3,868 research outputs found
Primary Amoebic (Naegleria fowleri) Meningoencephalitis Presenting as Status Epilepticus
Primary amebic meningoencephalitis (PAM) is a rare entity. Usual presenting features are fever, headache and seizures with meningeal signs and this disease carries high mortality rate. We present a case report of PAM presenting as status epilepticus
Self-consistent quantum effects in the quark meson coupling model
We derive the equation of state of nuclear matter including vacuum
polarization effects arising from the nucleons and the sigma mesons in the
quark-meson coupling model which incorporates explicitly quark degrees of
freedom with quark coupled to the scalar and vector mesons. This leads to a
softer equation of state for nuclear matter giving a lower value of
incompressibility than would be reached without quantum effects. The {\it
in-medium} nucleon and sigma meson masses are also calculated in a
self-consistent manner.Comment: 10 pages, latex, 5 figure
Bright White-Light Emitting Manganese and Copper Co-Doped ZnSe Quantum Dots
Cataloged from PDF version of article.Doubly doped quantum dots with highly efficient (17 %) white-light emission (WLE) have been directly synthesized using a one-pot hot-injection technique (see picture). The generation of WLE was due to the judicious manipulation of the synthesis strategy for the co-doping of the host material-ZnSe quantum dots-with Mn and Cu. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
Time-Average Measurement of Velocity, Density, Temperature, and Turbulence Using Molecular Rayleigh Scattering
Measurement of time-averaged velocity, density, temperature, and turbulence in gas flows using a nonintrusive, point-wise measurement technique based on molecular Rayleigh scattering is discussed. Subsonic and supersonic flows in a 25.4-mm diameter free jet facility were studied. The developed instrumentation utilizes a Fabry-Perot interferometer to spectrally resolve molecularly scattered light from a laser beam passed through a gas flow. The spectrum of the scattered light contains information about velocity, density, and temperature of the gas. The technique uses a slow scan, low noise 16-bit depth CCD camera to record images of the fringes formed by Rayleigh scattered light passing through the interferometer. A kinetic theory model of the Rayleigh scattered light is used in a nonlinear least squares fitting routine to estimate the unknown parameters from the fringe images. The ability to extract turbulence information from the fringe image data proved to be a challenge since the fringe is broadened by not only turbulence, but also thermal fluctuations and aperture effects from collecting light over a range of scattering angles. Figure 1 illustrates broadening of a Rayleigh spectrum typical of flow conditions observed in this work due to aperture effects and turbulence for a scattering angle, chi(sub s), of 90 degrees, f/3.67 collection optics, mean flow velocity, u(sub k), of 300 m/s, and turbulent velocity fluctuations, sigma (sub uk), of 55 m/s. The greatest difficulty in processing the image data was decoupling the thermal and turbulence broadening in the spectrum. To aid in this endeavor, it was necessary to seed the ambient air with smoke and dust particulates; taking advantage of the turbulence broadening in the Mie scattering component of the spectrum of the collected light (not shown in the figure). The primary jet flow was not seeded due to the difficulty of the task. For measurement points lacking particles, velocity, density, and temperature information could reliably be recovered, however the turbulence estimates contained significant uncertainty. Resulting flow parameter estimates are presented for surveys of Mach 0.6, 0.95, and 1.4 jet flows. Velocity, density, and temperature were determined with accuracies of 5 m/s, 1.5%, and 1%, respectively, in flows with no particles present, and with accuracies of 5 m/s, 1-4%, and 2% in flows with particles. Comparison with hotwire data for the Mach 0.6 condition demonstrated turbulence estimates with accuracies of about 5 m/s outside the jet core where Mie scattering from dust/smoke particulates aided in the estimation of turbulence. Turbulence estimates could not be recovered with any significant accuracy for measurement points where no particles were present
FORMULATION DESIGN AND IN VITRO EVALUATION OF BILAYER SUSTAINED RELEASE MATRIX TABLETS OF DOXOFYLLINE
Objective: To develop bilayer matrix tablet of Doxofylline by providing a loading dose followed by the maintenance dose that suppose to enhance the therapeutic efficacy the drug for acute and sustainable asthma.Methods: Both immediate release layer and sustained release layer were prepared by wet granulation methods. Different Pre compression and post compression characterization of the tablet were carried out. Swelling studies were carried out for all the formulation. To optimise the immediate release layer, similarity (f2) and difference factor (f1) were calculated and optimised IR formulation was used for all formulations of bilayer tablet. In-vitro release studies were carried out in USP II paddle type dissolution apparatus for different formulations and release kinetic studies were carried out different kinetic model. FTIR and DSC studies were carried out for pure drug Doxofylline, IR layer and SR layer of optimised formulation to know the physical and chemical compatibility of drug and excipients. Accelerated stability studies were carried out to confirm the stability of dosage forms.Results: Pre compression and post compression parameters satisfied with pharmacopeia specifications. The formulation that contained highest percent of HPMC had highest swelling index. Formulation DBMF6 showed an initial release of 44% of drug within one hour as the loading dose and remaining drug were sustained release up to 12 h. Release kinetic followed Hixon-Crowell kinetic model with drug release mechanism quasi-fickian diffusion. From accelerated stability studies no significant changes in physicochemical properties were noticed.Conclusion: Doxofylline bilayer matrix tablets were successfully developed and can be used as an alternative to the conventional dosage form because it can be therapeutically beneficial for management of asthma.Â
Synergistic Hypergolic Ignition of Amino End Group in Monomers and Polymers
A few monomers, oligomers and polymers with amino end groups have been discovered to undergo synergistic ignition with red fuming nitric acid (RFNA) when mixed with large quantities of magnesium powder. Aluminium powder under similar conditions does not ignite the mixture while powders of Zn, Co and Cu cause the ignition. Amongst the polymers used in the experiment commercially available nylon 6 is the most important which may be used as a binder for rocket propellant fuel grains, hypergolic with RFNA. Degree of polymerisation or the chain length of the polymers does not drastically affect the synergistic ignition of the polymer mixture with magnesium powder but high molecular weight and fully aromatised polymers like Kevlar and Nomex fail to ignite under similar conditions. Based upon the earlier work of the authors, explanations for the phenomena oberved have been provided in terms of creation of hot spots leading to ignition at the amino end groups
Prospects for GMRT to Observe Radio Waves from UHE Particles Interacting with the Moon
Ultra high energy (UHE) particles of cosmic origin impact the lunar regolith
and produce radio signals through Askaryan effect, signals that can be detected
by Earth based radio telescopes. We calculate the expected sensitivity for
observation of such events at the Giant Metrewave Radio Telescope (GMRT), both
for UHE cosmic rays (CR) and UHE neutrino interactions. We find that for 30
days of observation time a significant number of detectable events is expected
above eV for UHECR or neutrino fluxes close to the current limits.
Null detection over a period of 30 days will lower the experimental bounds on
UHE particle fluxes by magnitudes competitive to both present and future
experiments at the very highest energies.Comment: 21 pages, 9 figure
Inflation with improved D3-brane potential and the fine tunings associated with the model
We investigate brane-antibrane inflation in a warped deformed conifold
background that includes contributions to the potential arising from imaginary
anti-self-dual (IASD) fluxes including the term with irrational scaling
dimension discovered recently. We find that the model can give rise to required
number of e-foldings; observational constraint on COBE normalization is easily
satisfied and low value of the tensor to scalar ratio of perturbations is
achieved. We observe that these corrections to the effective potential help in
relaxing the severe fine tunings associated with the earlier analysis.Comment: 8 pages, 4 figures; typos corrected, minor clarifications and new
refs added, to appear in epj
Algorithmic aspects of disjunctive domination in graphs
For a graph , a set is called a \emph{disjunctive
dominating set} of if for every vertex , is either
adjacent to a vertex of or has at least two vertices in at distance
from it. The cardinality of a minimum disjunctive dominating set of is
called the \emph{disjunctive domination number} of graph , and is denoted by
. The \textsc{Minimum Disjunctive Domination Problem} (MDDP)
is to find a disjunctive dominating set of cardinality .
Given a positive integer and a graph , the \textsc{Disjunctive
Domination Decision Problem} (DDDP) is to decide whether has a disjunctive
dominating set of cardinality at most . In this article, we first propose a
linear time algorithm for MDDP in proper interval graphs. Next we tighten the
NP-completeness of DDDP by showing that it remains NP-complete even in chordal
graphs. We also propose a -approximation
algorithm for MDDP in general graphs and prove that MDDP can not be
approximated within for any unless NP
DTIME. Finally, we show that MDDP is
APX-complete for bipartite graphs with maximum degree
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