bluuebunny/crossref_metadata_2025_split huggingface dataset:
Gypenosides Prevent H2O2-Induced Retinal Ganglion Cell Apoptosis by Concurrently Suppressing the Neuronal Oxidative Stress and Inflammatory Response
Authors: Zhang Hong-Kan , Ye Yuan , Li Kai-Jun , Zhao Zhen-ni , He Jian-Feng 
Published: January 2020

AbstractOur previous study demonstrated that gypenosides (Gp) exert protective effects on retinal nerve fibers and axons in a mouse model of experimental autoimmune optic neuritis. However, the therapeutic mechanisms remain unclear. Thus, in this study, a model of oxidative damage in retinal ganglion cells (RGCs) was established to investigate the protective effect of Gp, and its possible influence on oxidative stress in RGCs. Treatment of cells with H2O2 induced RGC injury owing to the generation of intracellular reactive oxygen species (ROS). In addition, the activities of antioxidative enzymes decreased and the expression of inflammatory factors increased, resulting in an increase in cellular apoptosis. Gp helped RGCs to become resistant to oxidation damage by directly reducing the amount of ROS in cells and exerting protective effects against H2O2-induced apoptosis. Treatment with Gp also reduced the generation of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2), and increased nuclear respiratory factor 2 (Nrf-2) levels so as to increase the levels of heme oxygenase-1 (HO-1) and glutathione peroxidase 1/2 (Gpx1/2), which can enhance antioxidation in RGCs. In conclusion, our data indicate that neuroprotection by Gp involves its antioxidation and anti-inflammation effects. Gp prevents apoptosis through a mitochondrial apoptotic pathway. This finding might provide novel insights into understanding the mechanism of the neuroprotective effects of gypenosides in the treatment of optic neuritis.
Combining scanning tunneling microscope (STM) imaging and local manipulation to probe the high dose oxidation structure of the Si(111)-7×7 surface
Authors: Kaya Dogan , Cobley Richard J. , Palmer Richard E. 
Published: January 2020

AbstractUnderstanding the atomistic formation of oxide layers on semiconductors is important for thin film fabrication, scaling down conventional devices and for the integration of emerging research materials. Here, the initial oxidation of Si(111) is studied using the scanning tunneling microscope. Prior to the complete saturation of the silicon surface with oxygen, we are able to probe the atomic nature of the oxide layer formation. We establish the threshold for local manipulation of inserted oxygen sites to be +3.8 V. Only by combining imaging with local atomic manipulation are we able to determine whether inserted oxygen exists beneath surface-bonded oxygen sites and differentiate between sites that have one and more than one oxygen atom inserted beneath the surface. Prior to the creation of the thin oxide film we observe a flip in the manipulation rates of inserted oxygen sites consistent with more oxygen inserting beneath the silicon surface.
A comprehensive review of nanoparticles applications in the oil and gas industry
Authors: Alsaba Mortadha T. , Al Dushaishi Mohammed F. , Abbas Ahmed K. 
Published: January 2020

AbstractWith the increased attention toward nanotechnology and their innovative use for different industries including but not limited to food, biomedical, electronics, materials, etc, the application of nanotechnology or nanoparticles in the oil and gas industry is a subject undergoing intense study by major oil companies, which is reflected through the huge amount of funds invested on the research and development, with respect to the nanotechnology. Nanotechnology has been recently investigated extensively for different applications in the oil and gas industry such as drilling fluids and enhanced oil recovery in addition to other applications including cementing and well stimulation. In this paper, comprehensive literature was conducted to review the different applications of nanotechnology in the oil and gas industry. A summary of all nanoparticles used along with a detailed analysis of their performance in improving the targeted parameters is comprehensively presented. The main objective of this review was to provide a comprehensive summary of the different successful applications of nanotechnology and its associated challenges, which could be very helpful for future researches and applications.
The Hidden Wounds of Hurricane Dorian: Why Emergency Response Must Look Beyond Physical Trauma
Authors: Dunne-Sosa Andrea , Cotter Tom 
Published: January 2020

ABSTRACTProject HOPE, a global health and humanitarian assistance organization, has responded to some of the world’s largest natural disasters and humanitarian and health crises for more than 60 years. As natural disasters increase in frequency and intensity, otherwise effective health systems can become compromised, and - although less visible than traumatic injuries – populations with chronic diseases can be significantly impacted. Emergency preparedness and response efforts must adapt to address issues around continuity of care, access to pharmaceuticals, strengthening cold chain mechanisms, restoring supply chains, and educating patients with chronic illnesses on emergency preparedness. Project HOPE designs medical teams and supply donations to work alongside, rather than parallel to, existing health care infrastructure, laying the foundation for the long-term recovery of the health system.
SAME-SEX RELATIONS AND THE CATHOLIC CHURCH: HOW LAW AND DOCTRINE HAVE EVOLVED, 1820–2020
Authors: Reid Charles J. 
Published: January 2020

AbstractThis article surveys the evolution of the Catholic Church's official response to same-sex relations over the last two centuries. While the church has not altered its condemnation of same-sex relations, the justifications it offers for this negative judgment have shifted substantially, and they have moved, especially recently, in a direction that makes possible the acceptance of same-sex relations at some future—and perhaps not too-distant—date. This article explores the manualist tradition of the nineteenth and early to mid-twentieth centuries; twentieth-century developments in canon law; and the period of retrenchment and reaction under popes John Paul II and Benedict XVI. Its final section looks at developments under Pope Francis. It closes by considering the way the church's teaching shifted over the course of its history—penance and the forgiveness of sins; anti-Semitism; and the sin against natural-law of taking interest on a loan (usury). It proposes that we might witness the church undergo a similar shift on same-sex relations.
Late Thermal Pulse Models and the Rapid Evolution of V839 Ara
Authors: Lawlor Timothy M. 
Published: January 2020

AbstractWe present evolution calculations from the Asymptotic Giant Branch (AGB) to the Planetary Nebula (PNe) phase for models of mass 1.0 to 2.0 M⊙ over a range of metallicities. The understanding of these objects plays an important role in galactic evolution and composition. Here, we particularly focus on Late Thermal Pulse (LTP) models, which are models that experience an intense helium-shell pulse that occurs just following AGB departure and causes a rapid looping evolution between the AGB and PN phases. The transient phases only last decades and centuries while increasing and decreasing in temperature dramatically. We use our models to make comparisons to V839 Ara (SAO 244567). This star has been observed rapidly heating over more than 50 years. Observations have proven difficult to model because the central star has a small radius, high surface gravity, and low temperature compared to our models.
AGB stars of the Magellanic Clouds as seen within the Δa photometric system
Authors: Paunzen Ernst , Janík Jan , Kurfürst Petr , Liška Jiří , Netopil Martin , Skarka Marek , Zejda Miloslav 
Published: January 2020

AbstractThe a-index samples the flux of the 5200 Å region by comparing the flux at the center with the adjacent regions. The final intrinsic peculiarity index Δa was defined as the difference between the individual a-values and the a-values of normal stars of the same colour (spectral type). Here we present, for the first time, a case study to detect and analyse Asymptotic Giant Branch (AGB) stars in the Magellanic Clouds. For this, we use our photometric survey of the Magellanic Clouds within the a-index. We find that AGB stars can be easily detected on the basis of their Δa index in an efficient way.
Unravelling the sulphur chemistry of AGB stars
Authors: Danilovich Taïssa 
Published: January 2020

AbstractThere are clear differences in what sulphur molecules form in AGB circumstellar envelopes (CSEs) across chemical types. CS forms more readily in the CSEs of carbon stars, while SO and SO2 have only been detected towards oxygen-rich stars. However, we have also discovered differences in sulphur chemistry based on the density of the CSE, as traced by mass-loss rate divided by expansion velocity. For example, the radial distribution of SO is drastically different between AGB stars with lower and higher density CSEs. H2S can be found in high abundances towards higher density oxygen-rich stars, whereas SiS accounts for a significant portion of the circumstellar sulphur for higher density carbon stars.
Exploring dust mass and dust properties of nearby AGB stars
Authors: Wiegert J. , Groenewegen M. A. T. ,   the STARLAB team
Published: January 2020

AbstractLow and intermediate mass stars evolve to the asymptotic red giant branch (AGB) late in their lives. These are surrounded by a circumstellar envelope (CSE) filled with gas and dust. The dust is formed close to the star at sublimation radii and is pushed away by the stellar wind. The dust in turn pushes gases from the envelope into the interstellar medium, thus enriching it with metals. This poster summary is a general description of the next piece of a larger project, whereas the first half has been published by Nicolaes et al. (2018). We now aim to use radiative transfer simulations to model spectral energy distributions (SED) of dust and fit them to far-infrared observations for the same 40 sources. We will use 2D and 3D simulations and models containing several dust species simultaneously.
On the circumstellar envelopes of semi-regular long-period variables
Authors: Díaz-Luis J. J. , Alcolea J. , Bujarrabal V. , Santander-García M. , Gómez-Garrido M. , Desmurs J.-F. 
Published: January 2020

AbstractThe mass loss process along the AGB phase is crucial for the formation of circumstellar envelopes (CSEs), which in the post-AGB phase will evolve into planetary nebulae (PNe). There are still important issues that need to be further explored in this field; in particular, the formation of axially symmetric PNe from spherical CSEs. To address the problem, we have conducted high S/N IRAM 30 m observations of 12COJ = 1−0 and J = 2−1, and 13COJ = 1−0 in a volume-limited unbiased sample of semi-regular variables (SRs). We also conducted Yebes 40 m SiO J = 1−0 observations in 1/2 of the sample in order to complement our 12CO observations. We report a moderate correlation between mass loss rate and the 12CO(1−0)−to−12CO(2−1) line intensity ratio, introducing a possible new method for determining mass loss rates of SRs with short analysis time. We also find that for several stars the SiO profiles are very similar to the 12CO profiles, a totally unexpected result unless these are non-standard envelopes.
Dust properties in the circumstellar environment of carbon stars
Authors: Mečina M. , Aringer B. , Brunner M. , Kerschbaum F. , Groenewegen M. A. T. , Nowotny W. 
Published: January 2020

AbstractHerschel PACS imaging observations of carbon stars show well-resolved spherically symmetric detached shells around several objects. In the case of U Hya the shell is additionally detected in scattered visible light and in the far UV. The remarkable spherical symmetry justifies a straightforward application of 1D models to constrain the properties of the dust envelope, whose modulation in density is a consequence of short epochs of highly increased mass loss and/or wind-wind interaction between outflows of different velocity. We perform dust radiative transfer calculations, first based on a parametrised density distribution, and in a more sophisticated approach on a combination of stationary wind models. The impact of dust properties, particularly grain geometry, on the results is highlighted.
Characterisation of long-period variables in the Magellanic Clouds
Authors: Trabucchi Michele , Wood Peter R. , Montalbán Josefina , Marigo Paola , Pastorelli Giada , Girardi Léo 
Published: January 2020

AbstractVariability due to stellar pulsation on the Asymptotic Giant Branch (AGB) has a great potential for applications such as distance measurements, the study the evolution of stars and galaxies, and the estimate of global stellar parameters, as well as to constrain stellar evolutionary models. Given the importance of long-period variables (LPVs) in this sense, and given the lack of recent, updated sets of pulsation models, we computed an extended grid of pulsation models widely covering the space of AGB stellar parameters, including up-to-date opacities and accounting for the chemical evolution associated with third dredge-up events. We present the relevant properties of this grid and discuss the main results it allowed to obtain in terms of the interpretation of the observed properties of LPVs in the Large Magellanic Cloud (LMC).
The missing mass conundrum of post-common-envelope planetary nebulae
Authors: Santander-García Miguel , Jones David , Alcolea Javier , Wesson Roger , Bujarrabal Valentín 
Published: January 2020

AbstractMost planetary nebulae (PNe) show beautiful, axisymmetric morphologies despite their progenitor stars being essentially spherical. Angular momentum provided by a close binary companion is widely invoked as the main agent that would help eject an axisymmetric nebula, after a brief phase of engulfment of the secondary within the envelope of the Asymptotic Giant Branch (AGB) star, known as a common envelope (CE). The evolution on the AGB would thus be interrupted abruptly, its (still quite) massive envelope fully ejected to form the PN, which should be more massive than a PN coming from the same star were it single. We test this hypothesis by deriving the ionised+molecular masses of a pilot sample of post-CE PNe and comparing them to a regular PNe sample. We find the mass of post-CE PNe to be actually lower, on average, than their regular counterparts, raising some doubts on our understanding of these intriguing objects.
Mass loss rates of Li-rich AGB/RGB stars
Authors: Macie Walter J. , Costa Roberto D. D. 
Published: January 2020

AbstractA sample of AGB/RGB stars with an excess of Li abundances is considered in order to estimate their mass loss rates. Our method is based on a correlation between the Li abundances and the stellar luminosity, using a modified version of the Reimers formula. We have adopted a calibration based on an empirical correlation between the mass loss rate and stellar parameters. We conclude that most Li-rich stars have lower mass loss rates compared with the majority of AGB/RGB stars, which show no evidences of Li enhancements, so that the Li enrichment process is probably not associated with an increased mass loss rate.
Long Period Variables in Local Group dwarf Irregular Galaxies
Authors: Menzies John 
Published: January 2020

AbstractThe long-term SAAO survey of Local Group galaxies in the near-infrared (JHKs) has included five dwarf irregulars (dIrr), namely, NGC 6822, IC 1613, WLM, Sgr dIG and NGC 3109. We have found long-period (Mira) variables in all of them. Most of the Miras, which follow a linear LMC period-luminosity (PL) relation well, are carbon-rich. A small group of oxygen-rich Miras are brighter than the linear PL relation predicts, presumably because they are undergoing hot-bottom burning (HBB).
Extended Dust Emission from Nearby Evolved stars
Authors: Dharmawardena Thavisha E. , Kemper Francisca , Scicluna Peter , Wouterloot Jan G. A. , Trejo Alfonso , Srinivasan Sundar , Cami Jan , Zijlstra Albert , Marshall Jonathan P. ,   the NESS collaboration
Published: January 2020

AbstractWe derive azimuthally-averaged surface-brightness profiles of 16 AGB stars in the far-IR and sub-mm with the aim of studying the resolved historic mass loss in the extended circumstellar envelope. The PSF-subtracted extended component fluxes were found to be ∼40% of the total source flux. By fitting SEDs at each radial point we derive the dust temperature, column density and spectral index of emissivity via Bayesian inference. The measured dust-to-gas ratios were somewhat consistent with canonical values however with a large scatter.
The evolution of DARWIN: current status of wind models for AGB stars
Authors: Bladh Sara 
Published: January 2020

AbstractThe slow, dense winds observed in evolved asymptotic giant branch (AGB) stars are usually attributed to a combination of dust formation in the dynamical inner atmosphere of these stars and momentum transfer from stellar photons interacting with the newly formed dust particles. Wind models calculated with the DARWIN code, using this mass-loss scenario, have successfully produced outflows with dynamical and photometric properties compatible with observations, for both C-type and M-type AGB stars. Presented here is an overview of the DARWIN models currently available and what output these models produce, as well as future plans.
Oxygen-rich Long Period Variables in the X-Shooter Spectral Library
Authors: Lançon Ariane , Gonneau Anas , Trager Scott C. , Prugniel Philippe , Arentsen Anke , Chen Yanping , Dries Matthijs , Loup Cécile , Lyubenova Mariya , Peletier Reynier , Telliez Laure , Vazdekis Alexandre ,   the XSL Collaboration
Published: January 2020

AbstractThe X-Shooter Spectral Library (XSL) contains more than 800 spectra of stars across the color-magnitude diagram, that extend from near-UV to near-IR wavelengths (320-2450 nm). We summarize properties of the spectra of O-rich Long Period Variables in the XSL, such as phase-related features, and we confront the data with synthetic spectra based on static and dynamical stellar atmosphere models. We discuss successes and remaining discrepancies, keeping in mind the applications to population synthesis modeling that XSL is designed for.
Stellar Wind Accretion and Raman O VI Spectroscopy of the Symbiotic Star AG Draconis
Authors: Lee Young-Min , Heo Jeong-Eun , Lee Hee-Won , Lee Ho-Gyu , Angeloni Rodolfo , Di Mille Francesco , Palma Tali 
Published: January 2020

AbstractRaman scattered O VI features at 6825 Å and 7082 Å found in symbiotic stars are important spectroscopic tools to probe the mass transfer process. Adopting a Monte Carlo approach, we perform a profile analysis of Raman O VI features of the yellow SySt AG Draconis and make a comparison with the spectrum obtained with CFHT. It is assumed that the accretion flow is convergent on the entering side with enhanced O VI emission and the flux ratio F(1032)/F(1038)∼1, whereas on the opposite side the flow is divergent with low O VI emission and F(1032/F(1038)∼2. Our best fit to the spectrum is obtained from our model with a mass-loss rate of the giant ∼4 × 10−7 M⊙ yr−1. A slight red wing excess in the spectrum suggests the presence of bipolar neutral components receding in the directions perpendicular to the binary orbital plane with a speed ∼70km s−1
Post-RGB and Post-AGB stars as tracers of binary evolution
Authors: Kamath Devika 
Published: January 2020

AbstractBinary interactions can alter the intrinsic properties of stars (such as: pulsation, mass-loss, photospheric chemistry, dust-formation, circumstellar envelope morphology etc.) and can even play a dominant role in determining its ultimate fate. While past studies have shown that binarity can end the AGB life of a star, recent studies have revealed that in specific cases binarity also pre-maturely terminate the RGB evolution. A characteristic feature of evolved binaries is the presence of a Keplerian circumbinary disc of gas and dust which plays a lead role in the evolution of the systems. In this article, I will review our advances in the research landscape of post-RGB and post-AGB binary stars, focussing on their observational properties, spectral energy distribution, photospheric chemistry, the evolution of their stable circumbinary discs, and the evolutionary connection between the enigmatic post-AGB/post-RGB binaries, and other systems whose primary component is a white dwarf.
Modelling dust around Nearby Evolved Stars Survey (NESS) Targets
Authors: Srinivasan Sundar , Dharmawardena T. , Kemper F. , Scicluna P. ,   The NESS Collaboration
Published: January 2020

AbstractWe present radiative transfer modelling of the dust around U Ant, a well-studied detached-shell source. U Ant is among the >400 sources targeted by the Nearby Evolved Stars Survey (NESS; PI: P. Scicluna), and the procedure used to model this source will be applied to the rest of the AGB sample in NESS.
Comprehensive Panchromatic Data Analyses and Photoionization Modeling of NGC 6781
Authors: Ueta Toshiya , Otsuka Masaaki ,   the HerPlaNS consortium
Published: January 2020

AbstractWe characterized the dusty circumstellar nebula and central star of the C-rich bipolar planetary nebula (PN) NGC 6781 using our own Herschel data augmented with the archival data from UV to radio and constructed one of the most comprehensive photoionization PN models ever produced consisting of the ionized, atomic and molecular gas components as well as the dust component. We reproduced the observed spectral energy distribution (SED), constrained by 136 observational data points. The total nebula mass was estimated to be 0.41 M⊙, with a significant fraction (about 70 %) of it existing in the photo-dissociation region (PDR) surrounding the ionized nebula. This finding demonstrates the critical importance of the PDR in PNe, which are typically recognized as the hallmark of ionized/H+ region. It is therefore essential to characterize the PDR of the circumstellar nebula to understand material recycling in the Milky Way and other galaxies.
The common-envelope wind model for type Ia supernovae
Authors: Meng Xiangcun , Podsiadlowski Philipp. 
Published: January 2020

AbstractWe have developed a new version of the SD model for type Ia supernovae (SNe Ia) in which a common envelope (CE) is assumed to form if the mass-transfer rate between a carbon/oxygen white dwarf (CO WD) and its companion exceeds a critical accretion rate. Based on this model, we found that both SN 2002cx-like and SN Ia-CSM objects may share a similar origin, i.e. these peculiar objects may originate from the explosion of hybrid carbon/oxygen/neon white dwarfs (CONe WDs) in SD systems, where SNe Ia-CSM explode in systems with a massive CE of ∼1 M⊙, while SN 2002cx-like events correspond to events without a massive CE.
Population of AGB stars in the outer Galaxy
Authors: Szczerba Ryszard , Gezer Ilknur , Yung Bosco H. K. , Sewiło Marta 
Published: January 2020

AbstractWe present preliminary results of a study aimed at identifying and characterizing the Asymptotic Giant Branch (AGB) stars in the outer Galaxy using the color-color diagram (CCD) that combines the Spitzer Space Telescope and 2MASS photometry: Ks – [8.0] vs. Ks – [24]. Our initial study concentrates on a region in the outer Galactic plane around a galactic longitude l of 105°, where we identified 777 O-rich and 200 C-rich AGB star candidates.