3,260 research outputs found
Spontaneously generated atomic entanglement in free space: reinforced by incoherent pumping
We study spontaneously generated entanglement (SGE) between two identical
multilevel atoms in free space via vacuum-induced radiative coupling. We show
that the SGE in two-atom systems may initially increase with time but
eventually vanishes in the time scale determined by the excited state lifetime
and radiative coupling strength between the two atoms. We demonstrate that a
steady-state SGE can be established by incoherently pumping the excited states
of the two-atom system. We have shown that an appropriate rate of incoherent
pump can help producing optimal SGE. The multilevel systems offer us more
chanel to establish entanglement. The system under consideration could be
realized in a tight trap or atoms/ions doped in a solid substrate.Comment: have some difference with published version (please see PRA
SPECTROSCOPIC AND VOLUMETRIC TECHNIQUES FOR THE ESTIMATION OF IVABRADINE IMPURITY 3,3'-(PROPANE-1,3-DIYL)BIS(7,8-DIMETHOXY-1,3,4,5-TETRAHYDRO-2H-BENZO[D]AZEPIN-2-ONE)
Objective: Two simple and sensitive techniques - one spectrophotometric and one titrimetric- have been developed for the determination of 3,3'-(propane-1,3-diyl)bis(7,8-dimethoxy-1,3,4,5-tetrahydro-2H-benzo[d]azepin-2-one) commonly known as ivabradine impurity-9 (IVA-9).
Methods: The spectrophotometric method is based on the oxidation of drug impurity by excess cerium (IV) sulphate in acidic medium and the subsequent reaction of the remaining Ce(IV) with a known amount of ferrous ammonium sulphate. The resultant ferric ion is then made to react with thiocyanate in acid medium to form a brown coloured complex which is analyzed spectrophotometrically against the reagent blank. In the volumetric method, the un-reacted Ce(IV) is titrated against standard ferrous ammonium sulphate to estimate the quantity of IVA-9.
Results: The colored complex showed an absorption maximum at 479 nm when measured spectrophotometrically. The stated methods are validated statistically using the International Council for Harmonization guidelines-ICH Q2(R1) for precision and accuracy. The method showed a linear response from 0.5 to 100µg/ml with a correlation coefficient of 0.9985
Conclusion : No estimation techniques have been reported to date for the determination of this molecule. The proposed techniques may be used for the routine quantification in its pure form and also in presence of its parent drug molecule Ivabradine
Aging display's effect on interpretation of digital pathology slides
It is our conjecture that the variability of colors in a pathology image
effects the interpretation of pathology cases, whether it is diagnostic
accuracy, diagnostic confidence, or workflow efficiency. In this paper, digital
pathology images are analyzed to quantify the perceived difference in color
that occurs due to display aging, in particular a change in the maximum
luminance, white point, and color gamut. The digital pathology images studied
include diagnostically important features, such as the conspicuity of nuclei.
Three different display aging models are applied to images: aging of luminance
& chrominance, aging of chrominance only, and a stabilized luminance &
chrominance (i.e., no aging). These display models and images are then used to
compare conspicuity of nuclei using CIE deltaE2000, a perceptual color
difference metric. The effect of display aging using these display models and
images is further analyzed through a human reader study designed to quantify
the effects from a clinical perspective. Results from our reader study indicate
significant impact of aged displays on workflow as well as diagnosis as follow.
As compared to the originals (no-aging), slides with the effect of aging
simulated were significantly more difficult to read (p-value of 0.0005) and
took longer to score (p-value of 0.02). Moreover, luminance+chrominance aging
significantly reduced inter-session percent agreement of diagnostic scores
(p-value of 0.0418)
Geometric quantum computation using fictitious spin- 1/2 subspaces of strongly dipolar coupled nuclear spins
Geometric phases have been used in NMR, to implement controlled phase shift
gates for quantum information processing, only in weakly coupled systems in
which the individual spins can be identified as qubits. In this work, we
implement controlled phase shift gates in strongly coupled systems, by using
non-adiabatic geometric phases, obtained by evolving the magnetization of
fictitious spin-1/2 subspaces, over a closed loop on the Bloch sphere. The
dynamical phase accumulated during the evolution of the subspaces, is refocused
by a spin echo pulse sequence and by setting the delay of transition selective
pulses such that the evolution under the homonuclear coupling makes a complete
rotation. A detailed theoretical explanation of non-adiabatic geometric
phases in NMR is given, by using single transition operators. Controlled phase
shift gates, two qubit Deutsch-Jozsa algorithm and parity algorithm in a
qubit-qutrit system have been implemented in various strongly dipolar coupled
systems obtained by orienting the molecules in liquid crystal media.Comment: 37 pages, 17 figure
Lipopolysaccharide Increases the Expression of Multidrug Resistance-Associated Protein 1 (ABCC1) in Macrophages
Multidrug resistance-associated protein 1 (MRP-1) is a ubiquitously expressed member of the ATP-binding cassette transporter family. MRP-1 is one of the primary transporters of glutathione and glutathione conjugates. This protein also transports antiretroviral therapeutics, such as HIV-1 protease inhibitors (PI). We hypothesized that inflammatory mediators that activate macrophages would modify the expression and activity of MRP-1 in macrophages. Real time PCR assays western blots and calcein efflux assays were used to show that exposure of macrophage cell line RAW 264.7 to LPS increased expression of MRP-1 at the level of mRNA and protein, as well as at the level of functional activity. Treatment of macrophages with LPS resulted in 2-fold increases of MRP-1 expression or functional activity. LPS-mediated increases in calcein efflux were repressed by the MRP-specific inhibitor MK-571. These results suggest that the effectiveness of HIV-1 PI therapy may be compromised by the presence of opportunistic infections
Qubit metrology and decoherence
Quantum properties of the probes used to estimate a classical parameter can
be used to attain accuracies that beat the standard quantum limit. When qubits
are used to construct a quantum probe, it is known that initializing qubits
in an entangled "cat state," rather than in a separable state, can improve the
measurement uncertainty by a factor of . We investigate how the
measurement uncertainty is affected when the individual qubits in a probe are
subjected to decoherence. In the face of such decoherence, we regard the rate
at which qubits can be generated and the total duration of a
measurement as fixed resources, and we determine the optimal use of
entanglement among the qubits and the resulting optimal measurement uncertainty
as functions of and .Comment: 24 Pages, 3 Figure
Fluorescent Excitation of Spectral Lines in Planetary Nebulae
Fluorescent excitation of spectral lines is demonstrated as a function of
temperature-luminosity and the distance of the emitting region from the central
stars of planetary nebulae. The electron densities and temperatures are
determined, and the method is exemplified through a detailed analysis of
spectral observations of a high excitation PN, NGC 6741, observed by Hyung and
Aller(1997). Fluorescence should also be important in the determination of
element abundances. It is suggested that the method could be generally applied
to determine or constrain the luminosity and the region of spectral emission in
other intensively radiative sources such as novae, supernovae, and active
galactic nuclei.Comment: 5 pages, 4 figures (fig.4 in color), ApJ (in press
A validated RP-HPLC method for simultaneous determination of Metformin HCl and Vildagliptin in pharmaceutical formulation
A selective and sensitive reverse phase high performance liquid chromatographic (RP-HPLC) method has been developed for the separation and quantification of metformin HCl (MET) and vildagliptin (VILD) in tablet dosage form. The determination was carried out using phenomenax C18 column (4.6150 mm) as a stationary phase and mobile phase comprised of phosphate buffer (pH6.0): methanol (65:35v/v). The pH of phosphate buffer is adjusted to 6.0 by using orthophosphoric acid. The flow rate was maintained at 1.0ml/min and the eluent was monitored at 255nm.The retention time of MET and VILD were 1.503 min and 5.530 min respectively. The method was validated in terms of linearity, precision, accuracy, ruggedness, specificity and robustness. The method was linear over the range 50-150 g/ml for both MET (r = 0.999) and VILD (0.998). For precision studies; RSD for MET and VILD were 0.24 and 0.14 respectively. The percentage recoveries for both drugs from their tablets were 100.16 and 99.98 respectively. Inter-day; intra-day RSD for both drugs were found be 0.27 and 0.26, 0.13 and 0.29 respectively
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