bluuebunny/crossref_metadata_2025_split huggingface dataset:
Identification and characterization of a new sulfoacetaldehyde reductase from the human gut bacterium Bifidobacterium kashiwanohense
Authors: Zhou Yan , Wei Yifeng , Nanjaraj Urs Ankanahalli N. , Lin Lianyun , Xu Tong , Hu Yiling , Ang Ee Lui , Zhao Huimin , Yuchi Zhiguang , Zhang Yan 
Published: June 2019

Abstract
Hydroxyethylsulfonate (isethionate (Ise)) present in mammalian tissues is thought to be derived from aminoethylsulfonate (taurine), as a byproduct of taurine nitrogen assimilation by certain anaerobic bacteria inhabiting the taurine-rich mammalian gut. In previously studied pathways occurring in environmental bacteria, isethionate is generated by the enzyme sulfoacetaldehyde reductase IsfD, belonging to the short-chain dehydrogenase/reductase (SDR) family. An unrelated sulfoacetaldehyde reductase SarD, belonging to the metal-dependent alcohol dehydrogenase superfamily (M-ADH), was recently discovered in the human gut sulfite-reducing bacterium Bilophila wadsworthia (BwSarD). Here we report the structural and biochemical characterization of a sulfoacetaldehyde reductase from the human gut fermenting bacterium Bifidobacterium kashiwanohense (BkTauF). BkTauF belongs to the M-ADH family, but is distantly related to BwSarD (28% sequence identity). The crystal structures of BkTauF in the apo form and in a binary complex with NAD+ were determined at 1.9 and 3.0 Å resolution, respectively. Mutagenesis studies were carried out to investigate the involvement of active site residues in binding the sulfonate substrate. Our studies demonstrate the presence of sulfoacetaldehyde reductase in Bifidobacteria, with a possible role in isethionate production as a byproduct of taurine nitrogen assimilation.
Variability of young stellar objects in the star-forming region Pelican Nebula
Authors: Bhardwaj A. , Panwar N. , Herczeg G. J. , Chen W. P. , Singh H. P. 
Published: June 2019

Context. Pre-main-sequence variability characteristics can be used to probe the physical processes leading to the formation and initial evolution of both stars and planets.
Aims. The photometric variability of pre-main-sequence stars is studied at optical wavelengths to explore star–disk interactions, accretion, spots, and other physical mechanisms associated with young stellar objects.
Methods. We observed a field of 16′ × 16′ in the star-forming region Pelican Nebula (IC 5070) at BVRI wavelengths for 90 nights spread over one year in 2012−2013. More than 250 epochs in the VRI bands are used to identify and classify variables up to V ∼ 21 mag. Their physical association with the cluster IC 5070 is established based on the parallaxes and proper motions from the Gaia second data release (DR2). Multiwavelength photometric data are used to estimate physical parameters based on the isochrone fitting and spectral energy distributions.
Results. We present a catalog of optical time-series photometry with periods, mean magnitudes, and classifications for 95 variable stars including 67 pre-main-sequence variables towards star-forming region IC 5070. The pre-main-sequence variables are further classified as candidate classical T Tauri and weak-line T Tauri stars based on their light curve variations and the locations on the color-color and color-magnitude diagrams using optical and infrared data together with Gaia DR2 astrometry. Classical T Tauri stars display variability amplitudes up to three times the maximum fluctuation in disk-free weak-line T Tauri stars, which show strong periodic variations. Short-term variability is missed in our photometry within single nights. Several classical T Tauri stars display long-lasting (≥10 days) single or multiple fading and brightening events of up to two magnitudes at optical wavelengths. The typical mass and age of the pre-main-sequence variables from the isochrone fitting and spectral energy distributions are estimated to be ≤1 M⊙ and ∼2 Myr, respectively. We do not find any correlation between the optical amplitudes or periods with the physical parameters (mass and age) of pre-main-sequence stars.
Conclusions. The low-mass pre-main-sequence stars in the Pelican Nebula region display distinct variability and color trends and nearly 30% of the variables exhibit strong periodic signatures attributed to cold spot modulations. In the case of accretion bursts and extinction events, the average amplitudes are larger than one magnitude at optical wavelengths. These optical magnitude fluctuations are stable on a timescale of one year.
The complex chemistry of hot cores in Sgr B2(N): influence of cosmic-ray ionization and thermal history
Authors: Bonfand M. , Belloche A. , Garrod R. T. , Menten K. M. , Willis E. , Stéphan G. , Müller H. S. P. 
Published: June 2019

Context. As the number of complex organic molecules (COMs) detected in the interstellar medium increases, it becomes even more important to place meaningful constraints on the origins and formation pathways of such chemical species. The molecular cloud Sagittarius B2(N) is host to several hot molecular cores in the early stage of star formation, where a great variety of COMs are detected in the gas phase. Given its exposure to the extreme conditions of the Galactic center (GC) region, Sgr B2(N) is one of the best targets to study the impact of environmental conditions on the production of COMs.
Aims. Our main goal is to characterize the physico-chemical evolution of Sgr B2(N)’s sources in order to explain their chemical differences and constrain their environmental conditions.
Methods. The chemical composition of Sgr B2(N)’s hot cores, N2, N3, N4, and N5 is derived by modeling their 3 mm emission spectra extracted from the Exploring Molecular Complexity with ALMA (EMoCA) imaging spectral line survey performed with the Atacama Large Millimeter/submillimeter Array (ALMA). We derived the density distribution in the envelope of the sources based on the masses computed from the ALMA dust continuum emission maps. We used the radiative transfer code RADMC-3D to compute temperature profiles and inferred the current luminosity of the sources based on the COM rotational temperatures derived from population diagrams. We used published results of 3D radiation-magnetohydrodynamical (RMHD) simulations of high-mass star formation to estimate the time evolution of the source properties. We employed the astrochemical code MAGICKAL to compute time-dependent chemical abundances in the sources and to investigate how physical properties and environmental conditions influence the production of COMs.
Results. The analysis of the abundances of 11 COMs detected toward Sgr B2(N2-N5) reveals that N3 and N5 share a similar chemical composition while N2 differs significantly from the other sources. We estimate the current luminosities of N2, N3, N4, and N5 to be 2.6 × 105 L⊙, 4.5 × 104 L⊙, 3.9 × 105 L⊙, and 2.8 × 105 L⊙, respectively. We find that astrochemical models with a cosmic-ray ionization rate of 7 × 10−16 s−1 best reproduce the abundances with respect to methanol of ten COMs observed toward Sgr B2(N2-N5). We also show that COMs still form efficiently on dust grains with minimum dust temperatures in the prestellar phase as high as 15 K, but that minimum temperatures higher than 25 K are excluded.
Conclusions. The chemical evolution of Sgr B2(N2-N5) strongly depends on their physical history. A more realistic description of the hot cores’ physical evolution requires a more rigorous treatment with RMHD simulations tailored to each hot core.
Retour d’expérience sur la traitabilité d’une nitrosamine en production d’eau potable à l’échelle pilote
Authors: Helmer C. , Neveu A. , Hauchard V. , Hassanzadeh S. , Danel O. 
Published: June 2019

La présence de N-nitrosomorpholine (N-MOR) et de son précurseur, la morpholine (MOR), a été détectée en 2012 dans le forage d’Yport, l’une des principales ressources d’eau brute du Havre Seine Métropole. La valeur en N-MOR a ponctuellement dépassé le seuil de 100 ng/L recommandé pour l’eau distribuée par la direction générale de la santé. Dans ce contexte, la collectivité a sollicité une étude visant définir la filière de traitement cible adaptée à l’élimination de ces micropolluants émergents. Le souhait de la collectivité étant de privilégier des solutions de traitement retirant les micropolluants plutôt que celles les transformant, l’étude a évalué les performances des procédés d’adsorption sur charbon actif et d’osmose inverse basse pression (OIBP), séparément et en couplage. Deux types de charbon et trois types de membranes ont été testés. Les essais pilotes menés sur site ont montré que la mise en œuvre de charbon actif en poudre (CAP) au sein d’un réacteur spécifique permet une élimination acceptable de la N-MOR (60 % max) à condition de mettre en œuvre un taux de traitement élevé (› 25 g/m3) et un temps de contact limité (10 h max.) pour éviter les phénomènes de désorption. L’élimination de la MOR par le CAP est quant à elle très limitée (10 % max). Les essais pilotes sur membranes d’OIBP (seuil de coupure ‹ 200 Da) ont mis en avant une élimination élevée (environ 90 %) de la N-MOR et plus limitée de la MOR de 15 à 85 % selon les membranes testées. Transposer les résultats obtenus de l’échelle pilote à l’échelle industrielle est possible pour la filtration membranaire, mais plus difficile pour le réacteur CAP, du fait qu’il n’existe pas à ce jour de technologies adaptées aux conditions optimales définies (taux élevé, âge des boues de CAP faible).
X-linked Charcot–Marie–Tooth Disease Presenting with Stuttering Stroke-like Symptoms
Authors: Hardy Duriel I. , Licht Daniel J. , Vossough Arastoo , Kirschen Matthew P. 
Published: June 2019

AbstractX-linked Charcot–Marie–Tooth disease (CMTX1) is the second most common form of Charcot–Marie–Tooth disease (CMT). It is caused by a mutation in the gap junction β 1 (GJB1) gene, which encodes for connexin-32. In addition to the peripheral neuropathy and foot deformities observed in classic CMT, central nervous system symptoms and magnetic resonance imaging (MRI) signal abnormalities in the brain have been reported in patients with CMTX1. Here we describe two cases of adolescent males who presented with stuttering neurologic deficits that were initially suggestive of acute ischemic stroke and were ultimately diagnosed with genetically confirmed CMTX1. Both patients had evidence of T2 hyperintensity and decreased diffusion on MRI in the centrum semiovale, posterior corona radiata, posterior periventricular white matter, and corpus callosum. Though rare, these cases illustrate the importance of comprehensive neurologic history, physical examination, and appropriate diagnostic evaluation.
Operational range of a ferrofluid pocket bearing
Authors: Boots A S T , Spronck J W , van Ostayen R A J , Lampaert S G E 
Published: June 2019

Abstract
Ferrofluid pocket bearings are interesting for fast and precise positioning systems thank to the absence of stick-slip, the low viscous friction and their cost-effective nature. However, the characteristics of the bearing change due to over(de)compression since air escapes out of the enclosed pocket. This article presents an experimentally validated model that includes the air mass inside the pocket in the calculation of the equilibrium position of the ferrofluid bearing. Moreover, a simple and efficient way to obtain the operational range of the bearing is presented and a sensitivity analysis was performed. The sensitivity analysis showed that ferrofluid pocket bearings are always self-aligning and that the tilt stiffness increases when the fly height decreases or the tilt angle increases.
Doping dependence of the pinning efficiency in K-doped Ba122 single crystals prior to and after fast neutron irradiation
Authors: Kagerbauer D , Ishida S , Mishev V , Song D , Ogino H , Eisaki H , Nakajima M , Iyo A , Eisterer M 
Published: June 2019

Abstract
A sharp peak was observed in the doping dependence of the critical current density, J
c, in potassium doped Ba122 single crystals. This behavior is in contrast to the doping dependence of the transition temperature, T
c, which varies much more smoothly around its maximum. We performed fast neutron irradiation on the crystals in order to find out whether the J
c peak results from intrinsic properties or the particular defect landscape. Fast neutrons are known to introduce defects up to a size of a few nanometers, which have proven to be more efficient for flux pinning than the crystallographic defects in the pristine crystals. We find that the peak in J
c shifts to higher doping levels after the irradiation, broadens, and roughly follows the shape of the T
c curve. Moreover, a power law between J
c and T
c is observed in the irradiated crystals, which can be explained by relations between fundamental parameters and T
c observed previously in iron-based superconductors. This power law does not hold for the pristine crystals which indicates that the doping dependence of J
c results from an enhanced pinning efficiency in the under-doped area of the phase diagram.
Quantum gradient descent and Newton’s method for constrained polynomial optimization
Authors: Rebentrost Patrick , Schuld Maria , Wossnig Leonard , Petruccione Francesco , Lloyd Seth 
Published: June 2019

Abstract
Optimization problems in disciplines such as machine learning are commonly solved with iterative methods. Gradient descent algorithms find local minima by moving along the direction of steepest descent while Newton’s method takes into account curvature information and thereby often improves convergence. Here, we develop quantum versions of these iterative optimization algorithms and apply them to polynomial optimization with a unit norm constraint. In each step, multiple copies of the current candidate are used to improve the candidate using quantum phase estimation, an adapted quantum state exponentiation scheme, as well as quantum matrix multiplications and inversions. The required operations perform polylogarithmically in the dimension of the solution vector and exponentially in the number of iterations. Therefore, the quantum algorithm can be useful for high-dimensional problems where a small number of iterations is sufficient.
Optimal control for feedback cooling in cavityless levitated optomechanics
Authors: Ferialdi Luca , Setter Ashley , Toroš Marko , Timberlake Chris , Ulbricht Hendrik 
Published: June 2019

Abstract
We consider feedback cooling in a cavityless levitated optomechanics setup, and we investigate the possibility to improve the feedback implementation. We apply optimal control theory to derive the optimal feedback signal both for quadratic (parametric) and linear (electric) feedback. We numerically compare optimal feedback against the typical feedback implementation used for experiments. In order to do so, we implement a state estimation scheme that takes into account the modulation of the laser intensity. We show that such an implementation allows us to increase the feedback strength, leading to faster cooling rates and lower center-of-mass temperatures.
Magnetic phase diagram of the quantum spin chain compound SrCo2V2O8: a single-crystal neutron diffraction study
Authors: Shen L , Zaharko O , Birk J O , Jellyman E , He Z , Blackburn E 
Published: June 2019

Abstract
We explore magnetic order in the quantum spin chain compound SrCo2V2O8 up to 14.9 T and down to 50 mK, using single-crystal neutron diffraction. Upon cooling in zero-field, commensurate antiferromagnetic (C-AFM) order with modulation vector

k

C

= (0, 0, 1) develops below T
N ≃ 5.0 K. Applying an external magnetic field (H∥c axis) destabilizes this C-AFM order, leading to an order-disorder transition between T
N and ∼1.5 K. Below 1.5 K, a commensurate to incommensurate (IC-AFM) transition occurs at 3.9 T, above which the magnetic reflections can be indexed by

k

IC

= (0, 0, 1 ± δl). The incommensurability δl scales monotonically with H until the IC-AFM order disappears around 7.0 T. Magnetic reflections modulated by

k

C

emerge again at higher fields. While the characters of the C-AFM, IC-AFM and the emergent AFM order in SrCo2V2O8 appear to fit the descriptions of the Néel, longitudinal spin density wave and transverse AFM order observed in the related compound BaCo2V2O8, our results also reveal several unique signatures that are not present in the latter, highlighting the inadequacy of mean-field theory in addressing the complex magnetic order in systems of this class.
Efficient swap algorithms for molecular dynamics simulations of equilibrium supercooled liquids
Authors: Berthier Ludovic , Flenner Elijah , Fullerton Christopher J , Scalliet Camille , Singh Murari 
Published: June 2019

Abstract
It was recently demonstrated that a simple Monte Carlo (MC) algorithm involving the swap of particle pairs dramatically accelerates the equilibrium sampling of simulated supercooled liquids. We propose two numerical schemes integrating the efficiency of particle swaps into equilibrium molecular dynamics (MD) simulations. We first develop a hybrid MD/MC scheme combining molecular dynamics with the original swap Monte Carlo. We implement this hybrid method in LAMMPS, a software package employed by a large community of users. Secondly, we define a continuous time version of the swap algorithm where both the positions and diameters of the particles evolve via Hamilton’s equations of motion. For both algorithms, we discuss in detail various technical issues as well as the optimisation of simulation parameters. We compare the numerical efficiency of all available swap algorithms and discuss their relative merits.
Freshwater requirements of large-scale bioenergy plantations for limiting global warming to 1.5 °C
Authors: Stenzel Fabian , Gerten Dieter , Werner Constanze , Jägermeyr Jonas 
Published: June 2019

Abstract
Limiting mean global warming to well below 2 °C will probably require substantial negative emissions (NEs) within the 21st century. To achieve these, bioenergy plantations with subsequent carbon capture and storage (BECCS) may have to be implemented at a large scale. Irrigation of these plantations might be necessary to increase the yield, which is likely to put further pressure on already stressed freshwater systems. Conversely, the potential of bioenergy plantations (BPs) dedicated to achieving NEs through CO2 assimilation may be limited in regions with low freshwater availability. This paper provides a first-order quantification of the biophysical potentials of BECCS as a negative emission technology contribution to reaching the 1.5 °C warming target, as constrained by associated water availabilities and requirements. Using a global biosphere model, we analyze the availability of freshwater for irrigation of BPs designed to meet the projected NEs to fulfill the 1.5 °C target, spatially explicitly on areas not reserved for ecosystem conservation or agriculture. We take account of the simultaneous water demands for agriculture, industries, and households and also account for environmental flow requirements (EFRs) needed to safeguard aquatic ecosystems. Furthermore, we assess to what extent different forms of improved water management on the suggested BPs and on cropland may help to reduce the freshwater abstractions. Results indicate that global water withdrawals for irrigation of BPs range between ∼400 and ∼3000 km3 yr−1, depending on the scenario and the conversion efficiency of the carbon capture and storage process. Consideration of EFRs reduces the NE potential significantly, but can partly be compensated for by improved on-field water management.
The importance of municipal and agricultural demands in future water shortages in the United States
Authors: Warziniack Travis , Brown Thomas C 
Published: June 2019

Abstract
We examine how future changes in water yield and demand will affect the likelihood of water shortages and the efficacy of some of the most common methods for dealing with water shortages and meeting municipal demands, including improvements in water use efficiency and transfers of water between sectors of the economy. We find that more than 45.8 million people, primarily in the Southwest, central Great Plains, and southern California, would already be experiencing regular water shortages in the absence of groundwater mining. By 2060, that number would grow to over 136.2 million people. Among the reasons we find for increased likelihood of water shortages, reduced water yield is the most prevalent, affecting 80% of water basins in the US In the American West, nearly half of the water basins are projected to see an increase in shortages. We estimate future water withdrawals in the industrial and commercial and thermoelectric sectors will remain fairly steady, but withdrawals in the domestic and public sector are expected to rise. The Colorado River and Rio Grande regions see the largest percentage increases in projected domestic and public water use as well as the greatest percentage decreases in projected water yield. To cover new municipal demands, transfers from agriculture may be needed, in which case, significant impacts to agriculture will occur in northern New Mexico, parts of Utah, Nevada, and Washington where municipal demands are projected to grow to 25%–50% of agricultural water use. The situation is more extreme in northern Arizona and eastern Texas, where additional municipal demands are projected to be six times the amount used by agriculture.
The makings of higher-order polyploids. A commentary on: ‘The story of promiscuous crucifers: origin and genome evolution of an invasive species, Cardamine occulta (Brassicaceae), and its relatives’
Authors: Chester Michael 
Published: June 2019

This article comments on:Terezie Mandáková, Judita Zozomová-Lihová, Hiroshi Kudoh, Yunpeng Zhao, Martin A. Lysak, and Karol Marhold. 2019. The story of promiscuous crucifers: origin and genome evolution of an invasive species, Cardamine occulta (Brassicaceae), and its relatives. Annals of Botany 124(2): 209–220.