (Y), 516 (Z), 544 (V), and 656 (S) nm for many years was an important tool to determine interstellar reddenings and distances of single stars due to its ability to classify stars of all temperatures in spectral classes and luminosity classes in the presence of different interstellar reddenings. At present, Gaia DR2 presents distances to stars with an unprecedented accuracy at least up to 3 kpc. However, multicolor photometry, which allows the classification of stars as well as the preliminary determination of stellar temperatures, gravities, metallicities and interstellar reddenings, remains an important method for distant stars. Here we present an empirical calibration of the intrinsic color indices of the Vilnius system in terms of physical parameters of stars for dwarf and giant stars of spectral classes F-G-K-M. In any attempted photometric determination of physical parameters of stars it is important to have an extensive and homogeneous sample of spectroscopically determined parameters for stars for which there are also accurate photometric data. As a source catalogue for the Vilnius photometry the latest updated version of the Catalogue of Photoelectric Observations in the Vilnius System was used, which contains compilations from the published photometry for about 11 000 stars. The stars which had both the Gaia DR2 parallaxes and the determinations of stellar parameters from high-dispersion spectra were extracted from this catalogue. The final sample contains more than 1500 stars of spectral classes F-M. The majority of these stars (ca 70%) are not reddened, for others the values of interstellar reddening AV were determined using the regular techniques of photometric classification in the Vilnius system. The absolute magnitudes MV and consequently the luminosity classes were determined using Gaia DR2 parallaxes. We present the analytical expressions for the effective temperature Teff and surface gravity logg and evaluate the errors of solutions for dwarf and giant stars. To test the accuracy of the proposed method, we have compared our results with the stars observed by Gaia and with the stellar parameters available from the large spectroscopic surveys: APOGEE, Gaia-ESO, GALAH, LAMOST, RAVE and SEGUE. The results of comparison contain 5-6 % outliers.

The proposed method allows the fast and straightforward evaluation of stellar physical parameters for the stars observed in the Vilnius photometric system. Despite the fact, that the accuracy of determination is significantly lower than in the case of spectroscopic methods, the method described may be useful for distant faint stars, which are still inaccessible for spectroscopic observations.
Report on Communicating Astronomy with the Public (CAP) Conference 2018
Authors: Sandu Oana , Cheung Sze-leung
Published: March 2020

Since 2003, the Communicating Astronomy with the Public (CAP) Conference has facilitated the exchange of ideas and best practices among professionals in the field. This paper reports on the latest edition, CAP 2018, organised in Fukuoka, Japan. It presents a few quantitative outcomes of the conference, the programme and a selection of ideas that were presented and discussed during the meeting. For further details, please consult the Book of Proceedings Communication Astronomy with the Public Conference 2018 2nd Edition, available at: https://www.communicatingastronomy.org/cap2018/
FM14 Session 4: Outreach Action and Advocacy in the Context of IAU’s 2020-2030 Strategic Plan
Authors: Cheung Sze-leung , Waller William H. , Shibata Yukiko , Usuda-Sato Kumiko , Himmelfarb Berenice , Canas Lina , Agata Hidehiko , Gomes Nuno R. C. , Doran Rosa
Published: March 2020

Section 4 of the FM14 focus on the outreach action and advocacy in the context of IAUs 2020-2030 Strategic Plan. This paper also contains supplementary materials that point to contributed talks and poster presentations that can be found online.
The Transient and Intermittent Nature of Slow Slip
Authors: Jolivet R. , Frank W. B.
Published: March 2020

To first order, faults are locked while stress builds up to a devastating earthquake. However, we know that faults also slip slowly. After decades of geophysical observation, slow slip is now recognized as part of a continuum of transient deformation ranging from the dynamic propagation of seismic rupture to aseismic events over a wide range of durations and sizes. A growing body of evidence suggests that large‐scale slow slip events can be decomposed into a multitude of smaller, temporally clustered events. Slow slip is more frequent and more dynamic than is suggested by conceptual models of rate‐strengthening, stable slip.
A Lagrangian View of Trace Elements and Isotopes in the North Pacific
Authors: Hayes Christopher T. , Fitzsimmons Jessica N. , Jensen Laramie T. , Lanning Nathan T. , Hatta Mariko , McGee David , Boyle Edward A.
Published: March 2020

Ocean time‐series sites are influenced by both temporal variability, as in situ conditions change, as well as spatial variability, as water masses move across the fixed observation point. To remove the effect of spatial variability, this study made sub‐daily Lagrangian observations of trace elements and isotopes (Al, Sc, Mn, Fe, Co, Ni, Cu, Zn, Cd, Pb, 232Th, and 230Th) in surface water over a 12‐day period (July–August 2015) in the North Pacific near the Hawaii Ocean Time‐series Station ALOHA. Additionally, a vertical profile in the upper 250 m was analyzed. This dataset is intercalibrated with GEOTRACES standards and provides a consistent baseline for trace element studies in the oligotrophic North Pacific. No diel changes in trace elements could be resolved, although day‐to‐day variations were resolved for some elements (Fe, Cu, and Zn), which may be related to organic matter cycling or ligand availability. Pb concentrations remained relatively constant during 1997–2015, presenting a change from previous decreases. Nutrient to trace element stoichiometric ratios were compared to those observed in phytoplankton as an indication of the extent of biological trace element utilization in this ecosystem, providing a basis for future ecological trace element studies.
Tidally Heated Convection and the Occurrence of Melting in Icy Satellites: Application to Europa
Authors: Vilella K. , Choblet G. , Tsao W.‐E. , Deschamps F.
Published: March 2020

Observations of icy satellites have revealed widespread marks of cryovolcanism. Because aqueous cryomagmas are negatively buoyant, two processes are required to explain these observations: one mechanism to generate melt close enough to the surface and another one to transport this melt to the surface. Here, we investigate the generation of melting in a systematic way, using a set of 85 numerical simulations where we vary the viscosity contrast, Rayleigh number, and tidal heating rate. Applied to Europa, considering a hydrosphere composed of pure water, our simulations suggest that isolated melt pockets can be generated close to the surface (
5 km) as long as the ice layer thickness (
) remains modest (
 km). However, the generation of melting becomes increasingly difficult as the amount of antifreeze compounds in the subsurface ocean increases. Furthermore, the proportion of melting increases very sharply with increasing tidal heating rate. In particular, when the tidal heating rate exceeds a threshold, an asymptotic regime is reached where the surface heat flux remains constant indicating that the tidal heat generated above this threshold is only used for melting the ice shell. In that regime, we found a direct relationship between the surface heat flux and
. Finally, we provide a new assessment of Europa's thermal state. Based on available constraints, we propose that the ice shell thickness should exceed 15 km. However,
15–35 km implies a tidal power (
2 TW) much larger than expected. An extrapolation of the trends suggested by our results indicates that a more reasonable tidal power (
1 TW) would involve
50–90 km.
Correction: Frataxin deficiency induces lipid accumulation and affects thermogenesis in brown adipose tissue
Authors: Turchi Riccardo , Tortolici Flavia , Guidobaldi Giulio , Iacovelli Federico , Falconi Mattia , Rufini Stefano , Faraonio Raffaella , Casagrande Viviana , Federici Massimo , De Angelis Lorenzo , Carotti Simone , Francesconi Maria , Zingariello Maria , Morini Sergio , Bernardini Roberta , Mattei Maurizio , La Rosa Piergiorgio , Piemonte Fiorella , Lettieri-Barbato Daniele , Aquilano Katia
Published: March 2020

Since online publication of this article, the authors noticed that there was a basic citation error in PubMed citation data. Specifically, the name of the author “Piergiorgio La Rosa” is cited as "Rosa P” in the PubMed citation, when it should be “La Rosa P”, “La Rosa” being the surname and “Piergiorgio” the name of the author.
A comparative study among machine learning and numerical models for simulating groundwater dynamics in the Heihe River Basin, northwestern China
Authors: Chen Chong , He Wei , Zhou Han , Xue Yaru , Zhu Mingda
Published: March 2020

Groundwater is unique resource for agriculture, domestic use, industry and environment in the Heihe River Basin, northwestern China. Numerical models are effective approaches to simulate and analyze the groundwater dynamics under changeable conditions and have been widely used all over the world. In this paper, the groundwater dynamics of the middle reaches of the Heihe River Basin was simulated using one numerical model and three machine learning algorithms (multi-layer perceptron (MLP); radial basis function network (RBF); support vector machine (SVM)). Historical groundwater levels and streamflow rates were used to calibrate/train and verify the different methods. The root mean square error and R2 were used to evaluate the accuracy of the simulation/training and verification results. The results showed that the accuracy of machine learning models was significantly better than that of numerical model in both stages. The SVM and RBF performed the best in training and verification stages, respectively. However, it should be noted that the generalization ability of numerical model is superior to the machine learning models because of the inclusion of physical mechanism. This study provides a feasible and accurate approach for simulating groundwater dynamics and a reference for model selection.
Secondary care provider attitudes towards patient generated health data from smartwatches
Authors: Alpert Jordan M. , Manini Todd , Roberts Megan , Kota Naga S. Prabhakar , Mendoza Tonatiuh V. , Solberg Laurence M. , Rashidi Parisa
Published: March 2020

Wearable devices, like smartwatches, are increasingly used for tracking physical activity, community mobility, and monitoring symptoms. Data generated from smartwatches (PGHD_SW) is a form of patient-generated health data, which can benefit providers by supplying frequent temporal information about patients. The goal of this study was to understand providers’ perceptions towards PGHD_SW adoption and its integration with electronic medical records. In-depth, semi-structured qualitative interviews were conducted with 12 providers from internal medicine, family medicine, geriatric medicine, nursing, surgery, rehabilitation, and anesthesiology. Diffusion of Innovations was used as a framework to develop questions and guide data analysis. The constant comparative method was utilized to formulate salient themes from the interviews. Four main themes emerged: (1) PGHD_SW is perceived as a relative advantage; (2) data are viewed as compatible with current practices; (3) barriers to overcome to effectively use PGHD_SW; (4) assessments from viewing sample data. Overall, PGHD_SW was valued because it enabled access to information about patients that were traditionally unattainable. It also can initiate discussions between patients and providers. Providers consider PGHD_SW important, but data preferences varied by specialty. The successful adoption of PGHD_SW will depend on tailoring data, frequencies of reports, and visualization preferences to correspond with the demands of providers.
Igf2bp3 maintains maternal RNA stability and ensures early embryo development in zebrafish
Authors: Ren Fan , Lin Qiaohong , Gong Gaorui , Du Xian , Dan Hong , Qin Wenying , Miao Ran , Xiong Yang , Xiao Rui , Li Xiaohui , Gui Jian-Fang , Mei Jie
Published: March 2020

Early embryogenesis relies on maternally inherited mRNAs. Although the mechanism of maternal mRNA degradation during maternal-to-zygotic transition (MZT) has been extensively studied in vertebrates, how the embryos maintain maternal mRNA stability remains unclear. Here, we identify Igf2bp3 as an important regulator of maternal mRNA stability in zebrafish. Depletion of maternaligf2bp3destabilizes maternal mRNAs prior to MZT and leads to severe developmental defects, including abnormal cytoskeleton organization and cell division. However, the process of oogenesis and the expression levels of maternal mRNAs in unfertilized eggs are normal in maternaligf2bp3mutants. Gene ontology analysis revealed that these functions are largely mediated by Igf2bp3-bound mRNAs. Indeed, Igf2bp3 depletion destabilizes while its overexpression enhances its targeting maternal mRNAs. Interestingly,igf2bp3overexpression in wild-type embryos also causes a developmental delay. Altogether, these findings highlight an important function of Igf2bp3 in controlling early zebrafish embryogenesis by binding and regulating the stability of maternal mRNAs.
Multi-frequency surface plasmons supported with a nanoscale non-uniform 2D electron gas formed due to a polar catastrophe at the oxide interface, dispersions, diffractions, and beyond
Authors: Wang Yingce , Zhao Hua , Wang Chao , Huo Dewang , Su Hang , Ma Xinyan , Zhang Jingwen
Published: March 2020

Recently, 2D electron gases (2DEGs) formed at oxide interfaces are drawing increasing attention as they cause a myriad of intriguing phenomena.
Deriving 2D M2X3 (M = Mo, W, X = S, Se) by periodic assembly of chalcogen vacancy lines in their MX2 counterparts
Authors: Wang Xiaowei , Guan Xiaoxiao , Ren Xibiao , Liu Tian , Huang Wei , Cao Juexian , Jin Chuanhong
Published: March 2020

A group of 2D transition mental sesqui-chalcogenides-M2X3 (M = Mo, W, X = S, Se) were fabricated via periodic assembly of chalcogen vacancy lines in their MX2 counterparts and were predicted to be narrow-band semiconducting with high carrier mobilities.
Transformation of carbon dioxide into carbon nanotubes for enhanced ion transport and energy storage
Authors: Kim Gi Mihn , Lim Won-Gwang , Kang Dohyung , Park Jae Hyun , Lee Hyunjoo , Lee Jinwoo , Lee Jae W.
Published: March 2020

CO2-derived-CNTs (CCNTs) prepared at 500–700 °C (1 atm) show excellent supercapacitance due to B/O doping and fast ion transport through mesoporous CCNT fibers.
Star amphiphilic block copolymers: synthesis via polymerization-induced self-assembly and crosslinking within nanoparticles, and solution and interfacial properties
Authors: Qian Sijia , Liu Rui , Han Guang , Shi Keyu , Zhang Wangqing
Published: March 2020

The star amphiphilic block copolymer of star s-PNIPAM-b-PS is synthesized and it shows characteristics significantly different from those of the linear block copolymer counterpart.
AIE-active Schiff base compounds as fluorescent probes for the highly sensitive and selective detection of Fe3+ ions
Authors: Harathi Jonnagaddala , Thenmozhi Kathavarayan
Published: March 2020

AIE-active Schiff base compounds were synthesized and photophysical properties were investigated. The compounds exhibited prominent sensing behaviour towards Fe3+ ion with enhanced selectivity, high association constants and low detection limits.
Cyclopentane rings in hydrophobic chains of a phospholipid enhance the bilayer stability to electric breakdown
Authors: Batishchev Oleg V. , Alekseeva Anna S. , Tretiakova Daria S. , Galimzyanov Timur R. , Chernyadyev Andrey Yu. , Onishchenko Natalia R. , Volynsky Pavel E. , Boldyrev Ivan A.
Published: March 2020

Bilayers of a phospholipid with cyclopentane-containing chains are stable to pore formation due to restricted conformational mobility of the chains and inability of the molecules to rearrange in order to line the edge of a hydrophilic pore.
Facile morphology control of gold(0) structures from aurophilic assemblies
Authors: Aguiló Elisabet , Dalmases Mariona , Lin Mengxi , Lima João Carlos , Gavara Raquel , Figuerola Albert , Llorca Jordi , Rodríguez Laura
Published: March 2020

Different gold microstructures have been synthesized by using supramolecular gold(i) organometallic compounds as templates and Ag nanoparticles as reducing agents.
Single atom catalysts: a surface heterocompound perspective
Authors: Kou Zongkui , Zang Wenjie , Wang Peikui , Li Xin , Wang John
Published: March 2020

Evolution of heterogeneous catalysts with steady down-sizing: from small particles, clusters, dots to single atoms, and now the “surface heterocompound”.
Construction of a combined enzyme system of graphene oxide and manganese peroxidase for efficient oxidation of aromatic compounds
Authors: Yang Shichao , Yang Jun , Wang Tao , Li Liuqing , Yu Siming , Jia Rong , Chen Ping
Published: March 2020

We report a highly efficient catalyst by a combination of graphene oxide and manganese peroxidase from Irpex lacteus F17 for the oxidation of aromatic substances and dye decolorization.
Selective fluorescence sensing of H2PO4−by the anion induced formation of self-assembled supramolecular polymers
Authors: Sabater Paula , Zapata Fabiola , Bastida Adolfo , Caballero Antonio
Published: March 2020

H2PO4−anions induced the formation of a fluorescent supramolecular polymer by halogen bonding interactions in a bromoimidazolium based tripodal receptor.
Living coordination–insertion copolymerization of 1-hexene and ligated α-olefins using an α-diimine nickel catalyst and preparation of metal–ligand coordination crosslinked polymers
Authors: Zhao Wenpeng , Dong Bo , Liu Heng , Hu Yanming , Zhang Xuequan
Published: March 2020

Metal–ligand coordination crosslinked polymers were prepared by coordination–insertion copolymerization of 1-hexene and ligated α-olefins.
Ammonia-etching-assisted nanotailoring of manganese silicate boosts faradaic capacity for high-performance hybrid supercapacitors
Authors: Dong Xueying , Zhang Yifu , Chen Qiang , Jiang Hanmei , Wang Qiushi , Meng Changgong , Kou Zongkui
Published: March 2020

Nanotailoring of active manganese silicate with an average particle size of about 20 nm is realized by an ammonia-etching-assisted route, delivering a 3.55-times higher faradaic capacity than the traditional yolk–shell counterpart in hybrid supercapacitors.
Dynamics of entangled polymers subjected to reptation and drift
Authors: Tejedor Andrés R. , Ramírez Jorge
Published: March 2020

Reptating linear polymers with drift give rise to enhanced transport properties.
The mechanism and role of intracellular α-ketoglutarate reduction in hepatic stellate cell activation
Authors: Zhao Jianjian , Jiang Yueping , Sun Xueguo , Liu Xishuang , Liu Fuguo , Song Mingquan , Zhang Lingyun
Published: March 2020

Background: The activation of hepatic stellate cells (HSCs) plays a central role in liver fibrosis. α-ketoglutarate is a natural metabolite and previous studies have shown that increase in intracellular α-ketoglutarate can inhibit HSC activation. Aim: The aim of the present study is to determine the changes and role of intracellular α-ketoglutarate in HSC activation and clarify its mechanism of action. Methods: A human HSC cell line (LX-2) and the primary mouse HSC were used in the present study. We detected the changes of intracellular α-ketoglutarate levels and the expression of enzymes involved in the metabolic processes during HSC activation. We used siRNA to determine the role of intracellular α-ketoglutarate in HSC activation and elucidate the mechanism of the metabolic changes. Results: Our results demonstrated that intracellular α-ketoglutarate levels decreased with an HSC cell line and primary mouse HSC activation, as well as the expression of isocitrate dehydrogenase 2 (IDH2), an enzyme that catalyzes the production of α-ketoglutarate. In addition, knockdown of IDH2 efficiently promoted the activation of HSCs, which was able to be reversed by introduction of an α-ketoglutarate analogue. Furthermore, we demonstrated that α-ketoglutarate regulated HSC activation is independent of transforming growth factor-β1 (TGF-β1). Conclusions: Our findings demonstrated that decrease in IDH2 expression limits the production of α-ketoglutarate during HSC activation and in turn promotes the activation of HSCs through a TGF-β1 independent pathway. The present study suggests that IDH2 and α-ketoglutarate may be potential new targets for the prevention and treatment of liver fibrosis.
Joint XMM-Newton and NuSTAR observations of the reflection spectrum of III Zw 2
Authors: Chamani Wara , Koljonen Karri , Savolainen Tuomas
Published: March 2020

Detecting and modeling the reprocessed hard X-ray emission component in the accretion flow, the so-called reflection spectrum, is a main tool used to estimate black hole spins in a wide range of astrophysical black holes, regardless of their mass or distance. In this work, we study the X-ray spectra of the Seyfert I galaxy III Zw 2 by using multiepoch XMM-Newton, NuSTAR, and Suzaku observations. The X-ray spectra exhibit a soft-excess below 1 keV and a prominent excess at the location of the broad Fe Kα line at 6.4 keV. To account for these spectral features, we fit the spectra with multiple models including an ionized partially covering absorber and an accretion disk reflection model. To fully resolve the reflection component, we analyzed jointly the XMM-Newton and NuSTAR observations taken in 2017 and archival XMM-Newton data from 2000. Assuming the reflection scenario, the resulting model fits support for a rapidly spinning black hole (a ≥ 0.98) in this radio-intermediate source. The X-ray spectra in 2000 and 2017 are remarkably similar; the only difference pertains to the reflection fraction, which is possibly due to a change in the geometry of the accretion flow. However, the Suzaku observation is markedly different, and we suggest this could be an effect of a jet contribution in the X-ray band, which is supported by the elevated radio flux during this observation.
Disk of 2MASS 15491331−3539118 = GQ Lup C as seen by HST and WISE
Authors: Lazzoni C. , Gratton R. , Alcalá J. M. , Desidera S. , Frasca A. , Manara C. F. , Mesa D. , Rigliaco E. , Vigan A. , Zurlo A.
Published: March 2020

Aims. Very recently, a second companion on a wider orbit has been discovered around GQ Lup. This is a low-mass accreting star that is partially obscured by a disk seen at high inclination. If detected, this disk may be compared to the known disk around the primary.

Methods. We detected this disk on archive HST and WISE data.

Results. The extended spectral energy distribution provided by these data confirms the presence of accretion from Hα emission and UV excess, and shows an IR excess attributable to a warm disk. In addition, we resolved the disk on the HST images. It is found to be roughly aligned with the disk of the primary. Both of them are roughly aligned with the Lupus I dust filament containing GQ Lup.
L’adoption du semis direct sous couvert végétal : transition douce ou rupture ?
Authors: Derrouch Damien , Dessaint Fabrice , Felten Émeline , Chauvel Bruno
Published: March 2020

Le semis direct sous couvert repose sur l’application simultanée et continue de trois principes : la réduction quasi-totale du travail du sol, une couverture organique des sols et une rotation diversifiée. Ce système agricole adopté en France à partir des années 2000 sous l’impulsion de groupes d’agriculteurs est en extension. Pour les agriculteurs, adopter un nouveau système agricole revient à modifier, de manière plus ou moins importante, leurs pratiques. Concernant le semis direct sous couvert végétal, peu d’informations existent. Cet article a pour objectif d’éclairer les modifications que peut induire sa mise en place. Pour cela, il s’appuie sur les réponses de 425 agriculteurs français à une enquête en ligne. Pour 30 % des agriculteurs, le semis direct sous couvert constitue une modification complète du système agricole. La réduction quasi-totale du travail du sol est le principe qui entraîne le plus de modifications (pour 96 % des agriculteurs). Au contraire, la diversification de la rotation connaît le moins de modifications (48 % des agriculteurs). L’absence d’une modification de la rotation peut s’expliquer par une rotation déjà diversifiée en place ou l’incapacité pour les agriculteurs d’ajouter de nouvelles cultures à leur rotation. L’optimisation de la couverture végétale du sol entraîne une modification des pratiques pour 67 % des agriculteurs. Durant les premières années, les agriculteurs s’orientent majoritairement vers l’utilisation de couverts temporaires plurispécifiques. Bouleversant certains fondamentaux de l’agriculture, ces agriculteurs minimisent les risques encourus en favorisant une transition progressive et en partageant les connaissances acquises.
Electroluminescence of thin film p-i-n diodes based on a-SiC:H with integrated Ge nanoparticles
Authors: Remes Zdenek , Stuchlik Jiri , Stuchlikova The-ha , Kupcik Jaroslav , Mortet Vincent , Taylor Andrew , Ashcheulov Petr , Volodin Vladimir Alekseevich
Published: March 2020

Hydrogenated amorphous substoichiometric silicon carbon alloys (a-SiC:H) with and without embedded Ge nanoparticles (NPs) have been prepared by plasma enhanced chemical vapour deposition combined with in-situ Ge evaporation and annealing on semi-transparent boron doped nano-crystalline diamond coated Ti grids. The presence of Ge NPs embedded in the amorphous phase has been confirmed by transmission electron microscopy and energy-dispersive X-ray spectroscopy analyses. Current-voltage (I–V) characteristics and near infrared electroluminescence (EL) spectra were measured to compare performance of diodes. The relatively strong EL appears in diodes with integrated Ge NPs near the direct band-gap transition of Ge at about 0.82 eV with an intensity strongly correlating with current density. However, it has also been found that Ge NPs integrated into a-SiC:H significantly deteriorates diode I–V characteristic.
Split ring resonator loaded EF-structured left-handed metamaterial for modern electronic communications
Authors: Tamim Ahmed Mahfuz , Faruque Mohammad Rashed Iqbal , Islam Mohammad Tariqul , Abdullah Sabirin
Published: March 2020

A novel miniaturised EF-structured metamaterial loaded with split ring resonator (SRR) has been developed and investigated for multi-band frequency applications. Miniaturisation is achieved by increasing the metallic strips to form EF-structure resonator. Commercially available, the advanced electromagnetic simulator has been utilised for the layout design and elaborated analysis of this developed left-handed metamaterial. The unit cell structure is embedded in low-cost FR4 dielectric substrate and size of the metamaterial is 11.11 × 11.11 mm2. Due to the miniaturised size, a highly effective medium ratio of about 14.82 is obtained. The developed left-handed metamaterial exhibits negative permittivity, negative permeability, and negative refractive index over multiple frequency ranges. Nicolson-Ross-Weir (NRW) method has been utilised for the extraction of the effective parameters. Thus, a novel metamaterial has been presented where the miniaturised size and its performances makes it compatible to use for the applications of 1.82 GHz, 2.22 GHz, 4.82 GHz, 5.89 GHz, 10.54 GHz, i.e. for digital cellular system (DCS), earth exploration-satellite communications (EESC), lower band 5G mobile communications, WiMAX applications, and military satellite applications, respectively. Furthermore, the metamaterial has average SAR reduction of about 44%. These results proceed to a guideway of better SAR reduction of modern electronic communications.
Enhanced optical performance of thermochromic VO2 based on multilayer designs
Authors: Liu Houao , Song Hao , Xie Hao , Yin Guanchao
Published: March 2020

VO2 is a widely studied thermochromic material for smart windows. In this work, we comprehensively studied optical responses of VO2-based multilayer structures. It is discovered that one-layer antireflection layer is capable of effectively enhancing both luminous transmittance (Tlum) and solar transmittance (Tsol), solar spectrum modulation (ΔTsol) is however quite moderate. Employing a two-top-layer strategy further improves the optical performance of VO2, especially with an increase of ΔTsol from 0.068 to 0.082. Remarkably, combining a layer with an index of 2.2 at the VO2/glass interface continues to enhance the optical performance, leading to the highest Tlum and ΔTsol among the investigated multilayer structures. Compared to the base structure of VO2/glass, it contributes to a relative enhancement of 26.4% (from 0.435 to 0.550) for Tlum (<τc), 35.3% (from 0.362 to 0.490) for Tlum (>τc), and 71.7% (from 0.060 to 0.103) for ΔTsol.
Dynamic characteristics for coal shearer cutting unit gearbox housing
Authors: Zhang Rui , Zhang Yimin
Published: March 2020

Long wall mining is most widely used in coal mining of China, and coal shearer is the most important machine due to its direct role in cutting coal. Nevertheless, coal mining enterprises are suffering from faults of coal shearer, especially cutting unit gearbox housing (CUGH). Published dynamic studies on CUGH have not considered the excitation caused by gear meshing and complete machine vibration. Due to the apparent lack of experimental validation of these published papers, the dynamic response of CUGH is not convincing. In this study, dynamic behavior of CUGH is investigated both theoretically and experimentally for finding out failure mechanism and improving reliability. Complete machine vibration and gear meshing vibration are two excitation sources for CUGH, and vibration is transferred via articulated holes and bearing holes. Hence, complete machine dynamics model is established for obtaining force on articulated holes. Dynamics model of gear transmission system is established for obtaining force on bearing holes. Stochastic cutting forces model is established as external load of complete machine dynamics model. Dynamics response is calculated by finite element model established by ANSYS. A measurement system to capture three-dimensional vibratory motions under realistic working conditions of coal mines is implemented by National Energy Mining Equipment Laboratory of China. Direct comparisons between predicted and measured results are presented to demonstrate the accuracy of the proposed model in predicting three-dimensional vibrations of CUGH. Maximum deformation and stress positions of CUGH are determined, and the excitation sources are investigated.
Körperlich-seelische Berührungen im Fokus der Psychoneuroimmunologie
Authors: Ott Michaela , Singer Magdalena , Brisch Karl Heinz , Schubert Christian
Published: March 2020

Die Psychoneuroimmunologie zeigt, dass Berührungs- und Bindungserfahrungen pränatal und in der frühen Kindheit unser Stresserleben und ‑verhalten bis ins hohe Alter „programmieren“. Infolgedessen leiden körperlich und seelisch traumatisierte Kinder später öfters unter entzündungsassoziierten Krankheiten und chronischen Schmerzen. Die Forschung belegt weiter, dass Berührungstraumen und der damit verbundene Schmerz überwunden werden können.
Toxicity of Atenolol and Propranolol on Rat Heart Mitochondria
Authors: Seydi Enayatollah , Tabbati Yasaman , Pourahmad Jalal
Published: March 2020

Propranolol and atenolol are known as β receptor blocker drugs. These drugs are used to treat some heart diseases. There are controversies in the relationship between the use of beta-blocker drugs and the level of reactive oxygen species (ROS). Mitochondria as one of the most important sources of ROS are considered as one of the targets of drug-induced cardiotoxicity. The aim of this study was to evaluate the effects of propranolol and atenolol on mitochondria isolated from the heart. To achieve this aim, several markers of mitochondrial and cellular toxicity were evaluated. The key results of this study are the increased ROS level, collapse in mitochondrial membrane potential (MMP), mitochondrial swelling and cytochrome c release as well as disruption of respiratory chain complex II in mitochondria in isolated heart mitochondria after exposure to propranolol and atenolol. The results indicate an increase in caspase-3 activity and a decrease in the ATP level in cardiomyocytes after exposure to propranolol and atenolol. The underlying mechanisms of propranolol and atenolol induced cardiotoxicity may be associated with alterations in mitochondrial function, oxidative stress, and changes in the mitochondrial membrane.
Skull-Base Inflammatory Pseudotumor Involving the Trigeminal and Facial Nerves: A Singular Presentation of a Rare Disease
Authors: Fiacchini Giacomo , Cambi Christina , Tavoni Antonio Gaetano , Bruschini Luca , Castellana Roberto , Dallan Iacopo , Berrettini Stefano
Published: March 2020

Inflammatory pseudotumor (IPT) is a rare disease that is often misinterpreted as a lymphoma or carcinoma. It may involve different body regions but most commonly the lungs and the orbital cavity. We report the case of a patient affected by an IPT of the trigeminal and facial nerves.

A 69-year-old male presented to our hospital with a right facial palsy arisen suddenly 2 days before. A magnetic resonance imaging (MRI) of the head showed an abnormal mass with homogeneous enhancement involving the deep lobe of the parotid gland, the parapharyngeal space, and the infratemporal fossa, extending along the trigeminal nerve and the facial nerve. The patient was planned for multiple transnasal biopsies in the nasopharynx, the region of the foramen ovale, and the deep lobe of the parotid gland, but the results were inconclusive, with no evidence of a malignant process. We considered the possibility that the lesion could be an IPT, and the patient was treated with prednisone and cyclophosphamide. Three months after the conclusion of the treatment, an MRI showed a complete radiological response.
Association between Food Deserts and Gestational Diabetes Mellitus in a Large Metropolitan Area
Authors: Banner Grace C. , Weaver Kingsley N. , Rushovich Tamara , York Sloane L. , Yee Lynn M.
Published: March 2020

Objective The aim of this study is to determine the relationship between urban food deserts and frequency and obstetric outcomes related to gestational diabetes.

Study Design We conducted a retrospective cohort study of singleton births in Chicago from 2010 to 2014. Birth certificate data were analyzed and geomapped by census tract. Census tracts were categorized as “food deserts” according to the USDA Food Access Research Atlas. The primary outcome was frequency of gestational diabetes. Secondary outcomes were assessed among women with gestational diabetes and their neonates.

Results Of the 191,947 eligible women, 8,709 (4.5%) were diagnosed with gestational diabetes. Those in food deserts were more likely to be younger, obese, minority race/ethnicity, and multiparous. Women in food deserts were less likely to develop gestational diabetes (3.8 vs. 4.8%, p < 0.01; adjusted odds ratio 0.91, 95% confidence interval 0.86–0.96). Women with gestational diabetes did not experience worse maternal and neonatal outcomes after controlling for potential confounders.

Conclusion In contrast to prior work, women in Chicago living within food deserts were less likely to develop gestational diabetes and did not experience poorer outcomes, suggesting environmental factors other than food access contribute to perinatal outcomes.