591 research outputs found
Rehabilitation of hand in subacute tetraplegic patients based on brain computer interface and functional electrical stimulation: a randomised pilot study
Objective. To compare neurological and functional outcomes between two groups of hospitalised
patients with subacute tetraplegia. Approach. Seven patients received 20 sessions of brain
computer interface (BCI) controlled functional electrical stimulation (FES) while five patients
received the same number of sessions of passive FES for both hands. The neurological
assessment measures were event related desynchronization (ERD) during movement attempt,
Somatosensory evoked potential (SSEP) of the ulnar and median nerve; assessment of hand
function involved the range of motion (ROM) of wrist and manual muscle test. Main results.
Patients in both groups initially had intense ERD during movement attempt that was not
restricted to the sensory-motor cortex. Following the treatment, ERD cortical activity restored
towards the activity in able-bodied people in BCI-FES group only, remaining wide-spread in
FES group. Likewise, SSEP returned in 3 patients in BCI-FES group, having no changes in FES
group. The ROM of the wrist improved in both groups. Muscle strength significantly improved
for both hands in BCI-FES group. For FES group, a significant improvement was noticed for
right hand flexor muscles only. Significance. Combined BCI-FES therapy results in better
neurological recovery and better improvement of muscle strength than FES alone. For spinal
cord injured patients, BCI-FES should be considered as a therapeutic tool rather than solely a
long-term assistive device for the restoration of a lost function
Goddard Robotic Telescope - Optical Follow-up of GRBs and Coordinated Observations of AGNs -
Since it is not possible to predict when a Gamma-Ray Burst (GRB) will occur
or when Active Galactic Nucleus (AGN) flaring activity starts,
follow-up/monitoring ground telescopes must be located as uniformly as possible
all over the world in order to collect data simultaneously with Fermi and Swift
detections. However, there is a distinct gap in follow-up coverage of
telescopes in the eastern U.S. region based on the operations of Swift.
Motivated by this fact, we have constructed a 14" fully automated optical
robotic telescope, Goddard Robotic Telescope (GRT), at the Goddard Geophysical
and Astronomical Observatory. The aims of our robotic telescope are 1) to
follow-up Swift/Fermi GRBs and 2) to perform the coordinated optical
observations of Fermi Large Area Telescope (LAT) AGN. Our telescope system
consists of off-the-shelf hardware. With the focal reducer, we are able to
match the field of view of Swift narrow instruments (20' x 20'). We started
scientific observations in mid-November 2008 and GRT has been fully remotely
operated since August 2009. The 3 sigma upper limit in a 30-second exposure in
the R filter is ~15.4 mag; however, we can reach to ~18 mag in a 600-second
exposures. Due to the weather condition at the telescope site, our observing
efficiency is 30-40% on average.Comment: 14 pages, 14 figures, accepted for publication in ASR special issue
on Neutron Stars and Gamma Ray Burst
Administration of human chorionic gonadotropin at embryo transfer induced ovulation of a first-wave dominant follicle and increased progesterone and transfer pregnancy rates
Beef Cattle Research, 2011 is known as Cattlemen’s Day, 2011Embryo transfer (ET) has become more widespread in recent years as a way to improve
cattle genetics. According to the annual statistical survey of the American Embryo
Transfer Association, more than 200,000 fresh and frozen bovine embryos were
transferred in 2008. But despite advancements in reproductive technologies that have
occurred since ET was commercialized in the 1970s, industrywide pregnancy rates are
only 62.4 and 56.9% for fresh and frozen-thawed ET, respectively. Using ET helps
avoid problems from failed fertilization; however, fertilization failure has been characterized
as a relatively unimportant factor of pregnancy loss. Approximately 10% of pregnancy
failures resulted from fertilization failure and another 10% from failed embryo
development. Approximately 20 to 25% of the pregnancy loss in an ET program could
be characterized as early embryonic loss
One-Dimensional Flows in the Quantum Hall System
We construct the c-function whose gradient determines the RG flow of the
conductivities (sigma_xy and sigma_xx) for a quantum Hall system, subject to
two assumptions. (1) We take the flow to be invariant with respect to the
infinite discrete symmetry group, recently proposed by several workers to
explain the `superuniversality' of the delocalization exponents in these
systems. (2) We also suppose the flow to be `quasi-holomorphic' (which we make
precise) in the sense that it is as close as possible to a one-dimensional flow
in the complex parameter sigma_xy +i sigma_xx. These assumptions together with
the known asymptotic behaviour for large sigma_xx, completely determine the
c-function, and so the phase diagram, for these systems. A complete description
of the RG flow also requires a metric in addition to the c-function, and we
identify the features which are required for this by the RG. A similar
construction produces the c-function for other systems enjoying an infinite
discrete symmetry, such as for supersymmetric QED.Comment: 17 pages of Te
Potential energy landscape-based extended van der Waals equation
The inherent structures ({\it IS}) are the local minima of the potential
energy surface or landscape, , of an {\it N} atom system.
Stillinger has given an exact {\it IS} formulation of thermodynamics. Here the
implications for the equation of state are investigated. It is shown that the
van der Waals ({\it vdW}) equation, with density-dependent and
coefficients, holds on the high-temperature plateau of the averaged {\it IS}
energy. However, an additional ``landscape'' contribution to the pressure is
found at lower . The resulting extended {\it vdW} equation, unlike the
original, is capable of yielding a water-like density anomaly, flat isotherms
in the coexistence region {\it vs} {\it vdW} loops, and several other desirable
features. The plateau energy, the width of the distribution of {\it IS}, and
the ``top of the landscape'' temperature are simulated over a broad reduced
density range, , in the Lennard-Jones fluid. Fits to the
data yield an explicit equation of state, which is argued to be useful at high
density; it nevertheless reproduces the known values of and at the
critical point
Exogenous NG-hydroxy-l-arginine causes nitrite production in vascular smooth muscle cells in the absence of nitric oxide synthase activity
AbstractNitric oxide (NO) production from exogenous NG-hydroxy-l-arginine (OH-l-Arg) was investigated in rat aortic smooth muscle cells in culture by measuring nitrite accumulation in the culture medium. As well, the interaction between OH-l-Arg and l-arginine uptake via the y+ cationic amino acid transporter was studied. In cells without NO-synthase activity, OH-l-Arg (1–1000 μM) induced a dose-dependent nitrite production with a half-maximal effective concentration (EC50) of 18.0 ± 1.5 μM (n = 4–7). This nitrite accumulation was not inhibited by the NO-synthase inhibitor NG-nitro-l-arginine methyl ester, l-NAME (300 μM). In contrast, it was abolished by miconazole (100 μM), an inhibitor of cytochrome P450. Incubation of vascular smooth muscle cells with LPS (10 μgml) induced an l-name inhibited nitrite accumulation, but did not enhance the OH-l-Arg induced nitrite production. OH-l-Arg and other cationic amino acids, L-lysine and l-ornithine, competitively inhibited [3H]-l-arginine uptake m rat aortic smooth muscle cells, with inhibition constants of 195 ± 23 μM(n = 12), 260 ± 40 μM(n= 5) and 330 ± 10 μM(n = 5), respectively. These results show that OH-l-Arg is recognized by the cationic l-amino acid carrier present in vascular smooth muscle cells and can be oxidized to NO and nitrite in these cells in the absence of NO-synthase, probably by cytochrome P450 or by a reaction involving a cytochrome P450 byproduct
Combination anti-Aβ treatment maximizes cognitive recovery and rebalances mTOR signaling in APP mice
Drug development for Alzheimer\u27s disease has endeavored to lower amyloid β (Aβ) by either blocking production or promoting clearance. The benefit of combining these approaches has been examined in mouse models and shown to improve pathological measures of disease over single treatment; however, the impact on cellular and cognitive functions affected by Aβ has not been tested. We used a controllable APP transgenic mouse model to test whether combining genetic suppression of Aβ production with passive anti-Aβ immunization improved functional outcomes over either treatment alone. Compared with behavior before treatment, arresting further Aβ production (but not passive immunization) was sufficient to stop further decline in spatial learning, working memory, and associative memory, whereas combination treatment reversed each of these impairments. Cognitive improvement coincided with resolution of neuritic dystrophy, restoration of synaptic density surrounding deposits, and reduction of hyperactive mammalian target of rapamycin signaling. Computational modeling corroborated by in vivo microdialysis pointed to the reduction of soluble/exchangeable Aβ as the primary driver of cognitive recovery
Relativistic effects and quasipotential equations
We compare the scattering amplitude resulting from the several quasipotential
equations for scalar particles. We consider the Blankenbecler-Sugar, Spectator,
Thompson, Erkelenz-Holinde and Equal-Time equations, which were solved
numerically without decomposition into partial waves. We analyze both
negative-energy state components of the propagators and retardation effects. We
found that the scattering solutions of the Spectator and the Equal-Time
equations are very close to the nonrelativistic solution even at high energies.
The overall relativistic effect increases with the energy. The width of the
band for the relative uncertainty in the real part of the scattering
matrix, due to different dynamical equations, is largest for
backward-scattering angles where it can be as large as 40%.Comment: Accepted for publication in Phys. Rev.
Effects of a nanoscopic filler on the structure and dynamics of a simulated polymer melt and the relationship to ultra-thin films
We perform molecular dynamics simulations of an idealized polymer melt
surrounding a nanoscopic filler particle to probe the effects of a filler on
the local melt structure and dynamics. We show that the glass transition
temperature of the melt can be shifted to either higher or lower
temperatures by appropriately tuning the interactions between polymer and
filler. A gradual change of the polymer dynamics approaching the filler surface
causes the change in the glass transition. We also find that while the bulk
structure of the polymers changes little, the polymers close to the surface
tend to be elongated and flattened, independent of the type of interaction we
study. Consequently, the dynamics appear strongly influenced by the
interactions, while the melt structure is only altered by the geometric
constraints imposed by the presence of the filler. Our findings show a strong
similarity to those obtained for ultra-thin polymer films (thickness nm) suggesting that both ultra-thin films and filled-polymer systems might
be understood in the same context
Opto-mechanical measurement of micro-trap via nonlinear cavity enhanced Raman scattering spectrum
High-gain resonant nonlinear Raman scattering on trapped cold atoms within a
high-fineness ring optical cavity is simply explained under a nonlinear
opto-mechanical mechanism, and a proposal using it to detect frequency of
micro-trap on atom chip is presented. The enhancement of scattering spectrum is
due to a coherent Raman conversion between two different cavity modes mediated
by collective vibrations of atoms through nonlinear opto-mechanical couplings.
The physical conditions of this technique are roughly estimated on Rubidium
atoms, and a simple quantum analysis as well as a multi-body semiclassical
simulation on this nonlinear Raman process is conducted.Comment: 7 pages, 2 figure
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