bluuebunny/crossref_metadata_2025_split huggingface dataset:
Origin of supermassive black holes in massive metal-poor protoclusters
Authors: Schleicher D R G , Reinoso B , Latif M , Klessen R S , Vergara M Z C , Das A , Alister P , Díaz V B , Solar P A 
Published: April 2022

ABSTRACT
While large numbers of supermassive black holes have been detected at z &gt; 6, their origin is still essentially unclear. Numerical simulations have shown that the conditions for the classical direct collapse scenario are very restrictive and fragmentation is very difficult to be avoided. We thus consider here a more general case of a dense massive protostar cluster at low metallicity (≲10−3 Z⊙) embedded in gas. We estimate the mass of the central massive object, formed via collisions and gas accretion, considering the extreme cases of a logarithmically flat and a Salpeter-type initial mass function. Objects with masses of at least 104 M⊙ could be formed for inefficient radiative feedback, whereas ∼103 M⊙ objects could be formed when the accretion time is limited via feedback. These masses will vary depending on the environment and could be considerably larger, particularly due to the continuous infall of gas into the cloud. As a result, one may form intermediate mass black holes of ∼104 M⊙ or more. Upcoming observations with the James Webb Space Telescope and other observatories may help us to detect such massive black holes and their environment, thereby shedding additional light on such a formation channel.
Explaining the differences in massive star models from various simulations
Authors: Agrawal Poojan , Szécsi Dorottya , Stevenson Simon , Eldridge Jan J , Hurley Jarrod 
Published: April 2022

ABSTRACT
The evolution of massive stars is the basis of several astrophysical investigations, from predicting gravitational-wave event rates to studying star formation and stellar populations in clusters. However, uncertainties in massive star evolution present a significant challenge when accounting for these models’ behaviour in stellar population studies. In this work, we present a comparison between five published sets of stellar models from the BPASS (Binary Population and Spectral Synthesis), BoOST (Bonn Optimized Stellar Tracks), Geneva, MIST (MESA Isochrones and Stellar Tracks), and PARSEC (PAdova and TRieste Stellar Evolution Code) simulations at near-solar metallicity. The different sets of stellar models have been computed using slightly different physical inputs in terms of mass-loss rates and internal mixing properties. Moreover, these models also employ various pragmatic methods to overcome the numerical difficulties that arise due to the presence of density inversions in the outer layers of stars more massive than 40 M⊙. These density inversions result from the combination of inefficient convection in the low-density envelopes of massive stars and the excess of radiative luminosity to the Eddington luminosity. We find that the ionizing radiation released by the stellar populations can change by up to 18 per cent, the maximum radial expansion of a star can differ between 100 and 1600 R⊙, and the mass of the stellar remnant can vary up to 20 M⊙ between the five sets of simulations. We conclude that any attempts to explain observations that rely on the use of models of stars more massive than 40 M⊙ should be made with caution.
Spectroscopic analysis of VVV CL001 cluster with MUSE
Authors: Olivares Carvajal J , Zoccali M , Rojas-Arriagada A , Contreras Ramos R , Gran F , Valenti E , Minniti J H 
Published: April 2022

ABSTRACTLike most spiral galaxies, the Milky Way contains a population of blue, metal-poor globular clusters and another of red, metal-rich ones. Most of the latter belong to the bulge, and therefore they are poorly studied compared to the blue (halo) ones because they suffer higher extinction and larger contamination from field stars. These intrinsic difficulties, together with a lack of low-mass bulge globular clusters, are reasons to believe that their census is not complete yet. Indeed, a few new clusters have been confirmed in the last few years. One of them is VVV CL001, the subject of the present study. We present a new spectroscopic analysis of the recently confirmed globular cluster VVV CL001, made by means of MUSE@VLT integral field data. Individual spectra were extracted for stars in the VVV CL001 field. Radial velocities were derived by cross-correlation with synthetic templates. Coupled with proper motions from the VVV (VISTA Variables in the Vía Láctea) survey, these data allow us to select 55 potential cluster members, for which we derive metallicities using the public code The Cannon. The mean radial velocity of the cluster is Vhelio = −324.9 ± 0.8 km s−1, as estimated from 55 cluster members. This high velocity, together with a low metallicity [Fe/H] = −2.04 ± 0.02 dex, suggests that VVV CL001 could be a very old cluster. The estimated distance is d = 8.23 ± 0.46 kpc, placing the cluster in the Galactic bulge. Furthermore, both its current position and the orbital parameters suggest that VVV CL001 is most probably a bulge globular cluster.
Study of the equatorial ionosphere using the Giant Metrewave Radio Telescope (GMRT) at sub-GHz frequencies
Authors: Mangla Sarvesh , Datta Abhirup 
Published: April 2022

ABSTRACTRadio interferometers, which are designed to observe astrophysical objects in the universe, can also be used to study the Earth’s ionosphere. Radio interferometers like the Giant Metrewave Radio Telescope (GMRT) detect variations in ionospheric total electron content (TEC) on a much wider spatial scale at a relatively higher sensitivity than traditional ionospheric probes like the Global Navigation Satellite System (GNSS). The hybrid configuration of the GMRT (compact core and extended arms) and its geographical location make this interferometer an excellent candidate to explore the sensitive regions between the northern crest of the Equatorial Ionization Anomaly (EIA) and the magnetic equator. For this work, a bright radio source, 3C 68.2, is observed from post-midnight to post-sunrise (∼ 9 h) to study the ionospheric activities at solar-minima. This study presents data reduction and processing techniques to measure differential TEC ($\delta \rm {TEC}$) between the set of antennas with an accuracy of 1 × 10−3 TECU. Furthermore, using these $\delta \rm {TEC}$ measurements, we have demonstrated techniques to compute the TEC gradient over the full array and micro-scale variation in 2D TEC gradient surface. These variations are well equipped to probe ionospheric plasma, especially during the night-time. Our study, for the first time, reports the capability of the GMRT to detect ionospheric activities. Our result validates, compared to previous studies with VLA, LOFAR, and MWA, the ionosphere over the GMRT is more active, which is expected due to its location near the magnetic equator.
ariadne: measuring accurate and precise stellar parameters through SED fitting
Authors: Vines Jose I , Jenkins James S 
Published: April 2022

ABSTRACTAccurately measuring stellar parameters is a key goal to increase our understanding of the observable Universe. However, current methods are limited by many factors, in particular, the biases and physical assumptions that are the basis for the underlying evolutionary or atmospheric models, those that these methods rely upon. Here, we introduce our code spectrAl eneRgy dIstribution bAyesian moDel averagiNg fittEr (ariadne), which tackles this problem by using Bayesian Model Averaging to incorporate the information from all stellar models to arrive at accurate and precise values. This code uses spectral energy distribution fitting methods, combined with precise Gaia distances, to measure the temperature, log g, [Fe/H], AV, and radius of a star. When compared with interferometrically measured radii ariadne produces values in excellent agreement across a wide range of stellar parameters, with a mean fractional difference of only 0.001 ± 0.070. We currently incorporate six different models, and in some cases we find significant offsets between them, reaching differences of up to 550 K and 0.6 R⊙ in temperature and radius, respectively. For example, such offsets in stellar radius would give rise to a difference in planetary radius of 60 per cent, negating homogeneity when combining results from different models. We also find a trend for stars smaller than 0.4–0.5 R⊙, which shows more work needs to be done to better model these stars, even though the overall extent is within the uncertainties of the interferometric measurements. We advocate for the use of ariadne to provide improved bulk parameters of nearby A to M dwarfs for future studies.
Influence of concomitant methotrexate use on the clinical effectiveness, retention, and safety of abatacept in biologic-naïve patients with rheumatoid arthritis:Post-hocsubgroup analysis of the ORIGAMI study
Authors: Azuma Takanori , Misaki Kenta , Kusaoi Makio , Suzuki Yoko , Higa Shinji , Kumon Yoshitaka , Yoshitama Tamami , Naniwa Taio , Yamada Shinsuke , Okano Tadashi , Takeuchi Kimihiko , Ikeda Kei , Higami Kenshi , Inoo Masayuki , Sawada Tetsuji , Kang Chonte , Hayashi Masatoshi , Nagaya Yuko , Hagiwara Takafumi , Shono Eisuke , Himeno Shinkichi , Tanaka Eiichi , Inoue Eisuke , Yoshizawa Yuri , Kadode Michiaki , Yamanaka Hisashi , Harigai Masayoshi 
Published: April 2022

ABSTRACTObjectivesWe performed post-hoc analyses of the ORIGAMI study to investigate whether concomitant methotrexate (MTX) influences the clinical outcomes of abatacept in biologic-naïve patients with rheumatoid arthritis.MethodsEnrolled patients (n = 325) were divided into two groups according to whether abatacept was prescribed without (MTX−) or with (MTX+) concomitant MTX. We compared the changes in Simplified Disease Activity Index (SDAI), Disease Activity Score-28 with C-reactive protein (DAS28-CRP), and Japanese Health Assessment Questionnaire (J-HAQ) through to 52 weeks of treatment, the abatacept retention rate, and safety.ResultsAt Week 52, the mean SDAI (8.9 vs. 8.8), DAS28-CRP (2.6 vs. 2.6), and J-HAQ (0.92 vs. 0.91) scores were comparable in the MTX− (n = 129) and MTX+ (n = 150) groups. Multivariable logistic regression revealed no significant association between MTX use and SDAI (low disease activity) or J-HAQ (minimum clinically important difference). The abatacept retention rates, estimated using the Kaplan–Meier method, were 73.2% and 66.7% in the MTX− and MTX+ groups, respectively. Adverse events occurred in 47.5% (of 139) and 52.2% (of 159) of patients in the MTX− and MTX+ groups, respectively.ConclusionThe effectiveness and safety of abatacept appeared comparable with or without concomitant MTX in this real-world clinical setting.
Iron Availability within the Leaf Vasculature Determines the Magnitude of Iron Deficiency Responses in Source and Sink Tissues inArabidopsis
Authors: Nguyen Nga T , Khan Mather A , Castro–Guerrero Norma A , Chia Ju-Chen , Vatamaniuk Olena K , Mari Stephane , Jurisson Silvia S , Mendoza-Cozatl David G 
Published: April 2022

AbstractIron (Fe) uptake and translocation in plants are fine-tuned by complex mechanisms that are not yet fully understood. In Arabidopsis thaliana, local regulation of Fe homeostasis at the root level has been extensively studied and is better understood than the systemic shoot-to-root regulation. While the root system is solely a sink tissue that depends on photosynthates translocated from source tissues, the shoot system is a more complex tissue, where sink and source tissues occur synchronously. In this study, and to gain better insight into the Fe deficiency responses in leaves, we overexpressed Zinc/Iron-regulated transporter-like Protein (ZIP5), an Fe/Zn transporter, in phloem-loading cells (proSUC2::AtZIP5) and determined the timing of Fe deficiency responses in sink (young leaves and roots) and source tissues (leaves). Transgenic lines overexpressing ZIP5 in companion cells displayed increased sensitivity to Fe deficiency in root growth assays. Moreover, young leaves and roots (sink tissues) displayed either delayed or dampened transcriptional responses to Fe deficiency compared to wild-type (WT) plants. We also took advantage of the Arabidopsis mutant nas4x-1 to explore Fe transcriptional responses in the opposite scenario, where Fe is retained in the vasculature but in an unavailable and precipitated form. In contrast to proSUC2::AtZIP5 plants, nas4x-1 young leaves and roots displayed a robust and constitutive Fe deficiency response, while mature leaves showed a delayed and dampened Fe deficiency response compared to WT plants. Altogether, our data provide evidence suggesting that Fe sensing within leaves can also occur locally in a leaf-specific manner.
Rare Palisading Variant of Dermatofibroma
Authors: Pun Stacey , Cassarino David 
Published: April 2022

Abstract:
Dermatofibromas (DFs) are benign lesions that typically present as firm papules or nodules on the legs of young- to middle-aged adults. DFs are histologically characterized by a dermal proliferation of spindled fibrohistiocytic cells forming intersecting fascicles and showing collagen entrapment. The palisading variant of DF was first described in 1986 and often presents as a dome-shaped nodule on the digits. Histologically, palisading DFs demonstrate central areas of nuclear palisading in parallel rows resembling Verocay bodies, with more typical areas of DF located peripherally. We report a case of a 33-year-old Hispanic woman who presented with a history of an asymptomatic, slow-growing lesion on her left arm present since her teenage years. Physical examination revealed a solitary, firm brown-to-white 5-mm papule on the left upper arm. A biopsy was performed and revealed a proliferation of spindle cells palisading around areas of hyalinized collagen. The many histologic variants of DF can sometimes create diagnostic confusion. Previously described cases of palisading DFs in the literature showed palisading resembling Verocay bodies and thus raising concern for a schwannoma or other neoplasm that display a “rippled” pattern. Our case is unique in that the architecture of the palisading areas instead resembled a necrobiotic granulomatous process such as granuloma annulare or a rheumatoid nodule at low power.
Effect of CYP2C19 genetic variants on bleeding and major adverse cardiovascular events in a cohort of Arab patients undergoing percutaneous coronary intervention and stent implantation
Authors: Ali Zainab Omer , Bader Loulia , Mohammed Shaaban , Arafa Salaheddin , Arabi Abdulrahman , Cavallari Larisa , Langaee Taimour , Mraiche Fatima , Rizk Nasser , Awaisu Ahmed , Shahin Mohamed H. , Elewa Hazem 
Published: April 2022

Introduction
One-third of patients have clopidogrel resistance that may lead to major adverse cardiac events (MACEs). By contrast, it was found that some clopidogrel-treated patients have hyperresponsive platelets that are associated with higher bleeding risk. Several studies have shown that polymorphisms in the gene encoding the CYP2C19 contribute to the variability in response to clopidogrel. Data on genetic and nongenetic factors affecting clopidogrel response in the Arab population are scarce. In this prospective cohort study, we sought to assess the association between the increased function allele (CYP2C19*17) and bleeding events, and validate the effect of the CYP2C19 genetic variants and nongenetic factors on the incidence of MACEs.

Methods
Blood samples were collected from patients that were undergoing percutaneous coronary intervention and receiving clopidogrel at the Heart Hospital, a specialist tertiary hospital in Doha, Qatar. Patients were followed for 12 months. Genotyping was performed for CYP2C19*2, *3, and *17 using TaqMan assays.

Results
In 254 patients, the minor allele frequencies were 0.13, 0.004, and 0.21 for *2, *3, and *17, respectively. Over a 12-month follow-up period, there were 21 bleeding events (8.5 events/100 patient-year). CYP2C19*17 carriers were found to be associated with increased risk of bleeding (OR, 21.6; 95% CI, 4.8–96.8; P < 0.0001). CYP2C19*2 or *3 carriers were found to be associated with increased risk of baseline and incident MACE combined (OR, 8.4; 95% CI, 3.2–23.9; P < 0.0001).

Conclusion
This study showed a significant association between CYP2C19*17 allele and the increased risk of bleeding, and CYP2C19*2 or *3 with MACE outcomes.
Composite CYP3A phenotypes influence tacrolimus dose-adjusted concentration in lung transplant recipients
Authors: Liu Michelle , Shaver Ciara M. , Birdwell Kelly A. , Heeney Stephanie A. , Shaffer Christian M. , Van Driest Sara L. 
Published: April 2022

Objectives
Interpatient variability in tacrolimus pharmacokinetics is attributed to metabolism by cytochrome P-450 3A4/5 isoenzymes (encoded by CYP3A4 and CYP3A5). Guidelines for adjusting tacrolimus based on CYP3A5 test results are published; however, CYP3A4 variants also contribute to the variability in tacrolimus pharmacokinetics. The effects of composite phenotypes incorporating CYP3A5 and CYP3A4 increased (*1G, *1B) and decreased (*22) function variants have not been evaluated. The objective of this study is to investigate the impact of both increased and decreased function CYP3A variants on weight and dose-adjusted tacrolimus concentration (C0/D).

Methods
We performed a single-center retrospective cohort study of lung transplant recipients to evaluate the median tacrolimus C0/D by composite CYP3A phenotype groups during the index transplant hospitalization. CYP3A4 and CYP3A5 alleles were used to classify patients into four CYP3A groups from least to most CYP3A activity. Exploratory analyses of ABCB1 and additional candidate genes were also assessed.

Results
Of the 92 included individuals, most (58) were CYP3A Group 2. The median tacrolimus C0/D differed significantly between CYP3A groups (P = 0.0001). CYP3A Group 2 median tacrolimus C0/D was 190.5 (interquartile range: 147.6–267.5) (ng/ml)/(mg/kg/d) and significantly higher than Group 4 [107.9 (90.4–116.1), P = 0.0001)]. Group 2 median tacrolimus C0/D did not significantly differ from Group 1 and Group 3 [373.5 (149.2–490.3) and 81.4 (62.6–184.1), respectively]. No significant differences in tacrolimus C0/D were found for the ABCB1 diplotypes.

Conclusion
These data indicate that a composite CYP3A phenotype incorporating both increase and decrease variant information from CYP3A4 in addition to CYP3A5 may significantly influence tacrolimus C0/D during the early postoperative period.
Management of Late Descemet's Membrane Detachment After Penetrating Keratoplasty in Keratoconus
Authors: Weller Julia M. , Kruse Friedrich E. , Schloetzer-Schrehardt Ursula , Tourtas Theofilos 
Published: April 2022

Purpose:
The purpose of this study was to describe the feasibility of Descemet membrane endothelial keratoplasty (DMEK) as a treatment modality for spontaneous detachment of DM (DMD) decades after penetrating keratoplasty (PK) for keratoconus.

Methods:
We describe the clinical characteristics and therapeutic surgical approach in 6 eyes of 5 patients with DMD. Clinical images, anterior segment optical coherence tomography scans, and histological findings are presented.

Results:
Mean age of patients at time of diagnosis was 60 years (range 56–66 years). Mean interval between PK and occurrence of DM detachment was 36 years (range 29–45 years). In 4 of 6 eyes, air injections into the anterior chamber were initially attempted to reattach DM to the stroma but without long-lasting effect. Two eyes underwent repeat PK because of pronounced ectasia after long-standing DMD and stromal scars. DMEK was performed successfully in 4 eyes leading to an increase in visual acuity and a reduction in central corneal thickness. Electron microscopy showed abnormal vacuolar inclusions and collagenous material in the posterior nonbanded layer and a separation of the anterior banded layer from the posterior nonbanded layer.

Conclusions:
This case series provides evidence that DMEK is a viable option in eyes with spontaneous DM detachment after PK. Visual outcome is limited by the persisting high astigmatism in the ectatic cornea. Illustrated by a small series of patients, the results of DMEK in this condition are presented and new findings about the pathophysiology are given.
Elucidating a Silent Illness: Hepatitis B Knowledge Among Asian Individuals in an Urban Center
Authors: Stahl Heidi J. , Wu Anna K. , Li Henry , Hu David , Liu Wei , Lam Suet Kam 
Published: April 2022

Background:
Despite comprising less than 6% of the US population, Asian individuals make up more than half of the approximately 1.6 million chronic hepatitis B virus (HBV) infections in the United States. The purpose of this investigation was to identify characteristics associated with HBV knowledge in this disproportionately affected population.

Methods:
A cross-sectional, multilingual survey study using convenience sampling was conducted in a Midwestern urban city to collect information on respondents' demographics, health care access, and HBV knowledge. Hepatitis B virus knowledge was categorized into epidemiology, natural history, transmission, and vaccination. Data were analyzed using Kruskal-Wallis and Spearman correlation tests.

Results:
Of the 174 individuals who completed surveys, 139 (79.9%) were Asian. Characteristics of univariate analyses associated with higher knowledge scores included younger age (18-49 years), proficiency in reading English, college education, current employment status, physician using preferred language, last physician's visit in 2018 or prior, perceived lack of time to see a physician, use of emergency department, prior HBV vaccination, prior HBV testing, higher level of self-reported knowledge about HBV, and acquiring health information from the Internet, messaging applications, friends, and family (P < .05). In the multivariable analysis, shorter residency in the United States (0-10 years), current employment status, having heard of HBV, and confidence in their HBV knowledge were associated with higher knowledge scores.

Conclusion:
Knowledge deficits existed in our study population regarding HBV transmission, vaccination, and epidemiology, while knowledge was higher regarding HBV natural history. Education efforts should be designed to improve knowledge deficits about HBV for individuals with risk factors using culturally sensitive Internet and social media platforms.