bluuebunny/crossref_metadata_2025_split huggingface dataset:
Repetitive Traumatic Brain Injury Is Associated With TDP-43 Alterations, Neurodegeneration, and Glial Activation in Mice
Authors: Rajič Bumber Jelena , Pilipović Kristina , Janković Tamara , Dolenec Petra , Gržeta Nika , Križ Jasna , Župan Gordana 
Published: November 2020

Abstract
Increasing evidence points to a relationship between repetitive mild traumatic brain injury (mTBI), the Tar DNA binding protein 43 (TDP-43) pathology and some neurodegenerative diseases, but the underlying pathophysiological mechanisms are still unknown. We examined TDP-43 regulation, neurodegeneration, and glial responses following repetitive mTBI in nontransgenic mice and in animals with overexpression of human mutant TDP-43 protein (TDP-43G348C). In the frontal cortices of the injured nontransgenic animals, early TDP-43 cytoplasmatic translocation and overexpression of the protein and its pathological forms were detected. In the injured animals of both genotypes, neurodegeneration and pronounced glial activity were detected in the optic tract. In TDP-43G348C mice, these changes were significantly higher at day 7 after the last mTBI compared with the values in the nontransgenic animals. Results of this study suggest that the changes in the TDP-43 regulation in the frontal cortices of the nontransgenic animals were a transient stress response to the brain injury. Repetitive mTBI did not produce additional TDP-43 dysregulation or neurodegeneration or pronounced gliosis in the frontal cortex of TDP-43G348C mice. Our research also suggests that overexpression of mutated human TDP-43 possibly predisposes the brain to more intense neurodegeneration and glial activation in the optic tract after repetitive mTBI.
Combining Hypothermia and Oleuropein Subacutely Protects Subcortical White Matter in a Swine Model of Neonatal Hypoxic-Ischemic Encephalopathy
Authors: Lee Jennifer K , Santos Polan T , Chen May W , O’Brien Caitlin E , Kulikowicz Ewa , Adams Shawn , Hardart Henry , Koehler Raymond C , Martin Lee J 
Published: November 2020

Abstract
Neonatal hypoxia-ischemia (HI) causes white matter injury that is not fully prevented by therapeutic hypothermia. Adjuvant treatments are needed. We compared myelination in different piglet white matter regions. We then tested whether oleuropein (OLE) improves neuroprotection in 2- to 4-day-old piglets randomized to undergo HI or sham procedure and OLE or vehicle administration beginning at 15 minutes. All groups received overnight hypothermia and rewarming. Injury in the subcortical white matter, corpus callosum, internal capsule, putamen, and motor cortex gray matter was assessed 1 day later. At baseline, piglets had greater subcortical myelination than in corpus callosum. Hypothermic HI piglets had scant injury in putamen and cerebral cortex. However, hypothermia alone did not prevent the loss of subcortical myelinating oligodendrocytes or the reduction in subcortical myelin density after HI. Combining OLE with hypothermia improved post-HI subcortical white matter protection by preserving myelinating oligodendrocytes, myelin density, and oligodendrocyte markers. Corpus callosum and internal capsule showed little HI injury after hypothermia, and OLE accordingly had minimal effect. OLE did not affect putamen or motor cortex neuron counts. Thus, OLE combined with hypothermia protected subcortical white matter after HI. As an adjuvant to hypothermia, OLE may subacutely improve regional white matter protection after HI.
Clinical-Pathological, Immunohistochemical, and Genetic Characterization of a Series of Posterior Pituitary Tumors
Authors: Barresi Valeria , Simbolo Michele , Gessi Marco , Rossi Sabrina , Caffo Maria , Eccher Albino , Angileri Filippo Flavio , Cannavò Salvatore , Brunelli Matteo , Scarpa Aldo 
Published: November 2020

Abstract
Posterior pituitary tumors are supposed to represent the morphological spectrum of a single entity. Herein, we report the clinical-pathological, immunohistochemical, and genetic features of 5 spindle cell oncocytomas (SCOs), 3 pituicytomas, and 1 granular cell tumor (GCT). SCOs had the highest local invasiveness and affected older subjects. The 3 histotypes differed in the content of spindle cells (predominant in pituicytoma and absent in GCT), presence of lymphocytic infiltrate (in SCO and GCT, but not in the pituicytoma) and EMA/GFAP staining (negative in GCT; EMA-positive/GFAP-negative in 4/5 SCO and GFAP-positive in 3/3 pituicytomas). Three SCOs and 1 pituicytoma analyzed with next-generation sequencing had no mutations in 409 genes. However, 1 SCO had previously unreported homozygous deletion of CDKN2A/B and another of SMARCA4, SMARCB1, and NF2. All 3 SCOs had loss of heterozygosity of chromosome 1p, while the pituicytoma had chromosome 19 homozygous loss and chromosomes 10, 13q, and 18q loss of heterozygosity. Since 1p and 13q losses were previously reported in 1 pituicytoma and 1 SCO, respectively, our data demonstrate that posterior pituitary tumors share common genetic alterations. The possibility that posterior pituitary tumors are SMARCA4/SMARCB1-deficient should be kept in mind in the differential diagnosis toward other entities.
Acute calcific periarthritis secondary to calcium hydroxyapatite crystal deposition in the wrist: a case report
Authors: Walker Joseph A , McLean Elizabeth R , Anakwe Raymond E 
Published: November 2020

ABSTRACTAcute calcific periarthritis (ACP) is an unusual cause of monoarticular pain characterised by the deposition of calcium hydroxyapatite in the peri-articular and intra-articular tissues. Although the most commonly affected joint is the shoulder, other joints may be involved, including the wrist. This case report describes a 57-year-old female presenting with wrist pain and swelling associated with amorphous calcification overlying the lunate. The patient improved with the use of non-steroidal anti-inflammatory drugs and splinting. Clinician awareness of the clinical presentation and radiographic features of ACP is important to reduce unnecessary invasive diagnostic procedures such as joint aspiration.
Pott’s puffy tumour in an immunosuppressed adult: case report and systematic review of literature
Authors: Paw Ekta , Ong Chelsea T W , Vangaveti Venkat 
Published: November 2020

Abstract
This case is of a 34-year-old immunocompromised male with Pott’s puffy tumour, which was treated with antibiotics and endoscopic sinus surgery. Pott’s puffy tumour is typically a complication of frontal sinusitis in children and immunocompromise can be a precipitating factor.
A search was conducted of Embase, Medline, CINAHL, Cochrane, Google Scholar, Informit and Scopus of ‘Pott’s Puffy’ and variations of this phrase. Initial 804 records were reviewed by title, abstract and full text.
Of the unique papers identified, 155 only included paediatric patients and 128 included adult patients. After title, abstract and full-text review of 13 papers were identified describing Pott’s puffy tumour in immunocompromised patients.
Immunosuppression was noted as a risk factor in only a small number of cases, with diabetes mellitus being the most common. A few cases did note immunosuppression due to newer immunomodulatory agents being used for treatment of autoimmune conditions.
The Ursa Major association of galaxies – VI: a relative dearth of gas-rich dwarf galaxies
Authors: Busekool E , Verheijen M A W , van der Hulst J M , Tully R B , Trentham N , Zwaan M A 
Published: November 2020

ABSTRACT
We determined the H i mass function of galaxies in the Ursa Major association of galaxies using a blind Very Large Array (VLA) D-array survey, consisting of 54 pointings in a cross-pattern, covering the centre as well as the outskirts of the Ursa Major volume. The calculated H i mass function has best-fitting Schechter parameters θ* = 0.19 ± 0.11 Mpc−3, log $\mbox{$M^*_{\rm H\,{\small I}}$}\ /\mathrm{ M}_{\odot } = 9.8 \pm 0.8$, and α = −0.92 ± 0.16. The high-mass end is determined by a complementary, targeted Westerbork Synthesis Radio Telescope (WSRT) survey, and the low-mass end is determined by the blind VLA survey. The slope is significantly shallower than the slopes of the H i Parkes All Sky Survey (α = −1.37 ± 0.03 ± 0.05) and Arecibo Legacy Fast Arecibo L-band Feed Array (α = −1.33 ± 0.02) H i mass functions, which are measured over much larger volumes and cover a wider range of cosmic environments: There is a relative lack of low-H i mass galaxies in the Ursa Major region. This difference in the slope strongly hints at an environmental dependence of the H i mass function slope.
Colliding stellar wind modelling of the X-ray emission from WR 140
Authors: Zhekov Svetozar A 
Published: November 2020

ABSTRACT
We modelled the Chandra and Rossi X-ray Timing Explorer X-ray spectra of the massive binary WR 140 in the framework of the standard colliding stellar wind (CSW) picture. Models with partial electron heating at the shock fronts are a better representation of the X-ray data than those with complete temperature equalization. Emission measure of the X-ray plasma in the CSW region exhibits a considerable decrease at orbital phases near periastron. This is equivalent to variable effective mass-loss rates over the binary orbit. At orbital phases near periastron, a considerable X-ray absorption in excess to that from the stellar winds in WR 140 is present. The standard CSW model provides line profiles that in general do not match well the observed line profiles of the strong line features in the X-ray spectrum of WR 140. The variable effective mass-loss rate could be understood qualitatively in CSW picture of clumpy stellar winds where clumps are efficiently dissolved in the CSW region near apastron but not at periastron. However, future development of CSW models with non-spherically symmetric stellar winds might be needed to get a better correspondence between theory and observations.
Are stellar-mass binary black hole mergers isotropically distributed?
Authors: Stiskalek Richard , Veitch John , Messenger Chris 
Published: November 2020

ABSTRACT
The Advanced LIGO and Advanced Virgo gravitational wave detectors have detected a population of binary black hole mergers in their first two observing runs. For each of these events, we have been able to associate a potential sky location region represented as a probability distribution on the sky. Thus, at this point we may begin to ask the question of whether this distribution agrees with the isotropic model of the Universe, or if there is any evidence of anisotropy. We perform Bayesian model selection between an isotropic and a simple anisotropic model, taking into account the anisotropic selection function caused by the underlying antenna patterns and sensitivity of the interferometers over the sidereal day. We find an inconclusive Bayes factor of 1.3: 1, suggesting that the data from the first two observing runs are insufficient to pick a preferred model. However, the first detections were mostly poorly localized in the sky (before the Advanced Virgo joined the network), spanning large portions of the sky and hampering detection of potential anisotropy. It will be appropriate to repeat this analysis with events from the recent third LIGO observational run and a more sophisticated cosmological model.
Multifrequency study of a double–double radio galaxy J0028+0035
Authors: Marecki A , Jamrozy M , Machalski J , Pajdosz-Śmierciak U 
Published: November 2020

ABSTRACT
We report the discovery of a double–double radio source (DDRS) J0028+0035. We observed it with LOFAR, GMRT, and the VLA. By combining our observational data with those from the literature, we gathered an appreciable set of radio flux density measurements covering the range from 74 MHz to 14 GHz. This enabled us to carry out an extensive review of physical properties of the source and its dynamical evolution analysis. In particular, we found that, while the age of the large-scale outer lobes is about 245 Myr, the renewal of the jet activity, which is directly responsible for the double–double structure, took place only about 3.6 Myr ago after about 11 Myr long period of quiescence. Another important property typical for DDRSs and also present here is that the injection spectral indices for the inner and the outer pair of lobes are similar. The jet powers in J0028+0035 are similar too. Both these circumstances support our inference that it is, in fact, a DDRS which was not recognized as such so far because of the presence of a coincident compact object close to the inner double so that the centre of J0028+0035 is apparently a triple.
Intermediate mass black hole formation in compact young massive star clusters
Authors: Rizzuto Francesco Paolo , Naab Thorsten , Spurzem Rainer , Giersz Mirek , Ostriker J P , Stone N C , Wang Long , Berczik Peter , Rampp M 
Published: November 2020

ABSTRACT
Young dense massive star clusters are promising environments for the formation of intermediate mass black holes (IMBHs) through collisions. We present a set of 80 simulations carried out with nbody6++gpu of 10 models of compact $\sim 7 \times 10^4 \, \mathrm{M}_{\odot }$ star clusters with half-mass radii Rh ≲ 1 pc, central densities $\rho _\mathrm{core} \gtrsim 10^5 \, \mathrm{M}_\odot \, \mathrm{pc}^{-3}$, and resolved stellar populations with 10 per cent primordial binaries. Very massive stars (VMSs) up to $\sim 400 \, \mathrm{M}_\odot$ grow rapidly by binary exchange and three-body scattering with stars in hard binaries. Assuming that in VMS–stellar black hole (BH) collisions all stellar material is accreted on to the BH, IMBHs with masses up to $M_\mathrm{BH} \sim 350 \, \mathrm{M}_\odot$ can form on time-scales of ≲15 Myr, as qualitatively predicted from Monte Carlo mocca simulations. One model forms an IMBH of 140 $\mathrm{M_{\odot }}$ by three BH mergers with masses of 17:28, 25:45, and 68:70 $\mathrm{M_{\odot }}$ within ∼90 Myr. Despite the stochastic nature of the process, formation efficiencies are higher in more compact clusters. Lower accretion fractions of 0.5 also result in IMBH formation. The process might fail for values as low as 0.1. The IMBHs can merge with stellar mass BHs in intermediate mass ratio inspiral events on a 100 Myr time-scale. With 105 stars, 10 per cent binaries, stellar evolution, all relevant dynamical processes, and 300 Myr simulation time, our large suite of 80 simulations indicate another rapid IMBH formation channel in young and compact massive star clusters.
Multi-frequency temporal and spectral variability study of blazar PKS 1424−418
Authors: Abhir J , Joseph J , Patel S R , Bose D 
Published: November 2020

ABSTRACT
A study of blazar PKS 1424−418 was carried out using multi-waveband data collected by the Fermi Large Area Telescope (Fermi-LAT), Swift X-Ray Telescope (Swift-XRT), Swift UltraViolet and Optical Telescope (Swift-UVOT), and Small and Moderate Aperture Research Telescope System (SMARTS) between MJD 56000 and MJD 56600 (2012 March 14–2013 November 4). Two flaring episodes were identified by analysing the gamma-ray light curve. Simultaneous multi-waveband spectral energy distributions (SEDs) were obtained for those two flaring periods. A cross-correlation analysis of infrared (IR)–optical and γ-ray data suggested that the emission originated from the same region. We have set a lower limit for the Doppler factor using the highest energy photon observed from this source during the flaring periods, which should be &gt;12. The broad-band emission mechanism was studied by modelling the SED using the leptonic emission mechanism.
The SALT survey of helium-rich hot subdwarfs: methods, classification, and coarse analysis
Authors: Jeffery C S , Miszalski B , Snowdon E 
Published: November 2020

ABSTRACT
A medium- and high-resolution spectroscopic survey of helium-rich hot subdwarfs is being carried out using the Southern African Large Telescope (SALT). Objectives include the discovery of exotic hot subdwarfs and of sequences connecting chemically peculiar subdwarfs of different types. The first phase consists of medium-resolution spectroscopy of over 100 stars selected from low-resolution surveys. This paper describes the selection criteria, and the observing, classification, and analysis methods. It presents 107 spectral classifications on the MK-like Drilling system and 106 coarse analyses (${T_{\rm eff}}, \log g, \log y$) based on a hybrid grid of zero-metal non-LTE and line-blanketed LTE model atmospheres. For 75 stars, atmospheric parameters have been derived for the first time. The sample may be divided into six distinct groups including the classical ‘helium-rich’ sdO stars with spectral types (Sp) sdO6.5–sdB1 (74) comprising carbon-rich (35) and carbon-weak (39) stars, very hot He-sdO’s with Sp ≲ sdO6 (13), extreme helium stars with luminosity class ≲5 (5), intermediate helium-rich subdwarfs with helium class 25–35 (8), and intermediate helium-rich subdwarfs with helium class 10–25 (6). The last covers a narrow spectral range (sdB0–sdB1) including two known and four candidate heavy-metal subdwarfs. Within other groups are several stars of individual interest, including an extremely metal-poor helium star, candidate double-helium subdwarf binaries, and a candidate low-gravity He-sdO star.
Species cycling and the enhancement of ammonia in pre-stellar cores
Authors: von Procházka Azrael A , Millar T J 
Published: November 2020

ABSTRACT
The quantity of NH3 produced on grain surfaces in the pre-stellar core is thought to be one of the determining factors regarding the chemical complexity achievable at later stages of stellar birth. In order to investigate how this quantity might be influenced by the gas–grain cycling of molecular material within the cloud, we employ a modified rates gas–grain chemical code and follow the time-dependent chemistry of NH3 as the system evolves. Our models incorporate an updated version of the most recent UDfA network of reaction rate coefficients, desorption from the grains through standard thermal and non-thermal processes, and physisorbed and chemisorbed binding of atomic and molecular hydrogen to a population of carbonaceous and siliceous grains. We find that (1) observable abundances of NH3 can exist in the gas phase of our models at early times when the N atom is derived from CN via an efficient early-time hydrocarbon chemistry, (2) a time-dependent gradient exists in the observational agreement between different species classes in our models, consistent with possible physical substructures within the TMC-1 Cyanopolyyne Peak, and (3) the gaseous and solid-state abundances of NH3 are sensitive to the presence of gas–grain cycling within the system. Our results suggest that the degree of chemical complexity achievable at later stages of the cloud’s chemical evolution is indeed influenced by the manner in which the gas–grain cycling occurs.
The Gaia spectrophotometric standard stars survey – IV. Results of the absolute photometry campaign
Authors: Altavilla G , Marinoni S , Pancino E , Galleti S , Bellazzini M , Sanna N , Rainer M , Tessicini G , Carrasco J M , Bragaglia A , Schuster W J , Cocozza G , Gebran M , Voss H , Federici L , Masana E , Jordi C , Monguió M , Castro A , Peña-Guerrero M A , Pérez-Villegas A 
Published: November 2020

ABSTRACT
We present Johnson–Kron–Cousins BVRI photometry of 228 candidate spectrophotometric standard stars for the external (absolute) flux calibration of Gaia data. The data were gathered as part of a 10-yr observing campaign with the goal of building the external grid of flux standards for Gaia and we obtained absolute photometry, relative photometry for constancy monitoring, and spectrophotometry. Preliminary releases of the flux tables were used to calibrate the first two Gaia releases. This paper focuses on the imaging frames observed in good sky conditions (about 9100). The photometry will be used to validate the ground-based flux tables of the Gaia spectrophotometric standard stars and to correct the spectra obtained in non-perfectly photometric observing conditions for small zero-point variations. The absolute photometry presented here is tied to the Landolt standard stars system to ≃1 per cent or better, depending on the photometric band. Extensive comparisons with various literature sources show an overall ≃1 per cent agreement, which appears to be the current limit in the accuracy of flux calibrations across various samples and techniques in the literature. The Gaia photometric precision is presently of the order of 0.1 per cent or better, thus various ideas for the improvement of photometric calibration accuracy are discussed.
Origins and Long-Term Patterns of Copy-Number Variation in Rhesus Macaques
Authors: Thomas Gregg W C , Wang Richard J , Nguyen Jelena , Alan Harris R , Raveendran Muthuswamy , Rogers Jeffrey , Hahn Matthew W 
Published: November 2020

Abstract
Mutations play a key role in the development of disease in an individual and the evolution of traits within species. Recent work in humans and other primates has clarified the origins and patterns of single-nucleotide variants, showing that most arise in the father’s germline during spermatogenesis. It remains unknown whether larger mutations, such as deletions and duplications of hundreds or thousands of nucleotides, follow similar patterns. Such mutations lead to copy-number variation (CNV) within and between species, and can have profound effects by deleting or duplicating genes. Here, we analyze patterns of CNV mutations in 32 rhesus macaque individuals from 14 parent–offspring trios. We find the rate of CNV mutations per generation is low (less than one per genome) and we observe no correlation between parental age and the number of CNVs that are passed on to offspring. We also examine segregating CNVs within the rhesus macaque sample and compare them to a similar data set from humans, finding that both species have far more segregating deletions than duplications. We contrast this with long-term patterns of gene copy-number evolution between 17 mammals, where the proportion of deletions that become fixed along the macaque lineage is much smaller than the proportion of segregating deletions. These results suggest purifying selection acting on deletions, such that the majority of them are removed from the population over time. Rhesus macaques are an important biomedical model organism, so these results will aid in our understanding of this species and the disease models it supports.