599 research outputs found
Weight 2 blocks of general linear groups and modular Alvis-Curtis duality
We obtain the structure of weight 2 blocks and [2:1]-pairs of q-Schur
algebras, and compute explicitly the modular Alvis-Curtis duality for weight 2
blocks of finite general linear groups in non-defining characteristic.Comment: 27 pages; to appear in Int. Math. Res. No
Circulatory responses to hypoxia in experimental myocardial infarction
Hypoxia affecting circulatory responses in dogs, such as cardiac output, left ventricular dp/dt, and stroke volum
Liquid Transport Due to Light Scattering
Using experiments and theory, we show that light scattering by
inhomogeneities in the index of refraction of a fluid can drive a large-scale
flow. The experiment uses a near-critical, phase-separated liquid, which
experiences large fluctuations in its index of refraction. A laser beam
traversing the liquid produces a large-scale deformation of the interface and
can cause a liquid jet to form. We demonstrate that the deformation is produced
by a scattering-induced flow by obtaining good agreements between the measured
deformations and those calculated assuming this mechanism.Comment: 4 pages, 5 figures, submitted to Physical Review Letters v2: Edited
based on comments from referee
Nanoscale atomic waveguides with suspended carbon nanotubes
We propose an experimentally viable setup for the realization of
one-dimensional ultracold atom gases in a nanoscale magnetic waveguide formed
by single doubly-clamped suspended carbon nanotubes. We show that all common
decoherence and atom loss mechanisms are small guaranteeing a stable operation
of the trap. Since the extremely large current densities in carbon nanotubes
are spatially homogeneous, our proposed architecture allows to overcome the
problem of fragmentation of the atom cloud. Adding a second nanowire allows to
create a double-well potential with a moderate tunneling barrier which is
desired for tunneling and interference experiments with the advantage of
tunneling distances being in the nanometer regime.Comment: Replaced with the published version, 7 pages, 3 figure
Dislocation interaction with C in alpha-Fe: a comparison between atomic simulations and elasticity theory
The interaction of C atoms with a screw and an edge dislocation is modelled
at an atomic scale using an empirical Fe-C interatomic potential based on the
Embedded Atom Method (EAM) and molecular statics simulations. Results of atomic
simulations are compared with predictions of elasticity theory. It is shown
that a quantitative agreement can be obtained between both modelling techniques
as long as anisotropic elastic calculations are performed and both the
dilatation and the tetragonal distortion induced by the C interstitial are
considered. Using isotropic elasticity allows to predict the main trends of the
interaction and considering only the interstitial dilatation will lead to a
wrong interaction
Filtering spin with tunnel-coupled electron wave guides
We show how momentum-resolved tunneling between parallel electron wave guides
can be used to observe and exploit lifting of spin degeneracy due to Rashba
spin-orbit coupling. A device is proposed that achieves spin filtering without
using ferromagnets or the Zeeman effect.Comment: 4 pages, 4 figures, RevTex
Predictive significance of the six-minute walk distance for long-term survival in chronic hypercapnic respiratory failure
Background: The 6-min walk distance ( 6-MWD) is a global marker of functional capacity and prognosis in chronic obstructive pulmonary disease ( COPD), but less explored in other chronic respiratory diseases. Objective: To study the role of 6-MWD in chronic hypercapnic respiratory failure ( CHRF). Methods: In 424 stable patients with CHRF and non-invasive ventilation ( NIV) comprising COPD ( n = 197), restrictive diseases ( RD; n = 112) and obesity-hypoventilation- syndrome ( OHS; n = 115), the prognostic value of 6-MWD for long- term survival was assessed in relation to that of body mass index (BMI), lung function, respiratory muscle function and laboratory parameters. Results: 6-MWD was reduced in patients with COPD ( median 280 m; quartiles 204/350 m) and RD ( 290 m; 204/362 m) compared to OHS ( 360 m; 275/440 m; p <0.001 each). Overall mortality during 24.9 (13.1/40.5) months was 22.9%. In the 424 patients with CHRF, 6-MWD independently predicted mortality in addition to BMI, leukocytes and forced expiratory volume in 1 s ( p <0.05 each). In COPD, 6-MWD was strongly associated with mortality using the median {[} p <0.001, hazard ratio ( HR) = 3.75, 95% confidence interval (CI): 2.24-6.38] or quartiles as cutoff levels. In contrast, 6-MWD was only significantly associated with impaired survival in RD patients when it was reduced to 204 m or less (1st quartile; p = 0.003, HR = 3.31, 95% CI: 1.73-14.10), while in OHS 6-MWD had not any prognostic value. Conclusions: In patients with CHRF and NIV, 6-MWD was predictive for long- term survival particularly in COPD. In RD only severely reduced 6-MWD predicted mortality, while in OHS 6-MWD was relatively high and had no prognostic value. These results support a disease-specific use of 6-MWD in the routine assessment of patients with CHRF. Copyright (C) 2007 S. Karger AG, Basel
Identification of the initial molecular changes in response to circulating angiogenic cells-mediated therapy in critical limb ischemia
BackgroundCritical limb ischemia (CLI) constitutes the most aggressive form of peripheral arterial occlusive disease, characterized by the blockade of arteries supplying blood to the lower extremities, significantly diminishing oxygen and nutrient supply. CLI patients usually undergo amputation of fingers, feet, or extremities, with a high risk of mortality due to associated comorbidities.Circulating angiogenic cells (CACs), also known as early endothelial progenitor cells, constitute promising candidates for cell therapy in CLI due to their assigned vascular regenerative properties. Preclinical and clinical assays with CACs have shown promising results. A better understanding of how these cells participate in vascular regeneration would significantly help to potentiate their role in revascularization.Herein, we analyzed the initial molecular mechanisms triggered by human CACs after being administered to a murine model of CLI, in order to understand how these cells promote angiogenesis within the ischemic tissues.MethodsBalb-c nude mice (n:24) were distributed in four different groups: healthy controls (C, n:4), shams (SH, n:4), and ischemic mice (after femoral ligation) that received either 50 mu l physiological serum (SC, n:8) or 5x10(5) human CACs (SE, n:8). Ischemic mice were sacrificed on days 2 and 4 (n:4/group/day), and immunohistochemistry assays and qPCR amplification of Alu-human-specific sequences were carried out for cell detection and vascular density measurements. Additionally, a label-free MS-based quantitative approach was performed to identify protein changes related.ResultsAdministration of CACs induced in the ischemic tissues an increase in the number of blood vessels as well as the diameter size compared to ischemic, non-treated mice, although the number of CACs decreased within time. The initial protein changes taking place in response to ischemia and more importantly, right after administration of CACs to CLI mice, are shown.ConclusionsOur results indicate that CACs migrate to the injured area; moreover, they trigger protein changes correlated with cell migration, cell death, angiogenesis, and arteriogenesis in the host. These changes indicate that CACs promote from the beginning an increase in the number of vessels as well as the development of an appropriate vascular network.Institute of Health Carlos III, ISCIII; Junta de Andaluci
Effect of Doublon-Holon Binding on Mott transition---Variational Monte Carlo Study of Two-Dimensional Bose Hubbard Models
To understand the mechanism of Mott transitions in case of no magnetic
influence, superfluid-insulator (Mott) transitions in the S=0 Bose Hubbard
model at unit filling are studied on the square and triangular lattices, using
a variational Monte Carlo method. In trial many-body wave functions, we
introduce various types of attractive correlation factors between a
doubly-occupied site (doublon, D) and an empty site (holon, H), which play a
central role for Mott transitions, in addition to the onsite repulsive
(Gutzwiller) factor. By optimizing distance-dependent parameters, we study
various properties of this type of wave functions. With a hint from the Mott
transition arising in a completely D-H bound state, we propose an improved
picture of Mott transitions, by introducing two characteristic length scales,
the D-H binding length and the minimum D-D exclusion length
. Generally, a Mott transition occurs when becomes
comparable to . In the conductive (superfluid) state, domains of
D-H pairs overlap with each other (); thereby D and
H can propagate independently as density carriers by successively exchanging
the partners. In contrast, intersite repulsive Jastrow (D-D and H-H) factors
have little importance for the Mott transition.Comment: 16 pages, 22 figures, submitted to J. Phys. Soc. Jp
Molecular, phenotypic, and sample-associated data to describe pluripotent stem cell lines and derivatives
The use of induced pluripotent stem cells (iPSC) derived from independent patients and sources holds considerable promise to improve the understanding of development and disease. However, optimized use of iPSC depends on our ability to develop methods to efficiently qualify cell lines and protocols, monitor genetic stability, and evaluate self-renewal and differentiation potential. To accomplish these goals, 57 stem cell lines from 10 laboratories were differentiated to 7 different states, resulting in 248 analyzed samples. Cell lines were differentiated and characterized at a central laboratory using standardized cell culture methodologies, protocols, and metadata descriptors. Stem cell and derived differentiated lines were characterized using RNA-seq, miRNA-seq, copy number arrays, DNA methylation arrays, flow cytometry, and molecular histology. All materials, including raw data, metadata, analysis and processing code, and methodological and provenance documentation are publicly available for re-use and interactive exploration at https://www.synapse.org/pcbc. The goal is to provide data that can improve our ability to robustly and reproducibly use human pluripotent stem cells to understand development and disease
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