3,530 research outputs found
Effects of weightlessness on tissue proliferation
The repair of bone marrow stroma following mechanical injury was studied to obtain baseline data for a proposed space experiment regarding the effect of weightlessness on marrow stroma and other proliferating cell systems
A three-dimensional current meter for estuarine applications
A curr ent meter that is capable of measuring the high-frequency fluctuations of the three-dimensional velocity vector has been developed. The meter works on a doppler-shift principle. At high velocities, the meter has been shown to have an accuracy of better than 3%
A theory-based approach to understanding condom errors and problems reported by men attending an STI clinic
The official published version can be accessed from the link below - Copyright @ 2008 Springer VerlagWe employed the information–motivation–behavioral skills (IMB) model to guide an investigation of correlates for correct condom use among 278 adult (18–35 years old) male clients attending a sexually transmitted infection (STI) clinic. An anonymous questionnaire aided by a CD-recording of the questions was administered. Linear Structural Relations Program was used to conduct path analyses of the hypothesized IMB model. Parameter estimates showed that while information did not directly affect behavioral skills, it did have a direct (negative) effect on condom use errors. Motivation had a significant direct (positive) effect on behavioral skills and a significant indirect (positive) effect on condom use errors through behavioral skills. Behavioral skills had a direct (negative) effect on condom use errors. Among men attending a public STI clinic, these findings suggest brief, clinic-based, safer sex programs for men who have sex with women should incorporate activities to convey correct condom use information, instill motivation to use condoms correctly, and directly enhance men’s behavioral skills for correct use of condoms
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One Year Follow-up of a Randomized, Double-Blind, Placebo-Controlled Trial of Percutaneous Peripheral Nerve Stimulation for Chronic Neuropathic Pain Following Amputation
Abstract
INTRODUCTION
Over 85% of patients experience residual limb (RLP) and/or phantom limb (PLP) pain following amputation. Peripheral nerve stimulation (PNS) is a non-opioid approach to relieve postamputation neuropathic pain. A recent multicenter, randomized, double-blind, placebo-controlled study using a novel percutaneous PNS system demonstrated clinically and statistically significant improvements in pain and pain interference with PNS compared to placebo (Gilmore et al, 2019). This work presents prospective 1-yr follow-up to assess durability of pain relief and functional improvements.
METHODS
Over 85% of patients experience residual limb (RLP) and/or phantom limb (PLP) pain following amputation. Peripheral nerve stimulation (PNS) is a non-opioid approach to relieve post-amputation neuropathic pain. A recent multicenter, randomized, double-blind, placebo-controlled study using a novel percutaneous PNS system demonstrated clinically and statistically significant improvements in pain and pain interference with PNS compared to placebo (Gilmore et al, 2019). This work presents prospective one-year follow-up to assess durability of pain relief and functional improvements.
RESULTS
A significantly greater proportion of subjects who completed the 12-mo visit reported = 50% pain relief on the BPI-SF (5/8, 63%; average pain relief = 73% among responders) compared to the placebo group at the time of crossover (0/14, 0%, P = .003; average pain relief = 23%). A majority of subjects also reported = 50% reductions in pain interference at 12 mo (5/8, 63%). Two of 13 (15%) subjects in the placebo group reported sustained improvements in pain interference (P = .06). Average reduction in pain interference among responders in the PNS group was 87%.
CONCLUSION
This work suggests that PNS delivered over 60 d may provide clinically significant and enduring pain relief, enabling improved function and potentially reducing the need for a permanently implanted system
Long-range interactions of metastable helium atoms
Polarizabilities, dispersion coefficients, and long-range atom-surface
interaction potentials are calculated for the n=2 triplet and singlet states of
helium using highly accurate, variationally determined, wave functions.Comment: RevTeX, epsf, 4 fig
Chandra and RXTE Spectra of the Burster GS 1826-238
Using simultaneous observations from Chandra and RXTE, we investigated the
LMXB GS 1826-238 with the goal of studying its spectral and timing properties.
The uninterrupted Chandra observation captured 6 bursts (RXTE saw 3 of the 6),
yielding a recurrence time of 3.54 +/- 0.03 hr. Using the proportional counter
array on board RXTE, we made a probable detection of 611 Hz burst oscillations
in the decaying phases of the bursts with an average rms signal amplitude of
4.8%. The integrated persistent emission spectrum can be described as the dual
Comptonization of ~ 0.3 keV soft photons by a plasma with kT_e ~ 20 keV and an
optical depth of about 2.6 (interpreted as emission from the accretion disk
corona), plus the Comptonization of hotter ~ 0.8 keV seed photons by a ~ 6.8
keV plasma (interpreted as emission from or near the boundary layer). We
discovered evidence for a neutral Fe K\alpha emission line, and we found
interstellar Fe L_II and Fe L_III absorption features. The burst spectrum can
be fit by fixing the disk Comptonization parameters to the persistent emission
best-fit values, and adding a blackbody. The blackbody/seed photon temperature
at the peak of the burst is ~ 1.8 keV and returns to ~ 0.8 keV over 200 s. The
blackbody radius is consistent with R_bb = 10.3-11.7 km assuming a distance of
6 kpc; however, by accounting for the fraction of the surface that is obscured
by the disk as a function of binary inclination, we determined the source
distance must actually be near 5 kpc in order for the stellar radius to lie
within the commonly assumed range of 10-12 km.Comment: Accepted for publication in ApJ; 13 pages, 6 figure
Diffusion entropy and waiting time statistics of hard x-ray solar flares
We analyze the waiting time distribution of time distances between two
nearest-neighbor flares. This analysis is based on the joint use of two
distinct techniques. The first is the direct evaluation of the distribution
function , or of the probability, , that no time
distance smaller than a given is found. We adopt the paradigm of the
inverse power law behavior, and we focus on the determination of the inverse
power index , without ruling out different asymptotic properties that
might be revealed, at larger scales, with the help of richer statistics. The
second technique, called Diffusion Entropy (DE) method, rests on the evaluation
of the entropy of the diffusion process generated by the time series. The
details of the diffusion process depend on three different walking rules, which
determine the form and the time duration of the transition to the scaling
regime, as well as the scaling parameter . With the first two rules the
information contained in the time series is transmitted, to a great extent, to
the transition, as well as to the scaling regime. The same information is
essentially conveyed, by using the third rules, into the scaling regime, which,
in fact, emerges very quickly after a fast transition process. We show that the
significant information hidden within the time series concerns memory induced
by the solar cycle, as well as the power index . The scaling parameter
becomes a simple function of , when memory is annihilated. Thus,
the three walking rules yield a unique and precise value of if the memory
is wisely taken under control, or cancelled by shuffling the data. All this
makes compelling the conclusion that .Comment: 23 pages, 13 figure
Transformation of SV40-immortalized human uroepithelial cells by 3-methylcholanthrene increases IFN- and Large T Antigen-induced transcripts
<p>Abstract</p> <p>Background</p> <p>Simian Virus 40 (SV40) immortalization followed by treatment of cells with 3-methylcholanthrene (3-MC) has been used to elicit tumors in athymic mice. 3-MC carcinogenesis has been thoroughly studied, however gene-level interactions between 3-MC and SV40 that could have produced the observed tumors have not been explored. The commercially-available human uroepithelial cell lines were either SV40-immortalized (HUC) or SV40-immortalized and then 3-MC-transformed (HUC-TC).</p> <p>Results</p> <p>To characterize the SV40 - 3MC interaction, we compared human gene expression in these cell lines using a human cancer array and confirmed selected changes by RT-PCR. Many viral Large T Antigen (Tag) expression-related changes occurred in HUC-TC, and it is concluded that SV40 and 3-MC may act synergistically to transform cells. Changes noted in <it>IFP 9-27, 2'-5' OAS, IF 56, MxA </it>and <it>MxAB </it>were typical of those that occur in response to viral exposure and are part of the innate immune response. Because interferon is crucial to innate immune host defenses and many gene changes were interferon-related, we explored cellular growth responses to exogenous IFN-γ and found that treatment impeded growth in tumor, but not immortalized HUC on days 4 - 7. Cellular metabolism however, was inhibited in <it>both </it>cell types. We conclude that IFN-γ <it>metabolic </it>responses were functional in both cell lines, but IFN-γ <it>anti-proliferative </it>responses functioned only in tumor cells.</p> <p>Conclusions</p> <p>Synergism of SV40 with 3-MC or other environmental carcinogens may be of concern as SV40 is now endemic in 2-5.9% of the U.S. population. In addition, SV40-immortalization is a generally-accepted method used in many research materials, but the possibility of off-target effects in studies carried out using these cells has not been considered. We hope that our work will stimulate further study of this important phenomenon.</p
Pattern formation and selection in quasi-static fracture
Fracture in quasi-statically driven systems is studied by means of a discrete
spring-block model. Developed from close comparison with desiccation
experiments, it describes crack formation induced by friction on a substrate.
The model produces cellular, hierarchical patterns of cracks, characterized by
a mean fragment size linear in the layer thickness, in agreement with
experiments. The selection of a stationary fragment size is explained by
exploiting the correlations prior to cracking. A scaling behavior associated
with the thickness and substrate coupling, derived and confirmed by
simulations, suggests why patterns have similar morphology despite their
disparity in scales.Comment: 4 pages, RevTeX, two-column, 5 PS figures include
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