1,847 research outputs found
Extracellular signal-regulated kinases mediate the enhancing effects of inflammatory mediators on resurgent currents in dorsal root ganglion neurons
Previously we reported that a group of inflammatory mediators significantly enhanced resurgent currents in dorsal root ganglion neurons. To understand the underlying intracellular signaling mechanism, we investigated the effects of inhibition of extracellular signal-regulated kinases and protein kinase C on the enhancing effects of inflammatory mediators on resurgent currents in rat dorsal root ganglion neurons. We found that the extracellular signal-regulated kinases inhibitor U0126 completely prevented the enhancing effects of the inflammatory mediators on both Tetrodotoxin-sensitive and Tetrodotoxin-resistant resurgent currents in both small and medium dorsal root ganglion neurons. U0126 substantially reduced repetitive firing in small dorsal root ganglion neurons exposed to inflammatory mediators, consistent with prevention of resurgent current amplitude increases. The protein kinase C inhibitor Bisindolylmaleimide I also showed attenuating effects on resurgent currents, although to a lesser extent compared to extracellular signal-regulated kinases inhibition. These results indicate a critical role of extracellular signal-regulated kinases signaling in modulating resurgent currents and membrane excitability in dorsal root ganglion neurons treated with inflammatory mediators. It is also suggested that targeting extracellular signal-regulated kinases-resurgent currents might be a useful strategy to reduce inflammatory pain
ALD grown zinc oxide with controllable electrical properties
The paper presents results for zinc oxide films grown at low temperature
regime by Atomic Layer Deposition (ALD). We discuss electrical properties of
such films and show that low temperature deposition results in oxygen-rich ZnO
layers in which free carrier concentration is very low. For optimized ALD
process it can reach the level of 10^15 cm-3, while mobility of electrons is
between 20 and 50 cm2/Vs. Electrical parameters of ZnO films deposited by ALD
at low temperature regime are appropriate for constructing of the ZnO-based p-n
and Schottky junctions. We demonstrate that such junctions are characterized by
the rectification ratio high enough to fulfill requirements of 3D memories and
are deposited at temperature 100degC which makes them appropriate for
deposition on organic substrates.Comment: 29 pages, 9 figures, 64 references, review pape
Quantum creep and quantum creep transitions in 1D sine-Gordan chains
Discrete sine-Gordon (SG) chains are studied with path-integral molecular
dynamics. Chains commensurate with the substrate show the transition from
collective quantum creep to pinning at bead masses slightly larger than those
predicted from the continuous SG model. Within the creep regime, a field-driven
transition from creep to complete depinning is identified. The effects of
disorder in the external potential on the chain's dynamics depend on the
potential's roughness exponent , i.e., quantum and classical fluctuations
affect the current self-correlation functions differently for .Comment: 4 pages, 3 figure
Why Matrix theory works for oddly shaped membranes
We give a simple proof of why there is a Matrix theory approximation for a
membrane shaped like an arbitrary Riemann surface. As corollaries, we show that
noncompact membranes cannot be approximated by matrices and that the Poisson
algebra on any compact phase space is U(infinity). The matrix approximation
does not appear to work properly in theories such as IIB string theory or
bosonic membrane theory where there is no conserved 3-form charge to which the
membranes couple.Comment: 8 pages, 4 figures, revtex; references adde
EPRL/FK Group Field Theory
The purpose of this short note is to clarify the Group Field Theory vertex
and propagators corresponding to the EPRL/FK spin foam models and to detail the
subtraction of leading divergences of the model.Comment: 20 pages, 2 figure
Morita Duality and Large-N Limits
We study some dynamical aspects of gauge theories on noncommutative tori. We
show that Morita duality, combined with the hypothesis of analyticity as a
function of the noncommutativity parameter Theta, gives information about
singular large-N limits of ordinary U(N) gauge theories, where the large-rank
limit is correlated with the shrinking of a two-torus to zero size. We study
some non-perturbative tests of the smoothness hypothesis with respect to Theta
in theories with and without supersymmetry. In the supersymmetric case this is
done by adapting Witten's index to the present situation, and in the
nonsupersymmetric case by studying the dependence of energy levels on the
instanton angle. We find that regularizations which restore supersymmetry at
high energies seem to preserve Theta-smoothness whereas nonsupersymmetric
asymptotically free theories seem to violate it. As a final application we use
Morita duality to study a recent proposal of Susskind to use a noncommutative
Chern-Simons gauge theory as an effective description of the Fractional Hall
Effect. In particular we obtain an elegant derivation of Wen's topological
order.Comment: 41 pages, Harvmac. Some corrections to section 6.3. Comments added on
Hall Effec
Sustainable Reduction of Sleepiness through Salutogenic Self-Care Procedure in Lunch Breaks: A Pilot Study
The aim of the study was to elucidate the immediate, intermediate, and anticipatory sleepiness reducing effects of a salutogenic self-care procedure called progressive muscle relaxation (PMR), during lunch breaks. The second exploratory aim deals with determining the onset and long-term time course of sleepiness changes. In order to evaluate the intraday range and interday change of the proposed relaxation effects, 14 call center agents were assigned to either a daily 20-minute self-administered PMR or a small talk (ST) group during a period of seven months. Participants' levels of sleepiness were analyzed in a controlled trial using anticipatory, postlunchtime, and afternoon changes of sleepiness as indicated by continuously determined objective reaction time measures (16,464 measurements) and self-reports administered five times per day, once per month (490 measurements). Results indicate that, in comparison to ST, the PMR break (a) induces immediate, intermediate, and anticipatory reductions in sleepiness; (b) these significant effects remarkably show up after one month, and sleepiness continues to decrease for at least another five months. Although further research is required referring to the specific responsible mediating variables, our results suggest that relaxation based lunch breaks are both accepted by employees and provide a sustainable impact on sleepiness
Demonstrating high-precision photometry with a CubeSat: ASTERIA observations of 55 Cancri e
ASTERIA (Arcsecond Space Telescope Enabling Research In Astrophysics) is a 6U
CubeSat space telescope (10 cm x 20 cm x 30 cm, 10 kg). ASTERIA's primary
mission objective was demonstrating two key technologies for reducing
systematic noise in photometric observations: high-precision pointing control
and high-stabilty thermal control. ASTERIA demonstrated 0.5 arcsecond RMS
pointing stability and 10 milliKelvin thermal control of its camera
payload during its primary mission, a significant improvement in pointing and
thermal performance compared to other spacecraft in ASTERIA's size and mass
class. ASTERIA launched in August 2017 and deployed from the International
Space Station (ISS) November 2017. During the prime mission (November 2017 --
February 2018) and the first extended mission that followed (March 2018 - May
2018), ASTERIA conducted opportunistic science observations which included
collection of photometric data on 55 Cancri, a nearby exoplanetary system with
a super-Earth transiting planet. The 55 Cancri data were reduced using a custom
pipeline to correct CMOS detector column-dependent gain variations. A Markov
Chain Monte Carlo (MCMC) approach was used to simultaneously detrend the
photometry using a simple baseline model and fit a transit model. ASTERIA made
a marginal detection of the known transiting exoplanet 55 Cancri e
(~\Rearth), measuring a transit depth of ppm. This is the
first detection of an exoplanet transit by a CubeSat. The successful detection
of super-Earth 55 Cancri e demonstrates that small, inexpensive spacecraft can
deliver high-precision photometric measurements.Comment: 23 pages, 9 figures. Accepted in A
Recommended from our members
Clinical and radiologic features of extraskeletal myxoid chondrosarcoma including initial presentation, local recurrence, and metastases
Background: The aim of the study was to evaluate the clinical and imaging features of extraskeletal myxoid chondrosarcoma (EMC) including initial presentation, recurrence, and metastases. Patients and methods. In this institutional review board-approved retrospective study, imaging features of 13 patients with pathologically proven EMC seen from August 1995 to December 2011 were analyzed. The group included 3 women and 10 men and the mean age was 54 years (range 29–73 years). Imaging studies were evaluated by two radiologists in consensus. Location, size, and imaging features of primary tumors were recorded as well as the presence of recurrent disease and location of metastases. Results: Among 13 patients, 3 died during the timeframe of this study. Nine patients had primary tumor in the lower extremity, and average tumor size was 9.3 cm (range 3.3–18 cm). On MRI, primary tumors were hyperintense on T2, isointense to muscle on T1, and demonstrated peripheral/septal enhancement. Three patients had local recurrence and 12 had metastatic disease, with lung involvement being the most common. Tumor density on contrast enhanced CT ranged from 8.2 to 82.9 Hounsfield unit (HU). FDG-PET/CT imaging was performed in 3 patients. One patient had no FDG avid disease and 2 patients had metastatic disease with standard uptake values (SUV) of 2.8 and 7.4. The patient with intense FDG uptake demonstrated more solid appearing tumor burden and had the shortest survival. Conclusions: EMC is a rare tumor that often occurs in the lower extremities and frequently metastasizes to the lungs. Increased tumor density and increased FDG uptake may be related to more aggressive disease
The Measurement of Territorial Differences in the Information Society
Glutamine synthetase (GS, EC 6.3.1.2; also known as γ-glutamyl:ammonia ligase) catalyzes the ATP-dependent condensation of glutamate and ammonia to form glutamine. The enzyme has essential roles in different tissues and species, which have led to its consideration as a drug or an herbicide target. In this article, we describe studies aimed at the discovery of new antimicrobial agents targeting Mycobacterium tuberculosis, the causative pathogen of tuberculosis. A number of distinct classes of GS inhibitors with an IC50 of micromolar value or better were identified via high-throughput screening. A commercially available purine analogue similar to one of the clusters identified (the diketopurines), 1-[(3,4-dichlorophenyl)methyl]-3,7-dimethyl-8-morpholin-4-yl-purine-2,6-dione, was also shown to inhibit the enzyme, with a measured IC50 of 2.5 ± 0.4 μM. Two X-ray structures are presented: one is a complex of the enzyme with the purine analogue alone (2.55-Å resolution), and the other includes the compound together with methionine sulfoximine phosphate, magnesium and phosphate (2.2-Å resolution). The former represents a relaxed, inactive conformation of the enzyme, while the latter is a taut, active one. These structures show that the compound binds at the same position in the nucleotide site, regardless of the conformational state. The ATP-binding site of the human enzyme differs substantially, explaining why it has an ∼ 60-fold lower affinity for this compound than the bacterial GS. As part of this work, we devised a new synthetic procedure for generating l-(SR)-methionine sulfoximine phosphate from l-(SR)-methionine sulfoximine, which will facilitate future investigations of novel GS inhibitors
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