48,307 research outputs found
Comparison of analgesic effects and patient tolerability of nabilone and dihydrocodeine for chronic neuropathic pain: randomised, crossover, double blind study
<b>Objective</b>: To compare the analgesic efficacy and side effects of the synthetic cannabinoid nabilone with those of the weak opioid dihydrocodeine for chronic neuropathic pain.
<b>Design</b>: Randomised, double blind, crossover trial of 14 weeksâ duration comparing dihydrocodeine and nabilone.
<b>Setting</b>: Outpatient units of three hospitals in the United Kingdom.
<b>Participants</b>: 96 patients with chronic neuropathic pain, aged 23-84 years.
<b>Main outcome measures</b>: The primary outcome was difference between nabilone and dihydrocodeine in pain, as measured by the mean visual analogue score computed over the last 2 weeks of each treatment period. Secondary outcomes were changes in mood, quality of life, sleep, and psychometric function. Side effects were measured by a questionnaire.
<b>Intervention</b>: Patients received a maximum daily dose of 240 mg dihydrocodeine or 2 mg nabilone at the end of each escalating treatment period of 6 weeks. Treatment periods were separated by a 2 week washout period.
<b>Results</b>: Mean baseline visual analogue score was 69.6 mm (range 29.4-95.2) on a 0-100 mm scale. 73 patients were included in the available case analysis and 64 patients in the per protocol analysis. The mean score was 6.0 mm longer for nabilone than for dihydrocodeine (95% confidence interval 1.4 to 10.5) in the available case analysis and 5.6 mm (10.3 to 0.8) in the per protocol analysis. Side effects were more frequent with nabilone.
<b>Conclusion</b>: Dihydrocodeine provided better pain relief than the synthetic cannabinoid nabilone and had slightly fewer side effects, although no major adverse events occurred for either drug
Log-periodic modulation in one-dimensional random walks
We have studied the diffusion of a single particle on a one-dimensional
lattice. It is shown that, for a self-similar distribution of hopping rates,
the time dependence of the mean-square displacement follows an anomalous power
law modulated by logarithmic periodic oscillations. The origin of this
modulation is traced to the dependence on the length of the diffusion
coefficient. Both the random walk exponent and the period of the modulation are
analytically calculated and confirmed by Monte Carlo simulations.Comment: 6 pages, 7 figure
Orbitronics: the Intrinsic Orbital Hall Effect in p-Doped Silicon
The spin Hall effect depends crucially on the intrinsic spin-orbit coupling
of the energy band. Because of the smaller spin-orbit coupling in silicon, the
spin Hall effect is expected to be much reduced. We show that the electric
field in p-doped silicon can induce a dissipationless orbital current in a
fashion reminiscent of the spin Hall effect. The vertex correction due to
impurity scattering vanishes and the effect is therefore robust against
disorder. The orbital Hall effect can lead to the accumulation of local orbital
momentum at the edge of the sample, and can be detected by the Kerr effect.Comment: 4 page
Classification of finite dimensional modules of singly atypical type over the Lie superalgebras sl(m/n)
We classify the finite dimensional indecomposable sl(m/n)-modules with at
least a typical or singly atypical primitive weight. We do this classification
not only for weight modules, but also for generalized weight modules. We obtain
that such a generalized weight module is simply a module obtained by
``linking'' sub-quotient modules of generalized Kac-modules. By applying our
results to sl(m/1), we have in fact completely classified all finite
dimensional sl(m/1)-modules.Comment: 17 pages, Late
Stochastic Ergodicity Breaking: a Random Walk Approach
The continuous time random walk (CTRW) model exhibits a non-ergodic phase
when the average waiting time diverges. Using an analytical approach for the
non-biased and the uniformly biased CTRWs, and numerical simulations for the
CTRW in a potential field, we obtain the non-ergodic properties of the random
walk which show strong deviations from Boltzmann--Gibbs theory. We derive the
distribution function of occupation times in a bounded region of space which,
in the ergodic phase recovers the Boltzmann--Gibbs theory, while in the
non-ergodic phase yields a generalized non-ergodic statistical law.Comment: 5 pages, 3 figure
Manufacture of DPFC-DMS polymer in the SKG range
BPFC-DMS block copolymers were synthesized on a pre-pilot scale (i.e., to 5 Kg lots) and subsequently fabricated into clear, colorless films. Details of the synthesis procedures, property determinations, and film casting techniques are presented. Solubility, viscosity and molecular weight characteristics of the resulting product are reported
Three-dimensional carrier-dynamics simulation of terahertz emission from photoconductive switches
A semi-classical Monte Carlo model for studying three-dimensional carrier
dynamics in photoconductive switches is presented. The model was used to
simulate the process of photoexcitation in GaAs-based photoconductive antennas
illuminated with pulses typical of mode-locked Ti:Sapphire lasers. We analyzed
the power and frequency bandwidth of THz radiation emitted from these devices
as a function of bias voltage, pump pulse duration and pump pulse location. We
show that the mechanisms limiting the THz power emitted from photoconductive
switches fall into two regimes: when illuminated with short duration (<40 fs)
laser pulses the energy distribution of the Gaussian pulses constrains the
emitted power, while for long (>40 fs) pulses, screening is the primary
power-limiting mechanism. A discussion of the dynamics of bias field screening
in the gap region is presented. The emitted terahertz power was found to be
enhanced when the exciting laser pulse was in close proximity to the anode of
the photoconductive emitter, in agreement with experimental results. We show
that this enhancement arises from the electric field distribution within the
emitter combined with a difference in the mobilities of electrons and holes.Comment: 7 pages, 7 figure
Confinement effects in a guided-wave interferometer with millimeter-scale arm separation
Guided-wave atom interferometers measure interference effects using atoms
held in a confining potential. In one common implementation, the confinement is
primarily two-dimensional, and the atoms move along the nearly free dimension
under the influence of an off-resonant standing wave laser beam. In this
configuration, residual confinement along the nominally free axis can introduce
a phase gradient to the atoms that limits the arm separation of the
interferometer. We experimentally investigate this effect in detail, and show
that it can be alleviated by having the atoms undergo a more symmetric motion
in the guide. This can be achieved by either using additional laser pulses or
by allowing the atoms to freely oscillate in the potential. Using these
techniques, we demonstrate interferometer measurement times up to 72 ms and arm
separations up to 0.42 mm with a well controlled phase, or times of 0.91 s and
separations of 1.7 mm with an uncontrolled phase.Comment: 14 pages, 6 figure
Nonthermal X-Ray Emission from G266.2-1.2 (RX J0852.0-4622)
The newly discovered supernova remnant G266.2-1.2 (RX J0852.0-4622), along
the line of sight to the Vela SNR, was observed with ASCA for 120 ks. We find
that the X-ray spectrum is featureless, and well described by a power law,
extending to three the class of shell-type SNRs dominated by nonthermal X-ray
emission. Although the presence of the Vela SNR compromises our ability to
accurately determine the column density, the GIS data appear to indicate
absorption considerably in excess of that for Vela itself, indicating that
G266.2-1.2 may be several times more distant. An unresolved central source may
be an associated neutron star, though difficulties with this interpretation
persist.Comment: 4 pages, 5 figures, uses aipproc.sty & epsfig.sty. To appear in
"Young Supernova Remnants" (11th Annual Astrophysics Conference in Maryland),
S. S. Holt & U. Hwang (eds), AIP, New York (2001
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