7,278 research outputs found
Current Advance and Future Prospects of Tissue Engineering Approach to Dentin/Pulp Regenerative Therapy
published_or_final_versio
Deterministic quantum teleportation between distant atomic objects
Quantum teleportation is a key ingredient of quantum networks and a building
block for quantum computation. Teleportation between distant material objects
using light as the quantum information carrier has been a particularly exciting
goal. Here we demonstrate a new element of the quantum teleportation landscape,
the deterministic continuous variable (cv) teleportation between distant
material objects. The objects are macroscopic atomic ensembles at room
temperature. Entanglement required for teleportation is distributed by light
propagating from one ensemble to the other. Quantum states encoded in a
collective spin state of one ensemble are teleported onto another ensemble
using this entanglement and homodyne measurements on light. By implementing
process tomography, we demonstrate that the experimental fidelity of the
quantum teleportation is higher than that achievable by any classical process.
Furthermore, we demonstrate the benefits of deterministic teleportation by
teleporting a dynamically changing sequence of spin states from one distant
object onto another
Off-Diagonal Long-Range Order: Meissner Effect and Flux Quantization
There has been a proof by Sewell that the hypothesis of off-diagonal
long-range order in the reduced density matrix implies the Meissner
effect. We present in this note an elementary and straightforward proof that
not only the Meissner effect but also the property of magnetic flux
quantization follows from the hypothesis. It is explicitly shown that the two
phenomena are closely related, and phase coherence is the origin for both.Comment: 11 pages, Latex fil
Correlating Gene Transfection Efficiency and the Physical Properties of Various Cationic Poly(methacrylate) Systems
Transfection efficiencies of several polymeric gene carriers were compared and correlated quantitatively to the amounts of cellular accumulation of plasmid DNA and to the expression of mRNA by quantitative real time PCR. Three cationic methacrylate polymer systems with similar chemical structure were used in this study, namely: poly(dimethylamino)ethyl methacrylate (PDMA) homopolymer, PEO-b-PDMA copolymer and PEO-b-poly(diethylamino)ethyl methacrylate (PEO-b-PDEA) copolymer. Despite their similar chemical structures, their transfection efficiencies were significantly different. PEO-b-PDEA copolymer was significantly less efficient as gene carrier compared to both PDMA and PEO-b-PDMA systems. Results from quantitative real-time polymerase chain reaction (real-time PCR), cytotoxicity and Zeta potential measurements showed correlations between the physical properties of the polymers and the efficiencies of cellular uptake of the transgene and transfections. In the case of PEO-b-PDEA system, cytotoxicity was due primarily to the excess polymers that did not participate in the DNA binding. In addition, the inability of the polymer/DNA complexes to interact with cell effectively was identified as the main barrier for high efficiency of transfection. This study demonstrated that the use of quantitative real-time PCR in combination with other physical characterization techniques can provide greater insights into the transfection barrier at different cellular levels.Singapore-MIT Alliance (SMA
Bayesian detection of unmodeled bursts of gravitational waves
The data analysis problem of coherently searching for unmodeled
gravitational-wave bursts in the data generated by a global network of
gravitational-wave observatories has been at the center of research for almost
two decades. As data from these detectors is starting to be analyzed, a renewed
interest in this problem has been sparked. A Bayesian approach to the problem
of coherently searching for gravitational wave bursts with a network of
ground-based interferometers is here presented. We demonstrate how to
systematically incorporate prior information on the burst signal and its source
into the analysis. This information may range from the very minimal, such as
best-guess durations, bandwidths, or polarization content, to complete prior
knowledge of the signal waveforms and the distribution of sources through
spacetime. We show that this comprehensive Bayesian formulation contains
several previously proposed detection statistics as special limiting cases, and
demonstrate that it outperforms them.Comment: 18 pages, 3 figures, revisions based on referee comment
Association Behavior of Biotinylated and Non-Biotinylated PolyEthylene Oxide-b-Poly(2-(Diethylamino)Ethyl Methacrylate)
Biotinylated and non-biotinylated copolymers of ethylene oxide (EO) and 2-(diethylamino)ethyl methacrylate (DEAEMA) were synthesized by the atom transfer radical polymerization technique (ATRP). The chemical compositions of the copolymers as determined by NMR are represented by PEO₁₁₃PDEAEMA₇₀ and biotin-PEO₁₀₄PDEAEMA₉₃ respectively. The aggregation behavior of these polymers in aqueous solutions at different pHs and ionic strengths was studied using a combination of potentiometric titration, dynamic light scattering (DLS), static light scattering (SLS), and transmission electron microscopy (TEM). Both PEO-b-PDEAEMA and biotin-PEO-b-PDEAEMA diblock copolymers form micelles at high pH with hydrodynamic radii (Rh) of about 19 and 23 nm, respectively. At low pH, the copolymers are dispersed as unimers in solution with Rh of about 6-7 nm. However, at a physiological salt concentration (cs) of about 0.16M NaCl and a pH of 7-8, the copolymers form large loosely packed Guassian chains, which were not present at the low cs of 0.001M NaCl. The critical micelle concentrations (CMC) and the cytotoxicity of the copolymers were investigated to determine a suitable polymer concentration range for future biological applications. Both PEO-b-PDEAEMA and biotin-PEO-b-PDEAEMA diblock copolymers possess identical CMC values of about 0.0023 mg/g, while the cytotoxicity test indicated that the copolymers are not toxic up to 0.05mg/g (> 83% cell survival at this concentration).Singapore-MIT Alliance (SMA
Inferring Core-Collapse Supernova Physics with Gravitational Waves
Stellar collapse and the subsequent development of a core-collapse supernova
explosion emit bursts of gravitational waves (GWs) that might be detected by
the advanced generation of laser interferometer gravitational-wave
observatories such as Advanced LIGO, Advanced Virgo, and LCGT. GW bursts from
core-collapse supernovae encode information on the intricate multi-dimensional
dynamics at work at the core of a dying massive star and may provide direct
evidence for the yet uncertain mechanism driving supernovae in massive stars.
Recent multi-dimensional simulations of core-collapse supernovae exploding via
the neutrino, magnetorotational, and acoustic explosion mechanisms have
predicted GW signals which have distinct structure in both the time and
frequency domains. Motivated by this, we describe a promising method for
determining the most likely explosion mechanism underlying a hypothetical GW
signal, based on Principal Component Analysis and Bayesian model selection.
Using simulated Advanced LIGO noise and assuming a single detector and linear
waveform polarization for simplicity, we demonstrate that our method can
distinguish magnetorotational explosions throughout the Milky Way (D <~ 10kpc)
and explosions driven by the neutrino and acoustic mechanisms to D <~ 2kpc.
Furthermore, we show that we can differentiate between models for rotating
accretion-induced collapse of massive white dwarfs and models of rotating iron
core collapse with high reliability out to several kpc.Comment: 22 pages, 9 figure
Concentration and activity of matrix metalloproteinases and tissue inhibitors of matalloproteinases in the wall of abdominal aortic aneurysm at different wall stress
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