72 research outputs found
Association between ultrasound assessment of glenohumeral subluxation and shoulder pain, muscle strength, active range of movement and upper limb function in people with stroke
Background: Glenohumeral subluxation (GHS) is a commonly reported post-stroke complication which has a negative effect on rehabilitation. Objective: To explore the association between GHS and other clinical outcomes in people with post-stroke hemiplegia. Methods: Patients with post-stroke hemiplegia (n=105, 71±11 years, median time since stroke 5.6 weeks), who gave informed consent, were recruited. GHS was assessed by the ultrasound method. Assessment of shoulder pain (visual analogue scale), active range of movement (AROM), muscle strength (Medical Research Council Scale), muscle tone (Modified Ashworth Scale) and the upper limb section of the Motor Assessment Scale (MAS) was undertaken. Results: GHS was present in 65 (62%) patients. There was a moderate negative correlation between GHS and muscle strength (r=-0.54,
The Maximal Abelian Gauge, Monopoles, and Vortices in SU(3) Lattice Gauge Theory
We report on calculations of the heavy quark potential in SU(3) lattice gauge
theory. Full SU(3) results are compared to three cases which involve
gauge-fixing and projection. All of these start from the maximal abelian gauge
(MAG), in its simplest form. The first case is abelian projection to U(1)xU(1).
The second keeps only the abelian fields of monopoles in the MAG. The third
involves an additional gauge-fixing to the indirect maximal center gauge
(IMCG), followed by center projection to Z(3). At one gauge
fixing/configuration, the string tensions calculated from MAG U(1)xU(1), MAG
monopoles, and IMCG Z(3) are all less than the full SU(3) string tension. The
projected string tensions further decrease, by approximately 10%, when account
is taken of gauge ambiguities. Comparison is made with corresponding results
for SU(2). It is emphasized that the formulation of the MAG is more subtle for
SU(3) than for SU(2), and that the low string tensions may be caused by the
simple MAG form used. A generalized MAG for SU(3) is formulated.Comment: 22 pages, latex, 2 postscript figures. Replaced version has added
data at beta=6.0, analysis of Gribov ambiguities, extended tables of results,
discussion of scalin
Monopole Clustering and Color Confinement in the Multi-Instanton System
We study color confinement properties of the multi-instanton system, which
seems to carry an essence of the nonperturbative QCD vacuum. Here we assume
that the multi-instanton system is characterized by the infrared suppression of
instantons as for large size . We first
investigate a monopole-clustering appearing in the maximally abelian (MA) gauge
by considering the correspondence between instantons and monopoles. In order to
clarify the infrared monopole properties, we make the ``block-spin''
transformation for monopole currents. The feature of monopole trajectories
changes drastically with the instanton density. At a high instanton density,
there appears one very long and highly complicated monopole loop covering the
entire physical vacuum. Such a global network of long-monopole loops resembles
the lattice QCD result in the MA gauge. Second, we observe that the SU(2)
Wilson loop obeys an area law and the static quark potential is approximately
proportional to the distance between quark and anti-quark in the
multi-instanton system using the SU(2) lattice with a total volume of and a lattice spacing of . We extract the string tension from
the measurements of Wilson loops. With an instanton density
of and a average instanton size of , the
multi-instanton system provides the string tension of about
Flux-Tube Ring and Glueball Properties in the Dual Ginzburg-Landau Theory
An intuitive approach to the glueball using the flux-tube ring solution in
the dual Ginzburg-Landau theory is presented. The description of the flux-tube
ring as the relativistic closed string with the effective string tension
enables us to write the hamiltonian of the flux-tube ring using the Nambu-Goto
action. Analyzing the Schr\"odinger equation, we discuss the mass spectrum and
the wave function of the glueball. The lowest glueball state is found to have
the mass and the size .Comment: 24 pages, 6 figures, revte
Effects of a wearable exoskeleton stride management assist system (SMA®) on spatiotemporal gait characteristics in individuals after stroke: a randomized controlled trial
Sarcopenia; Aging-related loss of muscle mass and function
Sarcopenia is a loss of muscle mass and function in the elderly that reduces mobility, diminishes quality of life, and can lead to fall-related injuries, which require costly hospitalization and extended rehabilitation. This review focuses on the aging-related structural changes and mechanisms at cellular and subcellular levels underlying changes in the individual motor unit: specifically, the perikaryon of -motoneuron, its neuromuscular junction(s), and the muscle fibers that it innervates. Loss of muscle mass with aging, which is largely due to the progressive loss of motoneurons, is associated with reduced muscle fiber number and size. Muscle function progressively declines because motoneuron loss is not adequately compensated by reinnervation of muscle fibers by the remaining motoneurons. At the intracellular level, key factors are qualitative changes in posttranslational modifications of muscle proteins and the loss of coordinated control between contractile, mitochondrial, and sarcoplasmic reticulum protein expression. Quantitative and qualitative changes in skeletal muscle during the process of aging also have been implicated in the pathogenesis of acquired and hereditary neuromuscular disorders. In experimental models, specific intervention strategies have shown encouraging results on limiting deterioration of motor unit structure and function under conditions of impaired innervation. Translated to the clinic, if these or similar interventions, by saving muscle and improving mobility, could help alleviate sarcopenia in the elderly, there would be both great humanitarian benefits and large cost savings for health care systems
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