596 research outputs found
Bound States in Mildly Curved Layers
It has been shown recently that a nonrelativistic quantum particle
constrained to a hard-wall layer of constant width built over a geodesically
complete simply connected noncompact curved surface can have bound states
provided the surface is not a plane. In this paper we study the weak-coupling
asymptotics of these bound states, i.e. the situation when the surface is a
mildly curved plane. Under suitable assumptions about regularity and decay of
surface curvatures we derive the leading order in the ground-state eigenvalue
expansion. The argument is based on Birman-Schwinger analysis of Schroedinger
operators in a planar hard-wall layer.Comment: LaTeX 2e, 23 page
Effect of triamcinolone acetonide injections on hemiplegic shoulder pain: a randomized clinical trial.
Background and Purpose - Hemiplegic shoulder pain is not uncommon after stroke. Its origin is still unknown, and although many different methods of treatment are applied, none have yet been proved to be effective. We sought to study the efficacy of 3 injections of intra-articular triamcinolone acetonide on pain and arm function in stroke patients with hemiplegic shoulder pain. Methods - In a multicenter, randomized, placebo-controlled clinical trial, patients with hemiplegic shoulder pain received either 3 intra-articular injections of 40 mg triamcinolone acetonide or 1 mL physiological saline solution (placebo). Primary outcomes were pain measured according to 3 visual analogue scales (score range, 0 to 10), and arm function was measured by means of the Action Research Arm test and the Fugl-Meyer assessment scale; secondary outcomes were passive external rotation of the shoulder and general functioning measured according to Barthel Index and the Rehabilitation Activities Profile. Results - In the triamcinolone group (n=18), the median decrease in pain, 3 weeks after the last injection, was 2.3 (interquartile range, 0.3 to 4.3) versus 0.2 (interquartile range, -0.5 to 2.2) in the placebo group. This result was not statistically significant. The change in the other outcome measures did not differ significantly between the 2 treatment groups. Twenty-five patients reported side effects. Conclusions - In the 37 participants included in this study, triamcinolone injections seemed to decrease hemiplegic shoulder pain and to accelerate recovery, but this effect was not statistically significant. Therefore, on the basis of the results of this study, these injections cannot be recommended for the treatment of patients with hemiplegic shoulder pain
Radioimmunotherapy Improves Survival of Rats with Microscopic Liver Metastases of Colorectal Origin
BACKGROUND: Half of the patients with colorectal cancer develop liver metastases during the course of their disease. The aim of the present study was to assess the efficacy of radioimmunotherapy (RIT) with a radiolabeled monoclonal antibody (mAb) to treat experimental colorectal liver metastases. METHODS: Male Wag/Rij rats underwent a minilaparotomy with intraportal injection of 1 x 10(6) CC531 tumor cells. The biodistribution of (111)In-labeled MG1, 1 day after intravenous administration, was determined in vivo and compared with that of an isotype-matched control antibody (UPC-10). The maximal tolerated dose (MTD) of (177)Lu-labeled MG1 was determined and the therapeutic efficacy of (177)Lu-MG1 at MTD was compared with that of (177)Lu-UPC-10 and saline only. RIT was administered either at the day of tumor inoculation or 14 days after tumor inoculation. Primary endpoint was survival. RESULTS: (111)In-MG1 preferentially accumulated in CC531 liver tumors (9.2 +/- 3.7%ID/g), whereas (111)In-UPC-10 did not (0.8 +/- 0.1%ID/g). The MTD of (177)Lu-MG1 was 400 MBq/kg body weight. Both the administration of (177)Lu-MG1 and (177)Lu-UPC-10 had no side-effects except a transient decrease in body weight. The survival curves of the group that received (177)Lu-UPC-10 and the group that received saline only did not differ (P = 0.407). Administration of (177)Lu-MG1 RIT immediately after surgery improved survival significantly compared with administration of (177)Lu-UPC-10 (P = 0.009) whereas delayed treatment did not (P = 0.940). CONCLUSION: This study provides proof of principle that RIT can be an effective treatment modality for microscopic liver metastases, whereas RIT is not effective in larger tumors
Evidence of temperature-dependent effects on the estrogenic response of fish: implications with regard to climate change
The official published version can be obtained from the link below - Copyright @ 2008 Elsevier BV.Chemical risk assessment is fraught with difficulty due to the problem of accounting for the effects of mixtures. In addition to the uncertainty arising from chemical-to-chemical interactions, it is possible that environmental variables, such as temperature, influence the biological response to chemical challenge, acting as confounding factors in the analysis of mixture effects. Here, we investigate the effects of temperature on the response of fish to a defined mixture of estrogenic chemicals. It was anticipated that the response to the mixture may be exacerbated at higher temperatures, due to an increase in the rate of physiological processing. This is a pertinent issue in view of global climate change. Fathead minnows (Pimephales promelas) were exposed to the mixture in parallel exposure studies, which were carried out at different temperatures (20 and 30 degrees C). The estrogenic response was characterised using an established assay, involving the analysis of the egg yolk protein, vitellogenin (VTG). Patterns of VTG gene expression were also analysed using real-time QPCR. The results revealed that there was no effect of temperature on the magnitude of the VTG response after 2 weeks of chemical exposure. However, the analysis of mixture effects at two additional time points (24 h and 7 days) revealed that the response was induced more rapidly at the higher temperature. This trend was apparent from the analysis of effects both at the molecular and biochemical level. Whilst this indicates that climatic effects on water temperature are not a significant issue with regard to the long-term risk assessment of estrogenic chemicals, the relevance of short-term effects is, as yet, unclear. Furthermore, analysis of the patterns of VTG gene expression versus protein induction gives an insight into the physiological mechanisms responsible for temperature-dependent effects on the reproductive phenology of species such as roach. Hence, the data contribute to our understanding of the implications of global climate change for wild fish populations.This work was funded by a grant from the Natural Environment Research Council NE/D00389X/1). Additional support was provided by a small research grant from the Fisheries Society of the British Isles
Geometric Phase, Curvature, and Extrapotentials in Constrained Quantum Systems
We derive an effective Hamiltonian for a quantum system constrained to a
submanifold (the constraint manifold) of configuration space (the ambient
space) by an infinite restoring force. We pay special attention to how this
Hamiltonian depends on quantities which are external to the constraint
manifold, such as the external curvature of the constraint manifold, the
(Riemannian) curvature of the ambient space, and the constraining potential. In
particular, we find the remarkable fact that the twisting of the constraining
potential appears as a gauge potential in the constrained Hamiltonian. This
gauge potential is an example of geometric phase, closely related to that
originally discussed by Berry. The constrained Hamiltonian also contains an
effective potential depending on the external curvature of the constraint
manifold, the curvature of the ambient space, and the twisting of the
constraining potential. The general nature of our analysis allows applications
to a wide variety of problems, such as rigid molecules, the evolution of
molecular systems along reaction paths, and quantum strip waveguides.Comment: 27 pages with 1 figure, submitted to Phys. Rev.
Phosphorus nutrition in farmed Atlantic salmon (Salmo salar): life stage and temperature effects on bone pathologies
Bone health is important for a viable and ethically sound Atlantic salmon aquaculture industry. Two important
risk factors for vertebral deformities are dietary phosphorus and water temperature. Here, we explore the interplay between these two factors during a full production of Atlantic salmon. Salmon were fed one of three diets
(low 4.4–5.0 g kg−1, medium 7.1–7.6 g kg−1, or high 9.0–9.7 g kg−1 soluble phosphorus) from 3 to 500 g body
weight, followed by a common diet of 7.3 g kg−1 soluble phosphorus until harvest size at 4 kg. Additional groups
were included to investigate the effects of water temperatures of 10 vs 16 °C (low and high diets only) and the
switching of dietary phosphorus levels (from low to medium or high, from medium to low or high, from high to
low or medium), starting at seawater transfer (~100 g body weight) and lasting for 4 months (~500 g body
weight). During the experimental feeding period, the low phosphorus diet caused reduced bone mineralization
and stiffness and a greater prevalence of vertebral deformities, compared to the medium and high phosphorus
diets. However, the prevalence of severely deformed fish at harvest was reduced by switching from the low to
either the medium or high phosphorus diets for 4 months after seawater transfer, followed by rearing on the
standard commercial feed. Concurrently, switching from either the medium or high to a low phosphorus diet for
the same period following seawater transfer had no effect on vertebral deformities at harvest. The higher water
temperature for 4 months following seawater transfer increased the severity of deformities at harvest, irrespective of dietary phosphorus. Finally, low dietary phosphorus was associated with increased fillet damage, due
to ectopic connective tissue around the spine, at harvest. In conclusion, dietary phosphorus levels of 5 g kg−1 for
the initial 4 months in seawater are more of a risk factor for vertebral pathologies if preceded by low, but not
medium or high, dietary phosphorus in freshwater. However, dietary phosphorus levels may not play a role in
temperature induced radiologically detectable vertebral pathologies. Under the reported growing conditions and
diet compositions, a combination of 7.5–7.6 g kg−1 soluble phosphorus during freshwater and 5.0 g kg−1
Vortex phases in mesoscopic cylinders with suppressed surface superconductivity
Vortex structures in mesoscopic cylinder placed in external magnetic field
are studied under the general de Gennes boundary condition for the order
parameter corresponding to the suppression of surface superconductivity. The
Ginzburg-Landau equations are solved based on trial functions for the order
parameter for vortex-free, single-vortex, multivortex, and giant vortex phases.
The equilibrium vortex diagrams in the plane of external field and cylinder
radius and magnetization curves are calculated at different values of de Gennes
"extrapolation length" characterizing the boundary condition for the order
parameter. The comparison of the obtained variational results with some
available exact solutions shows good accuracy of our approach.Comment: RevTex, 11 pages, 10 figure
MIOPLASTIA EXPERIMENTAL DO ESFÍNCTER ANAL EXTERNO COM Fascia lata AUTÓLOGA, EM CÃES
A incontinência fecal em cães e gatos é uma situação na qual o proprietário tem
dificuldades para resolver as conseqüências advindas desta lesão, e geralmente os pacientes são
submetidos à eutanásia. Algumas técnicas cirúrgicas empregadas na esfincteroplastia são passíveis
de complicações como estenose anal ou incontinência fecal. Este experimento teve como objetivo
reconstituir o músculo esfíncter anal externo em cães, após iatrogenização da incontinência fecal.
Foram utilizados 10 cães hígidos, machos, sem raça definida, com peso variando entre 9 a14 kg.
Após incisão de pele circundando a abertura anal, procedeu-se a miectomia bilateral de esfíncter anal
externo, iatrogenizando-se a incontinência fecal, a qual foi diagnosticada por meio de avaliação física
diária. Trinta dias após, os pacientes foram novamente preparados para cirurgia asséptica e
submetidos à esfincteroplastia anal externa com o uso de Fascia lata autológa medindo 8 cm de
comprimento e 0,5 cm de largura, em média. Os dez cães incontinentes, em decorrência da
miectomia do esfíncter anal externo, apresentaram controle da emissão de fezes em 10 dias após a
realização da esfincteroplastia e mantiveram-se assim durante os dois meses de observação póscirúrgica.
Dessa maneira concluiu-se que a mioplastia do esfíncter anal externo com Fascia lata
autóloga, representa um procedimento eficaz de simples e rápida aplicação, podendo ser utilizado
rotineiramente para restabelecer a continência fecal em cães.
Experimental myoplasty of the external anal sphincter with autologous Fascia lata in dogs
Abstract
Fecal incontinence in dogs and cats is a hard condition for owners to solve the
consequences of this lesion, being patients usually subjected to euthanasia. Some surgical
techniques used in sphincteroplasty are prone to complications such as anal stenosis or fecal
incontinence. This experiment objectified to reconstruct the external anal sphincter in dogs after
iatrogeny of the fecal incontinence. Ten healthy male dogs of undefined breed, weight ranging from 9
to 14 kg, were used. After dermal incision surrounding the anal opening, bilateral myectomy of the
external anal sphincter was performer, with iatrogeny of fecal incontinence, diagnosed by daily
physical evaluation. Thirty days later, patients were again prepared for aseptic surgery and went under
external anal sphincteroplasty using autologous Fascia lata averaging 8 cm long and 0,5 cm wide.
Ten incontinent dogs, due to external anal sphincter myectomy, presented fecal control in ten days
after surgery and for the two subsequent months of follow-up. In conclusion, myoplasty of external
anal sphincter using autologous Fascia lata is a simple and effective treatment that can be used in
fecal incontinence in dogs
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