11,167 research outputs found
Haemodynamic and Clinical Assessment of Lateral Marginal Vein Excision in Patients with a Predominantly Venous Malformation of the Lower Extremity
ObjectiveThe purpose of the present study was to determine the effects of the surgical excision of lateral marginal veins (LMVs) in patients with a venous malformation (VM) affecting the lower extremity.MethodsPreoperative and postoperative air plethysmography (APG), CEAP classification C scores, and venous clinical severity scores (VCSS) of the 25 VM patients who underwent LMV excision were compared.ResultsAfter LMV excision, venous haemodynamic parameters revealed significantly increased ejection fraction (EF, 33.2 S.D.18.5% vs. 39.7 S.D.21.2%, P=.020), and reduced venous volume (VV, 235.0 S.D.141.8ml vs. 198.0 S.D.114.1ml, P=.016) and residual venous fraction (RVF, 62.4 S.D. 26.6% vs. 56.9 S.D. 25.3%, P=.046). Clinical assessments of affected limbs revealed significantly improved mean CEAP C scores and VCSS (preoperative score, 4.4 S.D.1.7 vs. postoperative score 2.4 S.D.1.7, P=.026) after LMV excision versus preoperative data.ConclusionHaemodynamic and clinical improvements were observed in patients with lower extremity VM after LMV excision
Arabidopsis ABCG14 is essential for the root-to-shoot translocation of cytokinin.
Cytokinins are phytohormones that induce cytokinesis and are essential for diverse developmental and physiological processes in plants. Cytokinins of the trans-zeatin type are mainly synthesized in root vasculature and transported to the shoot, where they regulate shoot growth. However, the mechanism of long-distance transport of cytokinin was hitherto unknown. Here, we report that the Arabidopsis ATP-binding cassette (ABC) transporter subfamily G14 (AtABCG14) is mainly expressed in roots and plays a major role in delivering cytokinins to the shoot. Loss of AtABCG14 expression resulted in severe shoot growth retardation, which was rescued by exogenous trans-zeatin application. Cytokinin content was decreased in the shoots of atabcg14 plants and increased in the roots, with consistent changes in the expression of cytokinin-responsive genes. Grafting of atabcg14 scions onto wild-type rootstocks restored shoot growth, whereas wild-type scions grafted onto atabcg14 rootstocks exhibited shoot growth retardation similar to that of atabcg14. Cytokinin concentrations in the xylem are reduced by similar to 90% in the atabcg14 mutant. These results indicate that AtABCG14 is crucial for the translocation of cytokinin to the shoot. Our results provide molecular evidence for the long-distance transport of cytokinin and show that this transport is necessary for normal shoot development.open118380Ysciescopu
Inflation and Gauge Hierarchy in Randall-Sundrum Compactification
We obtain the general inflationary solutions for the slab of five-dimensional
AdS spacetime where the fifth dimension is an orbifold and two
three-branes reside at its boundaries, of which the Randall-Sundrum model
corresponds to the static limit. The investigation of the general solutions and
their static limit reveals that the RS model recasts both the cosmological
constant problem and the gauge hierarchy problem into the balancing problem of
the bulk and the brane cosmological constants.Comment: 9 pages, revtex, minor changes and more references adde
Diffusion on a heptagonal lattice
We study the diffusion phenomena on the negatively curved surface made up of
congruent heptagons. Unlike the usual two-dimensional plane, this structure
makes the boundary increase exponentially with the distance from the center,
and hence the displacement of a classical random walker increases linearly in
time. The diffusion of a quantum particle put on the heptagonal lattice is also
studied in the framework of the tight-binding model Hamiltonian, and we again
find the linear diffusion like the classical random walk. A comparison with
diffusion on complex networks is also made.Comment: 5 pages, 6 figure
A genome-wide association study implicates the pleiotropic effect of NMUR2 on asthma and COPD
Asthma and chronic obstructive pulmonary disease (COPD) are two distinct diseases that are associated with chronic inflammation. They share common features in terms of their advanced stages and genetic factors. This study aimed to identify novel genes underlying both asthma and COPD using genome-wide association study (GWAS) to differentiate between the two diseases. We performed a GWAS of asthma and COPD in 7828 Koreans from three hospitals. In addition, we investigated genetic correlations. The UK Biobank dataset was used for the replication studies. We found that rs2961757, located near neuromedin U receptor 2 (NMUR2) on chromosome 5, was genome-wide significant ([Formula: see text] = 0.44, P-valueAsthma-COPD = 3.41 × 10-8), and significant results were replicated with the UK Biobank data ([Formula: see text] = 0.04, P-valueAsthma-COPD = 0.0431). A positive genetic correlation was observed between asthma and COPD (39.8% in the Korean dataset and 49.8% in the UK Biobank dataset). In this study, 40-45% of the genetic effects were common to asthma and COPD. Moreover, NMUR2 increases the risk of asthma development and suppresses COPD development. This indicates that NMUR2 allows for better differentiation of both diseases, which can facilitate tailored medical therapy
High-resolution Ce 3d-edge resonant photoemission study of CeNi_2
Resonant photoemission (RPES) at the Ce 3d -> 4f threshold has been performed
for alpha-like compound CeNi_2 with extremely high energy resolution (full
width at half maximum < 0.2 eV) to obtain bulk-sensitive 4f spectral weight.
The on-resonance spectrum shows a sharp resolution-limited peak near the Fermi
energy which can be assigned to the tail of the Kondo resonance. However, the
spin-orbit side band around 0.3 eV binding energy corresponding to the f_{7/2}
peak is washed out, in contrast to the RPES spectrum at the Ce 3d -> 4f RPES
threshold. This is interpreted as due to the different surface sensitivity, and
the bulk-sensitive Ce 3d -> 4f RPES spectra are found to be consistent with
other electron spectroscopy and low energy properties for alpha-like
Ce-transition metal compounds, thus resolves controversy on the interpretation
of Ce compound photoemission. The 4f spectral weight over the whole valence
band can also be fitted fairly well with the Gunnarsson-Schoenhammer
calculation of the single impurity Anderson model, although the detailed
features show some dependence on the hybridization band shape and (possibly) Ce
5d emissions.Comment: 4 pages, 3 figur
Dynamics of filaments and membranes in a viscous fluid
Motivated by the motion of biopolymers and membranes in solution, this
article presents a formulation of the equations of motion for curves and
surfaces in a viscous fluid. We focus on geometrical aspects and simple
variational methods for calculating internal stresses and forces, and we derive
the full nonlinear equations of motion. In the case of membranes, we pay
particular attention to the formulation of the equations of hydrodynamics on a
curved, deforming surface. The formalism is illustrated by two simple case
studies: (1) the twirling instability of straight elastic rod rotating in a
viscous fluid, and (2) the pearling and buckling instabilities of a tubular
liposome or polymersome.Comment: 26 pages, 12 figures, to be published in Reviews of Modern Physic
X-ray absorption spectroscopy study of diluted magnetic semiconductors: Zn1-xMxSe (M = Mn, Fe, Co) and Zn1-xMnxY (Y = Se, Te)
We have investigated 3d electronic states of doped transition metals in II-VI
diluted magnetic semiconductors, Zn1-xMxSe (M = Mn, Fe, Co) and Zn1-xMnxY (Y =
Se, Te), using the transition-metal L2,3-edge X-ray absorption spectroscopy
(XAS) measurements. In order to explain the XAS spectra, we employed a
tetragonal cluster model calculation, which includes not only the full ionic
multiplet structure but also configuration interaction (CI). The results show
that CI is essential to describe the experimental spectra adequately,
indicating the strong hybridization between the transition metal 3d and the
ligand p orbitals. In the study of Zn1-xMnxY (Y = Se, Te), we also found
considerable spectral change in the Mn L2,3-edge XAS spectra for different
ligands, confirming the importance of the hybridization effects in these
materials.Comment: This paper consists of 22 pages including 4 figures. This paper is
submitted to Physical Review
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