802 research outputs found
Endovascular exclusion of iliac artery to iliac vein fistula after lumbar disk surgery
AbstractIliac arteriovenous (AV) fistula is rare after lumbar disk surgery. Traditionally, open repair through the arterial lumen was performed. We report endovascular exclusion of an iliac AV fistula in a 41-year-old woman 8 years after lumbar diskectomy. An angiogram showed an AV fistula connecting the right common iliac artery and vein. This was repaired with placement of two covered wall stents in the right common artery and external iliac artery, and embolization of the right internal iliac artery. Contrast medium-enhanced computed tomography scan at 5 months confirmed elimination of the AV fistula and right iliac artery patency. This technique should be considered in management of iliac AV fistulas. (J Vasc Surg 2003;37:1091-3.
Outer Regions of the Milky Way
With the start of the Gaia era, the time has come to address the major
challenge of deriving the star formation history and evolution of the disk of
our MilkyWay. Here we review our present knowledge of the outer regions of the
Milky Way disk population. Its stellar content, its structure and its dynamical
and chemical evolution are summarized, focussing on our lack of understanding
both from an observational and a theoretical viewpoint. We describe the
unprecedented data that Gaia and the upcoming ground-based spectroscopic
surveys will provide in the next decade. More in detail, we quantify the expect
accuracy in position, velocity and astrophysical parameters of some of the key
tracers of the stellar populations in the outer Galactic disk. Some insights on
the future capability of these surveys to answer crucial and fundamental issues
are discussed, such as the mechanisms driving the spiral arms and the warp
formation. Our Galaxy, theMilkyWay, is our cosmological laboratory for
understanding the process of formation and evolution of disk galaxies. What we
learn in the next decades will be naturally transferred to the extragalactic
domain.Comment: 22 pages, 10 figures, Invited review, Book chapter in "Outskirts of
Galaxies", Eds. J. H. Knapen, J. C. Lee and A. Gil de Paz, Astrophysics and
Space Science Library, Springer, in pres
Local Anaesthetic Flush Reduces Postoperative Pain and Haematoma Formation After Great Saphenous Vein StrippingâA Randomised Controlled Trial
AbstractObjectivesTo observe the effect of local anaesthetic flush through the great saphenous vein (GSV) tunnel on postoperative pain and haematoma formation following saphenous vein stripping operations.DesignProspective, double-blind, randomised, control trial.MethodsOne hundred patients were randomized to receive 20ml of local anaesthetic (bupivacaine 0.25%+adrenaline) or saline control flush through the GSV tunnel after stripping in a double-blind study. Visual analogue pain scores were used to measure postoperative pain daily for the 1st week, then at 3 weeks and 6 weeks. Patients were examined during the 1st, 3rd and 6th week for haematoma formation.ResultsIn the control group the median postoperative pain score was 4 (range 0â7) in the immediate postoperative period compared to a median of 1 (range 0â4) in the LA group (p<0.001). The median pain score on day-4 was 4 (range 1â6) (control) vs. 1 (range 0â3) (LA group) (p<0.001, MannâWhitney Utest) and on day-6 it was 1 (range 0â5) (control) vs. 0 (range 0â5) (LA group) (p<0.001, MannâWhitney). Twelve patients (24%) developed a haematoma in the GSV tunnel in the control group compared to three patients (6%) in the LA group (p=0.007).ConclusionFlushing of the GSV tunnel with bupivacaine plus adrenaline significantly reduces postoperative pain and haematoma formation in patients undergoing GSV stripping for varicose veins
Differences in location and electrophyslologic properties of atrial tachycardias in structurally normal and abnormal hearts
The protein-protein interactions required for assembly of the Tn3 resolution synapse
The siteâspecific recombinase Tn3 resolvase initiates DNA strand exchange when two res recombination sites and six resolvase dimers interact to form a synapse. The detailed architecture of this intricate recombination machine remains unclear. We have clarified which of the potential dimerâdimer interactions are required for synapsis and recombination, using a novel complementation strategy that exploits a previously uncharacterized resolvase from Bartonella bacilliformis (âBartâ). Tn3 and Bart resolvases recognize different DNA motifs, via diverged Câterminal domains (CTDs). They also differ substantially at Nâterminal domain (NTD) surfaces involved in dimerization and synapse assembly. We designed NTDâCTD hybrid proteins, and hybrid res sites containing both Tn3 and Bart dimer binding sites. Using these components in in vivo assays, we demonstrate that productive synapsis requires a specific âR â interface involving resolvase NTDs at all three dimerâbinding sites in res . Synapses containing mixtures of wildâtype Tn3 and Bart resolvase NTD dimers are recombinationâdefective, but activity can be restored by replacing patches of Tn3 resolvase R interface residues with Bart residues, or vice versa . We conclude that the Tn3 /Bart family synapse is assembled exclusively by R interactions between resolvase dimers, except for the one special dimerâdimer interaction required for catalysis
Rotation measure variations for 20 millisecond pulsars
We report on variations in the mean position angle of the 20 millisecond
pulsars being observed as part of the Parkes Pulsar Timing Array (PPTA)
project. It is found that the observed variations are dominated by changes in
the Faraday rotation occurring in the Earth's ionosphere. Two ionospheric
models are used to correct for the ionospheric contribution and it is found
that one based on the International Reference Ionosphere gave the best results.
Little or no significant long-term variation in interstellar RM was found with
limits typically about 0.1 rad m yr in absolute value. In a few
cases, apparently significant RM variations over timescales of a few 100 days
or more were seen. These are unlikely to be due to localised magnetised regions
crossing the line of sight since the implied magnetic fields are too high. Most
probably they are statistical fluctuations due to random spatial and temporal
variations in the interstellar electron density and magnetic field along the
line of sight.Comment: Accepted for publication in Astrophysics & Space Scienc
Spin density wave dislocation in chromium probed by coherent x-ray diffraction
We report on the study of a magnetic dislocation in pure chromium. Coherent
x-ray diffraction profiles obtained on the incommensurate Spin Density Wave
(SDW) reflection are consistent with the presence of a dislocation of the
magnetic order, embedded at a few micrometers from the surface of the sample.
Beyond the specific case of magnetic dislocations in chromium, this work may
open up a new method for the study of magnetic defects embedded in the bulk.Comment: 8 pages, 7 figure
Continued adaptation of C4 photosynthesis after an initial burst of changes in the andropogoneae grasses
C4 photosynthesis is a complex trait that sustains fast growth and high productivity in tropical and subtropical conditions and evolved repeatedly in flowering plants. One of the major C4 lineages is Andropogoneae, a group of ⌠1,200 grass species that includes some of the world's most important crops and species dominating tropical and some temperate grasslands. Previous efforts to understand C4 evolution in the group have compared a few model C4 plants to distantly related C3 species, so that changes directly responsible for the transition to C4 could not be distinguished from those that preceded or followed it. In this study, we analyse the genomes of 66 grass species, capturing the earliest diversification within Andropogoneae as well as their C3 relatives. Phylogenomics combined with molecular dating and analyses of protein evolution show that many changes linked to the evolution of C4 photosynthesis in Andropogoneae happened in the Early Miocene, between 21 and 18âMa, after the split from its C3 sister lineage, and before the diversification of the group. This initial burst of changes was followed by an extended period of modifications to leaf anatomy and biochemistry during the diversification of Andropogoneae, so that a single C4 origin gave birth to a diversity of C4 phenotypes during 18 million years of speciation events and migration across geographic and ecological spaces. Our comprehensive approach and broad sampling of the diversity in the group reveals that one key transition can lead to a plethora of phenotypes following sustained adaptation of the ancestral state
Grain Surface Models and Data for Astrochemistry
AbstractThe cross-disciplinary field of astrochemistry exists to understand the formation, destruction, and survival of molecules in astrophysical environments. Molecules in space are synthesized via a large variety of gas-phase reactions, and reactions on dust-grain surfaces, where the surface acts as a catalyst. A broad consensus has been reached in the astrochemistry community on how to suitably treat gas-phase processes in models, and also on how to present the necessary reaction data in databases; however, no such consensus has yet been reached for grain-surface processes. A team of âŒ25 experts covering observational, laboratory and theoretical (astro)chemistry met in summer of 2014 at the Lorentz Center in Leiden with the aim to provide solutions for this problem and to review the current state-of-the-art of grain surface models, both in terms of technical implementation into models as well as the most up-to-date information available from experiments and chemical computations. This review builds on the results of this workshop and gives an outlook for future directions
Measurement of Exclusive rho+rho- Production in Mid-Virtuality Two-Photon Interactions and Study of the gamma gamma* -> rho rho Process at LEP
Exclusive rho+rho- production in two-photon collisions between a quasi-real
photon, gamma, and a mid-virtuality photon, gamma*, is studied with data
collected at LEP at centre-of-mass energies root(s)=183-209GeV with a total
integrated luminosity of 684.8pb^-1. The cross section of the gamma gamma* ->
rho+ rho- process is determined as a function of the photon virtuality, Q^2,
and the two-photon centre-of-mass energy, W_gg, in the kinematic region:
0.2GeV^2 < Q^2 <0.85GeV^2 and 1.1GeV < W_gg < 3GeV. These results, together
with previous L3 measurements of rho0 rho0 and rho+ rho- production, allow a
study of the gamma gamma* -> rho rho process over the Q^2-region 0.2GeV^2 < Q^2
< 30 GeV^2
- âŠ