75 research outputs found
Use of intraarticular injections of platelet-rich plasma in the treatment of knee osteoarthritis: A review article
Osteoarthritis is one of the most common degenerative conditions affecting knee joint. As our understanding in the disease pathogenesis is evolving, so do the treatment modalities. One of the postulated mechanisms suggests the production of inflammatory cytokines secondary to repeated micro trauma than in turn lead to cartilage damage overtime. Cartilage being avascular structure has limited potential for repair. Based on this, recent studies have been focusing on stimulating cartilage-healing process by growth factors. This is where platelet-rich plasma comes in to light. Literature is showing promising results of platelet-rich plasma in treating knee osteoarthritis. In this review we have discussed the preparation, composition, classification, uses of platelet-rich plasma as well as evidence for its efficacy and complications
Generation of three-qubit entangled states using coupled multi-quantum dots
We discuss a mechanism for generating a maximum entangled state (GHZ) in a
coupled quantum dots system, based on analytical techniques. The reliable
generation of such states is crucial for implementing solid-state based quantum
information schemes. The signature originates from a remarkably weak field
pulse or a far off-resonance effects which could be implemented using
technology that is currently being developed. The results are illustrated with
an application to a specific wide-gap semiconductor quantum dots system, like
Zinc Selenide (ZnSe) based quantum dots.Comment: 8 pages, 2 figure
Impact of Stratospheric Aerosol Geoengineering on Meteorological Droughts in West Africa
This study assesses changes in meteorological droughts in West Africa under a high greenhouse gas scenario, i.e., a representative concentration pathway 8.5 (RCP8.5), and under a scenario of stratospheric aerosol geoengineering (SAG) deployment. Using simulations from the Geoengineering Large Ensemble (GLENS) project that employed stratospheric sulfate aerosols injection to keep global mean surface temperature, as well as the interhemispheric and equator-to-pole temperature gradients at the 2020 level (present-day climate), we investigated the impact of SAG on meteorological droughts in West Africa. Analysis of the meteorological drought characteristics (number of drought events, drought duration, maximum length of drought events, severity of the greatest drought events and intensity of the greatest drought event) revealed that over the period from 2030–2049 and under GLENS simulations, these drought characteristics decrease in most regions in comparison to the RCP8.5 scenarios. On the contrary, over the period from 2070–2089 and under GLENS simulations, these drought characteristics increase in most regions compared to the results from the RCP8.5 scenarios. Under GLENS, the increase in drought characteristics is due to a decrease in precipitation. The decrease in precipitation is largely driven by weakened monsoon circulation due to the reduce of land–sea thermal contrast in the lower troposphere
Impact of Stratospheric Aerosol Geoengineering on Extreme Precipitation and Temperature indices in West Africa using GLENS simulations
This study assesses changes in extremes precipitation and temperature in West Africa under a high greenhouse gas scenario, i.e. a representative concentration pathway 8.5 (RCP8.5), and under a scenario of stratospheric aerosol geoengineering (SAG) deployment using the NCAR Community Earth System Model version 1 (CESM1-WACCM). We use results from the Geoengineering Large Ensemble (GLENS) simulations, where SAG is deployed to keep global surface temperatures at present day values. This impact study evaluates changes in some of the extreme climate indices recommended by the Expert Team Monitoring on Climate Change Detection and Indices (ETCCDI). The results indicate that SAG would effectively keep surface temperatures at present day-conditions across a range of indices compared to the control period, including Cold days, Cold nights and Cold Spell Duration Indicator which show no significant increase compared to the control period. Regarding the extremes precipitation, GLENS shows mostly a statistically significant increase in annual precipitation and statistically significant decrease in the number of heavy and very heavy precipitation events relative to the control period in some regions of Gulf of Guinea. In the Sahel, we notice a mix of statistically significant increase and decrease in Max 1-day and Max 5-days precipitation amount relative to the control period at the end of the 21st century when large amounts of SAG has been applied. The changes in extreme precipitation indices are linked to changes in Atlantic Multidecadal Oscillation (AMO), NINO3.4 and Indian Ocean Dipole (IOD) and these changes in extreme precipitation are driven by change in near surface specific humidty and atmospheric circulation
Some entanglement features of three-atoms Tavis-Cummings model: Cooperative case
In this paper we consider a system of identical three two-level atoms
interacting at resonance with a single-mode of the quantized field in a
lossless cavity. The initial cavity field is prepared in the coherent state
while the atoms are taken initially to be either in the uppermost excited state
"" or The -state or the -state. For this
system we investigate different kinds of atomic inversion and entanglement,
which arise between the different parts of the system due to the interaction.
Also the relationship, between entanglement and some other nonclassical effects
in the statistical properties, such as collapses and revivals in the atomic
inversion where superharmonic effects appear, is discussed. The -functions
for different cases are discussed. Most remarkably it is found that the
-state is more robust against energy losses, showing almost
coherent trapping and Schr\"odinger-cat states can not be produced from such
state. Also the entanglement of -state is more robust than the
-state. Another interesting feature found is that the state which
has no pairwise entanglement initially will have a much improvement of such
pairwise entanglement through the evolution. Sudden death and sudden revival of
atoms-pairwise entanglement are produced with the -state.Comment: 14 pages, 7 figure
Marginal and density atomic Wehrl entropies for the Jaynes-Cummings model
In this paper, we develop the notion of the marginal and density atomic Wehrl
entropies for two-level atom interacting with the single mode field, i.e.
Jaynes-Cummings model. For this system we show that there are relationships
between these quantities and both of the information entropies and the von
Neumann entropy.Comment: 13 pages, 3 figures, this is the final versio
On the evolution of superposition of squeezed displaced number states with the multiphoton Jaynes-Cummings model
In this paper we discuss the quantum properties for superposition of squeezed
displaced number states against multiphoton Jaynes-Cummings model (JCM). In
particular, we investigate atomic inversion, photon-number distribution,
purity, quadrature squeezing, Mandel parameter and Wigner function. We show
that the quadrature squeezing for three-photon absorption case can exhibit
revivals and collapses typical to those occurring in the atomic inversion for
one-photon absorption case. Also we prove that for odd number absorption
parameter there is a connection between the evolution of the atomic inversion
and the evolution of the Wigner function at the origin in phase space.
Furthermore, we show that the nonclassical states whose the Wigner functions
values at the origins are negative will be always nonclassical when they are
evolving through the JCM with even absorption parameter. Also we demonstrate
that various types of cat states can be generated via this system.Comment: 27 pages, 10 figure
Perspectives for a mixed two-qubit system with binomial quantum states
The problem of the relationship between entanglement and two-qubit systems in
which it is embedded is central to the quantum information theory. This paper
suggests that the concurrence hierarchy as an entanglement measure provides an
alternative view of how to think about this problem. We consider mixed states
of two qubits and obtain an exact solution of the time-dependent master
equation that describes the evolution of two two-level qubits (or atoms) within
a perfect cavity for the case of multiphoton transition. We consider the
situation for which the field may start from a binomial state. Employing this
solution, the significant features of the entanglement when a second qubit is
weakly coupled to the field and becomes entangled with the first qubit, is
investigated. We also describe the response of the atomic system as it varies
between the Rabi oscillations and the collapse-revival mode and investigate the
atomic inversion and the Q-function. We identify and numerically demonstrate
the region of parameters where significantly large entanglement can be
obtained. Most interestingly, it is shown that features of the entanglement is
influenced significantly when the multi-photon process is involved. Finally, we
obtain illustrative examples of some novel aspects of this system and show how
the off-resonant case can sensitize entanglement to the role of initial state
setting.Comment: 18 pages, 9 figure
Phase properties of the superposition of squeezed and displaced number states
We show that a nonlinear asymmetric directional coupler composed of a linear
waveguide and a nonlinear waveguide operating by nondegenerate parametric
amplification is an effective source of single-mode squeezed light. This is has
been demonstrated, under certain conditions and for specific modes, for
incident coherent beams in terms of the quasiprobability functions,
photon-number distribution and phase distribution.Comment: 17 pages, 4 figure
Multi-dimensional trio coherent states
We introduce a novel class of higher-order, three-mode states called
K-dimensional trio coherent states. We study their mathematical properties and
prove that they form a complete set in a truncated Fock space. We also study
their physical content by explicitly showing that they exhibit nonclassical
features such as oscillatory number distribution, sub-poissonian statistics,
Cauchy-Schwarz inequality violation and phase-space quantum interferences.
Finally, we propose an experimental scheme to realize the state with K=2 in the
quantized vibronic motion of a trapped ion.Comment: 17 pages, 12 figures, accepted for publication in J. Phys. A: Math.
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