bluuebunny/crossref_metadata_2025_split huggingface dataset:
Comprehensive broad-band study of accreting neutron stars with Suzaku: Is there a bi-modality in the X-ray spectrum?
Authors: Pradhan Pragati , Paul Biswajit , Bozzo Enrico , Maitra Chandreyee , Paul B C 
Published: January 2021

ABSTRACT
We present a broad-band spectral analysis of accreting neutron stars using data from XIS and PIN onboard Suzaku. From spectral fits of these sources with a single continuum model including a power law and high energy cut-off, cyclotron lines (where required), we studied the correlation between various spectral parameters. Among 39 sources we studied, 16 are those where the existence of a cyclotron line is known in literature, and 29 need a cut-off energy. Among these 29 sources, 18 have cut-off energy bunched in a range of 3–10 keV while for 11 sources, it spreads over 12–25 keV. This bi-modal behaviour is not based on the specific nature of the systems being a Be XRB or supergiant HMXB, nor on different beaming patterns characterizing their X-ray emission (as inferred from simultaneous study of their pulse profiles). The broad-band coverage of Suzaku also shows that the cut-off energies saturate for higher values of cyclotron line energies – consistent with previous works in literature – for both the groups and the width of the cyclotron line show a weak correlation with the cyclotron line energy. We also find an anticorrelation with luminosity for both spectral index and folding energy, respectively. Unlike previous works, we did not detect any anticorrelation between X-ray luminosity and EW of K α lines. Finally, we show that the EW and flux of the iron K α line are smaller in SFXTs than classical NS-HMXBs. We discuss these findings in terms of different properties of stellar winds and accretion mechanisms.
The effect of jet–ejecta interaction on the viewing angle dependence of kilonova light curves
Authors: Klion Hannah , Duffell Paul C , Kasen Daniel , Quataert Eliot 
Published: January 2021

ABSTRACT
The merger of two neutron stars produces an outflow of radioactive heavy nuclei. Within a second of merger, the central remnant is expected to also launch a relativistic jet, which shock-heats and disrupts a portion of the radioactive ejecta. Within a few hours, emission from the radioactive material gives rise to an ultraviolet, optical, and infrared transient (a kilonova). We use the endstates of a suite of 2D relativistic hydrodynamic simulations of jet–ejecta interaction as initial conditions for multidimensional Monte Carlo radiation transport simulations of the resulting viewing angle-dependent light curves and spectra starting at $1.5\, \mathrm{h}$ after merger. We find that on this time-scale, jet shock heating does not affect the kilonova emission for the jet parameters we survey. However, the jet disruption to the density structure of the ejecta does change the light curves. The jet carves a channel into the otherwise spheroidal ejecta, revealing the hot, inner regions. As seen from near (≲30°) the jet axis, the kilonova is brighter by a factor of a few and bluer. The strength of this effect depends on the jet parameters, since the light curves of more heavily disrupted ejecta are more strongly affected. The light curves and spectra are also more heavily modified in the ultraviolet than in the optical.
Spin evolution of neutron stars in two modes: implication for millisecond pulsars
Authors: Bhattacharyya Sudip 
Published: January 2021

ABSTRACT
An understanding of spin frequency (ν) evolution of neutron stars in the low-mass X-ray binary (LMXB) phase is essential to explain the observed ν-distribution of millisecond pulsars (MSPs), and to probe the stellar and binary physics, including the possibility of continuous gravitational wave emission. Here, using numerical computations we conclude that ν can evolve in two distinctly different modes, as ν may approach a lower spin equilibrium value (νeq,per) for persistent accretion for a long-term average accretion rate ($\dot{M}_{\rm av}$) greater than a critical limit ($\dot{M}_{\rm av,crit}$), and may approach a higher effective spin equilibrium value (νeq,eff) for transient accretion for $\dot{M}_{\rm av} \lt \dot{M}_{\rm av,crit}$. For example, when $\dot{M}_{\rm av}$ falls below $\dot{M}_{\rm av,crit}$ for an initially persistent source, ν increases considerably due to transient accretion, which is counter-intuitive. We also find that, contrary to what was suggested, a fast or sudden decrease of $\dot{M}_{\rm av}$ to zero in the last part of the LMXB phase is not essential for the genesis of spin-powered MSPs, and neutron stars could spin-up in this $\dot{M}_{\rm av}$-decreasing phase. Our findings imply that the traditional way of ν-evolution computation is inadequate in most cases, even for initially persistent sources, and may not even correctly estimate whether ν increases or decreases.
Search for translation arrest peptides encoded upstream of genes for components of protein localization pathways
Authors: Sakiyama Karen , Shimokawa-Chiba Naomi , Fujiwara Keigo , Chiba Shinobu 
Published: January 2021

AbstractRegulatory nascent peptides participate in the regulation of cellular functions by the mechanisms involving regulated translation arrest. A class of them in bacteria, called monitoring substrates, feedback-regulates the expression of a specific component of protein localization machinery. Three monitoring substrates, SecM, MifM and VemP have previously been identified. Here, we attempt at identifying additional arrest peptides in bacteria. Our bioinformatic searches over more than 400 bacterial genomic sequences for proteins that have the common characteristic features shared by the known monitoring substrates and subsequent in vitro and in vivo characterization of the highlighted sequences allowed the identification of three arrest peptides termed ApcA, ApdA and ApdP. ApcA and ApdA homologs are conserved among a subset of actinobacteria, whereas ApdP has homologs in a subset of α-proteobacteria. We demonstrate that these arrest peptides, in their ribosome-tethered nascent states, inhibit peptidyl transfer. The elongation arrest occurs at a specific codon near the 3′ end of the coding region, in a manner depending on the amino acid sequence of the nascent chain. Interestingly, the arrest sequences of ApcA, ApdA and ApdP share a sequence R-A-P-G/P that is essential for the elongation arrest.
Arabidopsis casein kinase 2 triggers stem cell exhaustion under Al toxicity and phosphate deficiency through activating the DNA damage response pathway
Authors: Wei Pengliang , Demulder Manon , David Pascale , Eekhout Thomas , Yoshiyama Kaoru Okamoto , Nguyen Long , Vercauteren Ilse , Eeckhout Dominique , Galle Margot , De Jaeger Geert , Larsen Paul , Audenaert Dominique , Desnos Thierry , Nussaume Laurent , Loris Remy , De Veylder Lieven 
Published: January 2021

Abstract
Aluminum (Al) toxicity and inorganic phosphate (Pi) limitation are widespread chronic abiotic and mutually enhancing stresses that profoundly affect crop yield. Both stresses strongly inhibit root growth, resulting from a progressive exhaustion of the stem cell niche. Here, we report on a casein kinase 2 (CK2) inhibitor identified by its capability to maintain a functional root stem cell niche in Arabidopsis thaliana under Al toxic conditions. CK2 operates through phosphorylation of the cell cycle checkpoint activator SUPPRESSOR OF GAMMA RADIATION1 (SOG1), priming its activity under DNA-damaging conditions. In addition to yielding Al tolerance, CK2 and SOG1 inactivation prevents meristem exhaustion under Pi starvation, revealing the existence of a low Pi-induced cell cycle checkpoint that depends on the DNA damage activator ATAXIA-TELANGIECTASIA MUTATED (ATM). Overall, our data reveal an important physiological role for the plant DNA damage response pathway under agriculturally limiting growth conditions, opening new avenues to cope with Pi limitation.
Sulfur transfer from the endophytic fungus Serendipita indica improves maize growth and requires the sulfate transporter SiSulT
Authors: Narayan Om Prakash , Verma Nidhi , Jogawat Abhimanyu , Dua Meenakshi , Johri Atul Kumar 
Published: January 2021

Abstract
A deficiency of the essential macronutrient sulfur leads to stunted plant growth and yield loss; however, an association with a symbiotic fungus can greatly improve nutrient uptake by the host plant. Here, we identified and functionally characterized a high-affinity sulfate transporter from the endophytic fungus Serendipita indica. SiSulT fulfills all the criteria expected of a functional sulfate transporter responding to sulfur limitation: SiSulT expression was induced when S. indica was grown under low-sulfate conditions, and heterologous expression of SiSulT complemented a yeast mutant lacking sulfate transport. We generated a knockdown strain of SiSulT by RNA interference to investigate the consequences of the partial loss of this transporter for the fungus and the host plant (maize, Zea mays) during colonization. Wild-type (WT) S. indica, but not the knockdown strain (kd-SiSulT), largely compensated for low-sulfate availability and supported plant growth. Colonization by WT S. indica also allowed maize roots to allocate precious resources away from sulfate assimilation under low-sulfur conditions, as evidenced by the reduction in expression of most sulfate assimilation genes. Our study illustrates the utility of the endophyte S. indica in sulfur nutrition research and offers potential avenues for agronomically sound amelioration of plant growth in low-sulfate environments.
Endosperm development is an autonomously programmed process independent of embryogenesis
Authors: Xiong Hanxian , Wang Wei , Sun Meng-Xiang 
Published: January 2021

Abstract
The seeds of flowering plants contain three genetically distinct structures: the embryo, endosperm, and seed coat. The embryo and endosperm need to interact and exchange signals to ensure coordinated growth. Accumulating evidence has confirmed that embryo growth is supported by the nourishing endosperm and regulated by signals originating from the endosperm. Available data also support that endosperm development requires communication with the embryo. Here, using single-fertilization mutants, Arabidopsis thaliana dmp8 dmp9 and gex2, we demonstrate that in the absence of a zygote and embryo, endosperm initiation, syncytium formation, free nuclear cellularization, and endosperm degeneration occur as in the wild type in terms of the cytological process and time course. Although rapid embryo expansion accelerates endosperm breakdown, our findings strongly suggest that endosperm development is an autonomously organized process, independent of egg cell fertilization and embryo–endosperm communication. This work confirms both the altruistic and self-directed nature of the endosperm during coordinated embryo–endosperm development. Our findings provide insights into the intricate interaction between the two fertilization products and will help to distinguish the physiological roles of the signaling between endosperm and embryo. These findings also open new avenues in agro-biotechnology for crop improvement.
The role of GDP-l-galactose phosphorylase in the control of ascorbate biosynthesis
Authors: Fenech Mario , Amorim-Silva Vítor , Esteban del Valle Alicia , Arnaud Dominique , Ruiz-Lopez Noemi , Castillo Araceli G , Smirnoff Nicholas , Botella Miguel A 
Published: January 2021

AbstractThe enzymes involved in l-ascorbate biosynthesis in photosynthetic organisms (the Smirnoff–Wheeler [SW] pathway) are well established. Here, we analyzed their subcellular localizations and potential physical interactions and assessed their role in the control of ascorbate synthesis. Transient expression of C terminal-tagged fusions of SW genes in Nicotiana benthamiana and Arabidopsis thaliana mutants complemented with genomic constructs showed that while GDP-d-mannose epimerase is cytosolic, all the enzymes from GDP-d-mannose pyrophosphorylase (GMP) to l-galactose dehydrogenase (l-GalDH) show a dual cytosolic/nuclear localization. All transgenic lines expressing functional SW protein green fluorescent protein fusions driven by their endogenous promoters showed a high accumulation of the fusion proteins, with the exception of those lines expressing GDP-l-galactose phosphorylase (GGP) protein, which had very low abundance. Transient expression of individual or combinations of SW pathway enzymes in N. benthamiana only increased ascorbate concentration if GGP was included. Although we did not detect direct interaction between the different enzymes of the pathway using yeast-two hybrid analysis, consecutive SW enzymes, as well as the first and last enzymes (GMP and l-GalDH) associated in coimmunoprecipitation studies. This association was supported by gel filtration chromatography, showing the presence of SW proteins in high-molecular weight fractions. Finally, metabolic control analysis incorporating known kinetic characteristics showed that previously reported feedback repression at the GGP step, combined with its relatively low abundance, confers a high-flux control coefficient and rationalizes why manipulation of other enzymes has little effect on ascorbate concentration.
Electric quadrupole form factors of singly heavy baryons with spin 3/2
Authors: Kim June-Young , Kim Hyun-Chul 
Published: January 2021

Abstract
We study the electromagnetic form factors of the lowest-lying singly heavy baryons in a pion mean-field approach, which is also known as the SU(3) chiral quark-soliton model. In the limit of the heavy-quark mass, the dynamics inside a singly heavy baryon is governed by the $N_c-1$ valence quarks, while the heavy quark remains as a static one. In this framework, a singly heavy baryon is described by combining the $N_c-1$ soliton with the singly heavy quark. In the infinitely heavy-quark mass limit, we can compute the electric quadrupole form factors of the baryon sextet with spin 3/2, with the rotational $1/N_c$ and linear corrections of the explicit flavor SU(3) symmetry breaking taken into account. We find that the sea-quark contributions or the Dirac-sea level contributions dominate over the valence-quark contributions in the lower $Q^2$ region. We examined the effects of explicit flavor SU(3) symmetry breaking in detail. The numerical results are also compared with the recent data from the lattice calculation with the unphysical value of the pion mass considered, which was used in the lattice calculation.
Post-COVID syndrome and suicide risk
Authors: Sher L 
Published: January 2021

Abstract
A significant number of coronavirus disease SARS-CoV-2 (COVID-19) patients continue to have symptoms related to COVID-19 after the acute phase of illness. This post-COVID condition is sometimes called ‘post-COVID syndrome’, ‘long COVID’ or ‘post-acute COVID-19’. Persistent psychiatric symptoms among COVID-19 survivors such as depression, anxiety, post-traumatic symptoms and cognitive impairment may be related to psychological factors and neurobiological injury. COVID-19 related neurological symptoms including anosmia, ageusia, dizziness, headache and seizures may persist for a long time after the acute COVID-19 illness. Many COVID-19 survivors experience persistent physical symptoms such as cough, fatigue, dyspnea and pain after recovering from their initial illness. There is a high probability that symptoms of psychiatric, neurological and physical illnesses, as well as inflammatory damage to the brain in individuals with post-COVID syndrome increase suicidal ideation and behavior in this patient population. COVID-19 survivors without post-COVID syndrome may also be at elevated suicide risk. Studies of suicidality in COVID-19 survivors are urgently needed and will be a new area of suicide research. An appropriate management of psychiatric, neurological and medical conditions may reduce suicide risk among COVID-19 survivors with or without post-COVID syndrome.
High burden of infections in Indian patients with Idiopathic Inflammatory Myopathy: validation of observations from the MyoCite dataset
Authors: Chatterjee Rudrarpan , Mehta Pankti , Agarwal Vikas , Gupta Latika 
Published: January 2021

Abstract

Objective
To determine the prevalence, profile and predictors of infections in an Indian cohort with idiopathic inflammatory myopathies (IIM).

Methods
We reviewed the records of a retrospective cohort with IIM enrolled from consecutive patients being followed up in the clinic, and these constituted the observation cohort. A newly diagnosed inception cohort with IIM were followed prospectively as the validation cohort for confirmation of observations and comparison with the observation cohort.

Results
Among the 68 patients in the observation cohort (average age 33.4 years, female:male 4.2:1), 37 (54.4%) experienced 54 infections between them; of these 54 infections, 21 (38.8%) were major and recurrent infections and they occurred in 11 patients (16.17%) over 3.08 years. Tuberculosis was the most common infection (12, 22.2%), with a predominance of extrapulmonary forms. Serum protein [odds ratio (OR) 0.44], platelets (0.44) at disease onset and daily steroid dose (1.04) predicted major infections on multivariate analysis. A higher daily dose of steroids at first infection correlated with number of recurrent infections. The infection-free 1-year survival was 73.8%.
Of the 70 patients in the validation cohort (average age 35.7 years, female:male 3.7:1), 3 had myositis attributed to an infection. A similar proportion of the cohort experienced infections (22, 33.3%) with similar number of major (10, 45.4%) and recurrent (4, 18%) infections being recorded. The most common infection was community-acquired pneumonia, followed by tuberculosis, with serum albumin (OR 0.25) at disease onset being the only predictor. The one-year infection-free survival rate was 64.7%. Those who had a major infection had increased mortality at 1 year, with a survival rate of 60%, compared with 89.09% in those without.
In both cohorts, a daily prednisone dose &gt;6.25 mg predisposed to major infections.

Conclusion
Major and recurrent infections are common in Indian IIM patients and confer higher risk for future infections and lower survival. Respiratory and atypical bacterial infections such as tuberculosis occur throughout the disease course.
Frugoside delays osteoarthritis progression via inhibiting miR-155-modulated synovial macrophage M1 polarization
Authors: Wang Hao , Zhang Haiyan , Fan Kai , Zhang Danyang , Hu Aihau , Zeng Xiangzhou , Liu Yan li , Tan Guanghong , Wang Hua 
Published: January 2021

AbstractObjectivesDirect inhibition of M1 polarization of synovial macrophages may be a useful therapeutic treatment for OA and OA-associated synovitis. Frugoside (FGS) is a cardiac glycoside compound isolated and extracted from Calotropis gigantea. Cardiac glycosides possess interesting anti-inflammatory potential. However, the corresponding activity of FGS has not been reported. Therefore, our aim was to find direct evidence of the effects of FGS on synovial macrophage M1 polarization and OA control.MethodsCollagenase was used to establish an experimental mouse OA model (CIOA) with considerable synovitis. Then, FGS was intra-articular administered. The mRNA and protein levels of iNOS were analysed by real-time PCR and Western blotting in vitro. Immunohistochemical and immunofluorescence staining were used to measure the expression of F4/80, iNOS, Col2α1 and MMP13 in vivo. The levels of pro-inflammatory cytokines in FGS-treated M1 macrophage culture supernatants were analysed by flow cytometry.ResultsFGS attenuates synovial inflammation and delays the development of OA in CIOA mice. Further results demonstrate that FGS inhibits macrophage M1 polarization in vitro and in vivo, which subsequently decreases the secretion of IL-6 and TNF-α, in turn delaying cartilage and extracellular matrix (ECM) degradation and chondrocyte hypertrophy. FGS inhibits macrophage M1 polarization by partially downregulating miR-155 levels.ConclusionThis study demonstrates that intra-articular injection of FGS is a potential strategy for OA prevention and treatment, even at an early stage of disease progression. This is a novel function of FGS and has promising future clinical applications.
Are musculoskeletal conditions neglected in national health surveys?
Authors: Ferreira Giovanni E , Buchbinder Rachelle , Zadro Joshua R , O’Keeffe Mary , Kharel Priti , Carballo-Costa Lidia , Oliveira Juliana S , Maher Christopher G 
Published: January 2021

Abstract

Objective
To describe the proportion of national health surveys that contain questions on the prevalence and consequences of musculoskeletal conditions.

Methods
We used a comprehensive search strategy to obtain national health surveys from the 218 countries listed by the World Bank. Two authors independently extracted information from each national health survey. Outcomes were the proportion of surveys that contained questions on the prevalence of musculoskeletal conditions using the Global Burden of Disease categorization of RA, OA, low back pain, neck pain, gout and other and contained condition-specific questions about activity limitation, severity of pain and work absence. We also measured how frequently the prevalence of low back pain was measured using a consensus-based standard definition for low back pain prevalence studies.

Results
We identified national health surveys from 170 countries. Sixty-two (36.4%), the majority from high-income countries (n = 43), measured the prevalence of at least one musculoskeletal condition. OA [53 (85.4%)], low back pain [39 (62.9%)] and neck pain [37 (59.7%)] were most commonly measured, while RA and gout prevalence were only measured in 10 (5.9%) and 3 (1.8%) surveys, respectively. A minority of surveys assessed condition-specific activity limitations [6 (3.6%)], pain severity [5 (2.9%)] and work absence [1 (0.6%)]. Only one survey used the consensus-based standard definition for low back pain.

Conclusion
Musculoskeletal conditions are neglected in the majority of national health surveys. Monitoring musculoskeletal conditions through ongoing surveys is crucial for the development and evaluation of health policies to reduce their burden.
Delineating phenotypes of Kawasaki disease and SARS-CoV-2-related inflammatory multisystem syndrome: a French study and literature review
Authors: Cherqaoui Bilade , Koné-Paut Isabelle , Yager Hélène , Bourgeois Fleur Le , Piram Maryam 
Published: January 2021

AbstractObjectiveTo better define the clinical distinctions between the new severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)-related paediatric inflammatory multisystem syndrome (PIMS) and Kawasaki disease (KD).MethodsWe compared three groups of patients: group 1, cases from our national historic KD database (KD-HIS), before the SARS-CoV-2 pandemic; group 2, patients with KD admitted to an intensive care unit (KD-ICU) from both our original cohort and the literature, before the SARS-CoV-2 pandemic; and group 3, patients with PIMS from the literature.ResultsKD-HIS included 425 patients [male:female ratio 1.3, mean age 2.8 years (s.d. 2.4)], KD-ICU 176 patients [male:female ratio 1.3, mean age 3.5 years (s.d. 3.1)] and PIMS 404 patients [male:female ratio 1.4, mean age 8.8 years (s.d. 3.7)]. As compared with KD-HIS patients, KD-ICU and PIMS patients had a higher proportion of cardiac failure, digestive and neurological signs. KD-ICU and PIMS patients also had a lower frequency of typical KD-mucocutaneous signs, lower platelet count, higher CRP and lower sodium level. As compared with KD-HIS and KD-ICU patients, PIMS patients were older and more frequently had myocarditis; they also had fewer coronary abnormalities and lower sodium levels. Unresponsiveness to IVIG was more frequent in KD-ICU than KD-HIS and PIMS patients.ConclusionOn clinical grounds, KD-HIS, KD-ICU and PIMS might belong to a common spectrum of non-specific pathogen-triggered hyperinflammatory states. The causes of increasing inflammation severity within the three entities and the different effects on the heart remain to be determined.