9,414 research outputs found
Treatment of stiff thoracic scoliosis by thoracoscopic anterior release combined with posterior instrumentation and fusion
Background. Thoracoscopic anterior release has been shown that it can effectively improve spinal flexibility in animal and human cadaveric studies, and has been advocated for use in patients with scoliosis. This prospective case series aims to investigate the improvement of the spinal flexibility and the effectiveness in deformity correction by anterior thoracoscopic release and posterior spinal fusion. Methods. Eleven patients with stiff idiopathic thoracic scoliosis underwent anterior thoracoscopic release followed by posterior instrumentation. The average number of discs excised was five. Spinal flexibility was assessed by the fulcrum bending technique. Cobb angle before and after the anterior release was compared. Results. The patients were followed for an average of 5.6 years (range 2.2 to 8.1 years). Fulcrum bending flexibility was increased from 39% before the thoracoscopic anterior spinal release to 54% after the release. The average Cobb angle before anterior release was 74° on the standing radiograph and 45° with the fulcrum-bending radiograph. This reduced to 34° on the fulcrum-bending radiograph after the release, and highly corresponded to the 31° measured at the post-operative standing radiograph. Conclusion. It was demonstrated in patients with stiff idiopathic thoracic scoliosis that thoracoscopic anterior spinal release can effectively improve the spinal flexibility and increase the correction of the spinal deformity.published_or_final_versio
Beta-blockers to prevent gastroesophageal varices in patients with cirrhosis.
BACKGROUND: Nonselective beta-adrenergic blockers decrease portal pressure and prevent variceal hemorrhage. Their effectiveness in preventing varices is unknown. METHODS: We randomly assigned 213 patients with cirrhosis and portal hypertension (minimal hepatic venous pressure gradient [HVPG] of 6 mm Hg) to receive timolol, a nonselective beta-blocker (108 patients), or placebo (105 patients). The primary end point was the development of gastroesophageal varices or variceal hemorrhage. Endoscopy and HVPG measurements were repeated yearly. RESULTS: During a median follow-up of 54.9 months, the rate of the primary end point did not differ significantly between the timolol group and the placebo group (39 percent and 40 percent, respectively; P=0.89), nor were there significant differences in the rates of ascites, encephalopathy, liver transplantation, or death. Serious adverse events were more common among patients in the timolol group than among those in the placebo group (18 percent vs. 6 percent, P=0.006). Varices developed less frequently among patients with a baseline HVPG of less than 10 mm Hg and among those in whom the HVPG decreased by more than 10 percent at one year and more frequently among those in whom the HVPG increased by more than 10 percent at one year. CONCLUSIONS: Nonselective beta-blockers are ineffective in preventing varices in unselected patients with cirrhosis and portal hypertension and are associated with an increased number of adverse events. (ClinicalTrials.gov number, NCT00006398.
On Glauber modes in Soft-Collinear Effective Theory
Gluon interactions involving spectator partons in collisions at hadronic
machines are investigated. We find a class of examples in which a mode, called
Glauber gluons, must be introduced to the effective theory for consistency.Comment: 19 pages, three figures. Uses JHEP3.cl
Gauge links for transverse momentum dependent correlators at tree-level
In this paper we discuss the incorporation of gauge links in hadronic matrix
elements that describe the soft hadronic physics in high energy scattering
processes. In this description the matrix elements appear in soft correlators
and they contain non-local combinations of quark and gluon fields. In our
description we go beyond the collinear approach in which case also the
dependence on transverse momenta of partons is taken into consideration. The
non-locality in the transverse direction leads to a complex gauge link
structure for the full process, in which color is entangled, even at
tree-level. We show that at tree-level in a 1-parton unintegrated (1PU)
situation, in which only the transverse momentum of one of the initial state
hadrons is relevant, one can get a factorized expression involving transverse
momentum dependent (TMD) distribution functions. We point out problems at the
level of two initial state hadrons, even for relatively simple processes such
as Drell-Yan scattering.Comment: 25 pages, corrected typos and updated reference
Testing and comparing two self-care-related instruments among older Chinese adults
Objectives The study aimed to test and compare the reliability and validity, including sensitivity and specificity of the two self-care-related instruments, the Self-care Ability Scale for the Elderly (SASE), and the Appraisal of Self-care Agency Scale-Revised (ASAS-R), among older adults in the Chinese context. Methods A cross-sectional design was used to conduct this study. The sample consisted of 1152 older adults. Data were collected by a questionnaire including the Chinese version of SASE (SASE-CHI), the Chinese version of ASAS-R (ASAS-R-CHI) and the Exercise of Self-Care Agency scale (ESCA). Homogeneity and stability, content, construct and concurrent validity, and sensitivity and specificity were assessed. Results The Cronbach's alpha (α) of SASE-CHI was 0.89, the item-to-total correlations ranged from r = 0.15 to r = 0.81, and the test-retest correlation coefficient (intra-class correlation coefficient, ICC) was 0.99 (95% CI, 0.99±1.00; P<0.001). The Cronbach's α of ASAS-R-CHI was 0.78, the item-to-total correlations ranged from r = 0.20 to r = 0.65, and the test-retest ICC was 0.95 (95% CI, 0.92±0.96; P<0.001). The content validity index (CVI) of SASE-CHI and ASAS-R-CHI was 0.96 and 0.97, respectively. The findings of exploratory and confirmatory factor analyses (EFA and CFA) confirmed a good construct validity of SASE-CHI and ASAS-R-CHI. The Pearson's rank correlation coefficients, as a measure of concurrent validity, between total score of SASE-CHI and ESCA and ASAS-R-CHI and ESCA were assessed to 0.65 (P<0.001) and 0.62 (P<0.001), respectively. Regarding ESCA as the criterion, the area under the receiver operator characteristic (ROC) curve for the cut-point of SASE-CHI and ASAS-R-CHI were 0.93 (95% CI, 0.91±0.94) and 0.83 (95% CI, 0.80±0.86), respectively. Conclusion There is no significant difference between the two instruments. Each has its own characteristics, but SASE-CHI is more suitable for older adults. The key point is that the users can choose the most appropriate scale according to the specific situation.publishedVersionNivå
Measurement of the Branching Fraction of J/psi --> pi+ pi- pi0
Using 58 million J/psi and 14 million psi' decays obtained by the BESII
experiment, the branching fraction of J/psi --> pi+ pi- pi0 is determined. The
result is (2.10+/-0.12)X10^{-2}, which is significantly higher than previous
measurements.Comment: 9 pages, 8 figures, RevTex
First observation of psi(2S)-->K_S K_L
The decay psi(2S)-->K_S K_L is observed for the first time using psi(2S) data
collected with the Beijing Spectrometer (BESII) at the Beijing Electron
Positron Collider (BEPC); the branching ratio is determined to be
B(psi(2S)-->K_S K_L) = (5.24\pm 0.47 \pm 0.48)\times 10^{-5}. Compared with
J/psi-->K_S K_L, the psi(2S) branching ratio is enhanced relative to the
prediction of the perturbative QCD ``12%'' rule. The result, together with the
branching ratios of psi(2S) decays to other pseudoscalar meson pairs
(\pi^+\pi^- and K^+K^-), is used to investigate the relative phase between the
three-gluon and the one-photon annihilation amplitudes of psi(2S) decays.Comment: 5 pages, 4 figures, 2 tables, submitted to Phys. Rev. Let
Fractal frontiers in cardiovascular magnetic resonance: towards clinical implementation
This article is distributed under the terms of the Creative Commons Attribution 4.0
International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and
reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to
the Creative Commons license, and indicate if changes were made.JCM: Higher Education Funding Council for England and the UK National
Institute for Health Research, University College London, Biomedical Research
Centre; GC: NIHR BRC University College London. DAB: Intramural research
program, National Institutes of Health
BMP2 Is superior to BMP4 for promoting human muscle-derived stem cell-mediated bone regeneration in a critical-sized calvarial defect model
Muscle-derived cells have been successfully isolated using a variety of different methods and have been shown to possess multilineage differentiation capacities, including an ability to differentiate into articular cartilage and bone in vivo; however, the characterization of human muscle-derived stem cells (hMDSCs) and their bone regenerative capacities have not been fully investigated. Genetic modification of these cells may enhance their osteogenic capacity, which could potentially be applied to bone regenerative therapies. We found that hMDSCs, isolated by the preplate technique, consistently expressed the myogenic marker CD56, the pericyte/endothelial cell marker CD146, and the mesenchymal stem cell markers CD73, CD90, CD105, and CD44 but did not express the hematopoietic stem cell marker CD45, and they could undergo osteogenic, chondrogenic, adipogenic, and myogenic differentiation in vitro. In order to investigate the osteoinductive potential of hMDSCs, we constructed a retroviral vector expressing BMP4 and GFP and a lentiviral vector expressing BMP2. The BMP4-expressing hMDSCs were able to undergo osteogenic differentiation in vitro and exhibited enhanced mineralization compared to nontransduced cells; however, when transplanted into a calvarial defect, they failed to regenerate bone. Local administration of BMP4 protein and cell pretreatment with N-acetylcysteine (NAC), which improves cell survival, did not enhance the osteogenic capacity of the retro-BMP4-transduced cells. In contrast, lenti-BMP2-transduced hMDSCs not only exhibited enhanced in vitro osteogenic differentiation but also induced robust bone formation and nearly completely healed a critical-sized calvarial defect in CD-1 nude mice 6 weeks following transplantation. Herovici's staining of the regenerated bone demonstrated that the bone matrix contained a large amount of type I collagen. Our findings indicated that the hMDSCs are likely mesenchymal stem cells of muscle origin and that BMP2 is more efficient than BMP4 in promoting the bone regenerative capacity of the hMDSCs in vivo. © 2013 Cognizant Comm. Corp
Material-independent crack arrest statistics: Application to indentation experiments
An extensive experimental study of indentation and crack arrest statistics is
presented for four different brittle materials (alumina, silicon carbide,
silicon nitride, glass). Evidence is given that the crack length statistics can
be described by a universal (i.e. material independent) distribution. The
latter directly derives from results obtained when modeling crack propagation
as a depinning phenomenon. Crack arrest (or effective toughness) statistics
appears to be fully characterized by two parameters, namely, an asymptotic
crack length (or macroscopic toughness) value and a power law size dependent
width. The experimental knowledge of the crack arrest statistics at one given
scale thus gives access to its knowledge at all scales
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