bluuebunny/crossref_metadata_2025 huggingface dataset:
Chitosan Gel Sheet Containing Polymeric Micelles: Synthesis and Gelation Properties of PEG-Grafted Chitosan
Authors: Yoshida Chikara , Uchida Yusuke , Ito Tomoki , Takami Taku , Murakami Yoshihiko
Published: September 2017

Wound-dressing sheet biomaterials can cover wound sites and enhance wound healing. In this study, a detailed evaluation of the factors affecting both the PEG modification percentage (PMP) in poly(ethylene glycol) (PEG)-grafted chitosan synthesis and the gelation properties of PEG-grafted chitosan was presented for constructing our novel hybrid hydrogel sheet consisting of PEG-grafted chitosan (a gel-forming polymer) and a reactive polymeric micelle (a crosslinker). It was confirmed that various factors (i.e., the weight ratio of PEG/chitosan, the pH of the buffer solution, reaction times, and reaction temperatures) in the preparation stage of PEG-grafted chitosans affected the PMP of PEG-grafted chitosans. Furthermore, the PMP of PEG-grafted chitosans affected their gelation properties. Finally, a ‘flexible’ hydrogel sheet that can be reversibly dried and moistened was successfully obtained. The dried rigid, thin sheet is expected to be suitable for stable preservation. The results obtained in this paper show that the incorporation of drug carriers into biomaterials is a novel approach to improve functionality.
APETx4, a Novel Sea Anemone Toxin and a Modulator of the Cancer-Relevant Potassium Channel KV10.1
Authors: Moreels Lien , Peigneur Steve , Galan Diogo , De Pauw Edwin , Béress Lászlo , Waelkens Etienne , Pardo Luis , Quinton Loïc , Tytgat Jan
Published: September 2017

The human ether-à-go-go channel (hEag1 or KV10.1) is a cancer-relevant voltage-gated potassium channel that is overexpressed in a majority of human tumors. Peptides that are able to selectively inhibit this channel can be lead compounds in the search for new anticancer drugs. Here, we report the activity-guided purification and electrophysiological characterization of a novel KV10.1 inhibitor from the sea anemone Anthopleura elegantissima. Purified sea anemone fractions were screened for inhibitory activity on KV10.1 by measuring whole-cell currents as expressed in Xenopus laevis oocytes using the two-microelectrode voltage clamp technique. Fractions that showed activity on Kv10.1 were further purified by RP-HPLC. The amino acid sequence of the peptide was determined by a combination of MALDI- LIFT-TOF/TOF MS/MS and CID-ESI-FT-ICR MS/MS and showed a high similarity with APETx1 and APETx3 and was therefore named APETx4. Subsequently, the peptide was electrophysiologically characterized on KV10.1. The selectivity of the toxin was investigated on an array of voltage-gated ion channels, including the cardiac human ether-à-go-go-related gene potassium channel (hERG or Kv11.1). The toxin inhibits KV10.1 with an IC50 value of 1.1 μM. In the presence of a similar toxin concentration, a shift of the activation curve towards more positive potentials was observed. Similar to the effect of the gating modifier toxin APETx1 on hERG, the inhibition of Kv10.1 by the isolated toxin is reduced at more positive voltages and the peptide seems to keep the channel in a closed state. Although the peptide also induces inhibitory effects on other KV and NaV channels, it exhibits no significant effect on hERG. Moreover, APETx4 induces a concentration-dependent cytotoxic and proapoptotic effect in various cancerous and noncancerous cell lines. This newly identified KV10.1 inhibitor can be used as a tool to further characterize the oncogenic channel KV10.1 or as a scaffold for the design and synthesis of more potent and safer anticancer drugs.
Influence of Powder Surface Contamination in the Ni-Based Superalloy Alloy718 Fabricated by Selective Laser Melting and Hot Isostatic Pressing
Authors: Kuo Yen-Ling , Kakehi Koji
Published: September 2017

The aim of this study was to gain a deep understanding of the microstructure-mechanical relationship between solid-state sintering and full-melting processes. The IN718 superalloy was fabricated by hot isostatic pressing (HIP) and selective laser melting (SLM). Continuous precipitates were clearly localized along the prior particle boundary (PPB) in the HIP materials, while SLM materials showed a microstructure free of PPB. The mechanical properties of specimens that underwent SLM + solution treatment and aging were comparable to those of conventional wrought specimens both at room temperature and 650 °C. However, a drop was observed in the ductility of HIP material at 650 °C. The brittle particles along the PPB were found to affect the HIP materials’ creep life and ductility during solid-state sintering.
Electrical Resistivity Measurement of Carbon Anodes Using the Van der Pauw Method
Authors: Rouget Geoffroy , Chaouki Hicham , Picard Donald , Ziegler Donald , Alamdari Houshang
Published: September 2017

The electrical resistivity of carbon anodes is an important parameter in the overall efficiency of the aluminum smelting process. The aim of this work is to explore the Van der Pauw (VdP) method as an alternative technique to the standard method, which is commonly used in the aluminum industry, in order to characterize the electrical resistivity of carbon anodes and to assess the accuracy of the method. For this purpose, a cylindrical core is extracted from the top of the anodes. The electrical resistivity of the core samples is measured according to the ISO 11713 standard method. This method consists of applying a 1 A current along the revolution axis of the sample, and then measuring the voltage drop on its side, along the same direction. Theoretically, this technique appears to be satisfying, but cracks in the sample that are generated either during the anode production or while coring the sample may induce high variations in the measured signal. The VdP method, as presented in 1958 by L.J. Van der Pauw, enables the electrical resistivity of any plain sample with an arbitrary shape and low thickness to be measured, even in the presence of cracks. In this work, measurements were performed using both the standard method and the Van der Pauw method, on both flawless and cracked samples. Results provided by the VdP method appeared to be more reliable and repeatable. Furthermore, numerical simulations using the finite element method (FEM) were performed in order to assess the effect of the presence of cracks and their thicknesses on the accuracy of the VdP method.
Ultra-Stretchable Interconnects for High-Density Stretchable Electronics
Authors: Shafqat Salman , Hoefnagels Johan , Savov Angel , Joshi Shivani , Dekker Ronald , Geers Marc
Published: September 2017

The exciting field of stretchable electronics (SE) promises numerous novel applications, particularly in-body and medical diagnostics devices. However, future advanced SE miniature devices will require high-density, extremely stretchable interconnects with micron-scale footprints, which calls for proven standardized (complementary metal-oxide semiconductor (CMOS)-type) process recipes using bulk integrated circuit (IC) microfabrication tools and fine-pitch photolithography patterning. Here, we address this combined challenge of microfabrication with extreme stretchability for high-density SE devices by introducing CMOS-enabled, free-standing, miniaturized interconnect structures that fully exploit their 3D kinematic freedom through an interplay of buckling, torsion, and bending to maximize stretchability. Integration with standard CMOS-type batch processing is assured by utilizing the Flex-to-Rigid (F2R) post-processing technology to make the back-end-of-line interconnect structures free-standing, thus enabling the routine microfabrication of highly-stretchable interconnects. The performance and reproducibility of these free-standing structures is promising: an elastic stretch beyond 2000% and ultimate (plastic) stretch beyond 3000%, with <0.3% resistance change, and >10 million cycles at 1000% stretch with <1% resistance change. This generic technology provides a new route to exciting highly-stretchable miniature devices.
Iron Absorption from Three Commercially Available Supplements in Gastrointestinal Cell Lines
Authors: Uberti Francesca , Morsanuto Vera , Ghirlanda Sabrina , Molinari Claudio
Published: September 2017

This study compares the absorption characteristics of two iron-based dietary supplements and their biocompatibility to bisglycinate iron, a common chelated iron form. The Caco-2 cell line—a model of human intestinal absorption—and GTL-16 cell line—a model of gastric epithelial cells—were used to perform the experiments; in the first experiments, the kinetics of absorption have been evaluated analyzing the divalent metal transporter 1 (DMT1) expression. Three different iron combinations containing 50 µM iron (named Fisioeme®, Sideral® and bisglycinate) were used for different stimulation times (1–24 h). After this, the effects of the three iron formulations were assessed in both a short and a long time, in order to understand the extrusion mechanisms. The effects of the three different formulations were also analyzed at the end of stimulation period immediately after iron removal, and after some time in order to clarify whether the mechanisms were irreversibly activated. Findings obtained in this study demonstrate that Fisioeme® was able to maintain a significant beneficial effect on cell viability compared to control, to Sideral®, and to iron bisglycinate. This observation indicates that Fisioeme® formulation is the most suitable for gastric and intestinal epithelial cells.
Multilayered Films Produced by Layer-by-Layer Assembly of Chitosan and Alginate as a Potential Platform for the Formation of Human Adipose-Derived Stem Cell aggregates
Authors: Hatami Javad , Silva Sandra , Oliveira Mariana , Costa Rui , Reis Rui , Mano João
Published: September 2017

The construction of multilayered films with tunable properties could offer new routes to produce biomaterials as a platform for 3D cell cultivation. In this study, multilayered films produced with five bilayers of chitosan and alginate (CHT/ALG) were built using water-soluble modified mesyl and tosyl–CHT via layer-by-layer (LbL) self-assembly. NMR results demonstrated the presences of mesyl (2.83 ppm) and tosyl groups (2.39, 7.37 and 7.70 ppm) in the chemical structure of modified chitosans. The buildup of multilayered films was monitored by quartz-crystal-microbalance (QCM-D) and film thickness was estimated using the Voigt-based viscoelastic model. QCM-D results demonstrated that CHT/ALG films constructed using mesyl or tosyl modifications (mCHT/ALG) were significantly thinner in comparison to the CHT/ALG films constructed with unmodified chitosan (p < 0.05). Adhesion analysis demonstrated that human adipose stem cells (hASCs) did not adhere to the mCHT/ALG multilayered films and formed aggregates with sizes between ca. 100–200 µm. In vitro studies on cell metabolic activity and live/dead staining suggested that mCHT/ALG multilayered films are nontoxic toward hACSs. Multilayered films produced via LbL assembly of ALG and off-the-shelf, water-soluble modified chitosans could be used as a scaffold for the 3D aggregates formation of hASCs in vitro.
Thermoresponsive and Reducible Hyperbranched Polymers Synthesized by RAFT Polymerisation
Authors: Tochwin Anna , El-Betany Alaa , Tai Hongyun , Chan Kai , Blackburn Chester , Wang Wenxin
Published: September 2017

Here, we report the synthesis of new thermoresponsive hyperbranched polymers (HBPs) via one-pot reversible addition-fragmentation chain transfer (RAFT) copolymerisation of poly(ethylene glycol)methyl ether methacrylate (PEGMEMA, Mn = 475 g/mol), poly(propylene glycol)methacrylate (PPGMA, Mn = 375 g/mol), and disulfide diacrylate (DSDA) using 2-cyanoprop-2-yl dithiobenzoate as a RAFT agent. DSDA was used as the branching agent and to afford the HBPs with reducible disulfide groups. The resulting HBPs were characterised by Nuclear Magnetic Resonance Spectroscopy (NMR) and Gel Permeation Chromatography (GPC). Differential Scanning Calorimetry (DSC) was used to determine lower critical solution temperatures (LCSTs) of these copolymers, which are in the range of 17–57 °C. Moreover, the studies on the reducibility of HBPs and swelling behaviours of hydrogels synthesized from these HBPs were conducted. The results demonstrated that we have successfully synthesized hyperbranched polymers with desired dual responsive (thermal and reducible) and crosslinkable (via thiol-ene click chemistry) properties. In addition, these new HBPs carry the multiplicity of reactive functionalities, such as RAFT agent moieties and multivinyl functional groups, which can afford them with the capacity for further bioconjugation and structure modifications.
Topological Models for Open-Knotted Protein Chains Using the Concepts of Knotoids and Bonded Knotoids
Authors: Goundaroulis Dimos , Gügümcü Neslihan , Lambropoulou Sofia , Dorier Julien , Stasiak Andrzej , Kauffman Louis
Published: September 2017

In this paper we introduce a method that offers a detailed overview of the entanglement of an open protein chain. Further, we present a purely topological model for classifying open protein chains by also taking into account any bridge involving the backbone. To this end, we implemented the concepts of planar knotoids and bonded knotoids. We show that the planar knotoids technique provides more refined information regarding the knottedness of a protein when compared to established methods in the literature. Moreover, we demonstrate that our topological model for bonded proteins is robust enough to distinguish all types of lassos in proteins.
Inter-System Differencing between GPS and BDS for Medium-Baseline RTK Positioning
Authors: Gao Wang , Gao Chengfa , Pan Shuguo , Meng Xiaolin , Xia Yan
Published: September 2017

An inter-system differencing model between two Global Navigation Satellite Systems (GNSS) enables only one reference satellite for all observations. If the associated differential inter-system biases (DISBs) are priori known, double-differenced (DD) ambiguities between overlapping frequencies from different GNSS constellations can also be fixed to integers. This can provide more redundancies for the observation model, and thus will be beneficial to ambiguity resolution (AR) and real-time kinematic (RTK) positioning. However, for Global Positioning System (GPS) and the regional BeiDou Navigation Satellite System (BDS-2), there are no overlapping frequencies. Tight combination of GPS and BDS needs to process not only the DISBs but also the single-difference ambiguity of the reference satellite, which is caused by the influence of different frequencies. In this paper, we propose a tightly combined dual-frequency GPS and BDS RTK positioning model for medium baselines with real-time estimation of DISBs. The stability of the pseudorange and phase DISBs is analyzed firstly using several baselines with the same or different receiver types. The dual-frequency ionosphere-free model with parameterization of GPS-BDS DISBs is proposed, where the single-difference ambiguity is estimated jointly with the phase DISB parameter from epoch to epoch. The performance of combined GPS and BDS RTK positioning for medium baselines is evaluated with simulated obstructed environments. Experimental results show that with the inter-system differencing model, the accuracy and reliability of RTK positioning can be effectively improved, especially for the obstructed environments with a small number of satellites available.
Sensitivity Enhancement in Low Cutoff Wavelength Long-Period Fiber Gratings by Cladding Diameter Reduction
Authors: Del Villar Ignacio , Partridge Matthew , Rodriguez Wenceslao , Fuentes Omar , Socorro Abian , Diaz Silvia , Corres Jesus , James Stephen , Tatam Ralph
Published: September 2017

The diameter of long-period fiber gratings (LPFGs) fabricated in optical fibers with a low cutoff wavelength was be reduced by hydrofluoric acid etching, enhancing the sensitivity to refractive index by more than a factor of 3, to 2611 nm/refractive index unit in the range from 1.333 to 1.4278. The grating period selected for the LPFGs allowed access to the dispersion turning point at wavelengths close to the visible range of the optical spectrum, where optical equipment is less expensive. As an example of an application, a pH sensor based on the deposition of a polymeric coating was analyzed in two situations: with an LPFG without diameter reduction and with an LPFG with diameter reduction. Again, a sensitivity increase of a factor of near 3 was obtained, demonstrating the ability of this method to enhance the sensitivity of thin-film-coated LPFG chemical sensors.
Chlordetect: Commercial Calcium Aluminate Based Conductimetric Sensor for Chloride Presence Detection
Authors: Torres-Luque Magda , Osma Johann , Sánchez-Silva Mauricio , Bastidas-Arteaga Emilio , Schoefs Franck
Published: September 2017

Chloride presence affects different environments (soil, water, concrete) decreasing their qualities. In order to assess chloride concentration this paper proposes a novel sensor for detecting and measuring it. This sensor is based on electric changes of commercial monocalcium aluminate (CA) when it interacts with chloride aqueous solutions. CA is used as a dielectric material between two coplanar capacitors. The geometry proposed for this sensor allows to assess the chloride content profile, or to make four times the same measurement. Besides, the experimental design gives us the possibility of study not just the chloride effect, but also the time and some geometric effects due to the sensor design. As a result, this sensor shows a limit of detection, sensitivity, and response time: 0.01 wt % Cl− and 0.06 wt % Cl−, and 2 min, respectively, comparable with other non invasive techniques as optical fibre sensors.
Financial Performance of Socially Responsible Firms: The Short- and Long-Term Impact
Authors: Charlo Maria , Moya Ismael , Muñoz Ana
Published: September 2017

The pressure of society for firms to adopt socially responsible behavior is evident. Yet, Corporate Social Responsibility (CSR) needs an economic justification. In response to this, there exists a comprehensive literature that analyzes the possible relation between social and business financial performance. During the last decade, the literature has been heading toward the carrying out of dynamic studies as researches find that the relationship between social and financial performance is not static. The purpose of this work is to analyze the relevance for the financial performance of Spanish listed firms of maintaining their responsible behavior. To do so, we carry out a comparison between two analyses—one cross-sectional, and the other longitudinal—to be able to conclude whether or not adopting responsible criteria makes a difference in business financial performance in the short and long-term. Some of the results obtained in the cross-sectional study are consolidated in the long-term study. In this sense, responsible firms exhibit a higher systematic risk and have greater size. As a conclusion, be responsible does not mean less stock profitability or a lower business result. It certainly contributes to firms continuing to voluntarily incorporate good corporate social responsibility practices into their business models. What is more, these results support the governmental policies and initiatives that bolster corporate social responsibility.
Long-Term Educational Sustainability: Educational Innovation in Social Vulnerability Contexts
Authors: Tur-Porcar Ana , Mas-Tur Alicia , Malonda Vidal Elisabeth
Published: September 2017

This paper investigates the behavior of children from low socioeconomic status families and examines the effects of a socioemotional education program on aggression in children. The results of the program are compared according to the children’s gender and age, the family structure, the parents’ educational attainment, and social status. The results show that applying socioemotional education programs reduces children’s aggression and encourages positive development during adolescence. This positive development fosters open, expressive behavior.
Manufacturing Process Innovation-Oriented Knowledge Evaluation Using MCDM and Fuzzy Linguistic Computing in an Open Innovation Environment
Authors: Wang Gangfeng , Tian Xitian , Hu Yongbiao , Evans Richard David , Tian Mingrui , Wang Rong
Published: September 2017

In today’s complex, constantly evolving and innovation-supporting manufacturing systems, knowledge plays a vital role in sustainable manufacturing process planning and problem-solving, especially in the case of Computer-Aided Process Innovation (CAPI). To obtain formalized and promising process innovation knowledge under the open innovation paradigm, it is necessary to evaluate candidate knowledge and encourage improvement suggestions based on actual innovation situations. This paper proposes a process innovation-oriented knowledge evaluation approach using Multi-Criteria Decision-Making (MCDM) and fuzzy linguistic computing. Firstly, a comprehensive hierarchy evaluation index system for process innovation knowledge is designed. Secondly, by combining an analytic hierarchy process with fuzzy linguistic computing, a comprehensive criteria weighting determination method is applied to effectively aggregate the evaluation of criteria weights for each criterion and corresponding sub-criteria. Furthermore, fuzzy linguistic evaluations of performance ratings for each criterion and corresponding sub-criteria are calculated. Thus, a process innovation knowledge comprehensive value can be determined. Finally, an illustrative example of knowledge capture, evaluation and knowledge-inspired process problem solving for micro-turbine machining is presented to demonstrate the applicability of the proposed approach. It is expected that our model would lay the foundation for knowledge-driven CAPI in sustainable manufacturing.
A Robust Method for Finding the Automated Best Matched Genes Based on Grouping Similar Fragments of Large-Scale References for Genome Assembly
Authors: Jung Jaehee , Kim Jong , Jeong Young-Sik , Yi Gangman
Published: September 2017

Big data research on genomic sequence analysis has accelerated considerably with the development of next-generation sequencing. Currently, research on genomic sequencing has been conducted using various methods, ranging from the assembly of reads consisting of fragments to the annotation of genetic information using a database that contains known genome information. According to the development, most tools to analyze the new organelles’ genetic information requires different input formats such as FASTA, GeneBank (GB) and tab separated files. The various data formats should be modified to satisfy the requirements of the gene annotation system after genome assembly. In addition, the currently available tools for the analysis of organelles are usually developed only for specific organisms, thus the need for gene prediction tools, which are useful for any organism, has been increased. The proposed method—termed the genome_search_plotter—is designed for the easy analysis of genome information from the related references without any file format modification. Anyone who is interested in intracellular organelles such as the nucleus, chloroplast, and mitochondria can analyze the genetic information using the assembled contig of an unknown genome and a reference model without any modification of the data from the assembled contig.
Oscillating Stars and the Evidence of Dark Matter. A Comment on “Can the Periodic Spectral Modulations Observed in 236 Sloan Sky Survey Stars Be Due To Dark Matter Effects?” by F. Tamburini and I. Licata
Authors: Capozziello Salvatore
Published: September 2017

Dark matter is probably the most fascinating enigma of modern physics [...]
Formation of Double Neutron Star Systems
Authors: Tauris T. M. , Kramer M. , Freire P. C. C. , Wex N. , Janka H.-T. , Langer N. , Podsiadlowski Ph. , Bozzo E. , Chaty S. , Kruckow M. U. , Heuvel E. P. J. van den , Antoniadis J. , Breton R. P. , Champion D. J.
Published: September 2017

Double neutron star (DNS) systems represent extreme physical objects and the endpoint of an exotic journey of stellar evolution and binary interactions. Large numbers of DNS systems and their mergers are anticipated to be discovered using the Square Kilometre Array searching for radio pulsars, and the high-frequency gravitational wave detectors (LIGO/VIRGO), respectively. Here we discuss all key properties of DNS systems, as well as selection effects, and combine the latest observational data with new theoretical progress on various physical processes with the aim of advancing our knowledge on their formation. We examine key interactions of their progenitor systems and evaluate their accretion history during the high-mass X-ray binary stage, the common envelope phase, and the subsequent Case BB mass transfer, and argue that the first-formed NSs have accreted at most

. We investigate DNS masses, spins, and velocities, and in particular correlations between spin period, orbital period, and eccentricity. Numerous Monte Carlo simulations of the second supernova (SN) events are performed to extrapolate pre-SN stellar properties and probe the explosions. All known close-orbit DNS systems are consistent with ultra-stripped exploding stars. Although their resulting NS kicks are often small, we demonstrate a large spread in kick magnitudes that may, in general, depend on the past interaction history of the exploding star and thus correlate with the NS mass. We analyze and discuss NS kick directions based on our SN simulations. Finally, we discuss the terminal evolution of close-orbit DNS systems until they merge and possibly produce a short γ-ray burst.
and the Diffuse Interstellar Bands: An Independent Laboratory Check
Authors: Spieler Steffen , Kuhn Martin , Postler Johannes , Simpson Malcolm , Wester Roland , Scheier Paul , Ubachs Wim , Bacalla Xavier , Bouwman Jordy , Linnartz Harold
Published: September 2017

In 2015, Campbell et al. presented spectroscopic laboratory gas phase data for the fullerene cation,

, that coincide with the reported astronomical spectra of two diffuse interstellar band (DIB) features at 9633 and 9578 Å. In the following year, additional laboratory spectra were linked to three other and weaker DIBs at 9428, 9366, and 9349 Å. The laboratory data were obtained using wavelength-dependent photodissociation spectroscopy of small (up to three) He-tagged

ion complexes, yielding rest wavelengths for the bare

cation by correcting for the He-induced wavelength shifts. Here we present an alternative approach to derive the rest wavelengths of the four most prominent

absorption features, using high-resolution laser dissociation spectroscopy of

embedded in ultracold He droplets. Accurate wavelengths of the bare fullerene cation are derived from linear wavelength shifts recorded for

species with n up to 32. A careful analysis of all of the available data results in precise rest wavelengths (in air) for the four most prominent

bands: 9631.9(1) Å, 9576.7(1) Å, 9427.5(1) Å, and 9364.9(1) Å. The corresponding bandwidths have been derived and the relative band intensity ratios are discussed.
Balmer Filaments in Tycho’s Supernova Remnant: An Interplay between Cosmic-ray and Broad-neutral Precursors
Authors: Knežević Sladjana , Läsker Ronald , van de Ven Glenn , Font Joan , Raymond John C. , Bailer-Jones Coryn A. L. , Beckman John , Morlino Giovanni , Ghavamian Parviz , Hughes John P. , Heng Kevin
Published: September 2017

We present Hα spectroscopic observations and detailed modeling of the Balmer filaments in the supernova remnant (SNR) Tycho (SN 1572). We used GH
α
FaS (Galaxy Hα Fabry–Pérot Spectrometer) on the William Herschel Telescope with a 3.′4 × 3.′4 field of view, 0.″2 pixel scale, and

σ

instr

=
8.1

km s−1 resolution at 1″ seeing for ∼10 hr, resulting in 82 spatial−spectral bins that resolve the narrow Hα line in the entire SN 1572 northeastern rim. For the first time, we can therefore mitigate artificial line broadening from unresolved differential motion and probe Hα emission parameters in varying shock and ambient medium conditions. Broad Hα line remains unresolved within spectral coverage of 392 km s−1. We employed Bayesian inference to obtain reliable parameter confidence intervals and to quantify the evidence for models with multiple line components. The median Hα narrow-line (NL) FWHM of all bins and models is

W

NL

=
(
54.8
±
1.8
)

km s−1 at the 95% confidence level, varying within [35, 72] km s−1 between bins and clearly broadened compared to the intrinsic (thermal) ≈20 km s−1. Possible line splits are accounted for, significant in

≈
18
%

of the filament, and presumably due to remaining projection effects. We also find widespread evidence for intermediate-line emission of a broad-neutral precursor, with a median

W

IL

=
(
180
±
14
)

km s−1 (95% confidence). Finally, we present a measurement of the remnant’s systemic velocity,

V

LSR

=
−
34

km s−1, and map differential line-of-sight motions. Our results confirm the existence and interplay of shock precursors in Tycho’s remnant. In particular, we show that suprathermal NL emission is near-universal in SN 1572, and that, in the absence of an alternative explanation, collisionless SNR shocks constitute a viable acceleration source for Galactic TeV cosmic-ray protons.
Modeling Coronal Response in Decaying Active Regions with Magnetic Flux Transport and Steady Heating
Authors: Ugarte-Urra Ignacio , Warren Harry P. , Upton Lisa A. , Young Peter R.
Published: September 2017

We present new measurements of the dependence of the extreme ultraviolet (EUV) radiance on the total magnetic flux in active regions as obtained from the Atmospheric Imaging Assembly (AIA) and the Helioseismic and Magnetic Imager on board the Solar Dynamics Observatory. Using observations of nine active regions tracked along different stages of evolution, we extend the known radiance—magnetic flux power-law relationship (

I
∝

Φ

α

) to the AIA 335 Å passband, and the Fe xviii 93.93 Å spectral line in the 94 Å passband. We find that the total unsigned magnetic flux divided by the polarity separation (

Φ

/

D

) is a better indicator of radiance for the Fe xviii line with a slope of

α
=
3.22
±
0.03

. We then use these results to test our current understanding of magnetic flux evolution and coronal heating. We use magnetograms from the simulated decay of these active regions produced by the Advective Flux Transport model as boundary conditions for potential extrapolations of the magnetic field in the corona. We then model the hydrodynamics of each individual field line with the Enthalpy-based Thermal Evolution of Loops model with steady heating scaled as the ratio of the average field strength and the length (

B

¯

/

L

) and render the Fe xviii and 335 Å emission. We find that steady heating is able to partially reproduce the magnitudes and slopes of the EUV radiance—magnetic flux relationships and discuss how impulsive heating can help reconcile the discrepancies. This study demonstrates that combined models of magnetic flux transport, magnetic topology, and heating can yield realistic estimates for the decay of active region radiances with time.
Strange Quark Stars in Binaries: Formation Rates, Mergers, and Explosive Phenomena
Authors: Wiktorowicz G. , Drago A. , Pagliara G. , Popov S. B.
Published: September 2017

Recently, the possible coexistence of a first family composed of “normal” neutron stars (NSs) with a second family of strange quark stars (QSs) has been proposed as a solution of problems related to the maximum mass and to the minimal radius of these compact stellar objects. In this paper, we study the mass distribution of compact objects formed in binary systems and the relative fractions of quark and NSs in different subpopulations. We incorporate the strange QS formation model provided by the two-families scenario, and we perform a large-scale population synthesis study in order to obtain the population characteristics. According to our results, the main channel for strange QS formation in binary systems is accretion from a secondary companion on an NS. Therefore, a rather large number of strange QSs form by accretion in low-mass X-ray binaries and this opens the possibility of having explosive GRB-like phenomena not related to supernovae and not due to the merger of two NSs. The number of double strange QS systems is rather small, with only a tiny fraction that merge within a Hubble time. This drastically limits the flux of strangelets produced by the merger, which turns out to be compatible with all limits stemming from Earth and lunar experiments. Moreover, this value of the flux rules out at least one relevant channel for the transformation of all NSs into strange QSs by strangelets’ absorption.
The Direct Effect of Toroidal Magnetic Fields on Stellar Oscillations: An Analytical Expression for the General Matrix Element
Authors: Kiefer René , Schad Ariane , Roth Markus
Published: September 2017

Where is the solar dynamo located and what is its modus operandi? These are still open questions in solar physics. Helio- and asteroseismology can help answer them by enabling us to study solar and stellar internal structures through global oscillations. The properties of solar and stellar acoustic modes are changing with the level of magnetic activity. However, until now, the inference on subsurface magnetic fields with seismic measures has been very limited. The aim of this paper is to develop a formalism to calculate the effect of large-scale toroidal magnetic fields on solar and stellar global oscillation eigenfunctions and eigenfrequencies. If the Lorentz force is added to the equilibrium equation of motion, stellar eigenmodes can couple. In quasi-degenerate perturbation theory, this coupling, also known as the direct effect, can be quantified by the general matrix element. We present the analytical expression of the matrix element for a superposition of subsurface zonal toroidal magnetic field configurations. The matrix element is important for forward calculations of perturbed solar and stellar eigenfunctions and frequency perturbations. The results presented here will help to ascertain solar and stellar large-scale subsurface magnetic fields, and their geometric configuration, strength, and change over the course of activity cycles.
The EDGE-CALIFA Survey: Interferometric Observations of 126 Galaxies with CARMA
Authors: Bolatto Alberto D. , Wong Tony , Utomo Dyas , Blitz Leo , Vogel Stuart N. , Sánchez Sebastián F. , Barrera-Ballesteros Jorge , Cao Yixian , Colombo Dario , Dannerbauer Helmut , García-Benito Rubén , Herrera-Camus Rodrigo , Husemann Bernd , Kalinova Veselina , Leroy Adam K. , Leung Gigi , Levy Rebecca C. , Mast Damián , Ostriker Eve , Rosolowsky Erik , Sandstrom Karin M. , Teuben Peter , van de Ven Glenn , Walter Fabian
Published: September 2017

We present interferometric CO observations, made with the Combined Array for Millimeter-wave Astronomy (CARMA) interferometer, of galaxies from the Extragalactic Database for Galaxy Evolution survey (EDGE). These galaxies are selected from the Calar Alto Legacy Integral Field Area (CALIFA) sample, mapped with optical integral field spectroscopy. EDGE provides good-quality CO data (3σ sensitivity

before inclination correction, resolution ∼1.4 kpc) for 126 galaxies, constituting the largest interferometric CO survey of galaxies in the nearby universe. We describe the survey and data characteristics and products, then present initial science results. We find that the exponential scale lengths of the molecular, stellar, and star-forming disks are approximately equal, and galaxies that are more compact in molecular gas than in stars tend to show signs of interaction. We characterize the molecular-to-stellar ratio as a function of Hubble type and stellar mass and present preliminary results on the resolved relations between the molecular gas, stars, and star-formation rate. We then discuss the dependence of the resolved molecular depletion time on stellar surface density, nebular extinction, and gas metallicity. EDGE provides a key data set to address outstanding topics regarding gas and its role in star formation and galaxy evolution, which will be publicly available on completion of the quality assessment.
Galaxies as High-resolution Telescopes
Authors: Barnacka Anna
Published: September 2017

Recent observations show a population of active galaxies with milliarcsecond offsets between optical and radio emission. Such offsets can be an indication of extreme phenomena associated with supermassive black holes including relativistic jets, binary supermassive black holes, or even recoiling supermassive black holes. However, the multi-wavelength structure of active galaxies at a few milliarcseconds cannot be resolved with direct observations. We propose using strong gravitational lensing to elucidate the multi-wavelength structure of sources. When sources are located close to the caustic of a lensing galaxy, even a small offset in the position of the sources results in a drastic difference in the position and magnification of mirage images. We show that the angular offset in the position of the sources can be amplified more than 50 times in the observed position of mirage images. We find that at least 8% of the observed gravitationally lensed quasars will be in the caustic configuration. The synergy between SKA and Euclid will provide an ideal set of observations for thousands of gravitationally lensed sources in the caustic configuration, which will allow us to resolve the multi-wavelength structure for a large ensemble of sources and to study the physical origin of radio emissions, their connection to supermassive black holes, and their cosmic evolution.
Failed Radiatively Accelerated Dusty Outflow Model of the Broad Line Region in Active Galactic Nuclei. I. Analytical Solution
Authors: Czerny B. , Li Yan-Rong , Hryniewicz K. , Panda S. , Wildy C. , Sniegowska M. , Wang J.-M. , Sredzinska J. , Karas V.
Published: September 2017

The physical origin of the broad line region in active galactic nuclei is still unclear despite many years of observational studies. The reason is that the region is unresolved, and the reverberation mapping results imply a complex velocity field. We adopt a theory-motivated approach to identify the principal mechanism responsible for this complex phenomenon. We consider the possibility that the role of dust is essential. We assume that the local radiation pressure acting on the dust in the accretion disk atmosphere launches the outflow of material, but higher above the disk the irradiation from the central parts causes dust evaporation and a subsequent fallback. This failed radiatively accelerated dusty outflow is expected to represent the material forming low ionization lines. In this paper we formulate simple analytical equations to describe the cloud motion, including the evaporation phase. The model is fully described just by the basic parameters of black hole mass, accretion rate, black hole spin, and viewing angle. We study how the spectral line generic profiles correspond to this dynamic. We show that the virial factor calculated from our model strongly depends on the black hole mass in the case of enhanced dust opacity, and thus it then correlates with the line width. This could explain why the virial factor measured in galaxies with pseudobulges differs from that obtained from objects with classical bulges, although the trend predicted by the current version of the model is opposite to the observed trend.
Non-relativistic Free–Free Emission due to the n-distribution of Electrons—Radiative Cooling and Thermally Averaged and Total Gaunt Factors
Authors: de Avillez Miguel A. , Breitschwerdt Dieter
Published: September 2017

Tracking the thermal evolution of plasmas, characterized by an n-distribution, using numerical simulations, requires the determination of the emission spectra and of the radiative losses due to free–free emission from the corresponding temperature-averaged and total Gaunt factors. Detailed calculations of the latter are presented and associated with n-distributed electrons with the parameter n ranging from 1 (corresponding to the Maxwell–Boltzmann distribution) to 100. The temperature-averaged and total Gaunt factors with decreasing n tend toward those obtained with the Maxwell–Boltzmann distribution. Radiative losses due to free–free emission in a plasma evolving under collisional ionization equilibrium conditions and composed by H, He, C, N, O, Ne, Mg, Si, S, and Fe ions, are presented. These losses decrease with a decrease in the parameter n, reaching a minimum when n = 1, and thus converge with the loss of thermal plasma. Tables of the thermal-averaged and total Gaunt factors calculated for n-distributions, and a wide range of electron and photon energies, are presented.
Simultaneous Observations of H2O and SiO Masers toward OH/IR Stars
Authors: Cho Chi-Young , Cho Se-Hyung , Kim Sungeun , Kim Jaeheon , Yoon Dong-hwan , Hwang Jihye
Published: September 2017

We performed simultaneous observations of SiO v = 1, 2, 29SiO v = 0, J = 1–0, and H2O

maser lines toward 252 OH/IR stars using the individual 21 m telescopes of the Korean VLBI Network (KVN). The observations for studying SiO and H2O maser properties associated with the different evolutionary stages of OH/IR stars were carried out from 2011 November to 2012 July. Both H2O and SiO masers were detected from 50 sources with a detection rate of 20% in one epoch of observation. One-sided SiO maser emissions without H2O were detected from 108 sources and H2O maser emission was detected from 11 sources, of which the detection rates were 43% and 4%, respectively. The overall detection rate of the SiO maser was 63%, and that of the H2O maser was 24%. There were 65 new detections in the SiO maser lines, 22 new detections in the H2O maser line, and 4 new detections in the 29SiO maser line. For the H2O and/or SiO maser- detected sources, mutual relations between SiO and H2O maser properties (including peak and integrated antenna temperatures, and full widths at zero power, etc.) are investigated based on a statistical analysis. We also investigate these maser properties on an IRAS two-color diagram related to stellar evolutionary sequences. In particular, a large number of SiO v = 2-only detected sources appear among the SiO-only detected sources compared to those of both H2O and SiO maser detected sources and also appear in the later evolutionary stages of asymptotic giant branch AGB stars in the IRAS two-color diagram. These results may be associated with the development of a hot and thick dust envelope at later stages of AGB evolution and the different excitation conditions of SiO v = 1 and v = 2 masers. Our observational results will be useful for statistical studies of circumstellar envelopes of OH/IR stars related to their late evolution and future very long baseline interferometry (VLBI) observations.
Perturbation of a Schwarzschild Black Hole Due to a Rotating Thin Disk
Authors: Čížek P. , Semerák O.
Published: September 2017

Will, in 1974, treated the perturbation of a Schwarzschild black hole due to a slowly rotating, light, concentric thin ring by solving the perturbation equations in terms of a multipole expansion of the mass-and-rotation perturbation series. In the Schwarzschild background, his approach can be generalized to perturbation by a thin disk (which is more relevant astrophysically), but, due to rather bad convergence properties, the resulting expansions are not suitable for specific (numerical) computations. However, we show that Green’s functions, represented by Will’s result, can be expressed in closed form (without multipole expansion), which is more useful. In particular, they can be integrated out over the source (a thin disk in our case) to yield good converging series both for the gravitational potential and for the dragging angular velocity. The procedure is demonstrated, in the first perturbation order, on the simplest case of a constant-density disk, including the physical interpretation of the results in terms of a one-component perfect fluid or a two-component dust in a circular orbit about the central black hole. Free parameters are chosen in such a way that the resulting black hole has zero angular momentum but non-zero angular velocity, as it is just carried along by the dragging effect of the disk.
Multi-Modal Imaging Including Optical Coherence Tomography Angiography in Patients With Posterior Multifocal Placoid Pigment Epitheliopathy
Authors: Werner Jens Ulrich , Enders Christian , Lang Gerhard Klaus , Lang Gabriele Elisabeth
Published: September 2017

BACKGROUND AND OBJECTIVE:

New imaging methods provide novel insights into the pathogenesis of acute posterior multifocal placoid pigment epitheliopathy (APMPPE).

PATIENTS AND METHODS:

Four patients (eight eyes) in acute, subacute, and late phases of the disease were analyzed with multi-modal imaging methods including optical coherence tomography angiography (OCTA), structural OCT, fundus photography, and fundus autofluorescence. One patient was observed during the entire disease course.

RESULTS:

In acute and subacute phases of the disease, an early blockage in fluorescein angiography was found. OCTA showed perfusion defects in choriocapillaris and choroid slabs. During the course of disease, perfusion deficits observed in OCTA imaging resolved first in the choroid and then in the choriocapillaris slab.

CONCLUSION:

Multi-modal imaging including OCTA supports the thesis that the underlying pathology of APMPPE is an inflammatory impairment of the choroidal circulation with secondary damage to the outer retina. OCTA might be able to replace fluorescein and indocyanine angiography in the diagnostic work-up of APMPPE.

[
Ophthalmic Surg Lasers Imaging Retina
. 2017;48:727–733.]
Don't Touch My Hair
Authors: Oling-Sisay Mary
Published: September 2017

Myriad studies on service-learning agree on the benefits of service-learning for students. Because projects are designed with the needs of students and institutions in mind, the experiences of the Black communities served are seldom highlighted nor are the intricacies of the multiple relationships addressed. Voices of marginalized groups especially the Black communities—the community that is the focus of this chapter—needs to be incorporated in authentic and intentional ways to advance transformational service-learning for all involved. This chapter begins to examine issues and opportunities for best case scenarios for service-learning projects in Black communities.
“I See Myself in Them”
Authors: Castrellón Liliana E. , Pérez-Torres Judith C.
Published: September 2017

This chapter explores a first-year ethnic studies course to highlight the importance of engaging the diversity within the classroom in relation to the diverse communities being served. Students participating in this course are self-identified Students of Color, many of whom are first generation college students, from lower socioeconomic communities. Introducing a Critical Race Service-Learning framework, the authors highlight how Students of Color in this course learn about race, class, gender, language, citizenship status, phenotype, sexuality, etc. to challenge the status quo while also actively engaging in service-learning with/in diverse communities as an empowering pedagogy. Findings indicate the foundational tools learned within the course pushed students to speak back to the educational inequities they witnessed at their service sites and experienced in K-12 to further empower them to continue giving back to their communities beyond college.
Doing Service-Learning on the Ground in Diverse K-12 Communities
Authors: Luter D. Gavin , Kronick Robert F.
Published: September 2017

This chapter is about designing service-learning and gives voice to college students engaging in service along with children and families who attend a culturally diverse urban Title One school. The various settings presented in this chapter show the numerous options open to service-learners in the University Assisted Community School. Engagement in this program realizes that schools with low resources have communities with low resources and communities with low resources have schools with low resources.