bluuebunny/crossref_metadata_2025 huggingface dataset:
Multicomponent DHOST analysis in galaxy clusters
Authors: Laudato Enrico , Salzano Vincenzo , Umetsu Keiichi
Published: January 2022

Extended theories of gravity with additional scalar degrees of freedom have recently acquired increasing interest due to the presence of a screening mechanism that allows suppressing at small scales (e.g. the Solar system scale) every modification restoring general relativity (GR). In this work, we consider a second-order extended theory of gravity belonging to the family of degenerate high-order scalar-tensor theories (DHOST) characterized by a partial breaking of the Vainshtein screening mechanism. We study this model in two different scenarios as a description of dark energy (DE) only and as a description of both dark matter (DM) and DE. Such scenarios have been tested here by analysing a sample of 16 high-mass galaxy clusters targeted by the cluster lensing and supernova survey with Hubble program using two complementary probes, namely X-ray and strong- and weak-gravitational lensing observations. In mass modelling, we adopt a multicomponent approach including hot gas and galactic stellar contributions. For the majority of the clusters in our sample, results show mild Bayesian evidence in favour of the DHOST model as a description of DE over GR. This model also appears to alleviate the discrepancy present in GR between X-ray hydrostatic and lensing mass estimates. For the second scenario, where gravity acts as both DE and DM due to the partial breaking of the Vainshtein screening mechanism at cluster scales, the model is statistically disfavoured compared to GR.
Quenching of satellite galaxies of Milky Way analogues: reconciling theory and observations
Authors: Font Andreea S , McCarthy Ian G , Belokurov Vasily , Brown Shaun T , Stafford Sam G
Published: January 2022

The vast majority of low-mass satellite galaxies around the Milky Way and M31 appear virtually devoid of cool gas and show no signs of recent or ongoing star formation. Cosmological simulations demonstrate that such quenching is expected and is due to the harsh environmental conditions that satellites face when joining the Local Group (LG). However, recent observations of Milky Way analogues in the SAGA survey present a very different picture, showing the majority of observed satellites to be actively forming stars, calling into question the realism of current simulations and the typicality of the LG. Here, we use the ARTEMIS suite of high-resolution cosmological hydrodynamical simulations to carry out a careful comparison with observations of dwarf satellites in the LG, SAGA, and the Local Volume (LV) survey. We show that differences between SAGA and the LG and LV surveys, as well as between SAGA and the ARTEMIS simulations, can be strongly reduced by considering differences in the host mass distributions and (more importantly) observational selection effects, specifically that low-mass satellites which have only recently been accreted are more likely to be star forming, have a higher optical surface brightness, and are therefore more likely to be included in the SAGA survey. This picture is confirmed using data from the deeper LV survey, which shows pronounced quenching at low masses, in accordance with the predictions of ΛCDM-based simulations.
A forward-modelling method to infer the dark matter particle mass from strong gravitational lenses
Authors: He Qiuhan , Robertson Andrew , Nightingale James , Cole Shaun , Frenk Carlos S , Massey Richard , Amvrosiadis Aristeidis , Li Ran , Cao Xiaoyue , Etherington Amy
Published: January 2022

A fundamental prediction of the cold dark matter (CDM) model of structure formation is the existence of a vast population of dark matter haloes extending to subsolar masses. By contrast, other dark matter models, such as a warm thermal relic (WDM), predict a cutoff in the mass function at a mass which, for popular models, lies approximately between 107 and $10^{10}\, {\rm M}_\odot$. We use mock observations to demonstrate the viability of a forward modelling approach to extract information about low-mass dark haloes lying along the line of sight to galaxy–galaxy strong lenses. This can be used to constrain the mass of a thermal relic dark matter particle, mDM. With 50 strong lenses at Hubble Space Telescope resolution and a maximum pixel signal-to-noise ratio of ∼50, the expected median 2σ constraint for a CDM-like model (with a halo mass cutoff at $10^{7}\, {\rm M}_\odot$) is $m_\mathrm{DM} \gt 4.10 \, \mathrm{keV}$ (50 per cent chance of constraining mDM to be better than 4.10 keV). If, however, the dark matter is a warm particle of $m_\mathrm{DM}=2.2 \, \mathrm{keV}$, our ‘approximate Bayesian computation’ method would result in a median estimate of mDM between 1.43 and 3.21 keV. Our method can be extended to the large samples of strong lenses that will be observed by future telescopes and could potentially rule out the standard CDM model of cosmogony. To aid future survey design, we quantify how these constraints will depend on data quality (spatial resolution and integration time) as well as on the lensing geometry (source and lens redshifts).
Dwarf galaxy luminosity functions and cluster environments
Authors: Hashimoto Yasuhiro , Böhringer Hans , Umetsu Keiichi
Published: January 2022

We report an investigation of the luminosity function (LF) of dwarf galaxies (Mi < −15) inside 33 clusters at z ∼ 0.15–0.3, to address the crucial but unsettled problem of the faint-end slope (FS) in the cluster environments that may hold a key to the missing-satellite problem related to the standard cold dark matter formation scenario. By using a wide field imager mounted on the 8 m-class telescope, Subaru Suprime-Cam, and by selecting clusters in an optimal redshift range, we achieve a crucial balance between the depth and the spatial coverage of observation, that is essential for cluster dwarf studies. The deep and wide observations also provide us with image-by-image local background correction and tailor-made detection incompleteness correction on every cluster and background fields. These two essential but intertwined corrections were unfortunately often ignored in the previous studies. We find, when the accurate background and detection incompleteness corrections are made in a combined manner, that the faint end of the cluster LF shows a relatively flat slope (α ∼ −1.2 to −1.4), comparable to the field LF. We also find: (1) FS becomes steeper at larger cluster-centric distance. (2) Blue dwarf galaxies tend to show steeper FS. (3) Galaxy LFs show steeper slopes inside clusters with high X-ray luminosity although cluster-to-cluster variations are significant. Investigations of the FS are sensitive to various systematics, and variations among individual clusters that we need to address carefully. With a slope of −1.2 to −1.4, our study does not show the excess of dwarfs previously reported in some observational studies. Our findings may indicate the missing-satellite problem remains in galaxy clusters.
Distribution of the diffuse interstellar band λ6614 in the NGC 2264, Rosette Nebula, and S147 regions
Authors: Ma Wen-Jing , Chen Jian-Jun , Li Yin-Bi , Wu Ke-Fei , Zhang Wei , Chen Xiang-lei , Luo A-Li , Ren Juan-Juan , Wu Chao-Jian , Wu Hong
Published: January 2022

Diffuse interstellar bands (DIBs) are absorption features arising from the interstellar medium, for which the carriers remain unclear. In this work, a total of 3115 stars in the regions of NGC 2264, the Rosette Nebula, and S147 are selected from LAMOST-MRS to study the spatial and velocity distributions of the DIB λ6614 carrier. From the spatial distribution, we find that DIB λ6614 carrier clouds appear to be widely and inhomogeneously distributed in the three target regions. They are either closer or further in distance, or much wider than the three nebulae, and there are gaps within them. The radial velocities of the DIB λ6614 carrier clouds are on average about 13, 20, and 10 km s−1 slower than the radial velocities of the nebulae in the NGC 2264, Rosette Nebula, and S147 regions, respectively. Furthermore, there is probably a high-extinction region from 0.6 to 0.8 kpc in the NGC 2264 direction, where the DIB λ6614 carrier vanishes. In the S147 region, the DIB λ6614 cloud is possibly discontinuous, and the tomographic evidence suggests that there are two DIB λ6614 clouds. The first cloud is at 0.3–0.9 kpc, which is in or near the Local Arm, while the second one emerges at about 1.8 kpc from the Sun and may be associated with S147 and in the Perseus Arm.
Numerical dissipation strongly affects the equatorial jet speed in simulations of hot Jupiter atmospheres
Authors: Hammond Mark , Abbot Dorian S
Published: January 2022

Hot Jupiters are tidally locked gaseous exoplanets with atmospheric circulations dominated by a super-rotating equatorial jet. Their global circulation is often studied with simulations in 3D general circulation models (GCMs). Energy builds up at the smallest scales in these models and must be dissipated. Many models use ‘hyperdiffusion’ for this, which applies a tendency to the prognostic variables based on a high-order Laplacian operator. This removes the unrealistic and unstable build-up of energy at small scales, and ideally does not affect the large-scale circulation. In this study, we show that hyperdiffusion can in fact affect the large-scale circulation of simulations of hot Jupiters. These planets have large velocity gradients, so hyperdiffusion can produce a momentum tendency that may affect the largest scales. We analyse four simulations with different hyperdiffusion parameters in the GCM THOR. These show that hyperdiffusion can affect the atmospheric zonal momentum budget as strongly as the physical forcing. The hyperdiffusion slows down and spreads out the jet, reducing its speed by more than $50{{\ \rm per\ cent}}$ at some levels. We analyse simulations from the GCMs MITgcm and Exo-FMS and compare the effects of their different dissipation methods. The drag on the jet due to hyperdiffusion can be reduced by using a weaker hyperdiffusion coefficient, a higher resolution, or higher order diffusion. We aim to provide a basis for a study to investigate the ‘real’ momentum budget and jet speed of hot Jupiters. This study shows the need to examine long-held modelling assumptions when studying novel exoplanets.
Far-ultraviolet investigation into the galactic globular cluster M30 (NGC 7099): I. Photometry and radial distributions
Authors: Mansfield Santana , Dieball Andrea , Kroupa Pavel , Knigge Christian , Zurek David R , Shara Michael , Long Knox S
Published: January 2022

We present a far-ultraviolet (FUV) study of the globular cluster M30 (NGC 7099). The images were obtained using the Advanced Camera for Surveys (ACS/SBC, F150LP, FUV) and the Wide Field Planetary Camera 2 (WFPC2, F300W, UV) which were both onboard the Hubble Space Telescope. The FUV − UV colour–magnitude diagram (CMD) shows a main sequence (MS) turnoff at FUV ≈ 22 mag and $FUV-UV\, \approx 3$ mag. The MS extends 4 mag below the turnoff, and a prominent horizontal branch (HB) and blue straggler (BS) sequence can be seen. A total of 1218 MS stars, 185 red giant branch stars, 47 BS stars, and 41 HB stars are identified, along with 78 sources blueward of the MS which consist of white dwarfs (WDs) and objects in the gap between the WDs and the MS that include potential cataclysmic variable (CV) candidates. The radial distribution of the BS population is concentrated towards the cluster centre, indicating that mass segregation has occurred. The blue and red sub-populations of the double BS sequence appear mixed in the ultraviolet CMD, and no significant central concentration of CV candidates is seen in this cluster.
High-energy neutrinos from fast winds in novae
Authors: Bednarek W , Śmiałkowski A
Published: January 2022

We discuss a scenario in which TeV neutrinos are produced during explosions of novae. It is argued that hadrons are accelerated to very high energies in the inner part of a nova wind, as a result of reconnection of the strong magnetic field of a white dwarf. Hadrons are expected to interact efficiently with a dense matter of the wind, either already during the acceleration process or during their advection with the equatorial wind. We calculate the neutrino spectra and estimate the muon neutrino event rates in the IceCube telescope, in the case of a few novae. In general, those event rates are unlikely to be detected with the present neutrino detectors. However, for a favourable location of the observer, some neutrino events might be detected not only from the class of novae recently detected in the GeV γ-rays by the Fermi-LAT (Large Area Telescope), but also from novae not detected in γ-rays. The GeV γ-ray emission observed from novae cannot originate in terms of the model discussed here, since protons are accelerated within a few stellar radii of the white dwarf, i.e. in the region in which GeV γ-rays are expected to be severely absorbed in the interactions with the radiation field and the matter of the wind.
Exploring the GRB population: robust afterglow modelling
Authors: Aksulu M D , Wijers R A M J , van Eerten H J , van der Horst A J
Published: January 2022

Gamma-ray bursts (GRBs) are ultra-relativistic collimated outflows, which emit synchrotron radiation throughout the entire electromagnetic spectrum when they interact with their environment. This afterglow emission enables us to probe the dynamics of relativistic blast waves, the microphysics of shock acceleration, and environments of GRBs. We perform Bayesian inference on a sample of GRB afterglow data sets consisting of 22 long GRBs and 4 short GRBs, using the afterglow model scalefit, which is based on 2D relativistic hydrodynamic simulations. We make use of Gaussian processes to account for systematic deviations in the data sets, which allows us to obtain robust estimates for the model parameters. We present the inferred parameters for the sample of GRBs and make comparisons between short and long GRBs in constant-density and stellar-wind-like environments. We find that in almost all respects such as energy and opening angle, short, and long GRBs are statistically the same. Short GRBs however have a markedly lower prompt gamma-ray emission efficiency than long GRBs. We also find that for long GRBs in ISM (interstellar medium)-like ambient media there is a significant anticorrelation between the fraction of thermal energy in the magnetic fields, ϵB, and the beaming corrected kinetic energy. Furthermore, we find no evidence that the mass-loss rates of the progenitor stars are lower than those of typical Wolf–Rayet stars.
Viscous energy dissipation of kink waves due to phase mixing in twisted coronal flux tubes
Authors: Ebrahimi Zanyar , Soler Roberto
Published: January 2022

We have studied viscous energy damping of kink Magnetohydrodynamic (MHD) waves in weakly twisted magnetic flux tubes. The flux tube has been modelled as a homogeneous internal region with a straight magnetic field, surrounded by a radially non-uniform and magnetically twisted transitional layer embedded in a homogeneous ambient with a straight field. Using a modal expansion technique, we have solved an initial value problem for the incompressible viscous MHD equations and obtained spatio-temporal behaviour of the perturbations of the kink mode in linear regime. In the transitional layer, the perturbations are subject to phase mixing which enhances the viscous effects in the region. We show that magnetic twist can increase or decrease the efficiency of viscous damping of the phase-mixed perturbations in the non-uniform transitional layer. Using the temporal evolution of the total energy, we have obtained the viscous dissipation time as a power function of the Reynolds number. Our results show that magnetic twist could decrease or increase the viscous dissipation time.
Dust and the intrinsic spectral index of quasar variations: hints of finite stress at the innermost stable circular orbit
Authors: Weaver John R , Horne Keith
Published: January 2022

We present a study of 9 242 spectroscopically confirmed quasars with multiepoch ugriz photometry from the SDSS Southern Survey. By fitting a separable linear model to each quasar’s spectral variations, we decompose their five-band spectral energy distributions into variable (disc) and non-variable (host galaxy) components. In modelling the disc spectra, we include attenuation by dust on the line of sight through the host galaxy to its nucleus. We consider five commonly used attenuation laws, and find that the best description is by dust similar to that of the Small Magellanic Cloud, inferring a lack of carbonaceous grains from the relatively weak 2175-Å absorption feature. We go on to construct a composite spectrum for the quasar variations spanning 700–8000 Å. By varying the assumed power-law Lν ∝ να spectral slope, we find a best-fitting value α = 0.71 ± 0.02, excluding at high confidence the canonical Lν ∝ ν1/3 prediction for a steady-state accretion disc with a T ∝ r−3/4 temperature profile. The bluer spectral index of the observed quasar variations instead supports the model of Agol & Krolik, and Mummery & Balbus, in which a steeper temperature profile, T ∝ r−7/8, develops as a result of finite magnetically induced stress at the innermost stable circular orbit extracting energy and angular momentum from the black hole spin.
Pulsations of microwave emission from a solar flare in a twisted loop caused by intrinsic magnetohydrodynamic oscillations
Authors: Smith Christopher , Gordovskyy M , Browning P K
Published: January 2022

We present results revealing microwave pulsations produced in a model of a flaring twisted solar coronal loop, without any external oscillatory driver. Two types of oscillations are identified: slowly decaying oscillations with a period of about 70–75 s and amplitude of about 5–10 per cent seen in loops both with and without energetic electrons, and oscillations with a period of about 40 s and amplitude of a few tens of per cent observed only in loops with energetic electrons for about 100 s after the onset of fast energy release. We interpret the longer-period oscillations as the result of a standing kink mode modulating the average magnetic field strength in the loop, whilst the short-period intermittent oscillations associated with energetic electrons are likely to be produced by fast variations of the electric field, which produces energetic electrons in this scenario. The slowly decaying oscillations can explain the quasi-periodic pulsations often observed in the flaring corona.
Kaniadakis-holographic dark energy: observational constraints and global dynamics
Authors: Hernández-Almada A , Leon Genly , Magaña Juan , García-Aspeitia Miguel A , Motta V , Saridakis Emmanuel N , Yesmakhanova Kuralay
Published: January 2022

We investigate Kaniadakis-holographic dark energy by confronting it with observations. We perform a Markov Chain Monte Carlo analysis using cosmic chronometers, supernovae type Ia, and Baryon Acoustic Oscillations data. Concerning the Kaniadakis parameter, we find that it is constrained around zero, namely around the value in which Kaniadakis entropy recovers standard Bekenstein-Hawking one. Additionally, for the present matter density parameter $\Omega _m^{(0)}$, we obtain a value slightly smaller compared to ΛCDM scenario. Furthermore, we reconstruct the evolution of the Hubble, deceleration, and jerk parameters extracting the deceleration-acceleration transition redshift as $z_T = 0.86^{+0.21}_{-0.14}$. Finally, performing a detailed local and global dynamical system analysis, we find that the past attractor of the Universe is the matter-dominated solution, while the late-time stable solution is the dark-energy-dominated one.
Novel Classes and Evolutionary Turnover of Histone H2B Variants in the Mammalian Germline
Authors: Raman Pravrutha , Rominger Mary C , Young Janet M , Molaro Antoine , Tsukiyama Toshio , Malik Harmit S
Published: January 2022

Histones and their posttranslational modifications facilitate diverse chromatin functions in eukaryotes. Core histones (H2A, H2B, H3, and H4) package genomes after DNA replication. In contrast, variant histones promote specialized chromatin functions, including DNA repair, genome stability, and epigenetic inheritance. Previous studies have identified only a few H2B variants in animals; their roles and evolutionary origins remain largely unknown. Here, using phylogenomic analyses, we reveal the presence of five H2B variants broadly present in mammalian genomes. Three of these variants have been previously described: H2B.1, H2B.L (also called subH2B), and H2B.W. In addition, we identify and describe two new variants: H2B.K and H2B.N. Four of these variants originated in mammals, whereas H2B.K arose prior to the last common ancestor of bony vertebrates. We find that though H2B variants are subject to high gene turnover, most are broadly retained in mammals, including humans. Despite an overall signature of purifying selection, H2B variants evolve more rapidly than core H2B with considerable divergence in sequence and length. All five H2B variants are expressed in the germline. H2B.K and H2B.N are predominantly expressed in oocytes, an atypical expression site for mammalian histone variants. Our findings suggest that H2B variants likely encode potentially redundant but vital functions via unusual chromatin packaging or nonchromatin functions in mammalian germline cells. Our discovery of novel histone variants highlights the advantages of comprehensive phylogenomic analyses and provides unique opportunities to study how innovations in chromatin function evolve.
Deleterious Mutations Accumulate Faster in Allopolyploid Than Diploid Cotton (Gossypium) and Unequally between Subgenomes
Authors: Conover Justin L , Wendel Jonathan F
Published: January 2022

Whole-genome duplication (polyploidization) is among the most dramatic mutational processes in nature, so understanding how natural selection differs in polyploids relative to diploids is an important goal. Population genetics theory predicts that recessive deleterious mutations accumulate faster in allopolyploids than diploids due to the masking effect of redundant gene copies, but this prediction is hitherto unconfirmed. Here, we use the cotton genus (Gossypium), which contains seven allopolyploids derived from a single polyploidization event 1–2 Million years ago, to investigate deleterious mutation accumulation. We use two methods of identifying deleterious mutations at the nucleotide and amino acid level, along with whole-genome resequencing of 43 individuals spanning six allopolyploid species and their two diploid progenitors, to demonstrate that deleterious mutations accumulate faster in allopolyploids than in their diploid progenitors. We find that, unlike what would be expected under models of demographic changes alone, strongly deleterious mutations show the biggest difference between ploidy levels, and this effect diminishes for moderately and mildly deleterious mutations. We further show that the proportion of nonsynonymous mutations that are deleterious differs between the two coresident subgenomes in the allopolyploids, suggesting that homoeologous masking acts unequally between subgenomes. Our results provide a genome-wide perspective on classic notions of the significance of gene duplication that likely are broadly applicable to allopolyploids, with implications for our understanding of the evolutionary fate of deleterious mutations. Finally, we note that some measures of selection (e.g., dN/dS, πN/πS) may be biased when species of different ploidy levels are compared.
Allograft dysfunction after lung transplantation for COPA syndrome: A case report and literature review
Authors: Matsubayashi Tadashi , Yamamoto Masaki , Takayama Saki , Otsuki Yoshiro , Yamadori Ichiro , Honda Yoshitaka , Izawa Kazushi , Nishikomori Ryuta , Oto Takahiro
Published: January 2022

Coatomer subunit alpha (COPA) syndrome is an autoinflammatory disease with autoimmune and autoinflammatory manifestations affecting lungs, joints, and kidneys. COPA syndrome is caused by heterozygous loss-of-function mutations in COPA gene, encoding α subunit of coatmer protein complex I (COP-I) coated vesicles. Mutant COPA induces constitutive activation of stimulator of interferon genes, leading to systemic inflammation and elevated type I interferon response. We have previously reported a Japanese family of COPA syndrome with a novel V242G mutation. Two out of four patients required lung transplantation due to intractable interstitial lung disease and respiratory failure. Both of them deceased after lung transplantation, one due to sepsis and the other due to allograft dysfunction possibly caused by the reccurent interstitial lung disease. The literature review indentified unfavorable outcome of the solid organ transplant in COPA syndrome and its related disease, however, precise clinico-pathological description of these cases has been scarce. Here, we report in detail the clinical course of our cases to clarify the pathophysiology of allograft dysfunction in COPA syndrome and propose potential therapeutic approaches to improve post-transplant graft survival.
Sal-type ABC-F proteins: intrinsic and common mediators of pleuromutilin resistance by target protection in staphylococci
Authors: Mohamad Merianne , Nicholson David , Saha Chayan Kumar , Hauryliuk Vasili , Edwards Thomas A , Atkinson Gemma C , Ranson Neil A , O’Neill Alex J
Published: January 2022

The first member of the pleuromutilin (PLM) class suitable for systemic antibacterial chemotherapy in humans recently entered clinical use, underscoring the need to better understand mechanisms of PLM resistance in disease-causing bacterial genera. Of the proteins reported to mediate PLM resistance in staphylococci, the least-well studied to date is Sal(A), a putative ABC-F NTPase that—by analogy to other proteins of this type—may act to protect the ribosome from PLMs. Here, we establish the importance of Sal proteins as a common source of PLM resistance across multiple species of staphylococci. Sal(A) is revealed as but one member of a larger group of Sal-type ABC-F proteins that vary considerably in their ability to mediate resistance to PLMs and other antibiotics. We find that specific sal genes are intrinsic to particular staphylococcal species, and show that this gene family is likely ancestral to the genus Staphylococcus. Finally, we solve the cryo-EM structure of a representative Sal-type protein (Sal(B)) in complex with the staphylococcal 70S ribosome, revealing that Sal-type proteins bind into the E site to mediate target protection, likely by displacing PLMs and other antibiotics via an allosteric mechanism.
Epitranscriptomic regulation of HIV-1 full-length RNA packaging
Authors: Pereira-Montecinos Camila , Toro-Ascuy Daniela , Ananías-Sáez Catarina , Gaete-Argel Aracelly , Rojas-Fuentes Cecilia , Riquelme-Barrios Sebastián , Rojas-Araya Bárbara , García-de-Gracia Francisco , Aguilera-Cortés Paulina , Chnaiderman Jonás , Acevedo Mónica L , Valiente-Echeverría Fernando , Soto-Rifo Ricardo
Published: January 2022

During retroviral replication, the full-length RNA serves both as mRNA and genomic RNA. However, the mechanisms by which the HIV-1 Gag protein selects the two RNA molecules that will be packaged into nascent virions remain poorly understood. Here, we demonstrate that deposition of N6-methyladenosine (m6A) regulates full-length RNA packaging. While m6A deposition by METTL3/METTL14 onto the full-length RNA was associated with increased Gag synthesis and reduced packaging, FTO-mediated demethylation promoted the incorporation of the full-length RNA into viral particles. Interestingly, HIV-1 Gag associates with the RNA demethylase FTO in the nucleus and contributes to full-length RNA demethylation. We further identified two highly conserved adenosines within the 5′-UTR that have a crucial functional role in m6A methylation and packaging of the full-length RNA. Together, our data propose a novel epitranscriptomic mechanism allowing the selection of the HIV-1 full-length RNA molecules that will be used as viral genomes.
Survival of patients who opt for dialysis versus conservative care: a systematic review and meta-analysis
Authors: Voorend Carlijn G N , van Oevelen Mathijs , Verberne Wouter R , van den Wittenboer Iris D , Dekkers Olaf M , Dekker Friedo , Abrahams Alferso C , van Buren Marjolijn , Mooijaart Simon P , Bos Willem Jan W
Published: January 2022

Background

Non-dialytic conservative care (CC) has been proposed as a treatment option for patients with kidney failure. This systematic review and meta-analysis aims at comparing survival outcomes between dialysis and CC in studies where patients made an explicit treatment choice.

Methods

Five databases were systematically searched from origin through 25 February 2021 for studies comparing survival outcomes among patients choosing dialysis versus CC. Adjusted and unadjusted survival rates were extracted and meta-analysis performed where applicable. Risk of bias analysis was performed according to the Cochrane Risk Of Bias In Non-randomized Studies of Interventions.

Results

A total of 22 cohort studies were included covering 21 344 patients. Most studies were prone to selection bias and confounding. Patients opting for dialysis were generally younger and had fewer comorbid conditions, fewer functional impairments and less frailty than patients who chose CC. The unadjusted median survival from treatment decision or an estimated glomerular filtration rate <15 mL/min/1.73 m2 ranged from 20 and 67 months for dialysis and 6 and 31 months for CC. Meta-analysis of 12 studies that provided adjusted hazard ratios (HRs) for mortality showed a pooled adjusted HR of 0.47 (95% confidence interval 0.39–0.57) for patients choosing dialysis compared with CC. In subgroups of patients with older age or severe comorbidities, the reduction of mortality risk remained statistically significant, although analyses were unadjusted.

Conclusions

Patients opting for dialysis have an overall lower mortality risk compared with patients opting for CC. However, a high risk of bias and heterogeneous reporting preclude definitive conclusions and results cannot be translated to an individual level.
Highly stable Co-doped MnO2 nanoarrays as enhanced cathode materials for aqueous zinc-ion batteries
Authors: Yao Jia , Ji Jie , Wan Houzhao , Duan Jinxia , Wang Xunying , Lv Lin , Ma Guokun , Tao Li , Wang Hanbin , Zhang Jun , Wang Hao
Published: January 2022

Aqueous zinc-ion batteries (ZIBs) are a promising battery technology because of low costs and high safety. However, dissolution, self-aggregation and irreversible phase changes during charge and discharge of cathode materials may severely restrict the cycle stability of ZIBs. The main objective of this work was to prepare a more stable cathode material. For this purpose, we successfully prepared transition metal Co-doped MnO2 (Co-MnO2) using a simple one-step potentiostatic electrodeposition method. Co-MnO2 showed a high specific capacity of 237 mAh g−1 at 0.1 A g−1. Even at a high current density of 4 A g−1, the capacity retention was 87 mAh g−1. When returning back to 0.1 A g−1, the capacity retention rate exceeded 100%. Compared with long-cycle performance of the undoped MnO2, the electrochemical performance of the ion-doped electrodes with transition metal was significantly improved. The results indicate that transition metal doped electrode material (here Co-MnO2) can significantly improve the electrochemical performance and structural stability of the electrode material and improve the cycling performance. The results are relevant for the developing advanced cathodes for ZIBs.
Desiccation increases the hatching of resting eggs of a freshwater calanoid copepod
Authors: Brazil Thamires , Caetano Ana Clara L , Vargas Anderson L , Bozelli Reinaldo L , Santangelo Jayme M
Published: January 2022

Many former permanent aquatic habitats now face occasional desiccation due to human activities. Zooplankton might recover from droughts after the hatching of resting eggs, but how desiccation duration affects the viability and hatching patterns of resting eggs is unclear. This study evaluated how desiccation of varying durations (0, 3, 6 and 9 months) affects the hatchling numbers of the freshwater calanoid Notodiaptomus iheringi inhabiting a permanent lake. Hatchlings were observed across all desiccation treatments, and hatchling abundance was higher in longer desiccation treatments. Resting eggs of N. iheringi survive desiccation for up to 9 months even though the tested population originated from sediments of a permanent lake. Desiccation may stimulate hatching by terminating dormancy and by weakening (wet) sediment adversity. Knowledge of the hatching patterns of resting eggs of varying taxa after desiccation can help to understand how zooplankton communities recover after droughts.
The tomato OST1–VOZ1 module regulates drought-mediated flowering
Authors: Chong Leelyn , Xu Rui , Huang Pengcheng , Guo Pengcheng , Zhu Mingku , Du Hai , Sun Xiaoli , Ku Lixia , Zhu Jian-Kang , Zhu Yingfang
Published: January 2022

Flowering is a critical agricultural trait that substantially affects tomato fruit yield. Although drought stress influences flowering time, the molecular mechanism underlying drought-regulated flowering in tomato remains elusive. In this study, we demonstrated that loss of function of tomato OPEN STOMATA 1 (SlOST1), a protein kinase essential for abscisic acid (ABA) signaling and abiotic stress responses, lowers the tolerance of tomato plants to drought stress. slost1 mutants also exhibited a late flowering phenotype under both normal and drought stress conditions. We also established that SlOST1 directly interacts with and phosphorylates the NAC (NAM, ATAF and CUC)-type transcription factor VASCULAR PLANT ONE-ZINC FINGER 1 (SlVOZ1), at residue serine 67, thereby enhancing its stability and nuclear translocation in an ABA-dependent manner. Moreover, we uncovered several SlVOZ1 binding motifs from DNA affinity purification sequencing analyses and revealed that SlVOZ1 can directly bind to the promoter of the major flowering-integrator gene SINGLE FLOWER TRUSS to promote tomato flowering transition in response to drought. Collectively, our data uncover the essential role of the SlOST1–SlVOZ1 module in regulating flowering in response to drought stress in tomato and offer insights into a novel strategy to balance drought stress response and flowering.
Heinz-resistant tomato cultivars exhibit a lignin-based resistance to field dodder (Cuscuta campestris) parasitism
Authors: Jhu Min-Yao , Farhi Moran , Wang Li , Philbrook Richard N , Belcher Michael S , Nakayama Hokuto , Zumstein Kristina S , Rowland Sarah D , Ron Mily , Shih Patrick M , Sinha Neelima R
Published: January 2022

Cuscuta species (dodders) are agriculturally destructive, parasitic angiosperms. These parasitic plants use haustoria as physiological bridges to extract nutrients and water from hosts. Cuscuta campestris has a broad host range and wide geographical distribution. While some wild tomato relatives are resistant, cultivated tomatoes are generally susceptible to C. campestris infestations. However, some specific Heinz tomato (Solanum lycopersicum) hybrid cultivars exhibit resistance to dodders in the field, but their defense mechanism was previously unknown. Here, we discovered that the stem cortex in these resistant lines responds with local lignification upon C. campestris attachment, preventing parasite entry into the host. Lignin Induction Factor 1 (LIF1, an AP2-like transcription factor), SlMYB55, and Cuscuta R-gene for Lignin-based Resistance 1, a CC-NBS-LRR (CuRLR1) are identified as factors that confer host resistance by regulating lignification. SlWRKY16 is upregulated upon C. campestris infestation and potentially negatively regulates LIF1 function. Intriguingly, CuRLR1 may play a role in signaling or function as an intracellular receptor for receiving Cuscuta signals or effectors, thereby regulating lignification-based resistance. In summary, these four regulators control the lignin-based resistance response in specific Heinz tomato cultivars, preventing C. campestris from parasitizing resistant tomatoes. This discovery provides a foundation for investigating multilayer resistance against Cuscuta species and has potential for application in other essential crops attacked by parasitic plants.
Expanding the plant genome editing toolbox with recently developed CRISPR–Cas systems
Authors: Wada Naoki , Osakabe Keishi , Osakabe Yuriko
Published: January 2022

Since its first appearance, CRISPR–Cas9 has been developed extensively as a programmable genome-editing tool, opening a new era in plant genome engineering. However, CRISPR–Cas9 still has some drawbacks, such as limitations of the protospacer-adjacent motif (PAM) sequence, target specificity, and the large size of the cas9 gene. To combat invading bacterial phages and plasmid DNAs, bacteria and archaea have diverse and unexplored CRISPR–Cas systems, which have the potential to be developed as a useful genome editing tools. Recently, discovery and characterization of additional CRISPR–Cas systems have been reported. Among them, several CRISPR–Cas systems have been applied successfully to plant and human genome editing. For example, several groups have achieved genome editing using CRISPR–Cas type I-D and type I-E systems, which had never been applied for genome editing previously. In addition to higher specificity and recognition of different PAM sequences, recently developed CRISPR–Cas systems often provide unique characteristics that differ from well-known Cas proteins such as Cas9 and Cas12a. For example, type I CRISPR–Cas10 induces small indels and bi-directional long-range deletions ranging up to 7.2 kb in tomatoes (Solanum lycopersicum L.). Type IV CRISPR–Cas13 targets RNA, not double-strand DNA, enabling highly specific knockdown of target genes. In this article, we review the development of CRISPR–Cas systems, focusing especially on their application to plant genome engineering. Recent CRISPR–Cas tools are helping expand our plant genome engineering toolbox.
Hydraulic vulnerability segmentation in compound-leaved trees: Evidence from an embolism visualization technique
Authors: Song Jia , Trueba Santiago , Yin Xiao-Han , Cao Kun-Fang , Brodribb Timothy J , Hao Guang-You
Published: January 2022

The hydraulic vulnerability segmentation (HVS) hypothesis implies the existence of differences in embolism resistance between plant organs along the xylem pathway and has been suggested as an adaptation allowing the differential preservation of more resource-rich tissues during drought stress. Compound leaves in trees are considered a low-cost means of increasing leaf area and may thus be expected to show evidence of strong HVS, given the tendency of compound-leaved tree species to shed their leaf units during drought. However, the existence and role of HVS in compound-leaved tree species during drought remain uncertain. We used an optical visualization technique to estimate embolism occurrence in stems, petioles, and leaflets of shoots in two compound-leaved tree species, Manchurian ash (Fraxinus mandshurica) and Manchurian walnut (Juglans mandshurica). We found higher (less negative) water potentials corresponding to 50% loss of conductivity (P50) in leaflets and petioles than in stems in both species. Overall, we observed a consistent pattern of stem > petiole > leaflet in terms of xylem resistance to embolism and hydraulic safety margins (i.e. the difference between mid-day water potential and P50). The coordinated variation in embolism vulnerability between organs suggests that during drought conditions, trees benefit from early embolism and subsequent shedding of more expendable organs such as leaflets and petioles, as this provides a degree of protection to the integrity of the hydraulic system of the more carbon costly stems. Our results highlight the importance of HVS as an adaptive mechanism of compound-leaved trees to withstand drought stress.
Variations in documentation of atrial fibrillation predicted by population and service level characteristics in primary health care in England
Authors: Routen Ash , Abner Sophia , Levene Louis S , Gillies Clare L L , Davies Melanie , Seidu Samuel , André Ng G , Khunti Kamlesh
Published: January 2022

Background

Identifying features associated with atrial fibrillation (AF) documentation could inform screening. This study used published data to describe differences in documented and estimated AF prevalence in general practices, and explored predictors of variations in AF prevalence.

Methods

Cross-sectional study of 7318 general practices in England. Descriptive and inferential statistics were undertaken. Multiple linear regression was used to model the difference between estimated AF and documented AF, adjusted for population, practice and practice performance variables.

Results

Documented AF prevalence was lower than estimated (− 0.55% 95% confidence intervals, −1.89, 2.99). The proportion of variability accounted for in the final regression model was 0.25. Factors positively associated with AF documentation (increase in difference between estimated and documented), were patients 65–74 years, 75 years +, Black or South Asian ethnicity, diabetes mellitus and practices in East and Midlands of England. Eight variables (female patients, deprivation score, heart failure and peripheral artery disease, total patients per practice, full-time GPs and nurses; and location in South of England) were negatively associated with AF documentation (reduction in difference).

Conclusion

Variations in AF documentation were predicted by several practice and population characteristics. Screening could target these sources of variation to decrease variation and improve AF documentation.
Bone mineral density, osteopenia and osteoporosis among US adults with cancer
Authors: Huang J -F , Tan Q -C , Bai H , Wang J , Bergman M , Wu Z
Published: January 2022

Background

Bone mineral deficits are one of the most common complications in cancer survivors. However, there are no studies evaluating bone mineral density (BMD) and the prevalence of osteopenia and osteoporosis among patients with different types of cancers.

Aim

The objective was to assess BMD and evaluate the prevalence of osteopenia and osteoporosis among US adults with cancer.

Design

A cross-section propensity score matching study.

Methods

We extracted data from National Health and Nutrition Examination Survey database from 2005 to 2018. We compared BMD in participants with and without cancer which was further analyzed according to cancer type. We conducted logistic regression to evaluate adjusted odds ratios of osteopenia and osteoporosis and determine risk factors for their development.

Results

We found that BMD was significantly higher in participants without cancer than cancer patients. Furthermore, the median BMD of patients with breast cancer or skin cancer (including melanoma) was significantly lower than participants without cancer. People with breast, lung, genitourinary and skin cancers were more likely to incur osteopenia/osteoporosis than those without cancer.

Conclusions

BMD differs depending upon type in survivors. Individuals with a history of cancer have a poor understanding of osteoporosis and its risk factors. Understanding risk factors in patients with cancers identified in our study may be helpful for preventing osteoporosis and fractures and the development of screening guidelines.
Evaluating the Revised National Institutes of Health clinical trial definition impact on recruitment progress
Authors: Kane Eugene I , Daumit Gail L , Fain Kevin M , Scherer Roberta W , McGinty Emma Elizabeth
Published: January 2022

Background

The National Institutes of Health (NIH) announced a revised, expanded definition of ‘clinical trial’ in 2014 to improve trial identification and administrative compliance. Some stakeholders voiced concerns that the policy added administrative burden potentially slowing research progress.

Methods

This quasi-experimental study examined the difference-in-differences impact of the new NIH clinical trial definition policy on participant recruitment progress in grants funded by the National Institute of Mental Health (NIMH).

Results

One hundred thirty-two funded clinical trial grants were identified. While more grants were identified as clinical trials under the revised definition, the difference-in-differences in recruitment progress before and after the policy change was not statistically significant.

Conclusions

The revised NIH clinical trial definition had no clear effect on recruitment progress in newly identified NIMH-funded clinical trials as compared to traditionally identified clinical trials. Concerns that administrative delays and burden could impact study progress may be alleviated by these initial results.
A systematic review and meta-analysis of mycobacterial infections in patients with idiopathic inflammatory myopathies
Authors: Haldule Saloni , Chatterjee Moumita , Goswami Rudra Prosad , Vadsaria Innara , Gaur Prithvi , Kavadichanda Chengappa , Misra Durga Prasanna , Chinoy Hector , Agarwal Vikas , Aggarwal Rohit , Gupta Latika
Published: January 2022

Objectives

Infections including tuberculosis (TB) are a leading cause of morbidity and mortality in idiopathic inflammatory myopathies (IIM). We systematically reviewed the prevalence of mycobacterial infections in patients with IIM.

Methods

We screened PUBMED, EMBASE and SCOPUS databases and conference abstracts (2015–20) for original articles using Covidence. Pooled estimates of prevalence were calculated.

Results

Of 83 studies (28 cohort studies, two case control and 53 case reports), 19 were analysed. Of 14 043 IIM patients, DM (54.41%) was the most common subset among TB. Most studies were from Asia with high prevalence (5.86%, 2.33%–10.60%). Pooled prevalence of mycobacterial infections among IIM was 3.58% (95% CI: 2.17%, 5.85%, P < 0.01). Disseminated and extrapulmonary forms (46.58%; 95% CI: 39.02%, 54.31%, P = 1.00) were as common as pulmonary TB (49.07%; 95% CI: 41.43%, 56.75%, P =0.99) both for I2=0. Muscle involvement, an otherwise rare site, was frequently seen in case reports (24.14%). M. tuberculosis (28.84%) was the most common pathogen followed by Mycobacterium avium complex (3.25%). Non-tuberculous mycobacteria were less common overall (6.25; 95% CI: 3.49%, 10.93%) I2=0, P =0.94. Subgroup analysis and meta-regression based on high vs low TB regions found prevalence 6.61% (2.96%, 11.33%) in high TB regions vs 2.05% (0.90%, 3.56%) in low TB regions. While death due to TB was occasionally reported (P =0.82), successful anti-tubercular treatment was common (13.95%).

Conclusion

TB is common in IIM, particularly in endemic regions though current data is largely heterogeneous. Extra-pulmonary forms and atypical sites including the muscle are frequent. Limited data suggests fair outcomes, although larger prospective studies may offer better understanding.