bluuebunny/crossref_metadata_2025_split huggingface dataset:
Cooperative Metabolism in a Three-Partner Insect-Bacterial Symbiosis Revealed by Metabolic Modeling
Authors: Ankrah Nana Y. D. , Luan Junbo , Douglas Angela E. 
Published: March 2017

ABSTRACTAn important factor determining the impact of microbial symbionts on their animal hosts is the balance between the cost of nutrients consumed by the symbionts and the benefit of nutrients released back to the host, but the quantitative significance of nutrient exchange in symbioses involving multiple microbial partners has rarely been addressed. In this study on the association between two intracellular bacterial symbionts, “CandidatusPortiera aleyrodidarum” and “CandidatusHamiltonella defensa,” and their animal host, the whiteflyBemisia tabaci, we apply metabolic modeling to investigate host-symbiont nutrient exchange. Ourin silicoanalysis revealed that >60% of the essential amino acids and related metabolites synthesized by “CandidatusPortiera aleyrodidarum” are utilized by the host, including a substantial contribution of nitrogen recycled from host nitrogenous waste, and that these interactions are required for host growth. In contrast, “CandidatusHamiltonella defensa” retains most or all of the essential amino acids and B vitamins that it is capable of synthesizing. Furthermore, “CandidatusHamiltonella defensa” suppresses host growthin silicoby competition with “CandidatusPortiera aleyrodidarum” for multiple host nutrients, by suppressing “CandidatusPortiera aleyrodidarum” growth and metabolic function, and also by consumption of host nutrients that would otherwise be allocated to host growth. The interpretation from these modeling outputs that “CandidatusHamiltonella defensa” is a nutritional parasite could not be inferred reliably from gene content alone but requires consideration of constraints imposed by the structure of the metabolic network. Furthermore, these quantitative models offer precise predictions for future experimental study and the opportunity to compare the functional organization of metabolic networks in different symbioses.IMPORTANCEThe metabolic functions of unculturable intracellular bacteria with much reduced genomes are traditionally inferred from gene content without consideration of how the structure of the metabolic network may influence flux through metabolic reactions. The three-compartment model of metabolic flux between two bacterial symbionts and their insect host constructed in this study revealed that one symbiont is structured to overproduce essential amino acids for the benefit of the host, but the essential amino acid production in the second symbiont is quantitatively constrained by the structure of its network, rendering it “selfish” with respect to these nutrients. This study demonstrates the importance of quantitative flux data for elucidation of the metabolic function of symbionts. Thein silicomethodology can be applied to other symbioses with intracellular bacteria.
Vibrio cholerae VciB Mediates Iron Reduction
Authors: Peng Eric D. , Payne Shelley M. 
Published: March 2017

ABSTRACT

Vibrio cholerae
is the causative agent of the severe diarrheal disease cholera.
V. cholerae
thrives within the human host, where it replicates to high numbers, but it also persists within the aquatic environments of ocean and brackish water. To survive within these nutritionally diverse environments,
V. cholerae
must encode the necessary tools to acquire the essential nutrient iron in all forms it may encounter. A prior study of systems involved in iron transport in
V. cholerae
revealed the existence of
vciB
, which, while unable to directly transport iron, stimulates the transport of iron through ferrous (Fe
2+
) iron transport systems. We demonstrate here a role for VciB in
V. cholerae
in which VciB stimulates the reduction of Fe
3+
to Fe
2+
, which can be subsequently transported into the cell with the ferrous iron transporter Feo. Iron reduction is independent of functional iron transport but is associated with the electron transport chain. Comparative analysis of VciB orthologs suggests a similar role for other proteins in the VciB family. Our data indicate that VciB is a dimer located in the inner membrane with three transmembrane segments and a large periplasmic loop. Directed mutagenesis of the protein reveals two highly conserved histidine residues required for function. Taken together, our results support a model whereby VciB reduces ferric iron using energy from the electron transport chain.

IMPORTANCE
Vibrio cholerae
is a prolific human pathogen and environmental organism. The acquisition of essential nutrients such as iron is critical for replication, and
V. cholerae
encodes a number of mechanisms to use iron from diverse environments. Here, we describe the
V. cholerae
protein VciB that increases the reduction of oxidized ferric iron (Fe
3+
) to the ferrous form (Fe
2+
), thus promoting iron acquisition through ferrous iron transporters. Analysis of VciB orthologs in
Burkholderia
and
Aeromonas
spp. suggest that they have a similar activity, allowing a functional assignment for this previously uncharacterized protein family. This study builds upon our understanding of proteins known to mediate iron reduction in bacteria.
Improving Outpatient Clinic Experience for Core Medical Trainees
Authors: King Natalie , Zhu Catherine 
Published: March 2017

Outpatient clinic experience is an important component of core medical training. Trainees are expected to attend up to 40 clinics, with a minimum requirement of 24, over the two-year programme. 1 Yet on a local and national level they have reported difficulties with attending even the minimum number of clinics, largely due to ward commitments and service demands. 5 A survey of local core medical trainees revealed a baseline mean clinic attendance of 0.5 clinics per month, with only 13% of trainees having attended the minimum number of clinics. The project aimed to increase the mean clinic attendance to one clinic per month, which would enable trainees to meet their curriculum requirements.Clinic attendance data was collected from core medical trainees at two-monthly intervals, to coincide with rotation changeover. The problem was initially discussed at our local medical faculty meeting and interventions were proposed. Firstly, an up to date clinic timetable was distributed and consultants encouraged to invite their trainees to clinic. Subsequently a clinic booking system was implemented, to enable trainees to arrange protected time in which to attend outpatient clinics. This intervention was unsuccessful in improving clinic attendance. A revised system of pre-allocating protected clinic time was therefore devised and implemented, which resulted in an increase in clinic attendance figures to above the target. Trainees have been allocated clinic days for the rest of the year, which should enable them to meet their curriculum requirements.Through the use of PDSA cycles, we were able to rapidly determine the effect of our interventions and make improvements that have led to an increase in trainee clinic attendance. This is a sustainable model that could be easily implemented by other hospital trusts for core medical trainees.
Reproductive Patterns Among Childhood and Adolescent Cancer Survivors in Sweden: A Population-Based Matched-Cohort Study
Authors: Armuand Gabriela , Skoog-Svanberg Agneta , Bladh Marie , Sydsjö Gunilla 
Published: March 2017

Purpose To compare the probability of a first live birth, age at time of birth, and time between diagnosis/referent date and birth between childhood and adolescent cancer survivors and an age-matched comparison group. Materials and Methods A total of 1,206 survivors was included in the study, together with 2,412 age-matched individuals from the general population. A Cox proportional hazards model was used to investigate first live birth after diagnosis/referent date. Data were stratified by sex, age at diagnosis, and diagnostic era (ie, diagnosis before 1988 v in 1988 or later). Results Overall, the probability of having a first live birth (hazard ratio [HR]) was significantly lower; men had lower HRs than women (HR, 0.65 v 0.79). There were no significant differences in the probability of having a first live birth among women diagnosed during adolescence (HR, 0.89), but the HR was lower among women with childhood cancers (HR, 0.47). Among male survivors, the situation was the opposite; men diagnosed during adolescence had lower HRs than survivors of childhood cancer (HR, 0.56 v 0.70). Examination of the data from the two diagnostic eras (before 1988 and 1988 or later) shows that the HR increased among female survivors after 1988 (HR, 0.71 v 0.90) and decreased among male survivors (HR, 0.72 v 0.59). A shorter time had elapsed between diagnosis/referent date and the birth of a first child among both male and female survivors compared with controls. In addition, female survivors were younger at time of birth. Conclusion The study demonstrates reduced probability of having a first live birth among cancer survivors diagnosed during childhood or adolescence; men were particularly vulnerable.
Intra-articular implantation of collagen scaffold carriers is safe in both native and arthrofibrotic rabbit knee joints
Authors: Walker J. A. , Ewald T. J. , Lewallen E. , Van Wijnen A. , Hanssen A. D. , Morrey B. F. , Morrey M. E. , Abdel M. P. , Sanchez-Sotelo J. 
Published: March 2017

Objectives Sustained intra-articular delivery of pharmacological agents is an attractive modality but requires use of a safe carrier that would not induce cartilage damage or fibrosis. Collagen scaffolds are widely available and could be used intra-articularly, but no investigation has looked at the safety of collagen scaffolds within synovial joints. The aim of this study was to determine the safety of collagen scaffold implantation in a validated in vivo animal model of knee arthrofibrosis. Materials and Methods A total of 96 rabbits were randomly and equally assigned to four different groups: arthrotomy alone; arthrotomy and collagen scaffold placement; contracture surgery; and contracture surgery and collagen scaffold placement. Animals were killed in equal numbers at 72 hours, two weeks, eight weeks, and 24 weeks. Joint contracture was measured, and cartilage and synovial samples underwent histological analysis. Results Animals that underwent arthrotomy had equivalent joint contractures regardless of scaffold implantation (-13.9° versus -10.9°, equivalence limit 15°). Animals that underwent surgery to induce contracture did not demonstrate equivalent joint contractures with (41.8°) or without (53.9°) collagen scaffold implantation. Chondral damage occurred in similar rates with (11 of 48) and without (nine of 48) scaffold implantation. No significant difference in synovitis was noted between groups. Absorption of the collagen scaffold occurred within eight weeks in all animals Conclusion Our data suggest that intra-articular implantation of a collagen sponge does not induce synovitis or cartilage damage. Implantation in a native joint does not seem to induce contracture. Implantation of the collagen sponge in a rabbit knee model of contracture may decrease the severity of the contracture. Cite this article: J. A. Walker, T. J. Ewald, E. Lewallen, A. Van Wijnen, A. D. Hanssen, B. F. Morrey, M. E. Morrey, M. P. Abdel, J. Sanchez-Sotelo. Intra-articular implantation of collagen scaffold carriers is safe in both native and arthrofibrotic rabbit knee joints. Bone Joint Res 2016;6:162–171. DOI: 10.1302/2046-3758.63.BJR-2016-0193.
Tax Avoidance through Controlled Foreign Companies under European Union Law with Specific Reference to Poland
Authors: Kuźniacki Błażej 
Published: March 2017

AbstractThis article demonstrates that tax avoidance via controlled foreign companies (CFCs) established in the most favourable tax environments among EU Member States such as Ireland, Luxembourg, the Netherlands, and Cyprus, remains a considerable problem. Not only does it affect taxpaying residents in the Member States but, indirectly, all taxpayers regardless of their EU affiliation, US multinational enterprises (MNEs), for example. Focusing on the use Polish taxpayers make of CFCs, this study undertakes a detailed legal analysis of the problem of tax avoidance under EU law by examining empirical data and EU law on tax avoidance. The choice of this topic is largely justified by the exponential rise in tax avoidance schemes through CFCs involving Polish taxpayers since the country’s accession to the EU. The legal analysis brings to light a series of weaknesses in the current EU law that make it possible for both EU and non-EU taxpayers to avoid taxation. As a solution to this problem, the author suggests that CFC rules should be designed so as to tax only “tax avoidance income” from CFCs. This would ensure their compliance with EU law as well as an effective prevention of tax avoidance via CFCs within the framework of EU law. Interestingly, the solution follows from the author’s interpretation of the concept of “wholly artificial arrangements” in favour of the internal market rather than from Action 3 of Base Erosion and Profit Shifting (BEPS) project or Anti-Tax Avoidance Directive as adopted by the Council on 12 July 2016.
On the Optical Spectrum of 89 Her
Authors: Kipper Tõnu 
Published: March 2017

AbstractThe high resolution spectra of a post-AGB candidate, binary system 89 Her, were analysed for the chemical composition. The star was found to be metal deficient with [Fe/H] = -0.50±0.20. No enhancement of s-process elements was found. The refractory elements are depleted but this is not the reason of metal deficiency. More than 320 narrow and weak emission lines from low levels of neutral metals were identified. Radial velocities of these lines coincide with the systemic velocity. We propose that the circum-binary dusty disk is observed face-on.
Star Classification Possibilities with the Gaia Spectrophotometers. III. The Classification Accuracy with Decontaminated BP/RP Spectra
Authors: Straižys V. , Lazauskaitė R. 
Published: March 2017

Abstract
A medium-band 12-color photometric system, based on the decontaminated Gaia BP/RP spectra, has been proposed in our Paper II. Here we analyze a possibility to apply some versions of this system for the determination of temperatures and gravities of stars both in the absence and the presence of interstellar reddening. The possibility to supplement this system with the broad BP and RP passbands is verified. We conclude that the system gives an acceptable accuracy of temperatures and luminosities if the accuracy of color indices is 0.02 mag or better and if the parallaxes of stars are known.
Galaxy Superclusters Detected in the Modified PF-Catalog Using the FOF Method
Authors: Panko E. 
Published: March 2017

Abstract
The Modified Catalog of Galaxy Clusters and Groups (Panko & Flin 2006, PF), covering an area of 5000 square degrees in the southern sky, was used as the input for the search of galaxy superclusters. Only the estimated redshifts could be used, since the PF catalog is a 2D catalog, with the calibration correlating the redshift of galaxy clusters with the magnitude of the tenth brightest cluster galaxy. Only galaxy clusters containing more than 50 galaxies were considered, and the FoF method was applied. The nearest neighbour distances for 1711 input clusters were calculated and analyzed, and 20 isolated clusters were found with the nearest neighbour at a distance greater than 68 h-1Mpc. A distance of 24 h-1 Mpc between clusters was selected for the supercluster search, and 49 superclusters containing from 4 to 9 galaxy clusters were detected. Calculations for each supercluster include: its inferred center, RA, Dec, zest, the maximum distance between supercluster members and the estimated supercluster shapes. A typical size of superclusters identified here is about 55 h-1 Mpc, and they appear mainly as elongated pancakes, with a weak correlation between the axes c/a and b/a, without a strong dependence on multiplicity.
A New Dynamical Parameter for the Study of Sticky Orbits in a 3D Galactic Model
Authors: Zotos Euaggelos E. 
Published: March 2017

AbstractA 3D dynamical model is used to study the motion in the central parts of an elliptical galaxy, hosting a massive and dense nucleus. Our aim is to investigate the regular or chaotic character of the motion, with emphasis in the different chaotic components, as well as the sticky regions of the dynamical system. In order to define the character of the motion in the 2D system, we use the classical method of the Poincaré x − p
Accretion Disk Structure and Kinematics of the Broad Line Regions in Selected AGN
Authors: Kollatschny W. , Zetzl M. 
Published: March 2017

AbstractBroad emission line regions in AGN are connected with the outer layers of accretion disks. This has been shown by means of line variability studies of individual AGN as well as line profile studies of AGN samples. We could model the broad-line profiles in AGN in a simple way only through rotational broadening of Lorentzian profiles. To individual emission lines belongs one typical Lorentz profile only with a fixed turbulence velocity: e.g., 500 km/s for Hβ, 3000 km/s for CIV λ1550. The rotation velocities in the broad line regions of the AGN range from 1000 to 7000 km/s.
The Case for Two Quasar Populations
Authors: Sulentic Jack , Marziani Paola , Zamfir Sebastian 
Published: March 2017

AbstractWe present evidence for two populations of quasars showing distinctly different broad line structure and kinematics. The first evidence for quasar dichotomy involve differences between radio-quiet and radio-loud sources. We proposed an alternate population A-B dichotomy based on optical, UV and X-ray spectroscopic properties. One of these populations (Pop. A: FWHM Hβ <4000 kms
Observations of the Galaxy NGC 3077 in the Narrow-Band [S II] and Hα Filters
Authors: Andjelić M. , Stavrev K. , Arbutina B. , Ilić D. , Urošević D. 
Published: March 2017

AbstractWe present observations of the H I tidal arm near a dwarf galaxy NGC 3077 (member of the M81 galaxy group) in the narrow-band [S II] and Hα filters. Observations were carried out in 2011 March with the 2 m RCC telescope at the NAO Rozhen, Bulgaria. Our search for possible supernova remnant candidates (identified as sources with enhanced [S II] emission relative to their Hα emission) in this region yielded no sources of this kind. Nevertheless, we found a number of objects with significant Hα emission that probably represent uncatalogued, low brightness H II regions.
Stochastic Processes Applied to Line Shapes
Authors: Stamm R. , Boland D. , Hammami R. , Capes H. , Catoire F. , Koubiti M. , Mekkaoui A. , Marandet Y. , Rosato J. , Godbert-Mouret L. , Christova M. 
Published: March 2017

Abstract
We present approaches using stochastic processes for the calculation of line broadening in plasmas. The derivation of model microfield methods (MMM) based on analytic formulations is recalled, as well as an approach using a simulation of the stochastic process. We discuss the possibility of an improvement of the stochastic process by comparing our first results to ab initio particle simulations coupled to a numerical integration of the emitters Schrödinger equation.
The Influence of Chemi-Ionization and Recombination Processes on Spectral Line Shapes in Stellar Atmospheres
Authors: Mihajlov Anatolij A. , Ignjatović Ljubinko M. , Srécković Vladimir A. , Dimitrijević Milan S. 
Published: March 2017

Abstract
The chemi-ionization processes in atom - Rydberg atom collisions, as well as the corresponding chemi-recombination processes, are considered as factors of influence on the atom exited-state populations in weakly ionized layers of stellar atmospheres. The presented results are related to the photospheres of the Sun and some M red dwarfs, as well as weakly ionized layers of DB white dwarf atmospheres. It has been found that the mentioned chemi-ionization and recombination processes dominate over the concurrent electron-atom and electron-ion ionization and recombination processes in all parts of the considered stellar atmospheres. The obtained results demonstrate the fact that the considered processes must have significant influence on the optical properties of stellar atmospheres. It is shown that these processes and their importance for non-local thermodynamic equilibrium (non-LTE) modeling of the solar atmospheres should be investigated further.
Cross Sections for Electron Impact Excitation of O VI Lines
Authors: Elabidi Haykel , Sahal-Bréchot Sylvie , Nessib Nébil Ben 
Published: March 2017

Abstract
Radiative atomic data and electron impact excitation cross sections for the 2s-2p transitions in O VI for transitions among the fine structure levels belonging to the 1s2nl (2 ≤ n ≤ 5) configurations have been calculated. We have extended the calculations of fine structure collision strengths up to 140 Ry and have compared our results at energies below 63 Ry to the R-matrix ones.
Stark Broadening of In III Lines in Astrophysical and Laboratory Plasma
Authors: Simić Z. , Dimitrijević M. S. , Kovačević A. , Sahal-Bréchot S. 
Published: March 2017

Abstract
In the deeper layers of hot stellar photospheres the Stark widths of spectral lines can be comparable and even larger than the thermal Doppler widths. Using the semiclassical perturbation method, we investigate the influence of the collisions with charged particles for the In III lines. We determine a number of Stark broadening parameters important in the atmospheres of A-type stars and white dwarfs. Also, the obtained results are compared with the available experimental data. The results will be included in the STARK-B database, the Virtual Atomic and Molecular Data Center and the Serbian Virtual Observatory.
The Search for Symbiotic Stars in the IPHAS Survey
Authors: Corradi R. L. M. 
Published: March 2017

Abstract
We have started a project to search for symbiotic stars using the data from IPHAS, the Hα survey of the Northern Galactic plane. Candidates are selected from the IPHAS photometric catalogue based on their colors, combined with the information in the near-infrared from 2MASS. So far, follow-up spectroscopy allowed us to discover 14 new symbiotic stars, compared to the 10 systems previously known in the IPHAS survey area. Their general characteristics and the most notable cases are briefly presented. the spectroscopic campaign also allowed us to refine the selection criteria for symbiotic stars in IPHAS. Perspectives, which include the extension of the survey in the Southern Galactic plane and a portion of the bulge (VPHAS+), are discussed.
The X-Ray Evolution of the Symbiotic Star V407 Cyg During its 2010 Outburst
Authors: Mukai K. , Nelson T. , Chomiuk L. , Donato D. , Sokoloski J. 
Published: March 2017

Abstract
We present a summary of Swift and Suzaku X-ray observations of the 2010 nova outburst of the symbiotic star, V407 Cyg. the Suzaku spectrum obtained on day 30 indicates the presence of the supersoft component from the white dwarf surface, as well as optically thin component from the shock between the nova ejecta and the Mira wind. the Swift observations then allow us to track the evolution of both components from day 4 to day 150. Most notable is the sudden brightening of the optically thin component around day 20. We identify this as the time when the blast wave reached the immediate vicinity of the photosphere of the Mira. We have developed a simpe model of the blast wave - wind interaction that can reproduce the gross features of the X-ray evolution of V407 Cyg. If the model is correct, the binary separation is likely to be larger than previously suggested and the mass-loss rate of the Mira is likely to be relatively low.