bluuebunny/crossref_metadata_2025_split huggingface dataset:
Infrared Properties of Asymptotic Giant Branch Stars in Our Galaxy and the Magellanic Clouds
Authors: Suh Kyung-Won 
Published: March 2020

Abstract
We investigate the infrared properties of asymptotic giant branch (AGB) stars in our Galaxy and the Magellanic Clouds using various infrared observational data and theoretical models. We use catalogs for the sample of 4996 AGB stars in our Galaxy and about 39,000 AGB stars in the Magellanic Clouds from the available literature. For each object in the sample, we cross-identify the 2MASS, Wide-field Infrared Survey Explorer, and Spitzer counterparts. To compare the physical properties of O- and C-rich AGB stars in our Galaxy and the Magellanic Clouds, we present IR two-color diagrams (2CDs) using various photometric data. We perform radiative transfer model calculations for AGB stars using various possible parameters of central stars and dust shells. Using the dust opacity functions of amorphous silicate and carbon, the theoretical dust shell models can roughly reproduce the observations of AGB stars on various IR 2CDs. Compared with our Galaxy, we find that the Magellanic Clouds are deficient in AGB stars with thick dust shells. Compared with the Large Magellanic Cloud (LMC), the Small Magellanic Cloud (SMC) is more deficient in AGB stars with thick dust shells. This could be because the Magellanic Clouds are more metal-poor than our Galaxy and the LMC is more metal-rich than the SMC. We also present the IR properties of known pulsating variables. Investigating the magnitude distributions at mid-IR (MIR) bands for AGB stars in the Magellanic Clouds, we find that the SMC is more deficient in bright AGB stars at MIR bands compared with the LMC.
The Clustering of X-Ray Luminous Quasars
Authors: Powell M. C. , Urry C. M. , Cappelluti N. , Johnson J. T. , LaMassa S. M. , Ananna T. T. , Kollmann K. E. 
Published: March 2020

Abstract
The clustering of active galactic nuclei (AGNs) sheds light on their typical large (Mpc-scale) environments, which can constrain the growth and evolution of supermassive black holes. Here we measure the clustering of luminous X-ray-selected AGNs in the Stripe 82X and XMM-XXL-north surveys around the peak epoch of black hole growth, in order to investigate the dependence of luminosity on large-scale AGN environment. We compute the auto-correlation function of AGNs in two luminosity bins,

erg s−1 at z ∼ 0.8 and L

X
≥ 1044.5 erg s−1 at z ∼ 1.8, and calculate the AGN bias taking into account the redshift distribution of the sources using three different methods. Our results show that while the less luminous sample has an inferred typical halo mass that is smaller than for the more luminous AGNs, the host halo mass may be less dependent on luminosity than suggested in previous work. Focusing on the luminous sample, we calculate a typical host halo mass of ∼1013

, which is similar to previous measurements of moderate-luminosity X-ray AGNs and significantly larger than the values found for optical quasars of similar luminosities and redshifts. We suggest that the clustering differences between different AGN selection techniques are dominated by selection biases, and not due to a dependence on AGN luminosity. We discuss the limitations of inferring AGN triggering mechanisms from halo masses derived by large-scale bias.
Giant Planet Swaps during Close Stellar Encounters
Authors: Wang Yi-Han , Perna Rosalba , Leigh Nathan W. C. 
Published: March 2020

Abstract
The discovery of planetary systems outside of the solar system has challenged some of the tenets of planetary formation. Among the difficult-to-explain observations are systems with a giant planet orbiting a very low mass star, such as the recently discovered GJ 3512b planetary system, where a Jupiter-like planet orbits an M star in a tight and eccentric orbit. Systems such as this one are not predicted by the core accretion theory of planet formation. Here we suggest a novel mechanism, in which the giant planet is born around a more typical Sun-like star (

), but is subsequently exchanged during a dynamical interaction with a flyby low-mass star (

). We perform state-of-the-art N-body simulations with

and

to study the statistical outcomes of this interaction, and show that exchanges result in high eccentricities for the new orbit around the low-mass star, while about half of the outcomes result in tighter orbits than the planet had around its birth star. We numerically compute the cross section for planet exchange, and show that an upper limit for the probability per planetary system to have undergone such an event is

Gyr−1, where a
p is the planet semimajor axis around the birth star, σ the velocity dispersion of the star cluster, and M
c the total mass of the star cluster. Hence these planet exchanges could be relatively common for stars born in open clusters and groups, should already be observed in the exoplanet database, and provide new avenues to create unexpected planetary architectures.
The Stars in M15 Were Born with the r-process*
Authors: Kirby Evan N. , Duggan Gina , Ramirez-Ruiz Enrico , Macias Phillip 
Published: March 2020

Abstract
High-resolution spectroscopy of stars on the red giant branch (RGB) of the globular cluster M15 has revealed a large (∼1 dex) dispersion in the abundances of r-process elements such as Ba and Eu. Neutron star mergers (NSMs) have been proposed as a major source of the r-process. However, most NSM models predict a delay time longer than the timescale for cluster formation. One possibility is that a NSM polluted the surfaces of stars in M15 long after the cluster finished forming. In this case, the abundances of the polluting elements would decrease in the first dredge-up as stars turn on to the RGB. We present Keck/DEIMOS abundances of Ba in 66 stars along the entire RGB and the top of the main sequence. The Ba abundances have no trend with stellar luminosity (evolutionary phase). Therefore, the stars were born with the Ba that they have today, and Ba did not originate in a source with a delay time longer than the timescale for cluster formation. In particular, if the source of Ba was a NSM, it would have had a very short delay time. Alternatively, if Ba enrichment took place before the formation of the cluster, an inhomogeneity of a factor of 30 in Ba abundance needs to be able to persist over the length scale of the gas cloud that formed M15, which is unlikely.
Site characterisation in Kangra Valley (NW Himalaya, India) by inversion of H/V spectral ratio from ambient noise measurements and its validation by multichannel analysis of surface waves technique
Authors: Ambrish Kumar Mahajan , Kumar Praveen 
Published: March 2020

ABSTRACTThe ambient noise measurements were performed at 200 sites in and around the upcoming urban centre of Kangra Valley to derive the predominant frequency of soil. The shear‐wave velocity of the soft soil cover is obtained by joint‐fit inversion modelling of the horizontal‐to‐vertical spectral ratio and the dispersion curves derived from multichannel simulation with one receiver survey. Simultaneously, shear‐wave velocity investigations were also performed employing an active 24‐channel engineering seismograph using multichannel analysis of surface waves. Finally, the derived one‐dimensional shear‐wave velocity profiles were compared between these two different approaches, which were found to be in good agreement. The shear‐wave velocity investigations of the study area have indicated that the majority of the sites either fall in soil class D (, stiff soil) or class C (, very stiff soil) as per NEHRP classification. The microtremor data also suggest high fundamental frequency (4 to >20 Hz) within and on the fringes of the basin, thus covering 80% of the study area, which is in agreement with the known shear‐wave velocity variation in the Kangra Valley. The large variation in high frequencies cannot be attributed to the presence of thick loose alluvial sediments (gravels and sand) but can be related to the presence of moraine deposits or bedrock (upper conglomerates) underneath the basin. However, a few isolated locations in the northern and southeastern parts of the basin are characterised by a low predominant frequency (2–3 Hz) or frequency less than even 2 Hz. The results further suggest that both multichannel analysis of surface waves and horizontal‐to‐vertical spectral ratio methods, in combination with multichannel simulation with one receiver, are complementary to each other and are suitable for estimating the shear‐wave velocity structure for hilly urban regions, where exploring a large area is a major challenge. The analysis further reveals that Kangra Valley can have a major devastation from a near‐source earthquake rather than from a far‐source event.
Mapping the Chromosomal Insertion Site of the GFP Transgene of UBC-GFP Mice to the MHC Locus
Authors: Liu Shanrun , Lockhart Jonathan R. , Fontenard Suean , Berlett Mike , Ryan Thomas M. 
Published: March 2020

Abstract
GFP is frequently used as a marker for tracking donor cells adoptively transplanted into recipient animals. The human ubiquitin C promoter (UBC)–driven-GFP transgenic mouse is a commonly used source of donor cells for this purpose. This mouse was initially generated in the C57BL/6 inbred strain and has been backcrossed into the BALB/cBy strain for over 11 generations. Both the C57BL/6 inbred and BALB/cBy congenic UBC-GFP lines are commercially available and have been widely distributed. These UBC-GFP lines can be a convenient resource for tracking donor cells in both syngenic MHC-matched and in allogenic MHC-mismatched studies as C57BL/6 (H-2b) and BALB/cBy (H-2d) have disparate MHC haplotypes. In this report, we surprisingly discover that the UBC-GFP BALB/cBy congenic mice still retain the H-2b MHC haplotype of their original C57BL/6 founder, suggesting that the UBC-GFP transgene integration site is closely linked to the MHC locus on chromosome 17. Using linear amplification–mediated PCR, we successfully map the UBC-GFP transgene to the MHC locus. This study highlights the importance and urgency of mapping the transgene integration site of transgenic mouse strains used in biomedical research. Furthermore, this study raises the possibility of alternative interpretations of previous studies using congenic UBC-GFP mice and focuses attention on the necessity for rigor and reproducibility in scientific research.
Cutting Edge: Activation-Induced Iron Flux Controls CD4 T Cell Proliferation by Promoting Proper IL-2R Signaling and Mitochondrial Function
Authors: Yarosz Emily L. , Ye Chenxian , Kumar Ajay , Black Chauna , Choi Eun-Kyung , Seo Young-Ah , Chang Cheong-Hee 
Published: March 2020

Abstract
Iron has long been established as a critical mediator of T cell development and proliferation. However, the mechanisms by which iron controls CD4 T cell activation and expansion remain poorly understood. In this study, we show that stimulation of CD4 T cells from C57BL/6 mice not only decreases total and labile iron levels but also leads to changes in the expression of iron homeostatic machinery. Additionally, restraining iron availability in vitro severely inhibited CD4 T cell proliferation and cell cycle progression. Although modulating cellular iron levels increased IL-2 production by activated T lymphocytes, CD25 expression and pSTAT5 levels were decreased, indicating that iron is necessary for IL-2R–mediated signaling. We also found that iron deprivation during T cell stimulation negatively impacts mitochondrial function, which can be reversed by iron supplementation. In all, we show that iron contributes to activation-induced T cell expansion by positively regulating IL-2R signaling and mitochondrial function.
An observational study to determine the sensitizing potential of orthopedic implants
Authors: Shanmugham Haridaran Anand , Handa Sanjeev , De Dipankar , Dhillon Mandeep Singh , Aggarwal Sameer 
Published: March 2020

Introduction:
Patients who receive orthopedic implants have been shown to develop sensitivity to its components and there are concerns that this sensitivity might lead to contact dermatitis or implant-related problems like loosening and/or failure. The objective of the study was to determine the sensitizing potential of orthopedic implants.

Methods:
Fifty-four patients undergoing knee, hip, or shoulder replacement surgeries between July 2014 and July 2015 were recruited. Patch tests were performed before the implant surgery with 10 allergens likely to be implicated in metal hypersensitivity. Postimplant patch test was performed 6 months after surgery. A majority of the patch tests were applied on the arms.

Results:
Four positive reactions were recorded in the preimplant patch tests – three positive reactions to nickel and one to chromium. Thirty patients made themselves available for the follow-up patch test. The incidence of new contact sensitivity to components of implants was 13.8% (4/29) at 6 months. One patient who had undergone knee replacement developed eczematous lesions around the knee joint after surgery. This patient tested negative to patch test at both the times.

Limitations:
Short follow-up duration and performing patch tests on the arms, a site known to elicit less positive patch test response compared to the back in sensitized individuals, are limitations of the study. Conclusion: There is an increase in the sensitivity to implanted components after 6 months of joint replacement surgery. The incidence of new sensitivity to a component of the implant was 13.8% (4/29). In this context, nickel is a good sensitizer and could sensitize 50% of patients who received a nickel-containing implant.
Levels of Polycyclic Aromatic Hydrocarbons (PAHs) in Beers: Consumption and Public Health Concerns
Authors: Okafor V. N. , Uche U. B. , Abailim R. C. 
Published: March 2020

Aim: The aim is to investigate some physicochemical properties of beers and polycyclic aromatic hydrocarbons contaminants in beer brewed with isomerized hop extract and in comparison with beers brewed with extracts from four Nigerian potential hop substitutes.
Study Design: Beers were brewed using isomerized hop extract and extracts from four Nigerian bitter vegetables. Analyses of physicochemical properties of the beers and for the presence of 16 specific target PAHs were carried out using their respective standard methods.
Place and Duration of Study: Analysis of physicochemical properties of the beers was done at Nigerian Breweries PLC, Enugu while analysis for PAHs was conducted at Central Laboratory, Nigerian Institute for Oceanography and Marine Research, Lagos between July, 2018 and November, 2019.
Methodology: Physicochemical properties of the beers (alcohol content, bitterness level, pH, specific gravity, colour) were determined using their respective standard methods. Gas chromatography/mass spectrometry was used in analyzing for PAHs [naphthalene, acenaphthylene, acenaphthene, phenanthrene, anthracene, fluoranthene, pyrene, benzo(a)anthracene, chrysene, benzo(b)fluoranthene, benzo(k)fluoranthene, benzo(a)pyrene, dibenzo(a,h)anthracene, indeno(1,2,3-cd)pyrene and benzo(g,h,i)perylene]. Four isotopically labelled PAHs (acenaphthene-d10, phenanthrene-d10, chrysene-d12 and perylene-d12) were used as internal standards.
Results: Alcohol content (%v//v) in the beer samples is A(5.20); B(4.28); C(4.40); D(4.43) and E(4.54), bitterness level in International Bitterness Units (IBU) is A(0.54); B(0.80); C(1.46); D(1.46) and E(0.08), pH is A(4.36); B(3.08); C(3.88); D(3.90) and E(3.87), specific gravity is A(10.06); B(10.00); C(10.00); D(10.06) and E(10.06), and beer colour is A(5.80); B(7.70); C(6.60); D(8.00) and E(7.40). All 16 EPA PAHs were not found in all the beer samples except pyrene which was detected in sample B at a concentration of 0.00402 mg/kg.
Conclusion: It is concluded that extracts from the four Nigerian bitter vegetables could be used as substitutes for isomerized hop extract and that consumption of beer produced using extract from G. kola poses great public health concerns.
Characterisation of a novel cold‐adapted calcium‐activated transglutaminase: implications for medicine and food processing
Authors: Alvarez Rebeca Garcia , Karki Pralav , Langleite Ida Elise , Bakksjø Ragna‐Johanne , Eichacker Lutz Andreas , Furnes Clemens 
Published: March 2020

Transglutaminases are a family of enzymes that catalyse the cross‐linking of proteins by forming covalent bonds between lysine and glutamine residues in various polypeptides. Cross‐linking reactions are involved in blood clots, skin formation, embryogenesis and apoptosis. Clinically, these enzymes appear to be implicated in neurodegenerative diseases, tumours and coeliac diseases. Transglutaminases have great potential for use in the food industry because of their ability to cross‐link proteins that are not normally linked. Here, a gene coding for transglutaminase from Atlantic cod was cloned into a bacterial expression vector and used to transform protein expression in a strain of Escherichia coli. The successful expression of recombinant transglutaminase protein from Atlantic cod (AcTG‐1) as a soluble protein upon induction at low temperature was confirmed by sodium dodecyl sulfate/polyacrylamide gel electrophoresis, immunoblotting and mass spectrometry analysis. Biochemical characterisation demonstrated that the transglutaminase was active between 0 and 65 °C, but was completely inactivated after 20‐min incubation at 70 °C. Interestingly, the enzyme displayed cold‐adapted features, such as temperature instability combined with high catalytic efficiency at low temperatures (8–16 °C). In addition, the enzyme had optimal activity at 50 °C, a new feature for a cold‐adapted enzyme. AcTG‐1 was active in the pH range from 6 to 9, with an optimum at pH 8, and required 5 mm calcium for maximum activity. Potential calcium‐binding sites in the enzyme were predictable, making the enzyme an appropriate model for studying structure–function relationships in the calcium‐dependent transglutaminase family. In vitro gel analysis revealed that transglutaminase cross‐linked casein, collagen and gelatin. The binding of fish fillets in the presence of recombinant AcTG‐1 provided further macroscopic proof for the potential application of AcTG‐1 as a biological cross‐linker in the food industry. Once binding occurred, fish fillets withstood further processing such as frying, boiling, freeze‐thawing and chilling. The low‐temperature activity and new enzymatic properties of AcTG‐1 appear to offer advantages over commercially available enzymatic glues in the food industry.
Anti‐Entrepreneurs Using Computation to Unscale Production
Authors: Louis‐Rosenberg Jesse , Rosenkrantz Jessica 
Published: March 2020

AbstractBeing multidisciplinary, digitally adept and small is the key to success of Jesse Louis‐Rosenberg and Jessica Rosenkrantz’s generative design studio Nervous System in upstate New York that works at the intersection of science, art and technology. Their projects are inspired by natural phenomena and at once they are biological researchers, artists and coders. This synthesis of expertise and practice creates beautiful and thoughtful objects.
Fast Reversible Phase Change Silicon for Visible Active Photonics
Authors: Wang Letian , Eliceiri Matthew , Deng Yang , Rho Yoonsoo , Shou Wan , Pan Heng , Yao Jie , Grigoropoulos Costas P. 
Published: March 2020

AbstractBoth amorphous and crystalline silicon are ubiquitous materials for electronics, photonics, and microelectromechanical systems. On‐demand control of Si crystallinity is crucial for device manufacturing and to overcome the limitations of current phase‐change materials (PCM) in active photonics. Fast reversible phase transformation in silicon, however, has never been accomplished due to the notorious challenge of amorphization. It is demonstrated that nanostructured Si can function as a PCM, since it can be reversibly crystallized and amorphized under nanosecond laser irradiation with different pulse energies. Reflection probing on a single nanodisk's phase transformations confirms the distinct mechanisms for crystallization and amorphization. The experimental results show that the relaxation time of undercooled silicon at 950 K is 10 ns. The phase change provides a 20% nonvolatile reflectivity modulation within 100 ns and can be repeated over 400 times. It is shown that such transformations are free of deformation upon solidification. Based on the switchable photonic properties in the visible spectrum, proof‐of‐concept experiments of dielectric color displays and dynamic wavefront control are shown. Therefore, nanostructured silicon is proposed as a chemically stable, deformation free, and complementary metal–oxide‐semiconductor compatible (CMOS) PCM for active photonics at visible wavelengths.
Metasurface‐Enabled Generation of Circularly Polarized Single Photons
Authors: Kan Yinhui , Andersen Sebastian K. H. , Ding Fei , Kumar Shailesh , Zhao Changying , Bozhevolnyi Sergey I. 
Published: March 2020

AbstractSingle photons carrying spin angular momentum (SAM), i.e., circularly polarized single photons generated typically by subjecting a quantum emitter (QE) to a strong magnetic field at low temperatures, are at the core of chiral quantum optics enabling nonreciprocal single‐photon configurations and deterministic spin‐photon interfaces. Here, a conceptually new approach to the room‐temperature generation of SAM‐coded single photons (SSPs) is described, which entails QE nonradiative coupling to surface plasmons being transformed, by interacting with an optical metasurface, into a collimated stream of SSPs with the designed handedness. Design, fabrication, and characterization of SSP sources, consisting of dielectric circular nanoridges with azimuthally varying widths deterministically fabricated on a dielectric‐protected silver film around a nanodiamond containing a nitrogen‐vacancy center, are reported. With properly engineered phases of QE‐originated fields scattered by nanoridges, the outcoupled photons are characterized by a well‐defined SAM (with the chirality >0.8) and high directionality (collection efficiency up to 92%).
Uniform and Large‐Area Cesium‐Based Quasi‐2D Perovskite Light‐Emitting Diodes Using Hot‐Casting Method
Authors: Kim Da Bin , Lee Seungjin , Jang Chung Hyeon , Park Jong Hyun , Lee Ah‐young , Song Myoung Hoon 
Published: March 2020

AbstractMetal halide perovskites have deep valence band maximums (VBMs). For example, the VBM of CsPbBr3 is 5.8–6.3 eV. Conjugated polymers can be a potential candidate for the hole transport layer because of their deep highest occupied molecular orbital levels, but their poor compatibility with a hydrophilic perovskite precursor results in the formation of a noncontinuous perovskite film. In addition, antisolvent dripping methods for fabricating perovskite films cause spatially inhomogeneous nucleation, which is undesirable for large‐scale applications. In this work, efficient and large‐area perovskite light‐emitting diodes (PeLEDs) are developed by introducing a poly(9‐vinylcarbazole) (PVK) interlayer and employing a hot‐casting method (substrate preheating). The PVK interlayer increases the depth of the VBM of NiOx (from 5.1 to 5.5 eV), resulting in efficient hole injection. The thermal energy of the preheated substrate facilitates not only the growth of a continuous and pinhole‐free perovskite film, but also the formation of a highly crystalline and preferentially oriented perovskite structure, resulting in improved luminescence properties. Therefore, PeLEDs fabricated using an optimal preheating temperature show an improved external quantum efficiency (from 3.08% to 8.44%) with spatially uniform electroluminescence. Finally, the development of uniform and large‐area PeLEDs (with an active area of 12.8 cm2) is demonstrated.